[skip ci] add relay modern support (#4458)

* validation support for unions and interfaces

* refactor SQL generation logic for improved readability

* '/v1/relay' endpoint for relay schema

* implement 'Node' interface and top level 'node' field resolver

* add relay toggle on graphiql

* fix explain api response & index plan id with query type

* add hasura mutations to relay

* add relay pytests

* update CHANGELOG.md

Co-authored-by: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Co-authored-by: Rishichandra Wawhal <rishi@hasura.io>
Co-authored-by: Rikin Kachhia <54616969+rikinsk@users.noreply.github.com>

CHANGELOG.md

@@ -2,7 +2,6 @@
 
 ## Next release
 
-
 ### Bug fixes and improvements
 
 (Add entries here in the order of: server, console, cli, docs, others)
@@ -97,7 +96,7 @@ Read more about the session argument for computed fields in the [docs](https://h
 A new `seeds` command is introduced in CLI, this will allow managing seed migrations as SQL files
 
 #### Creating seed
-```                                                        
+```
 # create a new seed file and use editor to add SQL content
 hasura seed create new_table_seed
 

console/src/components/Common/Tooltip/Tooltip.tsx

@@ -2,7 +2,6 @@ import React from 'react';
 import OverlayTrigger from 'react-bootstrap/lib/OverlayTrigger';
 import Tooltip from 'react-bootstrap/lib/Tooltip';
 import styles from './Tooltip.scss';
-
 const tooltipGen = (message: string) => {
   return <Tooltip id={message}>{message}</Tooltip>;
 };
@@ -28,5 +27,4 @@ const ToolTip: React.FC<TooltipProps> = ({
     )}
   </OverlayTrigger>
 );
-
-export default ToolTip;
+export default ToolTip;

server/graphql-engine.cabal

@@ -233,6 +233,7 @@ library
                      , ghc-heap-view
 
                      , directory
+                     , semigroups >= 0.19.1
 
   exposed-modules:     Control.Arrow.Extended
                      , Control.Arrow.Trans

server/src-lib/Data/HashMap/Strict/InsOrd/Extended.hs

@@ -1,25 +1,25 @@
 module Data.HashMap.Strict.InsOrd.Extended
-  ( OMap.elems
+  ( module OMap
   , groupTuples
   , groupListWith
   ) where
 
-import qualified Data.HashMap.Strict.InsOrd as OMap
+import           Data.HashMap.Strict.InsOrd as OMap
+import qualified Data.List                  as L
 import qualified Data.Sequence.NonEmpty     as NE
 
 import           Data.Hashable              (Hashable)
-import           Data.List                  (foldl')
 
-import           Prelude                    (Eq, Foldable, Functor, fmap, ($))
+import           Prelude                    (Eq, Foldable, Functor, fmap, undefined, ($))
 
 groupTuples
   :: (Eq k, Hashable k, Foldable t)
   => t (k, v) -> OMap.InsOrdHashMap k (NE.NESeq v)
 groupTuples =
-  foldl' groupFlds OMap.empty
+  L.foldl' groupFlds OMap.empty
   where
     groupFlds m (k, v) =
-      OMap.insertWith (\_ c -> c NE.|> v) k (NE.singleton v) m
+      OMap.insertWith (\_ c -> c `undefined` v) k (NE.singleton v) m
 
 groupListWith
   :: (Eq k, Hashable k, Foldable t, Functor t)

server/src-lib/Data/Sequence/NonEmpty.hs

@@ -5,8 +5,6 @@ module Data.Sequence.NonEmpty
   ( NESeq
   , pattern (:<||)
   , pattern (:||>)
-  , (<|)
-  , (|>)
   , singleton
   , head
   , tail
@@ -22,9 +20,6 @@ import           Data.Aeson
 import           Data.Foldable
 import           GHC.Generics    (Generic)
 
-infixr 5 <|
-infixl 5 |>
-
 data NESeq a = NESeq
   { head :: a
   , tail :: Seq.Seq a
@@ -59,12 +54,6 @@ instance ToJSON a => ToJSON (NESeq a) where
 singleton :: a -> NESeq a
 singleton a = NESeq a Seq.empty
 
-(|>) :: NESeq a -> a -> NESeq a
-NESeq h l |> v = NESeq h (l Seq.|> v)
-
-(<|) :: a -> NESeq a -> NESeq a
-v <| NESeq h l = NESeq v (h Seq.<| l)
-
 toSeq :: NESeq a -> Seq.Seq a
 toSeq (NESeq v l) = v Seq.<| l
 

server/src-lib/Hasura/GraphQL/Context.hs

@@ -76,9 +76,9 @@ traverseAction f = \case
   RFRaw x -> pure $ RFRaw x
 
 data QueryDB v
-  = QDBSimple      (RQL.AnnSimpleSelG v)
-  | QDBPrimaryKey  (RQL.AnnSimpleSelG v)
-  | QDBAggregation (RQL.AnnAggSelG    v)
+  = QDBSimple      (RQL.AnnSimpleSelG       v)
+  | QDBPrimaryKey  (RQL.AnnSimpleSelG       v)
+  | QDBAggregation (RQL.AnnAggregateSelectG v)
 
 data ActionQuery v
   = AQQuery !(RQL.AnnActionExecution v)

server/src-lib/Hasura/GraphQL/Execute.hs

@@ -43,8 +43,7 @@ import           Hasura.Prelude
 import           Hasura.RQL.DDL.Headers
 import           Hasura.RQL.Types
 import           Hasura.Server.Utils                    (RequestId, mkClientHeadersForward,
-                                                         mkSetCookieHeaders,
-                                                         userRoleHeader)
+                                                         mkSetCookieHeaders, userRoleHeader)
 import           Hasura.Server.Version                  (HasVersion)
 import           Hasura.Session
 
@@ -142,8 +141,8 @@ getExecPlanPartial userInfo sc enableAL queryType req = do
     getGCtx :: C.GQLContext
     getGCtx =
       case Map.lookup roleName contextMap of
-        Nothing                                           -> defaultContext
-        Just gql   -> gql
+        Nothing  -> defaultContext
+        Just gql -> gql
         -- TODO FIXME implement backend-only field access
         {-
         Just (RoleContext defaultGCtx maybeBackendGCtx)   ->
@@ -206,7 +205,7 @@ getResolvedExecPlan
 getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
   enableAL sc scVer queryType httpManager reqHeaders reqUnparsed = do
   planM <- liftIO $ EP.getPlan scVer (_uiRole userInfo)
-           opNameM queryStr planCache
+           opNameM queryStr queryType planCache
   let usrVars = _uiSession userInfo
   case planM of
     -- plans are only for queries and subscriptions
@@ -246,7 +245,7 @@ getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
         G.TypedOperationDefinition G.OperationTypeMutation _ varDefs _ selSet -> do
           -- (Here the above fragment inlining is actually executed.)
           inlinedSelSet <- EI.inlineSelectionSet fragments selSet
-          queryTx <- EM.convertMutationSelectionSet gCtx (_uiSession userInfo) httpManager reqHeaders
+          queryTx <- EM.convertMutationSelectionSet gCtx userInfo httpManager reqHeaders
                      inlinedSelSet varDefs (_grVariables reqUnparsed)
           -- traverse_ (addPlanToCache . EP.RPQuery) plan
           return $ MutationExecutionPlan $ queryTx

server/src-lib/Hasura/GraphQL/Execute/LiveQuery/Plan.hs

@@ -29,12 +29,13 @@ import qualified Data.Aeson.Casing                      as J
 import qualified Data.Aeson.Extended                    as J
 import qualified Data.Aeson.TH                          as J
 import qualified Data.HashMap.Strict                    as Map
+import qualified Data.HashMap.Strict.InsOrd             as OMap
+import qualified Data.HashMap.Strict.InsOrd             as OMap
+import qualified Data.Sequence                          as Seq
 import qualified Data.Text                              as T
 import qualified Data.UUID.V4                           as UUID
 import qualified Database.PG.Query                      as Q
 import qualified Language.GraphQL.Draft.Syntax          as G
-import qualified Data.HashMap.Strict.InsOrd             as OMap
-import qualified Data.Sequence                          as Seq
 
 -- remove these when array encoding is merged
 import qualified Database.PG.Query.PTI                  as PTI
@@ -43,24 +44,25 @@ import qualified PostgreSQL.Binary.Encoding             as PE
 import           Control.Lens
 import           Data.UUID                              (UUID)
 
-import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
 import qualified Hasura.GraphQL.Parser.Schema           as PS
+import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
 import qualified Hasura.RQL.DML.Select                  as DS
 import qualified Hasura.SQL.DML                         as S
 --import qualified Hasura.GraphQL.Execute.Query           as GEQ
 
 import           Hasura.Db
 import           Hasura.EncJSON
-import           Hasura.GraphQL.Parser.Column
+import           Hasura.GraphQL.Context
 import           Hasura.GraphQL.Execute.Prepare
 import           Hasura.GraphQL.Execute.Query
-import           Hasura.RQL.Types
+import           Hasura.GraphQL.Parser.Column
 import           Hasura.GraphQL.Resolve.Action
+import           Hasura.RQL.Types
+import           Hasura.Server.Version                  (HasVersion)
+import           Hasura.Session
 import           Hasura.SQL.Error
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
-import           Hasura.GraphQL.Context
-import           Hasura.Session
 
 -- -------------------------------------------------------------------------------------------------
 -- Multiplexed queries
@@ -72,7 +74,7 @@ toSQLSelect :: SubscriptionRootFieldResolved -> S.Select
 toSQLSelect = \case
   RFDB (QDBPrimaryKey s)  -> DS.mkSQLSelect DS.JASSingleObject s
   RFDB (QDBSimple s)      -> DS.mkSQLSelect DS.JASMultipleRows s
-  RFDB (QDBAggregation s) -> DS.mkAggSelect s
+  RFDB (QDBAggregation s) -> DS.mkAggregateSelect s
   RFAction s              -> DS.mkSQLSelect DS.JASSingleObject s
   -- QRFActionSelect s -> DS.mkSQLSelect DS.JASSingleObject s
   -- QRFActionExecuteObject s -> DS.mkSQLSelect DS.JASSingleObject s
@@ -279,6 +281,7 @@ $(J.deriveToJSON (J.aesonDrop 4 J.snakeCase) ''ReusableLiveQueryPlan)
 buildLiveQueryPlan
   :: ( MonadError QErr m
      , MonadIO m
+     , HasVersion
      )
   => PGExecCtx
   -> UserInfo
@@ -310,7 +313,7 @@ buildLiveQueryPlan pgExecCtx userInfo unpreparedAST = do
   (preparedAST, (queryVariableValues, querySyntheticVariableValues)) <- flip runStateT (mempty, Seq.empty) $
     for unpreparedAST \unpreparedQuery -> do
     traverseQueryRootField resolveMultiplexedValue unpreparedQuery
-    >>= traverseAction (DS.traverseAnnSimpleSel resolveMultiplexedValue . resolveAsyncActionQuery userInfo)
+    >>= traverseAction (DS.traverseAnnSimpleSelect resolveMultiplexedValue . resolveAsyncActionQuery userInfo)
 
 
 

server/src-lib/Hasura/GraphQL/Execute/Mutation.hs

@@ -67,37 +67,38 @@ convertMutationRootField
                , MonadIO m
                , MonadError QErr m
                )
-  => SessionVariables
+  => UserInfo
   -> HTTP.Manager
   -> HTTP.RequestHeaders
   -> Bool
   -> MutationRootField UnpreparedValue
   -> m (Either (LazyRespTx, HTTP.ResponseHeaders) RemoteField)
-convertMutationRootField usrVars manager reqHeaders stringifyNum = \case
-  RFDB (MDBInsert s)  -> noResponseHeaders $ convertInsert usrVars s stringifyNum
-  RFDB (MDBUpdate s)  -> noResponseHeaders $ convertUpdate usrVars s stringifyNum
-  RFDB (MDBDelete s)  -> noResponseHeaders $ convertDelete usrVars s stringifyNum
+convertMutationRootField userInfo manager reqHeaders stringifyNum = \case
+  RFDB (MDBInsert s)  -> noResponseHeaders $ convertInsert userSession s stringifyNum
+  RFDB (MDBUpdate s)  -> noResponseHeaders $ convertUpdate userSession s stringifyNum
+  RFDB (MDBDelete s)  -> noResponseHeaders $ convertDelete userSession s stringifyNum
   RFRemote remote     -> pure $ Right remote
-  RFAction (AMSync s) -> Left <$> first liftTx <$> resolveActionExecution s actionExecContext
-  RFAction (AMAsync s) -> noResponseHeaders =<< resolveActionMutationAsync s reqHeaders usrVars
+  RFAction (AMSync s) -> Left <$> first liftTx <$> resolveActionExecution userInfo s actionExecContext
+  RFAction (AMAsync s) -> noResponseHeaders =<< resolveActionMutationAsync s reqHeaders userSession
   RFRaw s             -> noResponseHeaders $ pure $ encJFromJValue s
   where
     noResponseHeaders :: RespTx -> m (Either (LazyRespTx, HTTP.ResponseHeaders) RemoteField)
     noResponseHeaders rTx = pure $ Left (liftTx rTx, [])
 
-    actionExecContext = ActionExecContext manager reqHeaders usrVars
+    userSession = _uiSession userInfo
+    actionExecContext = ActionExecContext manager reqHeaders $ _uiSession userInfo
 
 convertMutationSelectionSet
   :: (HasVersion, MonadIO m, MonadError QErr m)
   => GQLContext
-  -> SessionVariables
+  -> UserInfo
   -> HTTP.Manager
   -> HTTP.RequestHeaders
   -> G.SelectionSet G.NoFragments G.Name
   -> [G.VariableDefinition]
   -> Maybe GH.VariableValues
   -> m (ExecutionPlan (LazyRespTx, HTTP.ResponseHeaders) RemoteCall (G.Name, J.Value))
-convertMutationSelectionSet gqlContext usrVars manager reqHeaders fields varDefs varValsM = do
+convertMutationSelectionSet gqlContext userInfo manager reqHeaders fields varDefs varValsM = do
   -- Parse the GraphQL query into the RQL AST
   (unpreparedQueries, _reusability)
     :: (OMap.InsOrdHashMap G.Name (MutationRootField UnpreparedValue), QueryReusability)
@@ -106,7 +107,7 @@ convertMutationSelectionSet gqlContext usrVars manager reqHeaders fields varDefs
 
   -- Transform the RQL AST into a prepared SQL query
   -- TODO pass the correct stringifyNum somewhere rather than True
-  txs <- for unpreparedQueries $ convertMutationRootField usrVars manager reqHeaders True
+  txs <- for unpreparedQueries $ convertMutationRootField userInfo manager reqHeaders True
   let txList = OMap.toList txs
   case (mapMaybe takeTx txList, mapMaybe takeRemote txList) of
     (dbPlans, []) -> do
@@ -148,9 +149,9 @@ convertMutationSelectionSet gqlContext usrVars manager reqHeaders fields varDefs
       :: (G.Name, Either (LazyRespTx, HTTP.ResponseHeaders) RemoteField)
       -> Maybe (G.Name, (LazyRespTx, HTTP.ResponseHeaders))
     takeTx (name, Left tx) = Just (name, tx)
-    takeTx _ = Nothing
+    takeTx _               = Nothing
     takeRemote
       :: (G.Name, Either (LazyRespTx, HTTP.ResponseHeaders) RemoteField)
       -> Maybe (G.Name, RemoteField)
     takeRemote (name, Right remote) = Just (name, remote)
-    takeRemote _ = Nothing
+    takeRemote _                    = Nothing

server/src-lib/Hasura/GraphQL/Execute/Plan.hs

@@ -19,6 +19,7 @@ import qualified Data.Aeson.TH                          as J
 import qualified Hasura.Cache                           as Cache
 import qualified Hasura.GraphQL.Execute.LiveQuery       as LQ
 import qualified Hasura.GraphQL.Execute.Query           as EQ
+import qualified Hasura.GraphQL.Execute.Types           as ET
 import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
 import           Hasura.RQL.Types
 import           Hasura.Session
@@ -29,17 +30,19 @@ data PlanId
   , _piRole               :: !RoleName
   , _piOperationName      :: !(Maybe GH.OperationName)
   , _piQuery              :: !GH.GQLQueryText
+  , _piQueryType          :: !ET.GraphQLQueryType
   } deriving (Show, Eq, Ord, Generic)
 
 instance Hashable PlanId
 
 instance J.ToJSON PlanId where
-  toJSON (PlanId scVer rn opNameM query) =
+  toJSON (PlanId scVer rn opNameM query queryType) =
     J.object
     [ "schema_cache_version" J..= scVer
     , "role" J..= rn
     , "operation" J..= opNameM
     , "query" J..= query
+    , "query_type" J..= queryType
     ]
 
 newtype PlanCache
@@ -68,19 +71,19 @@ initPlanCache options =
 
 getPlan
   :: SchemaCacheVer -> RoleName -> Maybe GH.OperationName -> GH.GQLQueryText
-  -> PlanCache -> IO (Maybe ReusablePlan)
-getPlan schemaVer rn opNameM q (PlanCache planCache) =
+  -> ET.GraphQLQueryType -> PlanCache -> IO (Maybe ReusablePlan)
+getPlan schemaVer rn opNameM q queryType (PlanCache planCache) =
   Cache.lookup planId planCache
   where
-    planId = PlanId schemaVer rn opNameM q
+    planId = PlanId schemaVer rn opNameM q queryType
 
 addPlan
   :: SchemaCacheVer -> RoleName -> Maybe GH.OperationName -> GH.GQLQueryText
-  -> ReusablePlan -> PlanCache -> IO ()
-addPlan schemaVer rn opNameM q queryPlan (PlanCache planCache) =
+  -> ReusablePlan -> ET.GraphQLQueryType -> PlanCache -> IO ()
+addPlan schemaVer rn opNameM q queryPlan queryType (PlanCache planCache) =
   Cache.insert planId queryPlan planCache
   where
-    planId = PlanId schemaVer rn opNameM q
+    planId = PlanId schemaVer rn opNameM q queryType
 
 clearPlanCache :: PlanCache -> IO ()
 clearPlanCache (PlanCache planCache) =

server/src-lib/Hasura/GraphQL/Execute/Query.hs

@@ -37,9 +37,9 @@ import           Hasura.Prelude
 import           Hasura.RQL.DML.RemoteJoin
 import           Hasura.RQL.DML.Select                  (asSingleRowJsonResp)
 import           Hasura.RQL.Types
+import           Hasura.Session
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
-import           Hasura.Session
 
 import qualified Hasura.RQL.DML.Select                  as DS
 
@@ -165,7 +165,7 @@ irToRootFieldPlan vars prepped = \case
   QDBPrimaryKey s  -> mkPGPlan (DS.selectQuerySQL DS.JASSingleObject) s
   QDBAggregation s ->
     let (annAggSel, aggRemoteJoins) = getRemoteJoinsAggregateSelect s
-    in PGPlan (DS.selectAggQuerySQL annAggSel) vars prepped aggRemoteJoins
+    in PGPlan (DS.selectAggregateQuerySQL annAggSel) vars prepped aggRemoteJoins
   where
     mkPGPlan f simpleSel =
       let (simpleSel',remoteJoins) = getRemoteJoins simpleSel
@@ -182,9 +182,9 @@ traverseQueryRootField f =
   where
     f' :: QueryDB a -> f (QueryDB b)
     f' = \case
-      QDBSimple s       -> QDBSimple      <$> DS.traverseAnnSimpleSel f s
-      QDBPrimaryKey s   -> QDBPrimaryKey  <$> DS.traverseAnnSimpleSel f s
-      QDBAggregation s  -> QDBAggregation <$> DS.traverseAnnAggSel f s
+      QDBSimple s       -> QDBSimple      <$> DS.traverseAnnSimpleSelect f s
+      QDBPrimaryKey s   -> QDBPrimaryKey  <$> DS.traverseAnnSimpleSelect f s
+      QDBAggregation s  -> QDBAggregation <$> DS.traverseAnnAggregateSelect f s
 
 convertQuerySelSet
   :: forall m. (HasVersion, MonadError QErr m, MonadIO m)
@@ -265,9 +265,9 @@ convertQuerySelSet gqlContext userInfo manager reqHeaders fields varDefs varVals
       :: ActionQuery UnpreparedValue -> StateT PlanningSt m ActionQueryPlan
     convertActionQuery = \case
       AQQuery s -> (AQPQuery . fst) <$>
-        lift (resolveActionExecution s $ ActionExecContext manager reqHeaders usrVars)
+        lift (resolveActionExecution userInfo s $ ActionExecContext manager reqHeaders usrVars)
       AQAsync s -> AQPAsyncQuery <$>
-        DS.traverseAnnSimpleSel prepareWithPlan (resolveAsyncActionQuery userInfo s)
+        DS.traverseAnnSimpleSelect prepareWithPlan (resolveAsyncActionQuery userInfo s)
 
 -- use the existing plan and new variables to create a pg query
 queryOpFromPlan
@@ -341,3 +341,15 @@ mkGeneratedSqlMap resolved =
                 RRSql ps        -> Just ps
                 RRActionQuery _ -> Nothing
     in (alias, res)
+
+-- The GraphQL Query type
+data GraphQLQueryType
+  = QueryHasura
+  | QueryRelay
+  deriving (Show, Eq, Ord, Generic)
+instance Hashable GraphQLQueryType
+
+instance J.ToJSON GraphQLQueryType where
+  toJSON = \case
+    QueryHasura -> "hasura"
+    QueryRelay  -> "relay"

server/src-lib/Hasura/GraphQL/Explain.hs

@@ -11,13 +11,13 @@ import qualified Database.PG.Query                      as Q
 import qualified Language.GraphQL.Draft.Syntax          as G
 
 import           Hasura.EncJSON
+import           Hasura.GraphQL.Resolve.Action
 import           Hasura.Prelude
 import           Hasura.RQL.DML.Internal
 import           Hasura.RQL.Types
+import           Hasura.Server.Version                  (HasVersion)
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
-import           Hasura.Server.Version             (HasVersion)
-import           Hasura.GraphQL.Resolve.Action
 
 import qualified Hasura.GraphQL.Execute                 as E
 import qualified Hasura.GraphQL.Execute.LiveQuery       as E
@@ -26,11 +26,12 @@ import qualified Hasura.SQL.DML                         as S
 
 data GQLExplain
   = GQLExplain
-  { _gqeQuery :: !GH.GQLReqParsed
-  , _gqeUser  :: !(Maybe (Map.HashMap Text Text))
+  { _gqeQuery   :: !GH.GQLReqParsed
+  , _gqeUser    :: !(Maybe (Map.HashMap Text Text))
+  , _gqeIsRelay :: !(Maybe Bool)
   } deriving (Show, Eq)
 
-$(J.deriveJSON (J.aesonDrop 4 J.camelCase){J.omitNothingFields=True}
+$(J.deriveJSON (J.aesonDrop 4 J.snakeCase){J.omitNothingFields=True}
   ''GQLExplain
  )
 
@@ -117,24 +118,26 @@ explainGQLQuery
   -> QueryActionExecuter
   -> GQLExplain
   -> m EncJSON
-explainGQLQuery pgExecCtx sc sqlGenCtx enableAL actionExecuter (GQLExplain query userVarsRaw) = do
+explainGQLQuery pgExecCtx sc sqlGenCtx enableAL actionExecuter (GQLExplain query userVarsRaw maybeIsRelay) = do
+  userInfo <- mkUserInfo (URBFromSessionVariablesFallback adminRoleName) UAdminSecretSent sessionVariables
   (execPlan, queryReusability) <- runReusabilityT $
-    E.getExecPlanPartial userInfo sc enableAL query
+    E.getExecPlanPartial userInfo sc queryType enableAL query
   (gCtx, rootSelSet) <- case execPlan of
     E.GExPHasura (gCtx, rootSelSet) ->
       return (gCtx, rootSelSet)
-    E.GExPRemote _ _  ->
+    E.GExPRemote{}  ->
       throw400 InvalidParams "only hasura queries can be explained"
   case rootSelSet of
     GV.RQuery selSet ->
-      runInTx $ encJFromJValue <$> traverse (explainField userInfo gCtx sqlGenCtx actionExecuter)
-      (toList selSet)
+      runInTx $ encJFromJValue . map snd <$>
+        GV.traverseObjectSelectionSet selSet (explainField userInfo gCtx sqlGenCtx actionExecuter)
     GV.RMutation _ ->
       throw400 InvalidParams "only queries can be explained"
-    GV.RSubscription rootField -> do
-      (plan, _) <- E.getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability actionExecuter rootField
+    GV.RSubscription fields -> do
+      (plan, _) <- E.getSubsOp pgExecCtx gCtx sqlGenCtx userInfo
+                     queryReusability actionExecuter fields
       runInTx $ encJFromJValue <$> E.explainLiveQueryPlan plan
   where
-    usrVars = mkUserVars $ maybe [] Map.toList userVarsRaw
-    userInfo = mkUserInfo (fromMaybe adminRole $ roleFromVars usrVars) usrVars
+    queryType = bool E.QueryHasura E.QueryRelay $ fromMaybe False maybeIsRelay
+    sessionVariables = mkSessionVariablesText $ maybe [] Map.toList userVarsRaw
     runInTx = liftEither <=< liftIO . runExceptT . runLazyTx pgExecCtx Q.ReadOnly

server/src-lib/Hasura/GraphQL/LegacySchema.hs

@@ -236,7 +236,7 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
         in case riType relInfo of
           ObjRel -> [relFld]
           ArrRel -> bool [relFld] [relFld, aggRelFld] allowAgg
-      SFComputedField cf -> pure
+      SAFComputedField cf -> pure
         ( (ty, mkComputedFieldName $ _cfName cf)
         , RFComputedField cf
         )

server/src-lib/Hasura/GraphQL/LegacySchema/Builder.hs

@@ -8,6 +8,8 @@ module Hasura.GraphQL.Schema.Builder
   , addFieldsToTyAgg
   , addTypeInfoToTyAgg
   , addScalarToTyAgg
+  , QueryRootFieldMap
+  , MutationRootFieldMap
   , RootFields(..)
   , addQueryField
   , addMutationField
@@ -57,11 +59,14 @@ instance Semigroup TyAgg where
 instance Monoid TyAgg where
   mempty = TyAgg Map.empty Map.empty Set.empty Map.empty
 
+type QueryRootFieldMap = Map.HashMap G.Name (QueryCtx, ObjFldInfo)
+type MutationRootFieldMap = Map.HashMap G.Name (MutationCtx, ObjFldInfo)
+
 -- | A role-specific mapping from root field names to allowed operations.
 data RootFields
   = RootFields
-  { _rootQueryFields    :: !(Map.HashMap G.Name (QueryCtx, ObjFldInfo))
-  , _rootMutationFields :: !(Map.HashMap G.Name (MutationCtx, ObjFldInfo))
+  { _rootQueryFields    :: !QueryRootFieldMap
+  , _rootMutationFields :: !MutationRootFieldMap
   } deriving (Show, Eq)
 $(makeLenses ''RootFields)
 

server/src-lib/Hasura/GraphQL/LegacySchema/Function.hs

@@ -2,14 +2,17 @@ module Hasura.GraphQL.Schema.Function
   ( procFuncArgs
   , mkFuncArgsInp
   , mkFuncQueryFld
+  , mkFuncQueryConnectionFld
   , mkFuncAggQueryFld
   , mkFuncArgsTy
+  , mkFuncArgItemSeq
   ) where
 
 import qualified Data.Sequence                 as Seq
 import qualified Data.Text                     as T
 import qualified Language.GraphQL.Draft.Syntax as G
 
+import           Hasura.GraphQL.Resolve.Types
 import           Hasura.GraphQL.Schema.Common
 import           Hasura.GraphQL.Schema.Select
 import           Hasura.GraphQL.Validate.Types
@@ -92,6 +95,20 @@ mkFuncQueryFld funInfo descM =
 
     ty      = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableTy retTable
 
+mkFuncQueryConnectionFld
+  :: FunctionInfo -> Maybe PGDescription -> ObjFldInfo
+mkFuncQueryConnectionFld funInfo descM =
+  mkHsraObjFldInfo (Just desc) fldName (mkFuncArgs funInfo) ty
+  where
+    retTable = fiReturnType funInfo
+    funcName = fiName funInfo
+
+    desc = mkDescriptionWith descM $ "execute function " <> funcName
+           <<> " which returns " <>> retTable
+    fldName = qualObjectToName funcName <> "_connection"
+
+    ty = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy retTable
+
 {-
 
 function_aggregate(
@@ -118,3 +135,15 @@ mkFuncAggQueryFld funInfo descM =
     fldName = qualObjectToName funcName <> "_aggregate"
 
     ty = G.toGT $ G.toNT $ mkTableAggTy retTable
+
+
+mkFuncArgItemSeq :: FunctionInfo -> Seq (InputArgument FunctionArgItem)
+mkFuncArgItemSeq functionInfo =
+  let inputArgs = fiInputArgs functionInfo
+  in Seq.fromList $ procFuncArgs inputArgs nameFn resultFn
+  where
+    nameFn = \case
+      IAUserProvided fa       -> faName fa
+      IASessionVariables name -> Just name
+    resultFn arg gName = flip fmap arg $
+      \fa -> FunctionArgItem (G.Name gName) (faName fa) (faHasDefault fa)

server/src-lib/Hasura/GraphQL/NormalForm.hs

@@ -0,0 +1,300 @@
+{-# LANGUAGE RecordWildCards        #-}
+{-# LANGUAGE TypeFamilyDependencies #-}
+module Hasura.GraphQL.NormalForm
+  ( Selection(..)
+  , NormalizedSelection
+  , NormalizedSelectionSet
+  , NormalizedField
+  , SelectionSet(..)
+  , RootSelectionSet(..)
+  -- , toGraphQLOperation
+  , ArgsMap
+  , Field(..)
+  , Typename(..)
+  , IsField(..)
+  , toField
+  , AliasedFields(..)
+  , asObjectSelectionSet
+  , ObjectSelectionSet(..)
+  , ObjectSelectionSetMap
+  , traverseObjectSelectionSet
+  , InterfaceSelectionSet
+  , asInterfaceSelectionSet
+  , getMemberSelectionSet
+  , UnionSelectionSet
+  , ScopedSelectionSet(..)
+  , emptyScopedSelectionSet
+  , getUnionSelectionSet
+  , getInterfaceSelectionSet
+  , getObjectSelectionSet
+
+  , AnnInpVal(..)
+  , AnnGValue(..)
+  , AnnGObject
+  , AnnGEnumValue(..)
+  , hasNullVal
+  , getAnnInpValKind
+
+  , toGraphQLField
+  , toGraphQLSelectionSet
+  ) where
+
+import           Hasura.Prelude
+
+import qualified Data.Aeson                          as J
+import qualified Data.Aeson.Casing                   as J
+import qualified Data.Aeson.TH                       as J
+import qualified Data.HashMap.Strict                 as Map
+import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
+import qualified Language.GraphQL.Draft.Syntax       as G
+
+import qualified Hasura.RQL.Types.Column             as RQL
+import qualified Hasura.RQL.Types.Error              as RQL
+import           Hasura.SQL.Types
+import           Hasura.SQL.Value
+
+data Selection f s
+  = SelectionField !G.Alias !f
+  | SelectionInlineFragmentSpread !s
+  | SelectionFragmentSpread !G.Name !s
+  deriving (Show, Eq)
+
+-- | What a processed G.SelectionSet should look like
+type family NormalizedSelectionSet a = s | s -> a
+
+-- | What a processed G.Field should look like
+type family NormalizedField a
+
+type NormalizedSelection a
+  = Selection (NormalizedField a) (NormalizedSelectionSet a)
+
+-- | Ordered fields
+newtype AliasedFields f
+  = AliasedFields { unAliasedFields :: OMap.InsOrdHashMap G.Alias f }
+  deriving (Show, Eq, Functor, Foldable, Traversable, Semigroup)
+
+newtype ObjectSelectionSet
+  = ObjectSelectionSet { unObjectSelectionSet :: AliasedFields Field }
+  deriving (Show, Eq, Semigroup)
+
+traverseObjectSelectionSet
+  :: (Monad m) => ObjectSelectionSet -> (Field -> m a) -> m [(Text, a)]
+traverseObjectSelectionSet selectionSet f =
+  forM (OMap.toList $ unAliasedFields $ unObjectSelectionSet selectionSet) $
+    \(alias, field) -> (G.unName $ G.unAlias alias,) <$> f field
+
+type ObjectSelectionSetMap
+  = Map.HashMap G.NamedType ObjectSelectionSet
+
+data Typename = Typename
+  deriving (Show, Eq, Generic)
+
+data ScopedSelectionSet f
+  = ScopedSelectionSet
+  { _sssBaseSelectionSet    :: !(AliasedFields f)
+  -- ^ Fields that aren't explicitly defined for member types
+  , _sssMemberSelectionSets :: !ObjectSelectionSetMap
+  -- ^ SelectionSets of individual member types
+  } deriving (Show, Eq, Generic)
+
+
+
+emptyScopedSelectionSet :: ScopedSelectionSet f
+emptyScopedSelectionSet =
+  ScopedSelectionSet (AliasedFields mempty) mempty
+
+type InterfaceSelectionSet = ScopedSelectionSet Field
+
+type UnionSelectionSet = ScopedSelectionSet Typename
+
+data RootSelectionSet
+  = RQuery !ObjectSelectionSet
+  | RMutation !ObjectSelectionSet
+  | RSubscription !ObjectSelectionSet
+  deriving (Show, Eq)
+
+-- toGraphQLOperation :: RootSelectionSet -> G.ExecutableDefinition
+-- toGraphQLOperation = \case
+--   RQuery selectionSet ->
+--     mkExecutableDefinition G.OperationTypeQuery $
+--     toGraphQLSelectionSet $ SelectionSetObject selectionSet
+--   RMutation selectionSet ->
+--     mkExecutableDefinition G.OperationTypeQuery $
+--     toGraphQLSelectionSet $ SelectionSetObject selectionSet
+--   RSubscription opDef _ ->
+--     G.ExecutableDefinitionOperation $ G.OperationDefinitionTyped opDef
+--   where
+--     mkExecutableDefinition operationType selectionSet =
+--       G.ExecutableDefinitionOperation $ G.OperationDefinitionTyped $
+--       G.TypedOperationDefinition
+--         { G._todName = Nothing -- TODO, store the name too?
+--         , G._todDirectives = []
+--         , G._todType = operationType
+--         , G._todVariableDefinitions = []
+--         , G._todSelectionSet = selectionSet
+--         }
+
+
+data SelectionSet
+  = SelectionSetObject !ObjectSelectionSet
+  | SelectionSetUnion !UnionSelectionSet
+  | SelectionSetInterface !InterfaceSelectionSet
+  | SelectionSetNone
+  -- ^ in cases of enums and scalars
+  deriving (Show, Eq)
+
+getObjectSelectionSet :: SelectionSet -> Maybe ObjectSelectionSet
+getObjectSelectionSet = \case
+  SelectionSetObject s -> pure s
+  _ -> Nothing
+
+asObjectSelectionSet
+  :: (MonadError RQL.QErr m) => SelectionSet -> m ObjectSelectionSet
+asObjectSelectionSet selectionSet =
+  onNothing (getObjectSelectionSet selectionSet) $
+    RQL.throw500 "expecting ObjectSelectionSet"
+
+getUnionSelectionSet :: SelectionSet -> Maybe UnionSelectionSet
+getUnionSelectionSet = \case
+  SelectionSetUnion s -> pure s
+  _ -> Nothing
+
+getInterfaceSelectionSet :: SelectionSet -> Maybe InterfaceSelectionSet
+getInterfaceSelectionSet = \case
+  SelectionSetInterface s -> pure s
+  _ -> Nothing
+
+asInterfaceSelectionSet
+  :: (MonadError RQL.QErr m) => SelectionSet -> m InterfaceSelectionSet
+asInterfaceSelectionSet selectionSet =
+  onNothing (getInterfaceSelectionSet selectionSet) $
+  RQL.throw500 "expecting InterfaceSelectionSet"
+
+type ArgsMap = Map.HashMap G.Name AnnInpVal
+
+data Field
+  = Field
+  { _fName      :: !G.Name
+  , _fType      :: !G.NamedType
+  , _fArguments :: !ArgsMap
+  , _fSelSet    :: !SelectionSet
+  } deriving (Eq, Show)
+
+toGraphQLField :: G.Alias -> Field -> G.Field
+toGraphQLField alias Field{..} =
+  G.Field
+    { G._fName = _fName
+    , G._fArguments = [] -- TODO
+    , G._fDirectives = []
+    , G._fAlias = Just alias
+    , G._fSelectionSet =  toGraphQLSelectionSet _fSelSet
+    }
+
+toGraphQLSelectionSet :: SelectionSet -> G.SelectionSet
+toGraphQLSelectionSet = \case
+  SelectionSetObject selectionSet -> fromSelectionSet selectionSet
+  SelectionSetInterface selectionSet -> fromScopedSelectionSet selectionSet
+  SelectionSetUnion selectionSet -> fromScopedSelectionSet selectionSet
+  SelectionSetNone -> mempty
+  where
+    fromAliasedFields :: (IsField f) => AliasedFields f -> G.SelectionSet
+    fromAliasedFields =
+      map (G.SelectionField . uncurry toGraphQLField) .
+      OMap.toList . fmap toField . unAliasedFields
+    fromSelectionSet =
+      fromAliasedFields . unObjectSelectionSet
+    toInlineSelection typeName =
+      G.SelectionInlineFragment . G.InlineFragment (Just typeName) mempty .
+      fromSelectionSet
+    fromScopedSelectionSet (ScopedSelectionSet base specific) =
+      map (uncurry toInlineSelection) (Map.toList specific) <> fromAliasedFields base
+
+-- $(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
+--   ''Field
+--  )
+
+-- $(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
+--   ''InterfaceSelectionSet
+--  )
+
+-- $(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
+--   ''SelectionSet
+--  )
+
+class IsField f where
+  getFieldName :: f -> G.Name
+  getFieldType :: f -> G.NamedType
+  getFieldArguments :: f -> ArgsMap
+  getFieldSelectionSet :: f -> SelectionSet
+
+toField :: (IsField f) => f -> Field
+toField f =
+  Field (getFieldName f) (getFieldType f)
+  (getFieldArguments f) (getFieldSelectionSet f)
+
+instance IsField Field where
+  getFieldName = _fName
+  getFieldType = _fType
+  getFieldArguments = _fArguments
+  getFieldSelectionSet = _fSelSet
+
+instance IsField Typename where
+  getFieldName _ = "__typename"
+  getFieldType _ = G.NamedType "String"
+  getFieldArguments _ = mempty
+  getFieldSelectionSet _ = SelectionSetNone
+
+getMemberSelectionSet
+  :: IsField f
+  => G.NamedType -> ScopedSelectionSet f -> ObjectSelectionSet
+getMemberSelectionSet namedType (ScopedSelectionSet {..})  =
+  fromMaybe (ObjectSelectionSet (fmap toField _sssBaseSelectionSet)) $
+  Map.lookup namedType $ _sssMemberSelectionSets
+
+data AnnInpVal
+  = AnnInpVal
+  { _aivType     :: !G.GType
+  , _aivVariable :: !(Maybe G.Variable)
+  , _aivValue    :: !AnnGValue
+  } deriving (Show, Eq)
+
+type AnnGObject = OMap.InsOrdHashMap G.Name AnnInpVal
+
+-- | See 'EnumValuesInfo' for information about what these cases mean.
+data AnnGEnumValue
+  = AGESynthetic !(Maybe G.EnumValue)
+  | AGEReference !RQL.EnumReference !(Maybe RQL.EnumValue)
+  deriving (Show, Eq)
+
+data AnnGValue
+  = AGScalar !PGScalarType !(Maybe PGScalarValue)
+  | AGEnum !G.NamedType !AnnGEnumValue
+  | AGObject !G.NamedType !(Maybe AnnGObject)
+  | AGArray !G.ListType !(Maybe [AnnInpVal])
+  deriving (Show, Eq)
+
+$(J.deriveToJSON (J.aesonDrop 4 J.camelCase){J.omitNothingFields=True}
+  ''AnnInpVal
+ )
+
+instance J.ToJSON AnnGValue where
+  -- toJSON (AGScalar ty valM) =
+  toJSON = const J.Null
+    -- J.
+    -- J.toJSON [J.toJSON ty, J.toJSON valM]
+
+hasNullVal :: AnnGValue -> Bool
+hasNullVal = \case
+  AGScalar _ Nothing                -> True
+  AGEnum _ (AGESynthetic Nothing)   -> True
+  AGEnum _ (AGEReference _ Nothing) -> True
+  AGObject _ Nothing                -> True
+  AGArray _ Nothing                 -> True
+  _                                 -> False
+
+getAnnInpValKind :: AnnGValue -> Text
+getAnnInpValKind = \case
+  AGScalar _ _ -> "scalar"
+  AGEnum _ _   -> "enum"
+  AGObject _ _ -> "object"
+  AGArray _ _  -> "array"

server/src-lib/Hasura/GraphQL/RelaySchema.hs

@@ -0,0 +1,407 @@
+module Hasura.GraphQL.RelaySchema where
+
+import           Control.Lens.Extended          hiding (op)
+
+import qualified Data.HashMap.Strict            as Map
+import qualified Data.HashSet                   as Set
+import qualified Data.Text                      as T
+import qualified Language.GraphQL.Draft.Syntax  as G
+
+import           Hasura.GraphQL.Context
+import           Hasura.GraphQL.Resolve.Types
+import           Hasura.GraphQL.Validate.Types
+import           Hasura.Prelude
+import           Hasura.RQL.Types
+import           Hasura.Server.Utils            (duplicates)
+import           Hasura.Session
+import           Hasura.SQL.Types
+
+import           Hasura.GraphQL.Schema
+import           Hasura.GraphQL.Schema.BoolExp
+import           Hasura.GraphQL.Schema.Builder
+import           Hasura.GraphQL.Schema.Common
+import           Hasura.GraphQL.Schema.Function
+import           Hasura.GraphQL.Schema.OrderBy
+import           Hasura.GraphQL.Schema.Select
+
+mkNodeInterface :: [QualifiedTable] -> IFaceTyInfo
+mkNodeInterface relayTableNames =
+  let description = G.Description "An object with globally unique ID"
+  in mkIFaceTyInfo (Just description) nodeType (mapFromL _fiName [idField]) $
+     Set.fromList $ map mkTableTy relayTableNames
+  where
+    idField =
+        let description = G.Description "A globally unique identifier"
+        in mkHsraObjFldInfo (Just description) "id" mempty nodeIdType
+
+mkRelayGCtxMap
+  :: forall m. (MonadError QErr m)
+  => TableCache -> FunctionCache -> m GCtxMap
+mkRelayGCtxMap tableCache functionCache = do
+  typesMapL <- mapM (mkRelayGCtxMapTable tableCache functionCache) relayTables
+  typesMap <- combineTypes typesMapL
+  let gCtxMap  = flip Map.map typesMap $
+                 \(ty, flds, insCtx) -> mkGCtx ty flds insCtx
+  pure $ Map.map (flip RoleContext Nothing) gCtxMap
+  where
+    relayTables =
+      filter (tableFltr . _tiCoreInfo) $ Map.elems tableCache
+
+    tableFltr ti =
+      not (isSystemDefined $ _tciSystemDefined ti)
+      && isValidObjectName (_tciName ti)
+      && isJust (_tciPrimaryKey ti)
+
+    combineTypes
+      :: [Map.HashMap RoleName (TyAgg, RootFields, InsCtxMap)]
+      -> m (Map.HashMap RoleName (TyAgg, RootFields, InsCtxMap))
+    combineTypes maps = do
+      let listMap = foldr (Map.unionWith (++) . Map.map pure) mempty maps
+      flip Map.traverseWithKey listMap $ \roleName typeList -> do
+        let relayTableNames = map (_tciName . _tiCoreInfo) relayTables
+            tyAgg = addTypeInfoToTyAgg
+                    (TIIFace $ mkNodeInterface relayTableNames) $
+                    mconcat $ map (^. _1) typeList
+            insCtx = mconcat $ map (^. _3) typeList
+        rootFields <- combineRootFields roleName $ map (^. _2) typeList
+        pure (tyAgg, rootFields, insCtx)
+
+    combineRootFields :: RoleName -> [RootFields] -> m RootFields
+    combineRootFields roleName rootFields = do
+      let duplicateQueryFields = duplicates $
+            concatMap (Map.keys . _rootQueryFields) rootFields
+          duplicateMutationFields = duplicates $
+            concatMap (Map.keys . _rootMutationFields) rootFields
+
+      -- TODO: The following exception should result in inconsistency
+      when (not $ null duplicateQueryFields) $
+        throw400 Unexpected $ "following query root fields are duplicated: "
+        <> showNames duplicateQueryFields
+
+      when (not $ null duplicateMutationFields) $
+        throw400 Unexpected $ "following mutation root fields are duplicated: "
+        <> showNames duplicateMutationFields
+
+      pure $ mconcat $ mkNodeQueryRootFields roleName relayTables : rootFields
+
+mkRelayGCtxMapTable
+  :: (MonadError QErr m)
+  => TableCache
+  -> FunctionCache
+  -> TableInfo
+  -> m (Map.HashMap RoleName (TyAgg, RootFields, InsCtxMap))
+mkRelayGCtxMapTable tableCache funcCache tabInfo = do
+  m <- flip Map.traverseWithKey rolePerms $
+       mkRelayGCtxRole tableCache tn descM fields primaryKey validConstraints  tabFuncs viewInfo customConfig
+  adminSelFlds <- mkAdminSelFlds fields tableCache
+  adminInsCtx <- mkAdminInsCtx tableCache fields
+  let adminCtx = mkRelayTyAggRole tn descM (Just (cols, icRelations adminInsCtx))
+                 (Just (True, adminSelFlds)) (Just cols) (Just ())
+                 primaryKey validConstraints viewInfo tabFuncs
+      adminInsCtxMap = Map.singleton tn adminInsCtx
+  return $ Map.insert adminRoleName (adminCtx, adminRootFlds, adminInsCtxMap) m
+  where
+    TableInfo coreInfo rolePerms _ = tabInfo
+    TableCoreInfo tn descM _ fields primaryKey _ _ viewInfo _ customConfig = coreInfo
+    validConstraints = mkValidConstraints $ map _cName (tciUniqueOrPrimaryKeyConstraints coreInfo)
+    tabFuncs = filter (isValidObjectName . fiName) $
+               getFuncsOfTable tn funcCache
+    cols = getValidCols fields
+    adminRootFlds =
+      let insertPermDetails = Just ([], True)
+          selectPermDetails = Just (noFilter, Nothing, [], True)
+          updatePermDetails = Just (getValidCols fields, mempty, noFilter, Nothing, [])
+          deletePermDetails = Just (noFilter, [])
+
+          queryFields = getRelayQueryRootFieldsRole tn primaryKey fields tabFuncs
+                        selectPermDetails
+          mutationFields = getMutationRootFieldsRole tn primaryKey
+                           validConstraints fields insertPermDetails
+                           selectPermDetails updatePermDetails
+                           deletePermDetails viewInfo customConfig
+      in RootFields queryFields mutationFields
+
+mkRelayGCtxRole
+  :: (MonadError QErr m)
+  => TableCache
+  -> QualifiedTable
+  -> Maybe PGDescription
+  -> FieldInfoMap FieldInfo
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> [ConstraintName]
+  -> [FunctionInfo]
+  -> Maybe ViewInfo
+  -> TableConfig
+  -> RoleName
+  -> RolePermInfo
+  -> m (TyAgg, RootFields, InsCtxMap)
+mkRelayGCtxRole tableCache tn descM fields primaryKey constraints funcs viM tabConfigM role permInfo = do
+  selPermM <- mapM (getSelPerm tableCache fields role) selM
+  tabInsInfoM <- forM (_permIns permInfo) $ \ipi -> do
+    ctx <- mkInsCtx role tableCache fields ipi $ _permUpd permInfo
+    let permCols = flip getColInfos allCols $ Set.toList $ ipiCols ipi
+    return (ctx, (permCols, icRelations ctx))
+  let insPermM = snd <$> tabInsInfoM
+      insCtxM = fst <$> tabInsInfoM
+      updColsM = filterColumnFields . upiCols <$> _permUpd permInfo
+      tyAgg = mkRelayTyAggRole tn descM insPermM selPermM updColsM
+              (void $ _permDel permInfo) primaryKey constraints viM funcs
+      queryRootFlds = getRelayQueryRootFieldsRole tn primaryKey fields funcs
+                 (mkSel <$> _permSel permInfo)
+      mutationRootFlds = getMutationRootFieldsRole tn primaryKey constraints fields
+                       (mkIns <$> insM) (mkSel <$> selM)
+                       (mkUpd <$> updM) (mkDel <$> delM) viM tabConfigM
+      insCtxMap = maybe Map.empty (Map.singleton tn) insCtxM
+  return (tyAgg, RootFields queryRootFlds mutationRootFlds, insCtxMap)
+  where
+    RolePermInfo insM selM updM delM = permInfo
+    allCols = getCols fields
+    filterColumnFields allowedSet =
+      filter ((`Set.member` allowedSet) . pgiColumn) $ getValidCols fields
+    mkIns i = (ipiRequiredHeaders i, isJust updM)
+    mkSel s = ( spiFilter s, spiLimit s
+              , spiRequiredHeaders s, spiAllowAgg s
+              )
+    mkUpd u = ( flip getColInfos allCols $ Set.toList $ upiCols u
+              , upiSet u
+              , upiFilter u
+              , upiCheck u
+              , upiRequiredHeaders u
+              )
+    mkDel d = (dpiFilter d, dpiRequiredHeaders d)
+
+mkRelayTyAggRole
+  :: QualifiedTable
+  -> Maybe PGDescription
+  -- ^ Postgres description
+  -> Maybe ([PGColumnInfo], RelationInfoMap)
+  -- ^ insert permission
+  -> Maybe (Bool, [SelField])
+  -- ^ select permission
+  -> Maybe [PGColumnInfo]
+  -- ^ update cols
+  -> Maybe ()
+  -- ^ delete cols
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> [ConstraintName]
+  -- ^ constraints
+  -> Maybe ViewInfo
+  -> [FunctionInfo]
+  -- ^ all functions
+  -> TyAgg
+mkRelayTyAggRole tn descM insPermM selPermM updColsM delPermM pkeyCols constraints viM funcs =
+  let (mutationTypes, mutationFields) =
+        mkMutationTypesAndFieldsRole tn insPermM selFldsM updColsM delPermM pkeyCols constraints viM
+  in TyAgg (mkTyInfoMap allTypes <> mutationTypes)
+           (fieldMap <> mutationFields)
+            scalars ordByCtx
+  where
+    ordByCtx = fromMaybe Map.empty ordByCtxM
+
+    funcInpArgTys = bool [] (map TIInpObj funcArgInpObjs) $ isJust selFldsM
+
+    allTypes = queryTypes <> aggQueryTypes <> funcInpArgTys <> computedFieldFuncArgsInps
+
+    queryTypes = map TIObj selectObjects <>
+      catMaybes
+      [ TIInpObj <$> boolExpInpObjM
+      , TIInpObj <$> ordByInpObjM
+      , TIEnum <$> selColInpTyM
+      ]
+    aggQueryTypes = map TIObj aggObjs <> map TIInpObj aggOrdByInps
+
+    fieldMap = Map.unions $ catMaybes [boolExpInpObjFldsM, selObjFldsM]
+    scalars = selByPkScalarSet <> funcArgScalarSet <> computedFieldFuncArgScalars
+
+    selFldsM = snd <$> selPermM
+    selColNamesM = map pgiName . getPGColumnFields <$> selFldsM
+    selColInpTyM = mkSelColumnTy tn <$> selColNamesM
+    -- boolexp input type
+    boolExpInpObjM = case selFldsM of
+      Just selFlds  -> Just $ mkBoolExpInp tn selFlds
+      -- no select permission
+      Nothing ->
+        -- but update/delete is defined
+        if isJust updColsM || isJust delPermM
+        then Just $ mkBoolExpInp tn []
+        else Nothing
+
+    -- funcargs input type
+    funcArgInpObjs = flip mapMaybe funcs $ \func ->
+      mkFuncArgsInp (fiName func) (getInputArgs func)
+    -- funcArgCtx = Map.unions funcArgCtxs
+    funcArgScalarSet = funcs ^.. folded.to getInputArgs.folded.to (_qptName.faType)
+
+    -- helper
+    mkFldMap ty = Map.fromList . concatMap (mkFld ty)
+    mkFld ty = \case
+      SFPGColumn ci -> [((ty, pgiName ci), RFPGColumn ci)]
+      SFRelationship (RelationshipFieldInfo relInfo allowAgg cols permFilter permLimit maybePkCols _) ->
+        let relationshipName = riName relInfo
+            relFld = ( (ty, mkRelName relationshipName)
+                     , RFRelationship $ RelationshipField relInfo RFKSimple cols permFilter permLimit
+                     )
+            aggRelFld = ( (ty, mkAggRelName relationshipName)
+                        , RFRelationship $ RelationshipField relInfo RFKAggregate cols permFilter permLimit
+                        )
+            maybeConnFld = maybePkCols <&> \pkCols ->
+                           ( (ty, mkConnectionRelName relationshipName)
+                           , RFRelationship $ RelationshipField relInfo
+                             (RFKConnection pkCols) cols permFilter permLimit
+                           )
+        in case riType relInfo of
+          ObjRel -> [relFld]
+          ArrRel -> bool [relFld] ([relFld, aggRelFld] <> maybe [] pure maybeConnFld) allowAgg
+      SFComputedField cf -> pure
+        ( (ty, mkComputedFieldName $ _cfName cf)
+        , RFComputedField cf
+        )
+      SFRemoteRelationship remoteField -> pure
+        ( (ty, G.Name (remoteRelationshipNameToText (_rfiName remoteField)))
+        , RFRemoteRelationship remoteField
+        )
+
+    -- the fields used in bool exp
+    boolExpInpObjFldsM = mkFldMap (mkBoolExpTy tn) <$> selFldsM
+
+    -- table obj
+    selectObjects = case selPermM of
+      Just (_, selFlds) ->
+        [ (mkRelayTableObj tn descM selFlds)
+          {_otiImplIFaces = Set.singleton nodeType}
+        , mkTableEdgeObj tn
+        , mkTableConnectionObj tn
+        ]
+      Nothing -> []
+
+    -- aggregate objs and order by inputs
+    (aggObjs, aggOrdByInps) = case selPermM of
+      Just (True, selFlds) ->
+        let cols = getPGColumnFields selFlds
+            numCols = onlyNumCols cols
+            compCols = onlyComparableCols cols
+            objs = [ mkTableAggObj tn
+                   , mkTableAggregateFieldsObj tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+                   ] <> mkColAggregateFieldsObjs selFlds
+            ordByInps = mkTabAggOrdByInpObj tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+                        : mkTabAggregateOpOrdByInpObjs tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+        in (objs, ordByInps)
+      _ -> ([], [])
+
+    getNumericCols = onlyNumCols . getPGColumnFields
+    getComparableCols = onlyComparableCols . getPGColumnFields
+    onlyFloat = const $ mkScalarTy PGFloat
+
+    mkTypeMaker "sum" = mkColumnType
+    mkTypeMaker _     = onlyFloat
+
+    mkColAggregateFieldsObjs flds =
+      let numCols = getNumericCols flds
+          compCols = getComparableCols flds
+          mkNumObjFld n = mkTableColAggregateFieldsObj tn n (mkTypeMaker n) numCols
+          mkCompObjFld n = mkTableColAggregateFieldsObj tn n mkColumnType compCols
+          numFldsObjs = bool (map mkNumObjFld numAggregateOps) [] $ null numCols
+          compFldsObjs = bool (map mkCompObjFld compAggregateOps) [] $ null compCols
+      in numFldsObjs <> compFldsObjs
+    -- the fields used in table object
+    nodeFieldM =  RFNodeId tn . _pkColumns <$> pkeyCols
+    selObjFldsM = mkFldMap (mkTableTy tn) <$> selFldsM >>=
+                  \fm -> nodeFieldM <&> \nodeField ->
+                    Map.insert (mkTableTy tn, "id") nodeField fm
+    -- the scalar set for table_by_pk arguments
+    selByPkScalarSet = pkeyCols ^.. folded.to _pkColumns.folded.to pgiType._PGColumnScalar
+
+    ordByInpCtxM = mkOrdByInpObj tn <$> selFldsM
+    (ordByInpObjM, ordByCtxM) = case ordByInpCtxM of
+      Just (a, b) -> (Just a, Just b)
+      Nothing     -> (Nothing, Nothing)
+
+    -- computed fields' function args input objects and scalar types
+    mkComputedFieldRequiredTypes computedFieldInfo =
+      let ComputedFieldFunction qf inputArgs _ _ _ = _cfFunction computedFieldInfo
+          scalarArgs = map (_qptName . faType) $ toList inputArgs
+      in (, scalarArgs) <$> mkFuncArgsInp qf inputArgs
+
+    computedFieldReqTypes = catMaybes $
+      maybe [] (map mkComputedFieldRequiredTypes . getComputedFields) selFldsM
+
+    computedFieldFuncArgsInps = map (TIInpObj . fst) computedFieldReqTypes
+    computedFieldFuncArgScalars = Set.fromList $ concatMap snd computedFieldReqTypes
+
+mkSelectOpCtx
+  :: QualifiedTable
+  -> [PGColumnInfo]
+  -> (AnnBoolExpPartialSQL, Maybe Int, [T.Text]) -- select filter
+  -> SelOpCtx
+mkSelectOpCtx tn allCols (fltr, pLimit, hdrs) =
+  SelOpCtx tn hdrs colGNameMap fltr pLimit
+  where
+    colGNameMap = mkPGColGNameMap allCols
+
+getRelayQueryRootFieldsRole
+  :: QualifiedTable
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> FieldInfoMap FieldInfo
+  -> [FunctionInfo]
+  -> Maybe (AnnBoolExpPartialSQL, Maybe Int, [T.Text], Bool) -- select filter
+  -> QueryRootFieldMap
+getRelayQueryRootFieldsRole tn primaryKey fields funcs selM =
+    makeFieldMap $
+        funcConnectionQueries
+        <> catMaybes
+          [ getSelConnectionDet <$> selM <*> maybePrimaryKeyColumns
+          ]
+  where
+    maybePrimaryKeyColumns = fmap _pkColumns primaryKey
+    colGNameMap = mkPGColGNameMap $ getCols fields
+
+    funcConnectionQueries = fromMaybe [] $ getFuncQueryConnectionFlds
+                            <$> selM <*> maybePrimaryKeyColumns
+
+    getSelConnectionDet (selFltr, pLimit, hdrs, _) primaryKeyColumns =
+      selFldHelper (QCSelectConnection primaryKeyColumns)
+      (mkSelFldConnection Nothing) selFltr pLimit hdrs
+
+    selFldHelper f g pFltr pLimit hdrs =
+      ( f $ mkSelectOpCtx tn (getCols fields) (pFltr, pLimit, hdrs)
+      , g tn
+      )
+
+    getFuncQueryConnectionFlds (selFltr, pLimit, hdrs, _) primaryKeyColumns =
+      funcFldHelper (QCFuncConnection primaryKeyColumns) mkFuncQueryConnectionFld selFltr pLimit hdrs
+
+    funcFldHelper f g pFltr pLimit hdrs =
+      flip map funcs $ \fi ->
+      ( f $ FuncQOpCtx (fiName fi) (mkFuncArgItemSeq fi) hdrs colGNameMap pFltr pLimit
+      , g fi $ fiDescription fi
+      )
+
+mkNodeQueryRootFields :: RoleName -> [TableInfo] -> RootFields
+mkNodeQueryRootFields roleName relayTables =
+  RootFields (mapFromL (_fiName . snd) [nodeQueryDet]) mempty
+  where
+    nodeQueryDet =
+      ( QCNodeSelect nodeSelMap
+      , nodeQueryField
+      )
+
+    nodeQueryField =
+      let nodeParams = fromInpValL $ pure $
+                       InpValInfo (Just $ G.Description "A globally unique id")
+                       "id" Nothing nodeIdType
+      in mkHsraObjFldInfo Nothing "node" nodeParams $ G.toGT nodeType
+
+    nodeSelMap =
+      Map.fromList $ flip mapMaybe relayTables $ \table ->
+      let tableName = _tciName $ _tiCoreInfo table
+          allColumns = getCols $ _tciFieldInfoMap $ _tiCoreInfo table
+          selectPermM = _permSel <$> Map.lookup roleName
+                       (_tiRolePermInfoMap table)
+          permDetailsM = join selectPermM <&> \perm ->
+            ( spiFilter perm
+            , spiLimit perm
+            , spiRequiredHeaders perm
+            )
+          adminPermDetails = (noFilter, Nothing, [])
+      in (mkTableTy tableName,) . mkSelectOpCtx tableName allColumns
+         <$> bool permDetailsM (Just adminPermDetails) (isAdmin roleName)

server/src-lib/Hasura/GraphQL/Resolve.hs

@@ -12,6 +12,7 @@ module Hasura.GraphQL.Resolve
   , QueryRootFldUnresolved
   , QueryRootFldResolved
   , toPGQuery
+  , toSQLFromItem
 
   , RIntro.schemaR
   , RIntro.typeR
@@ -36,14 +37,17 @@ import qualified Hasura.GraphQL.Resolve.Insert     as RI
 import qualified Hasura.GraphQL.Resolve.Introspect as RIntro
 import qualified Hasura.GraphQL.Resolve.Mutation   as RM
 import qualified Hasura.GraphQL.Resolve.Select     as RS
+import qualified Hasura.GraphQL.Schema.Common      as GS
 import qualified Hasura.GraphQL.Validate           as V
 import qualified Hasura.RQL.DML.Select             as DS
 import qualified Hasura.SQL.DML                    as S
 
 data QueryRootFldAST v
-  = QRFPk !(DS.AnnSimpleSelG v)
+  = QRFNode !(DS.AnnSimpleSelG v)
+  | QRFPk !(DS.AnnSimpleSelG v)
   | QRFSimple !(DS.AnnSimpleSelG v)
-  | QRFAgg !(DS.AnnAggSelG v)
+  | QRFAgg !(DS.AnnAggregateSelectG v)
+  | QRFConnection !(DS.ConnectionSelect v)
   | QRFActionSelect !(DS.AnnSimpleSelG v)
   | QRFActionExecuteObject !(DS.AnnSimpleSelG v)
   | QRFActionExecuteList !(DS.AnnSimpleSelG v)
@@ -58,21 +62,28 @@ traverseQueryRootFldAST
   -> QueryRootFldAST a
   -> f (QueryRootFldAST b)
 traverseQueryRootFldAST f = \case
-  QRFPk s                  -> QRFPk <$> DS.traverseAnnSimpleSel f s
-  QRFSimple s              -> QRFSimple <$> DS.traverseAnnSimpleSel f s
-  QRFAgg s                 -> QRFAgg <$> DS.traverseAnnAggSel f s
-  QRFActionSelect s        -> QRFActionSelect <$> DS.traverseAnnSimpleSel f s
-  QRFActionExecuteObject s -> QRFActionExecuteObject <$> DS.traverseAnnSimpleSel f s
-  QRFActionExecuteList s   -> QRFActionExecuteList <$> DS.traverseAnnSimpleSel f s
+  QRFNode s                -> QRFNode <$> DS.traverseAnnSimpleSelectect f s
+  QRFPk s                  -> QRFPk <$> DS.traverseAnnSimpleSelect f s
+  QRFSimple s              -> QRFSimple <$> DS.traverseAnnSimpleSelect f s
+  QRFAgg s                 -> QRFAgg <$> DS.traverseAnnAggregateSelect f s
+  QRFActionSelect s        -> QRFActionSelect <$> DS.traverseAnnSimpleSelect f s
+  QRFActionExecuteObject s -> QRFActionExecuteObject <$> DS.traverseAnnSimpleSelect f s
+  QRFActionExecuteList s   -> QRFActionExecuteList <$> DS.traverseAnnSimpleSelect f s
+  QRFConnection s   -> QRFConnection <$> DS.traverseConnectionSelect f s
 
 toPGQuery :: QueryRootFldResolved -> Q.Query
 toPGQuery = \case
-  QRFPk s                  -> DS.selectQuerySQL DS.JASSingleObject s
-  QRFSimple s              -> DS.selectQuerySQL DS.JASMultipleRows s
-  QRFAgg s                 -> DS.selectAggQuerySQL s
-  QRFActionSelect s        -> DS.selectQuerySQL DS.JASSingleObject s
-  QRFActionExecuteObject s -> DS.selectQuerySQL DS.JASSingleObject s
-  QRFActionExecuteList s   -> DS.selectQuerySQL DS.JASMultipleRows s
+  QRFNode s                -> first (toQuery . DS.mkSQLSelect DS.JASSingleObject) $ RR.getRemoteJoins s
+  QRFPk s                  -> first (toQuery . DS.mkSQLSelect DS.JASSingleObject) $ RR.getRemoteJoins s
+  QRFSimple s              -> first (toQuery . DS.mkSQLSelect DS.JASMultipleRows) $ RR.getRemoteJoins s
+  QRFAgg s                 -> first (toQuery . DS.mkAggregateSelect) $ RR.getRemoteJoinsAggregateSelect s
+  QRFActionSelect s        -> first (toQuery . DS.mkSQLSelect DS.JASSingleObject) $ RR.getRemoteJoins s
+  QRFActionExecuteObject s -> first (toQuery . DS.mkSQLSelect DS.JASSingleObject) $ RR.getRemoteJoins s
+  QRFActionExecuteList s   -> first (toQuery . DS.mkSQLSelect DS.JASMultipleRows) $ RR.getRemoteJoins s
+  QRFConnection s          -> first (toQuery . DS.mkConnectionSelect) $ RR.getRemoteJoinsConnectionSelect s
+  where
+    toQuery :: ToSQL a => a -> Q.Query
+    toQuery = Q.fromBuilder . toSQL
 
 validateHdrs
   :: (Foldable t, QErrM m) => UserInfo -> t Text -> m ()
@@ -101,6 +112,13 @@ queryFldToPGAST fld actionExecuter = do
   opCtx <- getOpCtx $ V._fName fld
   userInfo <- asks getter
   case opCtx of
+    QCNodeSelect nodeSelectMap -> do
+      NodeIdData table pkeyColumnValues <- RS.resolveNodeId fld
+      case Map.lookup (GS.mkTableTy table) nodeSelectMap of
+        Nothing       -> throwVE $ "table " <> table <<> " not found"
+        Just selOpCtx -> do
+          validateHdrs userInfo (_socHeaders selOpCtx)
+          QRFNode <$> RS.convertNodeSelect selOpCtx pkeyColumnValues fld
     QCSelect ctx -> do
       validateHdrs userInfo (_socHeaders ctx)
       QRFSimple <$> RS.convertSelect ctx fld
@@ -125,13 +143,15 @@ queryFldToPGAST fld actionExecuter = do
       -- an SQL query, but in case of query actions it's converted into JSON
       -- and included in the action's webhook payload.
       markNotReusable
-      let f = case jsonAggType of
+      let jsonAggType = RA.mkJsonAggSelect $ _saecOutputType ctx
+          f = case jsonAggType of
              DS.JASMultipleRows -> QRFActionExecuteList
              DS.JASSingleObject -> QRFActionExecuteObject
-      f <$> actionExecuter (RA.resolveActionQuery fld ctx (userVars userInfo))
-      where
-        outputType = _saecOutputType ctx
-        jsonAggType = RA.mkJsonAggSelect outputType
+      f <$> actionExecuter (RA.resolveActionQuery fld ctx (_uiSession userInfo))
+    QCSelectConnection pk ctx ->
+      QRFConnection <$> RS.convertConnectionSelect pk ctx fld
+    QCFuncConnection pk ctx ->
+      QRFConnection <$> RS.convertConnectionFuncQuery pk ctx fld
 
 mutFldToTx
   :: ( HasVersion
@@ -187,3 +207,17 @@ getOpCtx f = do
   opCtxMap <- asks getter
   onNothing (Map.lookup f opCtxMap) $ throw500 $
     "lookup failed: opctx: " <> showName f
+
+toSQLFromItem :: S.Alias -> QueryRootFldResolved -> S.FromItem
+toSQLFromItem alias = \case
+  QRFNode s                -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
+  QRFPk s                  -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
+  QRFSimple s              -> fromSelect $ DS.mkSQLSelect DS.JASMultipleRows s
+  QRFAgg s                 -> fromSelect $ DS.mkAggregateSelect s
+  QRFActionSelect s        -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
+  QRFActionExecuteObject s -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
+  QRFActionExecuteList s   -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
+  QRFConnection s          -> flip (S.FISelectWith (S.Lateral False)) alias
+                              $ DS.mkConnectionSelect s
+  where
+    fromSelect = flip (S.FISelect (S.Lateral False)) alias

server/src-lib/Hasura/GraphQL/Resolve/Action.hs

@@ -36,6 +36,16 @@ import qualified Network.Wreq                   as Wreq
 
 import qualified Hasura.RQL.DML.Select          as RS
 
+import qualified Control.Concurrent.Async       as A
+import qualified Data.Aeson                     as J
+import qualified Data.Aeson.Casing              as J
+import qualified Data.Aeson.TH                  as J
+import qualified Data.ByteString.Lazy           as BL
+import qualified Data.CaseInsensitive           as CI
+import qualified Data.HashMap.Strict            as Map
+import qualified Data.Text                      as T
+import qualified Data.UUID                      as UUID
+import qualified Database.PG.Query              as Q
 import           Hasura.EncJSON
 import           Hasura.GraphQL.Execute.Prepare
 import           Hasura.GraphQL.Parser
@@ -48,9 +58,34 @@ import           Hasura.RQL.Types
 import           Hasura.RQL.Types.Run
 import           Hasura.Server.Utils            (mkClientHeadersForward, mkSetCookieHeaders)
 import           Hasura.Server.Version          (HasVersion)
+import           Hasura.Session
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value               (PGScalarValue (..), toTxtValue)
+import qualified Language.GraphQL.Draft.Syntax  as G
+import qualified Network.HTTP.Client            as HTTP
+import qualified Network.HTTP.Types             as HTTP
+import qualified Network.Wreq                   as Wreq
+
+-- import qualified Hasura.GraphQL.Resolve.Select     as GRS
+import qualified Hasura.RQL.DML.RemoteJoin      as RJ
+import qualified Hasura.RQL.DML.Select          as RS
+
+import           Hasura.EncJSON
+-- import           Hasura.GraphQL.Resolve.Context
+-- import           Hasura.GraphQL.Resolve.InputValue
+-- import           Hasura.GraphQL.Resolve.Select     (processTableSelectionSet)
+-- import           Hasura.GraphQL.Validate.SelectionSet
+import           Hasura.HTTP
+import           Hasura.RQL.DDL.Headers         (makeHeadersFromConf, toHeadersConf)
+import           Hasura.RQL.DDL.Schema.Cache
+import           Hasura.RQL.DML.Select          (asSingleRowJsonResp)
+import           Hasura.RQL.Types
+import           Hasura.RQL.Types.Run
+import           Hasura.Server.Utils            (mkClientHeadersForward, mkSetCookieHeaders)
+import           Hasura.Server.Version          (HasVersion)
 import           Hasura.Session
+import           Hasura.SQL.Types
+import           Hasura.SQL.Value               (PGScalarValue (..), toTxtValue)
 
 newtype ActionContext
   = ActionContext {_acName :: ActionName}
@@ -136,10 +171,11 @@ resolveActionExecution
      , MonadError QErr m
      , MonadIO m
      )
-  => AnnActionExecution UnpreparedValue
+  => UserInfo
+  -> AnnActionExecution UnpreparedValue
   -> ActionExecContext
   -> m (RespTx, HTTP.ResponseHeaders)
-resolveActionExecution annAction execContext = do
+resolveActionExecution userInfo annAction execContext = do
   let actionContext = ActionContext actionName
       handlerPayload = ActionWebhookPayload actionContext sessionVariables inputPayload
   (webhookRes, respHeaders) <- callWebhook manager outputType outputFields reqHeaders confHeaders
@@ -148,9 +184,17 @@ resolveActionExecution annAction execContext = do
         toTxtValue $ WithScalarType PGJSONB $ PGValJSONB $ Q.JSONB $ J.toJSON webhookRes
       selectAstUnresolved = processOutputSelectionSet webhookResponseExpression
                             outputType definitionList annFields stringifyNum
-  astResolved <- RS.traverseAnnSimpleSel (pure . unpreparedToTextSQL) selectAstUnresolved
-  let jsonAggType = mkJsonAggSelect outputType
-  return $ (,respHeaders) $ asSingleRowJsonResp (RS.selectQuerySQL jsonAggType astResolved) []
+  astResolved <- RS.traverseAnnSimpleSelect (pure . unpreparedToTextSQL) selectAstUnresolved
+  let (astResolvedWithoutRemoteJoins,maybeRemoteJoins) = RJ.getRemoteJoins astResolved
+      jsonAggType = mkJsonAggSelect outputType
+  return $ (,respHeaders) $
+    case maybeRemoteJoins of
+      Just remoteJoins ->
+        let query = Q.fromBuilder $ toSQL $
+                    RS.mkSQLSelect jsonAggType astResolvedWithoutRemoteJoins
+        in RJ.executeQueryWithRemoteJoins manager reqHeaders userInfo query [] remoteJoins
+      Nothing ->
+        asSingleRowJsonResp (Q.fromBuilder $ toSQL $ RS.mkSQLSelect jsonAggType astResolved) []
   where
     AnnActionExecution actionName outputType annFields inputPayload
       outputFields definitionList resolvedWebhook confHeaders
@@ -177,10 +221,17 @@ restrictActionExecuter errMsg _ =
 
 -- resolveActionQuery
 --   :: ( HasVersion
+--      , MonadReusability m
 --      , MonadError QErr m
+--      , MonadReader r m
 --      , MonadIO m
+--      , Has FieldMap r
+--      , Has OrdByCtx r
+--      , Has SQLGenCtx r
 --      )
---   => UserVars
+--   => Field
+--   -> ActionExecutionContext
+--   -> SessionVariables
 --   -> HTTP.Manager
 --   -> [HTTP.Header]
 --   -> m (RS.AnnSimpleSelG UnresolvedVal)
@@ -192,9 +243,10 @@ restrictActionExecuter errMsg _ =
 --                                forwardClientHeaders resolvedWebhook handlerPayload
 --   let webhookResponseExpression = RS.AEInput $ UVSQL $
 --         toTxtValue $ WithScalarType PGJSONB $ PGValJSONB $ Q.JSONB $ J.toJSON webhookRes
+--   selSet <- asObjectSelectionSet $ _fSelSet field
 --   selectAstUnresolved <-
 --     processOutputSelectionSet webhookResponseExpression outputType definitionList
---     (_fType field) $ _fSelSet field
+--     (_fType field) selSet
 --   return selectAstUnresolved
 --   where
 --     ActionExecutionContext actionName outputType outputFields definitionList resolvedWebhook confHeaders
@@ -254,12 +306,12 @@ resolveAsyncActionQuery
   -> RS.AnnSimpleSelG UnpreparedValue
 resolveAsyncActionQuery userInfo annAction =
   let annotatedFields = asyncFields <&> second \case
-        AsyncTypename t -> RS.FExp t
+        AsyncTypename t -> RS.AFExpression t
         AsyncOutput annFields ->
           -- See Note [Resolving async action query/subscription]
           let inputTableArgument = RS.AETableRow $ Just $ Iden "response_payload"
               jsonAggSelect = mkJsonAggSelect outputType
-          in RS.FComputedField $ RS.CFSTable jsonAggSelect $
+          in RS.AFComputedField $ RS.CFSTable jsonAggSelect $
              processOutputSelectionSet inputTableArgument outputType
              definitionList annFields stringifyNumerics
 
@@ -268,20 +320,20 @@ resolveAsyncActionQuery userInfo annAction =
         AsyncErrors    -> mkAnnFldFromPGCol "errors" PGJSONB
 
       tableFromExp = RS.FromTable actionLogTable
-      tableArguments = RS.noTableArgs
-                       { RS._taWhere = Just tableBoolExpression}
+      tableArguments = RS.noSelectArgs
+                       { RS._saWhere = Just tableBoolExpression}
       tablePermissions = RS.TablePerm annBoolExpTrue Nothing
 
-  in RS.AnnSelG annotatedFields tableFromExp tablePermissions
+  in RS.AnnSelectG annotatedFields tableFromExp tablePermissions
      tableArguments stringifyNumerics
   where
     AnnActionAsyncQuery actionName actionId outputType asyncFields definitionList stringifyNumerics = annAction
     actionLogTable = QualifiedObject (SchemaName "hdb_catalog") (TableName "hdb_action_log")
 
     -- TODO:- Avoid using PGColumnInfo
-    mkAnnFldFromPGCol col columnType =
-      flip RS.mkAnnColField Nothing $
-      PGColumnInfo (unsafePGCol col) (G.unsafeMkName col) 0 (PGColumnScalar columnType) True Nothing
+    mkAnnFldFromPGCol column columnType =
+      flip RS.mkAnnColumnField Nothing $
+      PGColumnInfo (unsafePGCol column) (G.unsafeMkName column) 0 (PGColumnScalar columnType) True Nothing
 
     tableBoolExpression =
       let actionIdColumnInfo = PGColumnInfo (unsafePGCol "id") $$(G.litName "id")
@@ -510,12 +562,12 @@ processOutputSelectionSet
   :: RS.ArgumentExp v
   -> GraphQLType
   -> [(PGCol, PGScalarType)]
-  -> RS.AnnFldsG v
+  -> RS.AnnFieldsG v
   -> Bool
   -> RS.AnnSimpleSelG v
 processOutputSelectionSet tableRowInput actionOutputType definitionList
   annotatedFields =
-  RS.AnnSelG annotatedFields selectFrom RS.noTablePermissions RS.noTableArgs
+  RS.AnnSelectG annotatedFields selectFrom RS.noTablePermissions RS.noSelectArgs
   where
     jsonbToPostgresRecordFunction =
       QualifiedObject "pg_catalog" $ FunctionName $

server/src-lib/Hasura/GraphQL/Resolve/BoolExp.hs

@@ -169,6 +169,10 @@ parseColExp nt n val = do
         fmapAnnBoolExp partialSQLExpToUnresolvedVal permExp
     RFComputedField _ -> throw500
           "computed fields are not allowed in bool_exp"
+    RFRemoteRelationship _ -> throw500
+          "remote relationships are not allowed in bool_exp"
+    RFNodeId _ _      -> throw500
+      "node id is not allowed in bool_exp"
 
 parseBoolExp
   :: ( MonadReusability m

server/src-lib/Hasura/GraphQL/Resolve/Context.hs

@@ -23,7 +23,7 @@ module Hasura.GraphQL.Resolve.Context
 
   , txtConverter
 
-  , withSelSet
+  , traverseObjectSelectionSet
   , fieldAsPath
   , resolvePGCol
   , module Hasura.GraphQL.Utils
@@ -33,21 +33,21 @@ module Hasura.GraphQL.Resolve.Context
 import           Data.Has
 import           Hasura.Prelude
 
-import qualified Data.HashMap.Strict           as Map
-import qualified Data.Sequence                 as Seq
-import qualified Database.PG.Query             as Q
-import qualified Language.GraphQL.Draft.Syntax as G
+import qualified Data.HashMap.Strict                  as Map
+import qualified Data.Sequence                        as Seq
+import qualified Database.PG.Query                    as Q
+import qualified Language.GraphQL.Draft.Syntax        as G
 
 import           Hasura.GraphQL.Resolve.Types
 import           Hasura.GraphQL.Utils
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
-import           Hasura.RQL.DML.Internal       (currentSession, sessVarFromCurrentSetting)
+import           Hasura.RQL.DML.Internal              (currentSession, sessVarFromCurrentSetting)
 import           Hasura.RQL.Types
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
 
-import qualified Hasura.SQL.DML                as S
+import qualified Hasura.SQL.DML                       as S
 
 getFldInfo
   :: (MonadError QErr m, MonadReader r m, Has FieldMap r)
@@ -65,9 +65,11 @@ getPGColInfo
 getPGColInfo nt n = do
   fldInfo <- getFldInfo nt n
   case fldInfo of
-    RFPGColumn pgColInfo -> return pgColInfo
-    RFRelationship _     -> throw500 $ mkErrMsg "relation"
-    RFComputedField _    -> throw500 $ mkErrMsg "computed field"
+    RFPGColumn pgColInfo   -> return pgColInfo
+    RFRelationship _       -> throw500 $ mkErrMsg "relation"
+    RFComputedField _      -> throw500 $ mkErrMsg "computed field"
+    RFRemoteRelationship _ -> throw500 $ mkErrMsg "remote relationship"
+    RFNodeId _ _           -> throw500 $ mkErrMsg "node id"
   where
     mkErrMsg ty =
       "found " <> ty <> " when expecting pgcolinfo for "
@@ -139,12 +141,6 @@ prepareColVal (WithScalarType scalarType colVal) = do
 txtConverter :: Applicative f => AnnPGVal -> f S.SQLExp
 txtConverter (AnnPGVal _ _ scalarValue) = pure $ toTxtValue scalarValue
 
-withSelSet :: (Monad m) => SelSet -> (Field -> m a) -> m [(Text, a)]
-withSelSet selSet f =
-  forM (toList selSet) $ \fld -> do
-    res <- f fld
-    return (G.unName $ G.unAlias $ _fAlias fld, res)
-
 fieldAsPath :: (MonadError QErr m) => Field -> m a -> m a
 fieldAsPath = nameAsPath . _fName
 

server/src-lib/Hasura/GraphQL/Resolve/Insert.hs

@@ -8,34 +8,36 @@ import           Data.Has
 import           Hasura.EncJSON
 import           Hasura.Prelude
 
-import qualified Data.Aeson                        as J
-import qualified Data.Aeson.Casing                 as J
-import qualified Data.Aeson.TH                     as J
-import qualified Data.HashMap.Strict               as Map
-import qualified Data.HashMap.Strict.InsOrd        as OMap
-import qualified Data.Sequence                     as Seq
-import qualified Data.Text                         as T
-import qualified Language.GraphQL.Draft.Syntax     as G
+import qualified Data.Aeson                           as J
+import qualified Data.Aeson.Casing                    as J
+import qualified Data.Aeson.TH                        as J
+import qualified Data.HashMap.Strict                  as Map
+import qualified Data.HashMap.Strict.InsOrd           as OMap
+import qualified Data.Sequence                        as Seq
+import qualified Data.Text                            as T
+import qualified Language.GraphQL.Draft.Syntax        as G
 
-import qualified Database.PG.Query                 as Q
-import qualified Hasura.RQL.DML.Insert             as RI
-import qualified Hasura.RQL.DML.Returning          as RR
+import qualified Database.PG.Query                    as Q
+import qualified Hasura.RQL.DML.Insert                as RI
+import qualified Hasura.RQL.DML.Returning             as RR
 
-import qualified Hasura.SQL.DML                    as S
+import qualified Hasura.SQL.DML                       as S
 
 import           Hasura.GraphQL.Resolve.BoolExp
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Resolve.Mutation
 import           Hasura.GraphQL.Resolve.Select
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
-import           Hasura.RQL.DML.Insert             (insertOrUpdateCheckExpr)
-import           Hasura.RQL.DML.Internal           (convAnnBoolExpPartialSQL, convPartialSQLExp,
-                                                    dmlTxErrorHandler, sessVarFromCurrentSetting)
+import           Hasura.RQL.DML.Insert                (insertOrUpdateCheckExpr)
+import           Hasura.RQL.DML.Internal              (convAnnBoolExpPartialSQL, convPartialSQLExp,
+                                                       sessVarFromCurrentSetting)
 import           Hasura.RQL.DML.Mutation
-import           Hasura.RQL.GBoolExp               (toSQLBoolExp)
+import           Hasura.RQL.DML.RemoteJoin
+import           Hasura.RQL.GBoolExp                  (toSQLBoolExp)
 import           Hasura.RQL.Types
+import           Hasura.Server.Version                (HasVersion)
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
 
@@ -473,7 +475,8 @@ convertInsert
   -> Field -- the mutation field
   -> m RespTx
 convertInsert role tn fld = prefixErrPath fld $ do
-  mutOutputUnres <- RR.MOutMultirowFields <$> resolveMutationFields (_fType fld) (_fSelSet fld)
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  mutOutputUnres <- RR.MOutMultirowFields <$> resolveMutationFields (_fType fld) selSet
   mutOutputRes <- RR.traverseMutationOutput resolveValTxt mutOutputUnres
   annVals <- withArg arguments "objects" asArray
   -- if insert input objects is empty array then
@@ -508,7 +511,8 @@ convertInsertOne
   -> Field -- the mutation field
   -> m RespTx
 convertInsertOne role qt field = prefixErrPath field $ do
-  tableSelFields <- processTableSelectionSet (_fType field) $ _fSelSet field
+  selSet <- asObjectSelectionSet $ _fSelSet field
+  tableSelFields <- processTableSelectionSet (_fType field) selSet
   let mutationOutputUnresolved = RR.MOutSinglerowObject tableSelFields
   mutationOutputResolved <- RR.traverseMutationOutput resolveValTxt mutationOutputUnresolved
   annInputObj <- withArg arguments "object" asObject

server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs

@@ -6,17 +6,19 @@ module Hasura.GraphQL.Resolve.Introspect
 import           Data.Has
 import           Hasura.Prelude
 
-import qualified Data.Aeson                         as J
-import qualified Data.HashMap.Strict                as Map
-import qualified Data.HashSet                       as Set
-import qualified Data.Text                          as T
-import qualified Language.GraphQL.Draft.Syntax      as G
+import qualified Data.Aeson                           as J
+import qualified Data.HashMap.Strict                  as Map
+import qualified Data.HashSet                         as Set
+import qualified Data.Text                            as T
+import qualified Hasura.SQL.Types                     as S
+import qualified Hasura.SQL.Value                     as S
+import qualified Language.GraphQL.Draft.Syntax        as G
 
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Validate.Context
-import           Hasura.GraphQL.Validate.Field
 import           Hasura.GraphQL.Validate.InputValue
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.Types
 
@@ -35,14 +37,15 @@ instance J.ToJSON TypeKind where
   toJSON = J.toJSON . T.pack . drop 2 . show
 
 withSubFields
-  :: (Monad m)
-  => SelSet
+  :: (MonadError QErr m)
+  => SelectionSet
   -> (Field -> m J.Value)
   -> m J.Object
-withSubFields selSet fn =
-  fmap Map.fromList $ forM (toList selSet) $ \fld -> do
-  val <- fn fld
-  return (G.unName $ G.unAlias $ _fAlias fld, val)
+withSubFields selSet fn = do
+  objectSelectionSet <- asObjectSelectionSet selSet
+  Map.fromList <$> traverseObjectSelectionSet objectSelectionSet fn
+  -- val <- fn fld
+  -- return (G.unName $ G.unAlias $ _fAlias fld, val)
 
 namedTyToTxt :: G.NamedType -> Text
 namedTyToTxt = G.unName . G.unNamedType
@@ -101,9 +104,9 @@ notBuiltinFld f =
 
 getImplTypes :: (MonadReader t m, Has TypeMap t) => AsObjType -> m [ObjTyInfo]
 getImplTypes aot = do
-   tyInfo :: TypeMap <- asks getter
+   tyInfo <- asks getter
    return $ sortOn _otiName $
-     Map.elems $ getPossibleObjTypes' tyInfo aot
+     Map.elems $ getPossibleObjTypes tyInfo aot
 
 -- 4.5.2.3
 unionR
@@ -139,19 +142,24 @@ ifaceR'
   => IFaceTyInfo
   -> Field
   -> m J.Object
-ifaceR' i@(IFaceTyInfo descM n flds) fld =
+ifaceR' ifaceTyInfo fld = do
+  dummyReadIncludeDeprecated fld
   withSubFields (_fSelSet fld) $ \subFld ->
-  case _fName subFld of
-    "__typename"    -> retJT "__Type"
-    "kind"          -> retJ TKINTERFACE
-    "name"          -> retJ $ namedTyToTxt n
-    "description"   -> retJ $ fmap G.unDescription descM
-    "fields"        -> fmap J.toJSON $ mapM (`fieldR` subFld) $
-                      sortOn _fiName $
-                      filter notBuiltinFld $ Map.elems flds
-    "possibleTypes" -> fmap J.toJSON $ mapM (`objectTypeR` subFld)
-                       =<< getImplTypes (AOTIFace i)
-    _               -> return J.Null
+    case _fName subFld of
+      "__typename"    -> retJT "__Type"
+      "kind"          -> retJ TKINTERFACE
+      "name"          -> retJ $ namedTyToTxt name
+      "description"   -> retJ $ fmap G.unDescription maybeDescription
+      "fields"        -> fmap J.toJSON $ mapM (`fieldR` subFld) $
+                        sortOn _fiName $
+                        filter notBuiltinFld $ Map.elems fields
+      "possibleTypes" -> fmap J.toJSON $ mapM (`objectTypeR` subFld)
+                         =<< getImplTypes (AOTIFace ifaceTyInfo)
+      _               -> return J.Null
+  where
+    maybeDescription = _ifDesc ifaceTyInfo
+    name = _ifName ifaceTyInfo
+    fields = _ifFields ifaceTyInfo
 
 -- 4.5.2.5
 enumTypeR
@@ -161,14 +169,64 @@ enumTypeR
   -> m J.Object
 enumTypeR (EnumTyInfo descM n vals _) fld =
   withSubFields (_fSelSet fld) $ \subFld ->
-  case _fName subFld of
-    "__typename"  -> retJT "__Type"
-    "kind"        -> retJ TKENUM
-    "name"        -> retJ $ namedTyToTxt n
-    "description" -> retJ $ fmap G.unDescription descM
-    "enumValues"  -> fmap J.toJSON $ mapM (enumValueR subFld) $
-                     sortOn _eviVal $ Map.elems (normalizeEnumValues vals)
-    _             -> return J.Null
+    case _fName subFld of
+      "__typename"  -> retJT "__Type"
+      "kind"        -> retJ TKENUM
+      "name"        -> retJ $ namedTyToTxt n
+      "description" -> retJ $ fmap G.unDescription descM
+      "enumValues"  -> do
+        includeDeprecated <- readIncludeDeprecated subFld
+        fmap J.toJSON $
+          mapM (enumValueR subFld) $
+          filter (\val -> includeDeprecated || not (_eviIsDeprecated val)) $
+          sortOn _eviVal $
+          Map.elems (normalizeEnumValues vals)
+      _             -> return J.Null
+
+readIncludeDeprecated
+  :: ( Monad m, MonadReusability m, MonadError QErr m )
+  => Field
+  -> m Bool
+readIncludeDeprecated subFld = do
+  let argM = Map.lookup "includeDeprecated" (_fArguments subFld)
+  case argM of
+    Nothing -> pure False
+    Just arg -> asScalarVal arg S.PGBoolean >>= \case
+      S.PGValBoolean b -> pure b
+      _ -> throw500 "unexpected non-Boolean argument for includeDeprecated"
+
+{- Note [Reusability of introspection queries with variables]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Introspection queries can have variables, too, in particular to influence one of
+two arguments: the @name@ argument of the @__type@ field, and the
+@includeDeprecated@ argument of the @fields@ and @enumValues@ fields.  The
+current code does not cache all introspection queries with variables correctly.
+As a workaround to this, whenever a variable is passed to an @includeDeprecated@
+argument, we mark the query as unreusable.  This is the purpose of
+'dummyReadIncludeDeprecated'.
+
+Now @fields@ and @enumValues@ are intended to be used when introspecting,
+respectively [object and interface types] and enum types.  However, it does not
+suffice to only call 'dummyReadIncludeDeprecated' for such types, since @fields@
+and @enumValues@ are valid GraphQL fields regardless of what type we are looking
+at.  So precisely because @__Type@ is _thought of_ as a union, but _not
+actually_ a union, we need to call 'dummyReadIncludeDeprecated' in all cases.
+
+See also issue #4547.
+-}
+
+dummyReadIncludeDeprecated
+  :: ( Monad m, MonadReusability m, MonadError QErr m )
+  => Field
+  -> m ()
+dummyReadIncludeDeprecated fld = do
+  selSet <- unAliasedFields . unObjectSelectionSet
+            <$> asObjectSelectionSet (_fSelSet fld)
+  forM_ (toList selSet) $ \subFld ->
+    case _fName subFld of
+      "fields"     -> readIncludeDeprecated subFld
+      "enumValues" -> readIncludeDeprecated subFld
+      _            -> return False
 
 -- 4.5.2.6
 inputObjR
@@ -276,7 +334,7 @@ inputValueR fld (InpValInfo descM n defM ty) =
 
 -- 4.5.5
 enumValueR
-  :: (Monad m)
+  :: (MonadError QErr m)
   => Field -> EnumValInfo -> m J.Object
 enumValueR fld (EnumValInfo descM enumVal isDeprecated) =
   withSubFields (_fSelSet fld) $ \subFld ->

server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs

@@ -33,7 +33,7 @@ import           Hasura.GraphQL.Resolve.BoolExp
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Resolve.Select       (processTableSelectionSet)
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.DML.Internal             (currentSession, sessVarFromCurrentSetting)
 import           Hasura.RQL.Types
@@ -44,15 +44,16 @@ resolveMutationFields
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => G.NamedType -> SelSet -> m (RR.MutFldsG UnresolvedVal)
+  => G.NamedType -> ObjectSelectionSet -> m (RR.MutFldsG UnresolvedVal)
 resolveMutationFields ty selSet = fmap (map (first FieldName)) $
-  withSelSet selSet $ \fld -> case _fName fld of
+  traverseObjectSelectionSet selSet $ \fld -> case _fName fld of
     "__typename"    -> return $ RR.MExp $ G.unName $ G.unNamedType ty
     "affected_rows" -> return RR.MCount
     "returning"     -> do
-      annFlds <- processTableSelectionSet (_fType fld) $ _fSelSet fld
+      annFlds <- asObjectSelectionSet (_fSelSet fld)
+                 >>= processTableSelectionSet (_fType fld)
       annFldsResolved <- traverse
-        (traverse (RS.traverseAnnFld convertPGValueToTextValue)) annFlds
+        (traverse (RS.traverseAnnField convertPGValueToTextValue)) annFlds
       return $ RR.MRet annFldsResolved
     G.Name t        -> throw500 $ "unexpected field in mutation resp : " <> t
   where
@@ -321,8 +322,9 @@ mutationFieldsResolver
      , Has OrdByCtx r, Has SQLGenCtx r
      )
   => Field -> m (RR.MutationOutputG UnresolvedVal)
-mutationFieldsResolver field =
-  RR.MOutMultirowFields <$> resolveMutationFields (_fType field) (_fSelSet field)
+mutationFieldsResolver field = do
+  asObjectSelectionSet (_fSelSet field) >>= \selSet ->
+    RR.MOutMultirowFields <$> resolveMutationFields (_fType field) selSet
 
 tableSelectionAsMutationOutput
   :: ( MonadReusability m, MonadError QErr m
@@ -331,7 +333,8 @@ tableSelectionAsMutationOutput
      )
   => Field -> m (RR.MutationOutputG UnresolvedVal)
 tableSelectionAsMutationOutput field =
-  RR.MOutSinglerowObject <$> processTableSelectionSet (_fType field) (_fSelSet field)
+  asObjectSelectionSet (_fSelSet field) >>= \selSet ->
+  RR.MOutSinglerowObject <$> processTableSelectionSet (_fType field) selSet
 
 -- | build mutation response for empty objects
 buildEmptyMutResp :: RR.MutationOutput -> EncJSON

server/src-lib/Hasura/GraphQL/Resolve/Select.hs

@@ -1,37 +1,47 @@
 module Hasura.GraphQL.Resolve.Select
   ( convertSelect
+  , convertConnectionSelect
+  , convertConnectionFuncQuery
   , convertSelectByPKey
   , convertAggSelect
   , convertFuncQuerySimple
   , convertFuncQueryAgg
   , parseColumns
   , processTableSelectionSet
+  , resolveNodeId
+  , convertNodeSelect
   , AnnSimpleSelect
   ) where
 
-import           Control.Lens                      ((^?), _2)
+import           Control.Lens                         (to, (^..), (^?), _2)
 import           Data.Has
 import           Data.Parser.JSONPath
 import           Hasura.Prelude
 
-import qualified Data.HashMap.Strict               as Map
-import qualified Data.HashMap.Strict.InsOrd        as OMap
-import qualified Data.List.NonEmpty                as NE
-import qualified Data.Sequence                     as Seq
-import qualified Data.Text                         as T
-import qualified Language.GraphQL.Draft.Syntax     as G
+import qualified Data.Aeson                           as J
+import qualified Data.Aeson.Internal                  as J
+import qualified Data.ByteString.Lazy                 as BL
+import qualified Data.HashMap.Strict                  as Map
+import qualified Data.HashMap.Strict.InsOrd           as OMap
+import qualified Data.List.NonEmpty                   as NE
+import qualified Data.Sequence                        as Seq
+import qualified Data.Text                            as T
+import qualified Language.GraphQL.Draft.Syntax        as G
 
-import qualified Hasura.RQL.DML.Select             as RS
-import qualified Hasura.SQL.DML                    as S
+import qualified Hasura.RQL.DML.Select                as RS
+import qualified Hasura.SQL.DML                       as S
 
 import           Hasura.GraphQL.Resolve.BoolExp
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
-import           Hasura.GraphQL.Schema             (isAggFld)
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Schema                (isAggregateField)
+import           Hasura.GraphQL.Schema.Common         (mkTableTy)
+import           Hasura.GraphQL.Validate
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
-import           Hasura.RQL.DML.Internal           (onlyPositiveInt)
+import           Hasura.RQL.DML.Internal              (onlyPositiveInt)
 import           Hasura.RQL.Types
+import           Hasura.Server.Utils
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
 
@@ -45,27 +55,29 @@ jsonPathToColExp t = case parseJSONPath t of
     elToColExp (Index i) = S.SELit $ T.pack (show i)
 
 
-argsToColOp :: (MonadReusability m, MonadError QErr m) => ArgsMap -> m (Maybe RS.ColOp)
-argsToColOp args = maybe (return Nothing) toOp $ Map.lookup "path" args
-  where
-    toJsonPathExp = fmap (RS.ColOp S.jsonbPathOp) . jsonPathToColExp
-    toOp v = asPGColTextM v >>= traverse toJsonPathExp
+argsToColumnOp :: (MonadReusability m, MonadError QErr m) => ArgsMap -> m (Maybe RS.ColumnOp)
+argsToColumnOp args = case Map.lookup "path" args of
+  Nothing -> return Nothing
+  Just txt -> do
+    mColTxt <- asPGColTextM txt
+    mColExps <- maybe (return Nothing) jsonPathToColExp mColTxt
+    pure $ RS.ColumnOp S.jsonbPathOp <$> mColExps
 
-type AnnFlds = RS.AnnFldsG UnresolvedVal
+type AnnFields = RS.AnnFieldsG UnresolvedVal
 
 resolveComputedField
   :: ( MonadReusability m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r, MonadError QErr m
      )
-  => ComputedField -> Field -> m (RS.ComputedFieldSel UnresolvedVal)
+  => ComputedField -> Field -> m (RS.ComputedFieldSelect UnresolvedVal)
 resolveComputedField computedField fld = fieldAsPath fld $ do
   funcArgs <- parseFunctionArgs argSeq argFn $ Map.lookup "args" $ _fArguments fld
   let argsWithTableArgument = withTableArgument funcArgs
   case fieldType of
     CFTScalar scalarTy -> do
-      colOpM <- argsToColOp $ _fArguments fld
+      colOpM <- argsToColumnOp $ _fArguments fld
       pure $ RS.CFSScalar $
-        RS.ComputedFieldScalarSel qf argsWithTableArgument scalarTy colOpM
+        RS.ComputedFieldScalarSelectect qf argsWithTableArgument scalarTy colOpM
     CFTTable (ComputedFieldTable _ cols permFilter permLimit) -> do
       let functionFrom = RS.FromFunction qf argsWithTableArgument Nothing
       RS.CFSTable RS.JASMultipleRows <$> fromField functionFrom cols permFilter permLimit fld
@@ -86,77 +98,142 @@ processTableSelectionSet
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => G.NamedType -> SelSet -> m AnnFlds
+  => G.NamedType -> ObjectSelectionSet -> m AnnFields
 processTableSelectionSet fldTy flds =
-  forM (toList flds) $ \fld -> do
+  fmap (map (\(a, b) -> (FieldName a, b))) $ traverseObjectSelectionSet flds $ \fld -> do
     let fldName = _fName fld
-    let rqlFldName = FieldName $ G.unName $ G.unAlias $ _fAlias fld
-    (rqlFldName,) <$> case fldName of
-      "__typename" -> return $ RS.FExp $ G.unName $ G.unNamedType fldTy
+    case fldName of
+      "__typename" -> return $ RS.AFExpression $ G.unName $ G.unNamedType fldTy
       _ -> do
         fldInfo <- getFldInfo fldTy fldName
         case fldInfo of
+          RFNodeId tn pkeys -> pure $ RS.AFNodeId tn pkeys
           RFPGColumn colInfo ->
-            RS.mkAnnColField colInfo <$> argsToColOp (_fArguments fld)
+            RS.mkAnnColumnField colInfo <$> argsToColumnOp (_fArguments fld)
           RFComputedField computedField ->
-            RS.FComputedField <$> resolveComputedField computedField fld
-          RFRelationship (RelationshipField relInfo isAgg colGNameMap tableFilter tableLimit) -> do
+            RS.AFComputedField <$> resolveComputedField computedField fld
+          RFRelationship (RelationshipField relInfo fieldKind colGNameMap tableFilter tableLimit) -> do
             let relTN = riRTable relInfo
                 colMapping = riMapping relInfo
                 rn = riName relInfo
-            if isAgg then do
-              aggSel <- fromAggField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
-              return $ RS.FArr $ RS.ASAgg $ RS.AnnRelG rn colMapping aggSel
-            else do
-              annSel <- fromField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
-              let annRel = RS.AnnRelG rn colMapping annSel
-              return $ case riType relInfo of
-                ObjRel -> RS.FObj annRel
-                ArrRel -> RS.FArr $ RS.ASSimple annRel
+            case fieldKind of
+              RFKSimple -> do
+                annSel <- fromField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
+                let annRel = RS.AnnRelationSelectG rn colMapping annSel
+                pure $ case riType relInfo of
+                  ObjRel -> RS.AFObjectRelation annRel
+                  ArrRel -> RS.AFArrayRelation $ RS.ASSimple annRel
+              RFKAggregate -> do
+                aggSel <- fromAggField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
+                pure $ RS.AFArrayRelation $ RS.ASAggregate $ RS.AnnRelationSelectG rn colMapping aggSel
+              RFKConnection pkCols -> do
+                connSel <- fromConnectionField (RS.FromTable relTN) pkCols tableFilter tableLimit fld
+                pure $ RS.AFArrayRelation $ RS.ASConnection $ RS.AnnRelationSelectG rn colMapping connSel
 
-type TableAggFlds = RS.TableAggFldsG UnresolvedVal
+          RFRemoteRelationship info ->
+            pure $ RS.AFRemote $ RS.RemoteSelect
+                                (unValidateArgsMap $ _fArguments fld) -- Unvalidate the input arguments
+                                (unValidateSelectionSet $ _fSelSet fld) -- Unvalidate the selection fields
+                                (_rfiHasuraFields info)
+                                (_rfiRemoteFields info)
+                                (_rfiRemoteSchema info)
+
+type TableAggregateFields = RS.TableAggregateFieldsG UnresolvedVal
 
 fromAggSelSet
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => PGColGNameMap -> G.NamedType -> SelSet -> m TableAggFlds
+  => PGColGNameMap -> G.NamedType -> ObjectSelectionSet -> m TableAggregateFields
 fromAggSelSet colGNameMap fldTy selSet = fmap toFields $
-  withSelSet selSet $ \f -> do
-    let fTy = _fType f
-        fSelSet = _fSelSet f
-    case _fName f of
+  traverseObjectSelectionSet selSet $ \Field{..} ->
+    case _fName of
       "__typename" -> return $ RS.TAFExp $ G.unName $ G.unNamedType fldTy
-      "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
-      "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
+      "aggregate"  -> do
+        objSelSet <-  asObjectSelectionSet _fSelSet
+        RS.TAFAgg <$> convertAggregateField colGNameMap _fType objSelSet
+      "nodes"      -> do
+        objSelSet <-  asObjectSelectionSet _fSelSet
+        RS.TAFNodes <$> processTableSelectionSet _fType objSelSet
       G.Name t     -> throw500 $ "unexpected field in _agg node: " <> t
 
-type TableArgs = RS.TableArgsG UnresolvedVal
+fromConnectionSelSet
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => G.NamedType -> ObjectSelectionSet -> m (RS.ConnectionFields UnresolvedVal)
+fromConnectionSelSet fldTy selSet = fmap toFields $
+  traverseObjectSelectionSet selSet $ \Field{..} ->
+    case _fName of
+      "__typename" -> return $ RS.ConnectionTypename $ G.unName $ G.unNamedType fldTy
+      "pageInfo"   -> do
+        fSelSet <-  asObjectSelectionSet _fSelSet
+        RS.ConnectionPageInfo <$> parsePageInfoSelectionSet _fType fSelSet
+      "edges"      -> do
+        fSelSet <-  asObjectSelectionSet _fSelSet
+        RS.ConnectionEdges <$> parseEdgeSelectionSet _fType fSelSet
+      -- "aggregate"  -> RS.TAFAgg <$> convertAggregateField colGNameMap fTy fSelSet
+      -- "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
+      G.Name t     -> throw500 $ "unexpected field in _connection node: " <> t
 
-parseTableArgs
+parseEdgeSelectionSet
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => G.NamedType -> ObjectSelectionSet -> m (RS.EdgeFields UnresolvedVal)
+parseEdgeSelectionSet fldTy selSet = fmap toFields $
+  traverseObjectSelectionSet selSet $ \f -> do
+    let fTy = _fType f
+    case _fName f of
+      "__typename" -> pure $ RS.EdgeTypename $ G.unName $ G.unNamedType fldTy
+      "cursor"     -> pure RS.EdgeCursor
+      "node"       -> do
+        fSelSet <- asObjectSelectionSet $ _fSelSet f
+        RS.EdgeNode <$> processTableSelectionSet fTy fSelSet
+      G.Name t     -> throw500 $ "unexpected field in Edge node: " <> t
+
+parsePageInfoSelectionSet
+  :: ( MonadReusability m, MonadError QErr m)
+  => G.NamedType -> ObjectSelectionSet -> m RS.PageInfoFields
+parsePageInfoSelectionSet fldTy selSet =
+  fmap toFields $ traverseObjectSelectionSet selSet $ \f ->
+    case _fName f of
+      "__typename"      -> pure $ RS.PageInfoTypename $ G.unName $ G.unNamedType fldTy
+      "hasNextPage"     -> pure RS.PageInfoHasNextPage
+      "hasPreviousPage" -> pure RS.PageInfoHasPreviousPage
+      "startCursor"     -> pure RS.PageInfoStartCursor
+      "endCursor"       -> pure RS.PageInfoEndCursor
+      -- "aggregate"  -> RS.TAFAgg <$> convertAggregateField colGNameMap fTy fSelSet
+      -- "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
+      G.Name t          -> throw500 $ "unexpected field in PageInfo node: " <> t
+
+type SelectArgs = RS.SelectArgsG UnresolvedVal
+
+parseSelectArgs
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m
      , Has FieldMap r, Has OrdByCtx r
      )
-  => PGColGNameMap -> ArgsMap -> m TableArgs
-parseTableArgs colGNameMap args = do
+  => PGColGNameMap -> ArgsMap -> m SelectArgs
+parseSelectArgs colGNameMap args = do
   whereExpM  <- withArgM args "where" parseBoolExp
   ordByExpML <- withArgM args "order_by" parseOrderBy
   let ordByExpM = NE.nonEmpty =<< ordByExpML
-  limitExpM  <- withArgM args "limit" parseLimit
+  limitExpM  <- withArgM args "limit" $
+                parseNonNegativeInt "expecting Integer value for \"limit\""
   offsetExpM <- withArgM args "offset" $ asPGColumnValue >=> openOpaqueValue >=> txtConverter
   distOnColsML <- withArgM args "distinct_on" $ parseColumns colGNameMap
   let distOnColsM = NE.nonEmpty =<< distOnColsML
   mapM_ (validateDistOn ordByExpM) distOnColsM
-  return $ RS.TableArgs whereExpM ordByExpM limitExpM offsetExpM distOnColsM
+  return $ RS.SelectArgs whereExpM ordByExpM limitExpM offsetExpM distOnColsM
   where
     validateDistOn Nothing _ = return ()
     validateDistOn (Just ordBys) cols = withPathK "args" $ do
       let colsLen = length cols
           initOrdBys = take colsLen $ toList ordBys
           initOrdByCols = flip mapMaybe initOrdBys $ \ob ->
-            case obiColumn ob of
-              RS.AOCPG pgCol -> Just pgCol
-              _              -> Nothing
+            case obiColumn  ob of
+              RS.AOCColumn pgCol -> Just $ pgiColumn pgCol
+              _                  -> Nothing
           isValid = (colsLen == length initOrdByCols)
                     && all (`elem` initOrdByCols) (toList cols)
 
@@ -175,12 +252,13 @@ fromField
   -> Maybe Int
   -> Field -> m AnnSimpleSelect
 fromField selFrom colGNameMap permFilter permLimitM fld = fieldAsPath fld $ do
-  tableArgs <- parseTableArgs colGNameMap args
-  annFlds   <- processTableSelectionSet (_fType fld) $ _fSelSet fld
+  tableArgs <- parseSelectArgs colGNameMap args
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  annFlds   <- processTableSelectionSet (_fType fld) selSet
   let unresolvedPermFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
   let tabPerm = RS.TablePerm unresolvedPermFltr permLimitM
   strfyNum <- stringifyNum <$> asks getter
-  return $ RS.AnnSelG annFlds selFrom tabPerm tableArgs strfyNum
+  return $ RS.AnnSelectG annFlds selFrom tabPerm tableArgs strfyNum
   where
     args = _fArguments fld
 
@@ -201,7 +279,8 @@ parseOrderBy
      , MonadReader r m
      , Has OrdByCtx r
      )
-  => AnnInpVal -> m [RS.AnnOrderByItemG UnresolvedVal]
+  => AnnInpVal
+  -> m [RS.AnnOrderByItemG UnresolvedVal]
 parseOrderBy = fmap concat . withArray f
   where
     f _ = mapM (withObject (getAnnObItems id))
@@ -212,7 +291,7 @@ getAnnObItems
      , MonadReader r m
      , Has OrdByCtx r
      )
-  => (RS.AnnObColG UnresolvedVal -> RS.AnnObColG UnresolvedVal)
+  => (RS.AnnOrderByElement UnresolvedVal -> RS.AnnOrderByElement UnresolvedVal)
   -> G.NamedType
   -> AnnGObject
   -> m [RS.AnnOrderByItemG UnresolvedVal]
@@ -224,7 +303,7 @@ getAnnObItems f nt obj = do
       <> showNamedTy nt <> " map"
     case ordByItem of
       OBIPGCol ci -> do
-        let aobCol = f $ RS.AOCPG $ pgiColumn ci
+        let aobCol = f $ RS.AOCColumn ci
         (_, enumValM) <- asEnumValM v
         ordByItemM <- forM enumValM $ \enumVal -> do
           (ordTy, nullsOrd) <- parseOrderByEnum enumVal
@@ -233,13 +312,13 @@ getAnnObItems f nt obj = do
 
       OBIRel ri fltr -> do
         let unresolvedFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal fltr
-        let annObColFn = f . RS.AOCObj ri unresolvedFltr
+        let annObColFn = f . RS.AOCObjectRelation ri unresolvedFltr
         flip withObjectM v $ \nameTy objM ->
           maybe (pure []) (getAnnObItems annObColFn nameTy) objM
 
       OBIAgg ri relColGNameMap fltr -> do
         let unresolvedFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal fltr
-        let aobColFn = f . RS.AOCAgg ri unresolvedFltr
+        let aobColFn = f . RS.AOCArrayAggregation ri unresolvedFltr
         flip withObjectM v $ \_ objM ->
           maybe (pure []) (parseAggOrdBy relColGNameMap aobColFn) objM
 
@@ -250,7 +329,7 @@ mkOrdByItemG ordTy aobCol nullsOrd =
 parseAggOrdBy
   :: (MonadReusability m, MonadError QErr m)
   => PGColGNameMap
-  -> (RS.AnnAggOrdBy -> RS.AnnObColG UnresolvedVal)
+  -> (RS.AnnAggregateOrderBy -> RS.AnnOrderByElement UnresolvedVal)
   -> AnnGObject
   -> m [RS.AnnOrderByItemG UnresolvedVal]
 parseAggOrdBy colGNameMap f annObj =
@@ -263,14 +342,14 @@ parseAggOrdBy colGNameMap f annObj =
           return $ mkOrdByItemG ordTy (f RS.AAOCount) nullsOrd
         return $ maybe [] pure ordByItemM
 
-      G.Name opT ->
+      G.Name opText ->
         flip withObject obVal $ \_ opObObj -> fmap catMaybes $
           forM (OMap.toList opObObj) $ \(colName, eVal) -> do
             (_, enumValM) <- asEnumValM eVal
             forM enumValM $ \enumVal -> do
               (ordTy, nullsOrd) <- parseOrderByEnum enumVal
-              col <- pgiColumn <$> resolvePGCol colGNameMap colName
-              let aobCol = f $ RS.AAOOp opT col
+              col <- resolvePGCol colGNameMap colName
+              let aobCol = f $ RS.AAOOp opText col
               return $ mkOrdByItemG ordTy aobCol nullsOrd
 
 parseOrderByEnum
@@ -287,15 +366,14 @@ parseOrderByEnum = \case
   G.EnumValue v                   -> throw500 $
     "enum value " <> showName v <> " not found in type order_by"
 
-parseLimit :: (MonadReusability m, MonadError QErr m) => AnnInpVal -> m Int
-parseLimit v = do
+parseNonNegativeInt
+  :: (MonadReusability m, MonadError QErr m) => Text -> AnnInpVal -> m Int
+parseNonNegativeInt errMsg v = do
   pgColVal <- openOpaqueValue =<< asPGColumnValue v
-  limit <- maybe noIntErr return . pgColValueToInt . pstValue $ _apvValue pgColVal
+  limit <- maybe (throwVE errMsg) return . pgColValueToInt . pstValue $ _apvValue pgColVal
   -- validate int value
   onlyPositiveInt limit
   return limit
-  where
-    noIntErr = throwVE "expecting Integer value for \"limit\""
 
 type AnnSimpleSel = RS.AnnSimpleSelG UnresolvedVal
 
@@ -311,14 +389,15 @@ fromFieldByPKey
   -> AnnBoolExpPartialSQL -> Field -> m AnnSimpleSel
 fromFieldByPKey tn colArgMap permFilter fld = fieldAsPath fld $ do
   boolExp <- pgColValToBoolExp colArgMap $ _fArguments fld
-  annFlds <- processTableSelectionSet fldTy $ _fSelSet fld
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  annFlds <- processTableSelectionSet fldTy selSet
   let tabFrom = RS.FromTable tn
       unresolvedPermFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal
                            permFilter
       tabPerm = RS.TablePerm unresolvedPermFltr Nothing
-      tabArgs = RS.noTableArgs { RS._taWhere = Just boolExp}
+      tabArgs = RS.noSelectArgs { RS._saWhere = Just boolExp}
   strfyNum <- stringifyNum <$> asks getter
-  return $ RS.AnnSelG annFlds tabFrom tabPerm tabArgs strfyNum
+  return $ RS.AnnSelectG annFlds tabFrom tabPerm tabArgs strfyNum
   where
     fldTy = _fType fld
 
@@ -345,14 +424,18 @@ convertSelectByPKey opCtx fld =
     SelPkOpCtx qt _ permFilter colArgMap = opCtx
 
 -- agg select related
-parseColumns :: (MonadReusability m, MonadError QErr m) => PGColGNameMap -> AnnInpVal -> m [PGCol]
+parseColumns
+  :: (MonadReusability m, MonadError QErr m)
+  => PGColGNameMap -> AnnInpVal -> m [PGCol]
 parseColumns allColFldMap val =
   flip withArray val $ \_ vals ->
     forM vals $ \v -> do
       (_, G.EnumValue enumVal) <- asEnumVal v
       pgiColumn <$> resolvePGCol allColFldMap enumVal
 
-convertCount :: (MonadReusability m, MonadError QErr m) => PGColGNameMap -> ArgsMap -> m S.CountType
+convertCount
+  :: (MonadReusability m, MonadError QErr m)
+  => PGColGNameMap -> ArgsMap -> m S.CountType
 convertCount colGNameMap args = do
   columnsM <- withArgM args "columns" $ parseColumns colGNameMap
   isDistinct <- or <$> withArgM args "distinct" parseDistinct
@@ -371,34 +454,33 @@ convertCount colGNameMap args = do
 toFields :: [(T.Text, a)] -> RS.Fields a
 toFields = map (first FieldName)
 
-convertColFlds
+convertColumnFields
   :: (MonadError QErr m)
-  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.ColFlds
-convertColFlds colGNameMap ty selSet = fmap toFields $
-  withSelSet selSet $ \fld ->
+  => PGColGNameMap -> G.NamedType -> ObjectSelectionSet -> m RS.ColumnFields
+convertColumnFields colGNameMap ty selSet = fmap toFields $
+  traverseObjectSelectionSet selSet $ \fld ->
     case _fName fld of
       "__typename" -> return $ RS.PCFExp $ G.unName $ G.unNamedType ty
-      n            -> (RS.PCFCol . pgiColumn) <$> resolvePGCol colGNameMap n
+      n            -> RS.PCFCol . pgiColumn <$> resolvePGCol colGNameMap n
 
-convertAggFld
+convertAggregateField
   :: (MonadReusability m, MonadError QErr m)
-  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.AggFlds
-convertAggFld colGNameMap ty selSet = fmap toFields $
-  withSelSet selSet $ \fld -> do
-    let fType = _fType fld
-        fSelSet = _fSelSet fld
-    case _fName fld of
+  => PGColGNameMap -> G.NamedType -> ObjectSelectionSet -> m RS.AggregateFields
+convertAggregateField colGNameMap ty selSet = fmap toFields $
+  traverseObjectSelectionSet selSet $ \Field{..} ->
+    case _fName of
       "__typename" -> return $ RS.AFExp $ G.unName $ G.unNamedType ty
       "count"      -> RS.AFCount <$> convertCount colGNameMap (_fArguments fld)
       n            -> do
-        colFlds <- convertColFlds colGNameMap fType fSelSet
-        unless (isAggFld n) $ throwInvalidFld n
-        return $ RS.AFOp $ RS.AggOp (G.unName n) colFlds
+        fSelSet <- asObjectSelectionSet _fSelSet
+        colFlds <- convertColumnFields colGNameMap _fType fSelSet
+        unless (isAggregateField n) $ throwInvalidFld n
+        return $ RS.AFOp $ RS.AggregateOp (G.unName n) colFlds
   where
       throwInvalidFld (G.Name t) =
         throw500 $ "unexpected field in _aggregate node: " <> t
 
-type AnnAggSel = RS.AnnAggSelG UnresolvedVal
+type AnnAggregateSelect = RS.AnnAggregateSelectG UnresolvedVal
 
 fromAggField
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
@@ -408,29 +490,162 @@ fromAggField
   -> PGColGNameMap
   -> AnnBoolExpPartialSQL
   -> Maybe Int
-  -> Field -> m AnnAggSel
+  -> Field -> m AnnAggregateSelect
 fromAggField selectFrom colGNameMap permFilter permLimit fld = fieldAsPath fld $ do
-  tableArgs   <- parseTableArgs colGNameMap args
-  aggSelFlds  <- fromAggSelSet colGNameMap (_fType fld) (_fSelSet fld)
+  tableArgs   <- parseSelectArgs colGNameMap args
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  aggSelFlds  <- fromAggSelSet colGNameMap (_fType fld) selSet
   let unresolvedPermFltr =
         fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
   let tabPerm = RS.TablePerm unresolvedPermFltr permLimit
   strfyNum <- stringifyNum <$> asks getter
-  return $ RS.AnnSelG aggSelFlds selectFrom tabPerm tableArgs strfyNum
+  return $ RS.AnnSelectG aggSelFlds selectFrom tabPerm tableArgs strfyNum
   where
     args = _fArguments fld
 
+fromConnectionField
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => RS.SelectFromG UnresolvedVal
+  -> NonEmpty PGColumnInfo
+  -> AnnBoolExpPartialSQL
+  -> Maybe Int
+  -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+fromConnectionField selectFrom pkCols permFilter permLimit fld = fieldAsPath fld $ do
+  (tableArgs, slice, split)   <- parseConnectionArgs pkCols args
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  connSelFlds  <- fromConnectionSelSet (_fType fld) selSet
+  strfyNum <- stringifyNum <$> asks getter
+  let unresolvedPermFltr =
+        fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
+      tabPerm = RS.TablePerm unresolvedPermFltr permLimit
+      annSel = RS.AnnSelectG connSelFlds selectFrom tabPerm tableArgs strfyNum
+  pure $ RS.ConnectionSelect pkCols split slice annSel
+  where
+    args = _fArguments fld
+
+parseConnectionArgs
+  :: forall r m.
+     ( MonadReusability m, MonadError QErr m, MonadReader r m
+     , Has FieldMap r, Has OrdByCtx r
+     )
+  => NonEmpty PGColumnInfo
+  -> ArgsMap
+  -> m ( SelectArgs
+       , Maybe RS.ConnectionSlice
+       , Maybe (NE.NonEmpty (RS.ConnectionSplit UnresolvedVal))
+       )
+parseConnectionArgs pKeyColumns args = do
+  whereExpM  <- withArgM args "where" parseBoolExp
+  ordByExpML <- withArgM args "order_by" parseOrderBy
+
+  slice <- case (Map.lookup "first" args, Map.lookup "last" args) of
+    (Nothing, Nothing) -> pure Nothing
+    (Just _, Just _)   -> throwVE "\"first\" and \"last\" are not allowed at once"
+    (Just v, Nothing)  -> Just . RS.SliceFirst <$> parseNonNegativeInt
+      "expecting Integer value for \"first\"" v
+    (Nothing, Just v)  -> Just . RS.SliceLast <$> parseNonNegativeInt
+      "expecting Integer value for \"last\"" v
+
+  maybeSplit <- case (Map.lookup "after" args, Map.lookup "before" args) of
+    (Nothing, Nothing) -> pure Nothing
+    (Just _, Just _)   -> throwVE "\"after\" and \"before\" are not allowed at once"
+    (Just v, Nothing)  -> fmap ((RS.CSKAfter,) . base64Decode) <$> asPGColTextM v
+    (Nothing, Just v)  -> fmap ((RS.CSKBefore,) . base64Decode) <$> asPGColTextM v
+
+  let ordByExpM = NE.nonEmpty =<< appendPrimaryKeyOrderBy <$> ordByExpML
+      tableArgs = RS.SelectArgs whereExpM ordByExpM Nothing Nothing Nothing
+
+  split <- mapM (uncurry (validateConnectionSplit ordByExpM)) maybeSplit
+  pure (tableArgs, slice, split)
+  where
+    appendPrimaryKeyOrderBy :: [RS.AnnOrderByItemG v] -> [RS.AnnOrderByItemG v]
+    appendPrimaryKeyOrderBy orderBys =
+      let orderByColumnNames =
+            orderBys ^.. traverse . to obiColumn . RS._AOCColumn . to pgiColumn
+          pkeyOrderBys = flip mapMaybe (toList pKeyColumns) $ \pgColumnInfo ->
+                         if pgiColumn pgColumnInfo `elem` orderByColumnNames then Nothing
+                         else Just $ OrderByItemG Nothing (RS.AOCColumn pgColumnInfo) Nothing
+      in orderBys <> pkeyOrderBys
+
+    validateConnectionSplit
+      :: Maybe (NonEmpty (RS.AnnOrderByItemG UnresolvedVal))
+      -> RS.ConnectionSplitKind
+      -> BL.ByteString
+      -> m (NonEmpty (RS.ConnectionSplit UnresolvedVal))
+    validateConnectionSplit maybeOrderBys splitKind cursorSplit = do
+      cursorValue <- either (const throwInvalidCursor) pure $
+                      J.eitherDecode cursorSplit
+      case maybeOrderBys of
+        Nothing -> forM pKeyColumns $
+          \pgColumnInfo -> do
+            let columnJsonPath = [J.Key $ getPGColTxt $ pgiColumn pgColumnInfo]
+            pgColumnValue <- maybe throwInvalidCursor pure $ iResultToMaybe $
+                             executeJSONPath columnJsonPath cursorValue
+            pgValue <- parsePGScalarValue (pgiType pgColumnInfo) pgColumnValue
+            let unresolvedValue = UVPG $ AnnPGVal Nothing False pgValue
+            pure $ RS.ConnectionSplit splitKind unresolvedValue $
+                   OrderByItemG Nothing (RS.AOCColumn pgColumnInfo) Nothing
+        Just orderBys ->
+          forM orderBys $ \orderBy -> do
+            let OrderByItemG orderType annObCol nullsOrder = orderBy
+            orderByItemValue <- maybe throwInvalidCursor pure $ iResultToMaybe $
+                                executeJSONPath (getPathFromOrderBy annObCol) cursorValue
+            pgValue <- parsePGScalarValue (getOrderByColumnType annObCol) orderByItemValue
+            let unresolvedValue = UVPG $ AnnPGVal Nothing False pgValue
+            pure $ RS.ConnectionSplit splitKind unresolvedValue $
+                   OrderByItemG orderType (() <$ annObCol) nullsOrder
+      where
+        throwInvalidCursor = throwVE "the \"after\" or \"before\" cursor is invalid"
+
+        iResultToMaybe = \case
+          J.ISuccess v -> Just v
+          J.IError{}   -> Nothing
+
+        getPathFromOrderBy = \case
+          RS.AOCColumn pgColInfo ->
+            let pathElement = J.Key $ getPGColTxt $ pgiColumn pgColInfo
+            in [pathElement]
+          RS.AOCObjectRelation relInfo _ obCol ->
+            let pathElement = J.Key $ relNameToTxt $ riName relInfo
+            in pathElement : getPathFromOrderBy obCol
+          RS.AOCArrayAggregation relInfo _ aggOb ->
+            let fieldName = J.Key $ relNameToTxt (riName relInfo) <> "_aggregate"
+            in fieldName : case aggOb of
+                 RS.AAOCount    -> [J.Key "count"]
+                 RS.AAOOp t col -> [J.Key t, J.Key $ getPGColTxt $ pgiColumn col]
+
+        getOrderByColumnType = \case
+          RS.AOCColumn pgColInfo -> pgiType pgColInfo
+          RS.AOCObjectRelation _ _ obCol -> getOrderByColumnType obCol
+          RS.AOCArrayAggregation _ _ aggOb ->
+            case aggOb of
+              RS.AAOCount        -> PGColumnScalar PGInteger
+              RS.AAOOp _ colInfo -> pgiType colInfo
+
 convertAggSelect
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => SelOpCtx -> Field -> m (RS.AnnAggSelG UnresolvedVal)
+  => SelOpCtx -> Field -> m (RS.AnnAggregateSelectG UnresolvedVal)
 convertAggSelect opCtx fld =
   withPathK "selectionSet" $
   fromAggField (RS.FromTable qt) colGNameMap permFilter permLimit fld
   where
     SelOpCtx qt _ colGNameMap permFilter permLimit = opCtx
 
+convertConnectionSelect
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => NonEmpty PGColumnInfo -> SelOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+convertConnectionSelect pkCols opCtx fld =
+  withPathK "selectionSet" $
+  fromConnectionField (RS.FromTable qt) pkCols permFilter permLimit fld
+  where
+    SelOpCtx qt _ _ permFilter permLimit = opCtx
+
 parseFunctionArgs
   :: (MonadReusability m, MonadError QErr m)
   => Seq.Seq a
@@ -506,10 +721,77 @@ convertFuncQueryAgg
      , Has OrdByCtx r
      , Has SQLGenCtx r
      )
-  => FuncQOpCtx -> Field -> m AnnAggSel
+  => FuncQOpCtx -> Field -> m AnnAggregateSelect
 convertFuncQueryAgg funcOpCtx fld =
   withPathK "selectionSet" $ fieldAsPath fld $ do
     selectFrom <- makeFunctionSelectFrom qf argSeq fld
     fromAggField selectFrom colGNameMap permFilter permLimit fld
   where
     FuncQOpCtx qf argSeq _ colGNameMap permFilter permLimit = funcOpCtx
+
+convertConnectionFuncQuery
+  :: ( MonadReusability m
+     , MonadError QErr m
+     , MonadReader r m
+     , Has FieldMap r
+     , Has OrdByCtx r
+     , Has SQLGenCtx r
+     )
+  => NonEmpty PGColumnInfo -> FuncQOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+convertConnectionFuncQuery pkCols funcOpCtx fld =
+  withPathK "selectionSet" $ fieldAsPath fld $ do
+    selectFrom <- makeFunctionSelectFrom qf argSeq fld
+    fromConnectionField selectFrom pkCols permFilter permLimit fld
+  where
+    FuncQOpCtx qf argSeq _ _ permFilter permLimit = funcOpCtx
+
+resolveNodeId
+  :: forall m. ( MonadError QErr m
+               , MonadReusability m
+               )
+  => Field -> m NodeIdData
+resolveNodeId field =
+  withPathK "selectionSet" $ fieldAsPath field $ do
+    nodeIdText <- asPGColText =<< getArg (_fArguments field) "id"
+    either (const throwInvalidNodeId) pure $
+      J.eitherDecode $ base64Decode nodeIdText
+  where
+    throwInvalidNodeId = throwVE "the node id is invalid"
+
+convertNodeSelect
+  :: ( MonadReusability m
+     , MonadError QErr m
+     , MonadReader r m
+     , Has FieldMap r
+     , Has OrdByCtx r
+     , Has SQLGenCtx r
+     )
+  => SelOpCtx
+  -> Map.HashMap PGCol J.Value
+  -> Field
+  -> m (RS.AnnSimpleSelG UnresolvedVal)
+convertNodeSelect selOpCtx pkeyColumnValues field =
+  withPathK "selectionSet" $ fieldAsPath field $ do
+    -- Parse selection set as interface
+    ifaceSelectionSet <- asInterfaceSelectionSet $ _fSelSet field
+    let tableObjectType = mkTableTy table
+        selSet = getMemberSelectionSet tableObjectType ifaceSelectionSet
+        unresolvedPermFilter = fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
+        tablePerm = RS.TablePerm unresolvedPermFilter permLimit
+    -- Resolve the table selection set
+    annFields <- processTableSelectionSet tableObjectType selSet
+    -- Resolve the Node id primary key column values
+    unresolvedPkeyValues <- flip Map.traverseWithKey pkeyColumnValues $
+      \pgColumn jsonValue -> case Map.lookup pgColumn pgColumnMap of
+        Nothing -> throwVE $ "column " <> pgColumn <<> " not found"
+        Just columnInfo -> (,columnInfo) . UVPG . AnnPGVal Nothing False <$>
+                           parsePGScalarValue (pgiType columnInfo) jsonValue
+    -- Generate the bool expression from the primary key column values
+    let pkeyBoolExp = BoolAnd $ flip map (Map.elems unresolvedPkeyValues) $
+          \(unresolvedValue, columnInfo) -> (BoolFld . AVCol columnInfo) [AEQ True unresolvedValue]
+        selectArgs = RS.noSelectArgs{RS._saWhere = Just pkeyBoolExp}
+    strfyNum <- stringifyNum <$> asks getter
+    pure $ RS.AnnSelectG annFields (RS.FromTable table) tablePerm selectArgs strfyNum
+  where
+    SelOpCtx table _ allColumns permFilter permLimit = selOpCtx
+    pgColumnMap = mapFromL pgiColumn $ Map.elems allColumns

server/src-lib/Hasura/GraphQL/Resolve/Types.hs

@@ -7,6 +7,9 @@ module Hasura.GraphQL.Resolve.Types
 import           Control.Lens.TH
 import           Hasura.Prelude
 
+import qualified Data.Aeson                     as J
+import qualified Data.Aeson.Casing              as J
+import qualified Data.Aeson.TH                  as J
 import qualified Data.HashMap.Strict            as Map
 import qualified Data.Sequence                  as Seq
 import qualified Data.Text                      as T
@@ -27,12 +30,17 @@ import           Hasura.SQL.Value
 
 import qualified Hasura.SQL.DML                 as S
 
+type NodeSelectMap = Map.HashMap G.NamedType SelOpCtx
+
 data QueryCtx
-  = QCSelect !SelOpCtx
+  = QCNodeSelect !NodeSelectMap
+  | QCSelect !SelOpCtx
+  | QCSelectConnection !(NonEmpty PGColumnInfo) !SelOpCtx
   | QCSelectPkey !SelPkOpCtx
   | QCSelectAgg !SelOpCtx
   | QCFuncQuery !FuncQOpCtx
   | QCFuncAggQuery !FuncQOpCtx
+  | QCFuncConnection !(NonEmpty PGColumnInfo) !FuncQOpCtx
   | QCAsyncActionFetch !ActionSelectOpContext
   | QCAction !ActionExecutionContext
   deriving (Show, Eq)
@@ -130,10 +138,16 @@ data ActionSelectOpContext
 -- used in resolvers
 type PGColGNameMap = Map.HashMap G.Name PGColumnInfo
 
+data RelationshipFieldKind
+  = RFKAggregate
+  | RFKSimple
+  | RFKConnection !(NonEmpty PGColumnInfo)
+  deriving (Show, Eq)
+
 data RelationshipField
   = RelationshipField
   { _rfInfo       :: !RelInfo
-  , _rfIsAgg      :: !Bool
+  , _rfIsAgg      :: !RelationshipFieldKind
   , _rfCols       :: !PGColGNameMap
   , _rfPermFilter :: !AnnBoolExpPartialSQL
   , _rfPermLimit  :: !(Maybe Int)
@@ -166,6 +180,8 @@ data ResolveField
   = RFPGColumn !PGColumnInfo
   | RFRelationship !RelationshipField
   | RFComputedField !ComputedField
+  | RFRemoteRelationship !RemoteFieldInfo
+  | RFNodeId !QualifiedTable !(NonEmpty PGColumnInfo)
   deriving (Show, Eq)
 
 type FieldMap = Map.HashMap (G.NamedType, G.Name) ResolveField
@@ -245,6 +261,13 @@ data InputFunctionArgument
   | IFAUnknown !FunctionArgItem -- ^ Unknown value, need to be parsed
   deriving (Show, Eq)
 
+data NodeIdData
+  = NodeIdData
+  { _nidTable   :: !QualifiedTable
+  , _nidColumns :: !(Map.HashMap PGCol J.Value)
+  } deriving (Show, Eq)
+$(J.deriveFromJSON (J.aesonDrop 4 J.snakeCase) ''NodeIdData)
+
 -- template haskell related
 $(makePrisms ''ResolveField)
 $(makeLenses ''ComputedField)

server/src-lib/Hasura/GraphQL/Schema/Action.hs

@@ -132,7 +132,7 @@ actionIdParser =
 actionOutputFields
   :: forall m n r. (MonadSchema n m, MonadTableInfo r m, MonadRole r m, Has QueryContext r)
   => AnnotatedObjectType
-  -> MaybeT m (Parser 'Output n (RQL.AnnFldsG UnpreparedValue))
+  -> MaybeT m (Parser 'Output n (RQL.AnnFieldsG UnpreparedValue))
 actionOutputFields outputObject = do
   let scalarOrEnumFields = map scalarOrEnumFieldParser $ toList $ _otdFields outputObject
   relationshipFields <- forM (_otdRelationships outputObject) $ traverse relationshipFieldParser
@@ -141,11 +141,11 @@ actionOutputFields outputObject = do
       outputTypeName = unObjectTypeName $ _otdName outputObject
       outputTypeDescription = _otdDescription outputObject
   pure $ P.selectionSet outputTypeName outputTypeDescription allFieldParsers
-         <&> parsedSelectionsToFields RQL.FExp
+         <&> parsedSelectionsToFields RQL.AFExpression
   where
     scalarOrEnumFieldParser
       :: ObjectFieldDefinition (G.GType, AnnotatedObjectFieldType)
-      -> FieldParser n (RQL.AnnFldG UnpreparedValue)
+      -> FieldParser n (RQL.AnnFieldG UnpreparedValue)
     scalarOrEnumFieldParser (ObjectFieldDefinition name _ description ty) =
       let (gType, objectFieldType) = ty
           fieldName = unObjectFieldName name
@@ -157,11 +157,11 @@ actionOutputFields outputObject = do
             AOFTEnum def   -> customEnumParser def
       in bool P.nonNullableField id (G.isNullable gType) $
          P.selection_ (unObjectFieldName name) description fieldParser
-         $> RQL.mkAnnColField pgColumnInfo Nothing
+         $> RQL.mkAnnColumnField pgColumnInfo Nothing
 
     relationshipFieldParser
       :: TypeRelationship TableInfo PGColumnInfo
-      -> MaybeT m (FieldParser n (RQL.AnnFldG UnpreparedValue))
+      -> MaybeT m (FieldParser n (RQL.AnnFieldG UnpreparedValue))
     relationshipFieldParser typeRelationship = do
       let TypeRelationship relName relType tableInfo fieldMapping = typeRelationship
           tableName = _tciName $ _tiCoreInfo tableInfo
@@ -175,10 +175,10 @@ actionOutputFields outputObject = do
               [ (unsafePGCol $ G.unName $ unObjectFieldName k, pgiColumn v)
               | (k, v) <- Map.toList fieldMapping
               ]
-            annotatedRelationship = RQL.AnnRelG tableRelName columnMapping selectExp
+            annotatedRelationship = RQL.AnnRelationSelectG tableRelName columnMapping selectExp
         in case relType of
-             ObjRel -> RQL.FObj annotatedRelationship
-             ArrRel -> RQL.FArr $ RQL.ASSimple annotatedRelationship
+             ObjRel -> RQL.AFObjectRelation annotatedRelationship
+             ArrRel -> RQL.AFArrayRelation $ RQL.ASSimple annotatedRelationship
 
 mkDefinitionList :: AnnotatedObjectType -> [(PGCol, PGScalarType)]
 mkDefinitionList annotatedOutputType =

server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs

@@ -52,7 +52,7 @@ orderByExp table selectPermissions = memoizeOn 'orderByExp table $ do
         FIColumn columnInfo -> do
           let fieldName = pgiName columnInfo
           pure $ P.fieldOptional fieldName Nothing orderByOperator
-            <&> fmap (pure . mkOrderByItemG (RQL.AOCPG $ pgiColumn columnInfo)) . join
+            <&> fmap (pure . mkOrderByItemG (RQL.AOCColumn columnInfo)) . join
         FIRelationship relationshipInfo -> do
           let remoteTable = riRTable relationshipInfo
           fieldName <- MaybeT $ pure $ G.mkName $ relNameToTxt $ riName relationshipInfo
@@ -63,13 +63,13 @@ orderByExp table selectPermissions = memoizeOn 'orderByExp table $ do
               otherTableParser <- lift $ orderByExp remoteTable perms
               pure $ do
                 otherTableOrderBy <- join <$> P.fieldOptional fieldName Nothing (P.nullable otherTableParser)
-                pure $ fmap (map $ fmap $ RQL.AOCObj relationshipInfo newPerms) otherTableOrderBy
+                pure $ fmap (map $ fmap $ RQL.AOCObjectRelation relationshipInfo newPerms) otherTableOrderBy
             ArrRel -> do
               let aggregateFieldName = fieldName <> $$(G.litName "_aggregate")
               aggregationParser <- lift $ orderByAggregation remoteTable perms
               pure $ do
                 aggregationOrderBy <- join <$> P.fieldOptional aggregateFieldName Nothing (P.nullable aggregationParser)
-                pure $ fmap (map $ fmap $ RQL.AOCAgg relationshipInfo newPerms) aggregationOrderBy
+                pure $ fmap (map $ fmap $ RQL.AOCArrayAggregation relationshipInfo newPerms) aggregationOrderBy
         FIComputedField _ -> empty
         FIRemoteRelationship _ -> empty
 
@@ -84,7 +84,7 @@ orderByAggregation
   :: forall m n r. (MonadSchema n m, MonadTableInfo r m, MonadRole r m)
   => QualifiedTable
   -> SelPermInfo
-  -> m (Parser 'Input n [OrderByItemG RQL.AnnAggOrdBy])
+  -> m (Parser 'Input n [OrderByItemG RQL.AnnAggregateOrderBy])
 orderByAggregation table selectPermissions = do
   -- WIP NOTE
   -- there is heavy duplication between this and Select.tableAggregationFields
@@ -113,16 +113,16 @@ orderByAggregation table selectPermissions = do
       description = G.Description $ "order by aggregate values of table \"" <> table <<> "\""
   pure $ P.object objectName (Just description) aggFields
   where
-    mkField :: PGColumnInfo -> InputFieldsParser n (Maybe (PGCol, OrderInfo))
+    mkField :: PGColumnInfo -> InputFieldsParser n (Maybe (PGColumnInfo, OrderInfo))
     mkField columnInfo =
       P.fieldOptional (pgiName columnInfo) (pgiDescription columnInfo) orderByOperator
-        <&> fmap (pgiColumn columnInfo,) . join
+        <&> fmap (columnInfo,) . join
 
     parseOperator
       :: G.Name
       -> G.Name
-      -> InputFieldsParser n [(PGCol, OrderInfo)]
-      -> InputFieldsParser n (Maybe [OrderByItemG RQL.AnnAggOrdBy])
+      -> InputFieldsParser n [(PGColumnInfo, OrderInfo)]
+      -> InputFieldsParser n (Maybe [OrderByItemG RQL.AnnAggregateOrderBy])
     parseOperator operator tableName columns =
       let opText     = G.unName operator
           -- FIXME: isn't G.Name a Monoid?

server/src-lib/Hasura/GraphQL/Schema/Select.hs

@@ -51,11 +51,11 @@ import           Hasura.SQL.Value
 
 
 type SelectExp       = RQL.AnnSimpleSelG UnpreparedValue
-type AggSelectExp    = RQL.AnnAggSelG UnpreparedValue
-type TableArgs       = RQL.TableArgsG UnpreparedValue
+type AggSelectExp    = RQL.AnnAggregateSelectG UnpreparedValue
+type SelectArgs       = RQL.SelectArgsG UnpreparedValue
 type TablePerms      = RQL.TablePermG UnpreparedValue
-type AnnotatedFields = RQL.AnnFldsG UnpreparedValue
-type AnnotatedField  = RQL.AnnFldG UnpreparedValue
+type AnnotatedFields = RQL.AnnFieldsG UnpreparedValue
+type AnnotatedField  = RQL.AnnFieldG UnpreparedValue
 
 
 
@@ -83,7 +83,7 @@ selectTable table fieldName description selectPermissions = do
   tableArgsParser    <- tableArgs table selectPermissions
   selectionSetParser <- tableSelectionSet table selectPermissions Nothing
   pure $ P.subselection fieldName description tableArgsParser selectionSetParser
-    <&> \(args, fields) -> RQL.AnnSelG
+    <&> \(args, fields) -> RQL.AnnSelectG
       { RQL._asnFields   = fields
       , RQL._asnFrom     = RQL.FromTable table
       , RQL._asnPerm     = tablePermissionsInfo selectPermissions
@@ -121,13 +121,13 @@ selectTableByPk table fieldName description selectPermissions = runMaybeT do
     <&> \(boolExpr, fields) ->
       let defaultPerms = tablePermissionsInfo selectPermissions
           whereExpr    = Just $ BoolAnd $ toList boolExpr
-      in RQL.AnnSelG
+      in RQL.AnnSelectG
            { RQL._asnFields   = fields
            , RQL._asnFrom     = RQL.FromTable table
            , RQL._asnPerm     = defaultPerms { RQL._tpLimit = Nothing }
              -- TODO: check whether this is necessary:        ^^^^^^^
              -- This is how it was in legacy code.
-           , RQL._asnArgs     = RQL.noTableArgs { RQL._taWhere = whereExpr }
+           , RQL._asnArgs     = RQL.noSelectArgs { RQL._saWhere = whereExpr }
            , RQL._asnStrfyNum = stringifyNum
            }
 
@@ -161,7 +161,7 @@ selectTableAggregate table fieldName description selectPermissions = runMaybeT d
         , RQL.TAFAgg <$> P.subselection_ $$(G.litName "aggregate") Nothing aggregateParser
         ]
   pure $ P.subselection fieldName description tableArgsParser aggregationParser
-    <&> \(args, fields) -> RQL.AnnSelG
+    <&> \(args, fields) -> RQL.AnnSelectG
       { RQL._asnFields   = fields
       , RQL._asnFrom     = RQL.FromTable table
       , RQL._asnPerm     = tablePermissionsInfo selectPermissions
@@ -249,7 +249,7 @@ tableSelectionSet table selectPermissions interfaceM = memoizeOn 'tableSelection
 
   let description  = G.Description . getPGDescription <$> _tciDescription tableInfo
   pure $ P.selectionSetObject tableName description fieldParsers (toList interfaceM)
-    <&> parsedSelectionsToFields RQL.FExp
+    <&> parsedSelectionsToFields RQL.AFExpression
 
 
 -- | User-defined function (AKA custom function)
@@ -268,7 +268,7 @@ selectFunction function fieldName description selectPermissions = do
   selectionSetParser <- tableSelectionSet table selectPermissions Nothing
   let argsParser = liftA2 (,) functionArgsParser tableArgsParser
   pure $ P.subselection fieldName description argsParser selectionSetParser
-    <&> \((funcArgs, tableArgs'), fields) -> RQL.AnnSelG
+    <&> \((funcArgs, tableArgs'), fields) -> RQL.AnnSelectG
       { RQL._asnFields   = fields
       , RQL._asnFrom     = RQL.FromFunction (fiName function) funcArgs Nothing
       , RQL._asnPerm     = tablePermissionsInfo selectPermissions
@@ -299,7 +299,7 @@ selectFunctionAggregate function fieldName description selectPermissions = runMa
         , RQL.TAFAgg <$> P.subselection_ $$(G.litName "aggregate") Nothing aggregateParser
         ]
   pure $ P.subselection fieldName description argsParser aggregationParser
-    <&> \((funcArgs, tableArgs'), fields) -> RQL.AnnSelG
+    <&> \((funcArgs, tableArgs'), fields) -> RQL.AnnSelectG
       { RQL._asnFields   = fields
       , RQL._asnFrom     = RQL.FromFunction (fiName function) funcArgs Nothing
       , RQL._asnPerm     = tablePermissionsInfo selectPermissions
@@ -323,7 +323,7 @@ tableArgs
   :: forall m n r. (MonadSchema n m, MonadTableInfo r m, MonadRole r m)
   => QualifiedTable
   -> SelPermInfo
-  -> m (InputFieldsParser n TableArgs)
+  -> m (InputFieldsParser n SelectArgs)
 tableArgs table selectPermissions = do
   boolExpParser <- boolExp table (Just selectPermissions)
   orderByParser <- orderByExp table selectPermissions
@@ -342,7 +342,7 @@ tableArgs table selectPermissions = do
     -- despite the schema explicitly declaring it as an int; the suspected goal
     -- of this was to allow for bigint offsets, but there's no surviving commit
     -- message or documentation that states it explicity. A visible artefact of
-    -- this is the fact that in the TableArgs we store a SQL expression for the
+    -- this is the fact that in the SelectArgs we store a SQL expression for the
     -- offet while the limit is stored as a normal int.
     --
     -- While it would be possible to write a custom parser that advertises
@@ -352,12 +352,12 @@ tableArgs table selectPermissions = do
     -- TODO: distinct_on must be validated ungainst order_by
     -- the check at Resolve/Select.hs:152 must be ported here
 
-    pure $ RQL.TableArgs
-      { RQL._taWhere    = whereF
-      , RQL._taOrderBy  = nonEmpty . concat =<< orderBy
-      , RQL._taLimit    = fromIntegral <$> limit
-      , RQL._taOffset   = txtEncoder . PGValInteger <$> offset
-      , RQL._taDistCols = nonEmpty =<< distinct
+    pure $ RQL.SelectArgs
+      { RQL._saWhere    = whereF
+      , RQL._saOrderBy  = nonEmpty . concat =<< orderBy
+      , RQL._saLimit    = fromIntegral <$> limit
+      , RQL._saOffset   = txtEncoder . PGValInteger <$> offset
+      , RQL._saDistinct = nonEmpty =<< distinct
       }
   where
     -- TH splices mess up ApplicativeDo
@@ -398,7 +398,7 @@ tableAggregationFields
   :: forall m n r. (MonadSchema n m, MonadTableInfo r m, MonadRole r m)
   => QualifiedTable
   -> SelPermInfo
-  -> m (Parser 'Output n RQL.AggFlds)
+  -> m (Parser 'Output n RQL.AggregateFields)
 tableAggregationFields table selectPermissions = do
   tableName  <- qualifiedObjectToName table
   allColumns <- tableSelectColumns table selectPermissions
@@ -447,7 +447,7 @@ tableAggregationFields table selectPermissions = do
       :: G.Name
       -> G.Name
       -> [FieldParser n RQL.PGColFld]
-      -> FieldParser n RQL.AggFld
+      -> FieldParser n RQL.AggregateField
     parseOperator operator tableName columns =
       let opText  = G.unName operator
           setName = tableName <> $$(G.litName "_") <> operator <> $$(G.litName "_fields")
@@ -455,7 +455,7 @@ tableAggregationFields table selectPermissions = do
           subselectionParser = P.selectionSet setName setDesc columns
             <&> parsedSelectionsToFields RQL.PCFExp
       in P.subselection_ operator Nothing subselectionParser
-         <&> (RQL.AFOp . RQL.AggOp opText)
+         <&> (RQL.AFOp . RQL.AggregateOp opText)
 
 lookupRemoteField'
   :: (MonadSchema n m, MonadTableInfo r m)
@@ -499,7 +499,7 @@ fieldSelection fieldInfo selectPermissions = do
           pathArg = jsonPathArg $ pgiType columnInfo
       field <- lift $ P.column (pgiType columnInfo) (G.Nullability $ pgiIsNullable columnInfo)
       pure $ P.selection fieldName (pgiDescription columnInfo) pathArg field
-        <&> RQL.mkAnnColField columnInfo
+        <&> RQL.mkAnnColumnField columnInfo
 
     FIRelationship relationshipInfo -> concat . maybeToList <$> runMaybeT do
       -- TODO: move this to a separate function?
@@ -514,10 +514,10 @@ fieldSelection fieldInfo selectPermissions = do
       relFieldName     <- lift $ textToName $ relNameToTxt relName
       otherTableParser <- lift $ selectTable otherTable relFieldName desc remotePerms
       let field = otherTableParser <&> \selectExp ->
-            let annotatedRelationship = RQL.AnnRelG relName colMapping selectExp
+            let annotatedRelationship = RQL.AnnRelationSelectG relName colMapping selectExp
             in case riType relationshipInfo of
-              ObjRel -> RQL.FObj annotatedRelationship
-              ArrRel -> RQL.FArr $ RQL.ASSimple annotatedRelationship
+              ObjRel -> RQL.AFObjectRelation annotatedRelationship
+              ArrRel -> RQL.AFArrayRelation $ RQL.ASSimple annotatedRelationship
       case riType relationshipInfo of
         ObjRel -> pure [field]
         ArrRel -> do
@@ -525,7 +525,7 @@ fieldSelection fieldInfo selectPermissions = do
               relAggDesc      = Just $ G.Description "An aggregate relationship"
           remoteAggField <- lift $ selectTableAggregate otherTable relAggFieldName relAggDesc remotePerms
           pure $ catMaybes [ Just field
-                           , fmap (RQL.FArr . RQL.ASAgg . RQL.AnnRelG relName colMapping) <$> remoteAggField
+                           , fmap (RQL.AFArrayRelation . RQL.ASAggregate . RQL.AnnRelationSelectG relName colMapping) <$> remoteAggField
                            ]
 
     FIComputedField computedFieldInfo ->
@@ -562,7 +562,7 @@ fieldSelection fieldInfo selectPermissions = do
           pure $ pure $ P.unsafeRawField (P.mkDefinition fieldName Nothing fieldInfo')
             `P.bindField` \G.Field{ G._fArguments = args, G._fSelectionSet = selSet } -> do
               remoteArgs <- P.ifParser remoteFieldsArgumentsParser args
-              pure $ RQL.FRemote $ RQL.RemoteSelect
+              pure $ RQL.AFRemote $ RQL.RemoteSelect
                 { _rselArgs          = remoteArgs
                 , _rselSelection     = selSet
                 , _rselHasuraColumns = _rfiHasuraFields remoteFieldInfo
@@ -697,7 +697,7 @@ computedFieldFunctionArgs ComputedFieldFunction{..} =
 
 
 -- FIXME: move to common?
-jsonPathArg :: MonadParse n => PGColumnType -> InputFieldsParser n (Maybe RQL.ColOp)
+jsonPathArg :: MonadParse n => PGColumnType -> InputFieldsParser n (Maybe RQL.ColumnOp)
 jsonPathArg columnType
   | isScalarColumnWhere isJSONType columnType =
       P.fieldOptional fieldName description P.string `P.bindFields` traverse toColExp
@@ -707,7 +707,7 @@ jsonPathArg columnType
     description = Just "JSON select path"
     toColExp textValue = case parseJSONPath textValue of
       Left err     -> parseError $ T.pack $ "parse json path error: " ++ err
-      Right jPaths -> return $ RQL.ColOp SQL.jsonbPathOp $ SQL.SEArray $ map elToColExp jPaths
+      Right jPaths -> return $ RQL.ColumnOp SQL.jsonbPathOp $ SQL.SEArray $ map elToColExp jPaths
     elToColExp (Key k)   = SQL.SELit k
     elToColExp (Index i) = SQL.SELit $ T.pack (show i)
 
@@ -726,7 +726,7 @@ computedField ComputedFieldInfo{..} selectPermissions = runMaybeT do
       let fieldArgsParser = do
             args  <- functionArgsParser
             colOp <- jsonPathArg $ PGColumnScalar scalarReturnType
-            pure $ RQL.FComputedField $ RQL.CFSScalar $ RQL.ComputedFieldScalarSel
+            pure $ RQL.AFComputedField $ RQL.CFSScalar $ RQL.ComputedFieldScalarSelect
               { RQL._cfssFunction  = _cffName _cfiFunction
               , RQL._cfssType      = scalarReturnType
               , RQL._cfssColumnOp  = colOp
@@ -741,7 +741,7 @@ computedField ComputedFieldInfo{..} selectPermissions = runMaybeT do
       let fieldArgsParser = liftA2 (,) functionArgsParser selectArgsParser
       pure $ P.subselection fieldName Nothing fieldArgsParser selectionSetParser <&>
         \((functionArgs', args), fields) ->
-          RQL.FComputedField $ RQL.CFSTable RQL.JASMultipleRows $ RQL.AnnSelG
+          RQL.AFComputedField $ RQL.CFSTable RQL.JASMultipleRows $ RQL.AnnSelectG
             { RQL._asnFields   = fields
             , RQL._asnFrom     = RQL.FromFunction (_cffName _cfiFunction) functionArgs' Nothing
             , RQL._asnPerm     = tablePermissionsInfo remotePerms
@@ -891,16 +891,16 @@ nodeField allTables = do
       (perms, pkeyColumns, fields) <-
         onNothing (Map.lookup table parseds) $ throwInvalidNodeId $ "the table " <>> ident
       whereExp <- buildNodeIdBoolExp columnValues pkeyColumns
-      return $ RQL.AnnSelG
+      return $ RQL.AnnSelectG
         { RQL._asnFields   = fields
         , RQL._asnFrom     = RQL.FromTable table
         , RQL._asnPerm     = tablePermissionsInfo perms
-        , RQL._asnArgs     = RQL.TableArgs
-          { RQL._taWhere    = Just whereExp
-          , RQL._taOrderBy  = Nothing
-          , RQL._taLimit    = Nothing
-          , RQL._taOffset   = Nothing
-          , RQL._taDistCols = Nothing
+        , RQL._asnArgs     = RQL.SelectArgs
+          { RQL._saWhere    = Just whereExp
+          , RQL._saOrderBy  = Nothing
+          , RQL._saLimit    = Nothing
+          , RQL._saOffset   = Nothing
+          , RQL._saDistinct = Nothing
           }
         , RQL._asnStrfyNum = stringifyNum
         }

server/src-lib/Hasura/GraphQL/Transport/HTTP.hs

@@ -44,7 +44,7 @@ runGQ reqId userInfo reqHdrs queryType req = do
   (telemTimeTot_DT, (telemCacheHit, telemLocality, (telemTimeIO_DT, telemQueryType, !resp))) <- withElapsedTime $ do
     E.ExecutionCtx _ sqlGenCtx pgExecCtx planCache sc scVer httpManager enableAL <- ask
     (telemCacheHit, execPlan) <- E.getResolvedExecPlan pgExecCtx planCache
-                userInfo sqlGenCtx enableAL sc scVer queryType httpManager reqHdrs req
+                                 userInfo sqlGenCtx enableAL sc scVer queryType httpManager reqHdrs req
     case execPlan of
       E.QueryExecutionPlan queryPlan -> do
         case queryPlan of
@@ -76,8 +76,8 @@ runGQ reqId userInfo reqHdrs queryType req = do
         return (telemCacheHit, Telem.Local, (telemTimeIO, telemQueryType, HttpResponse resp respHdrs))
       E.GExPRemote rsi opDef  -> do
         let telemQueryType | G._todType opDef == G.OperationTypeMutation = Telem.Mutation
-                            | otherwise = Telem.Query
-        (telemTimeIO, resp) <- E.execRemoteGQ reqId userInfo reqHdrs req rsi opDef
+                           | otherwise = Telem.Query
+        (telemTimeIO, resp) <- E.execRemoteGQ reqId userInfo reqHdrs req rsi $ G._todType opDef
         return (telemCacheHit, Telem.Remote, (telemTimeIO, telemQueryType, resp))
 -}
   let telemTimeIO = fromUnits telemTimeIO_DT

server/src-lib/Hasura/GraphQL/Validate.hs

@@ -1,8 +1,8 @@
 module Hasura.GraphQL.Validate
   ( validateGQ
   , showVars
-  , RootSelSet(..)
-  , SelSet
+  , RootSelectionSet(..)
+  , SelectionSet(..)
   , Field(..)
   , getTypedOp
   , QueryParts(..)
@@ -13,6 +13,9 @@ module Hasura.GraphQL.Validate
   , validateVariablesForReuse
 
   , isQueryInAllowlist
+  , unValidateArgsMap
+  , unValidateSelectionSet
+  , unValidateField
   ) where
 
 import           Hasura.Prelude
@@ -22,16 +25,24 @@ import           Data.Has
 import qualified Data.HashMap.Strict                    as Map
 import qualified Data.HashSet                           as HS
 import qualified Data.Sequence                          as Seq
+import qualified Data.Text                              as T
+import qualified Data.UUID                              as UUID
+import qualified Database.PG.Query                      as Q
 import qualified Language.GraphQL.Draft.Syntax          as G
 
+import           Hasura.GraphQL.NormalForm
+import           Hasura.GraphQL.Resolve.InputValue      (annInpValueToJson)
 import           Hasura.GraphQL.Schema
 import           Hasura.GraphQL.Transport.HTTP.Protocol
 import           Hasura.GraphQL.Validate.Context
-import           Hasura.GraphQL.Validate.Field
 import           Hasura.GraphQL.Validate.InputValue
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
+import           Hasura.RQL.DML.Select.Types
 import           Hasura.RQL.Types
 import           Hasura.RQL.Types.QueryCollection
+import           Hasura.SQL.Time
+import           Hasura.SQL.Value
 
 data QueryParts
   = QueryParts
@@ -137,19 +148,12 @@ validateFrag
 validateFrag (G.FragmentDefinition n onTy dirs selSet) = do
   unless (null dirs) $ throwVE
     "unexpected directives at fragment definition"
-  tyInfo <- getTyInfoVE onTy
-  objTyInfo <- onNothing (getObjTyM tyInfo) $ throwVE
-    "fragments can only be defined on object types"
-  return $ FragDef n objTyInfo selSet
-
-data RootSelSet
-  = RQuery !SelSet
-  | RMutation !SelSet
-  | RSubscription !Field
-  deriving (Show, Eq)
+  fragmentTypeInfo <- getFragmentTyInfo onTy
+  return $ FragDef n fragmentTypeInfo selSet
 
 validateGQ
-  :: (MonadError QErr m, MonadReader GCtx m, MonadReusability m) => QueryParts -> m RootSelSet
+  :: (MonadError QErr m, MonadReader GCtx m, MonadReusability m)
+  => QueryParts -> m RootSelectionSet
 validateGQ (QueryParts opDef opRoot fragDefsL varValsM) = do
   ctx <- ask
 
@@ -165,19 +169,22 @@ validateGQ (QueryParts opDef opRoot fragDefsL varValsM) = do
   -- build a validation ctx
   let valCtx = ValidationCtx (_gTypes ctx) annVarVals annFragDefs
 
-  selSet <- flip runReaderT valCtx $ denormSelSet [] opRoot $
+  selSet <- flip runReaderT valCtx $ parseObjectSelectionSet valCtx opRoot $
             G._todSelectionSet opDef
 
   case G._todType opDef of
     G.OperationTypeQuery -> return $ RQuery selSet
     G.OperationTypeMutation -> return $ RMutation selSet
     G.OperationTypeSubscription ->
-      case Seq.viewl selSet of
-        Seq.EmptyL     -> throw500 "empty selset for subscription"
-        fld Seq.:< rst -> do
-          unless (null rst) $
-            throwVE "subscription must select only one top level field"
-          return $ RSubscription fld
+      case OMap.toList $ unAliasedFields $ unObjectSelectionSet selSet of
+        []             -> throw500 "empty selset for subscription"
+        (_:rst) -> do
+          -- As an internal testing feature, we support subscribing to multiple
+          -- selection sets.  First check if the corresponding directive is set.
+          let multipleAllowed = G.Directive "_multiple_top_level_fields" [] `elem` G._todDirectives opDef
+          unless (multipleAllowed || null rst) $
+            throwVE "subscriptions must select one top level field"
+          return $ RSubscription selSet
 
 isQueryInAllowlist :: GQLExecDoc -> HS.HashSet GQLQuery -> Bool
 isQueryInAllowlist q = HS.member gqlQuery
@@ -204,3 +211,119 @@ getQueryParts (GQLReq opNameM q varValsM) = do
   return $ QueryParts opDef opRoot fragDefsL varValsM
   where
     (selSets, opDefs, fragDefsL) = G.partitionExDefs $ unGQLExecDoc q
+
+-- | Convert the validated arguments to GraphQL parser AST arguments
+unValidateArgsMap :: ArgsMap -> [RemoteFieldArgument]
+unValidateArgsMap argsMap =
+  map (\(n, inpVal) ->
+         let _rfaArgument = G.Argument n $ unValidateInpVal inpVal
+             _rfaVariable = unValidateInpVariable inpVal
+         in RemoteFieldArgument {..})
+  . Map.toList $ argsMap
+
+-- | Convert the validated field to GraphQL parser AST field
+unValidateField :: G.Alias -> Field -> G.Field
+unValidateField alias (Field name _ argsMap selSet) =
+  let args = map (\(n, inpVal) -> G.Argument n $ unValidateInpVal inpVal) $
+             Map.toList argsMap
+  in G.Field (Just alias) name args [] $ unValidateSelectionSet selSet
+
+-- | Convert the validated selection set to GraphQL parser AST selection set
+unValidateSelectionSet :: SelectionSet -> G.SelectionSet
+unValidateSelectionSet = \case
+  SelectionSetObject selectionSet -> fromSelectionSet selectionSet
+  SelectionSetInterface selectionSet -> fromScopedSelectionSet selectionSet
+  SelectionSetUnion selectionSet -> fromScopedSelectionSet selectionSet
+  SelectionSetNone -> mempty
+  where
+    fromAliasedFields :: (IsField f) => AliasedFields f -> G.SelectionSet
+    fromAliasedFields =
+      map (G.SelectionField . uncurry unValidateField) .
+      OMap.toList . fmap toField . unAliasedFields
+    fromSelectionSet =
+      fromAliasedFields . unObjectSelectionSet
+    toInlineSelection typeName =
+      G.SelectionInlineFragment . G.InlineFragment (Just typeName) mempty .
+      fromSelectionSet
+    fromScopedSelectionSet (ScopedSelectionSet base specific) =
+      map (uncurry toInlineSelection) (Map.toList specific) <> fromAliasedFields base
+
+-- | Get the variable definition and it's value (if exists)
+unValidateInpVariable :: AnnInpVal -> Maybe [(G.VariableDefinition,A.Value)]
+unValidateInpVariable inputValue =
+  case (_aivValue inputValue) of
+    AGScalar _ _ -> mkVariableDefnValueTuple inputValue
+    AGEnum _ _ -> mkVariableDefnValueTuple inputValue
+    AGObject _ o ->
+      (\obj ->
+         let listObjects = OMap.toList obj
+         in concat $
+         mapMaybe (\(_, inpVal) -> unValidateInpVariable inpVal) listObjects)
+      <$> o
+    AGArray _ _ -> mkVariableDefnValueTuple inputValue
+   where
+     mkVariableDefnValueTuple val = maybe Nothing (\vars -> Just [vars]) $
+                                     variableDefnValueTuple val
+
+     variableDefnValueTuple :: AnnInpVal -> Maybe (G.VariableDefinition,A.Value)
+     variableDefnValueTuple inpVal@AnnInpVal {..} =
+      let varDefn = G.VariableDefinition <$> _aivVariable <*> Just _aivType <*> Just Nothing
+      in (,) <$> varDefn <*> Just (annInpValueToJson inpVal)
+
+-- | Convert the validated input value to GraphQL value, if the input value
+-- is a variable then it will be returned without resolving it, otherwise it
+-- will be resolved
+unValidateInpVal :: AnnInpVal -> G.Value
+unValidateInpVal (AnnInpVal _ var val) = fromMaybe G.VNull $
+  -- if a variable is found, then directly return that, if not found then
+  -- convert it into a G.Value and return it
+  case var of
+    Just var' -> Just $ G.VVariable var'
+    Nothing ->
+      case val of
+        AGScalar _ v -> pgScalarToGValue <$> v
+        AGEnum _ v -> pgEnumToGEnum v
+        AGObject _ o ->
+          (G.VObject . G.ObjectValueG
+          . map (uncurry G.ObjectFieldG . (second unValidateInpVal))
+          . OMap.toList
+          ) <$> o
+        AGArray _ vs -> (G.VList . G.ListValueG . map unValidateInpVal) <$> vs
+
+  where
+    pgEnumToGEnum :: AnnGEnumValue -> Maybe G.Value
+    pgEnumToGEnum = \case
+      AGESynthetic v -> G.VEnum <$> v
+      AGEReference _ v -> (G.VEnum . G.EnumValue . G.Name . getEnumValue) <$> v
+
+    pgScalarToGValue :: PGScalarValue -> G.Value
+    pgScalarToGValue = \case
+      PGValInteger i  -> G.VInt $ fromIntegral i
+      PGValSmallInt i -> G.VInt $ fromIntegral i
+      PGValBigInt i   -> G.VInt $ fromIntegral i
+      PGValFloat f    -> G.VFloat $ realToFrac f
+      PGValDouble d   -> G.VFloat $ realToFrac d
+      -- TODO: Scientific is a danger zone; use its safe conv function.
+      PGValNumeric sc -> G.VFloat $ realToFrac sc
+      PGValMoney m    -> G.VFloat $ realToFrac m
+      PGValBoolean b  -> G.VBoolean b
+      PGValChar t     -> toStringValue $ T.singleton t
+      PGValVarchar t  -> toStringValue t
+      PGValText t     -> toStringValue t
+      PGValCitext t   -> toStringValue t
+      PGValDate d     -> toStringValue $ T.pack $ showGregorian d
+      PGValTimeStampTZ u -> toStringValue $ T.pack $
+                            formatTime defaultTimeLocale "%FT%T%QZ" u
+      PGValTimeStamp u   -> toStringValue $ T.pack $
+                            formatTime defaultTimeLocale "%FT%T%QZ" u
+      PGValTimeTZ (ZonedTimeOfDay tod tz) ->
+        toStringValue $ T.pack (show tod ++ timeZoneOffsetString tz)
+      PGNull _ -> G.VNull
+      PGValJSON (Q.JSON v)  -> jsonValueToGValue v
+      PGValJSONB (Q.JSONB v)  -> jsonValueToGValue v
+      PGValGeo v    -> jsonValueToGValue $ A.toJSON v
+      PGValRaster v -> jsonValueToGValue $ A.toJSON v
+      PGValUUID u    -> toStringValue $ UUID.toText u
+      PGValUnknown t ->  toStringValue t
+      where
+        toStringValue = G.VString . G.StringValue

server/src-lib/Hasura/GraphQL/Validate/Context.hs

@@ -4,6 +4,7 @@ module Hasura.GraphQL.Validate.Context
   , getInpFieldInfo
   , getTyInfo
   , getTyInfoVE
+  , getFragmentTyInfo
   , module Hasura.GraphQL.Utils
   ) where
 
@@ -19,11 +20,11 @@ import           Hasura.RQL.Types
 
 getFieldInfo
   :: ( MonadError QErr m)
-  => ObjTyInfo -> G.Name -> m ObjFldInfo
-getFieldInfo oti fldName =
-  onNothing (Map.lookup fldName $ _otiFields oti) $ throwVE $
+  => G.NamedType -> ObjFieldMap -> G.Name -> m ObjFldInfo
+getFieldInfo typeName fieldMap fldName =
+  onNothing (Map.lookup fldName fieldMap) $ throwVE $
   "field " <> showName fldName <>
-  " not found in type: " <> showNamedTy (_otiName oti)
+  " not found in type: " <> showNamedTy typeName
 
 getInpFieldInfo
   :: ( MonadError QErr m)
@@ -65,3 +66,13 @@ getTyInfoVE namedTy = do
   tyMap <- asks getter
   onNothing (Map.lookup namedTy tyMap) $
     throwVE $ "no such type exists in the schema: " <> showNamedTy namedTy
+
+getFragmentTyInfo
+  :: (MonadReader r m, Has TypeMap r, MonadError QErr m)
+  => G.NamedType -> m FragmentTypeInfo
+getFragmentTyInfo onType =
+  getTyInfoVE onType >>= \case
+    TIObj tyInfo -> pure $ FragmentTyObject tyInfo
+    TIIFace tyInfo -> pure $ FragmentTyInterface tyInfo
+    TIUnion tyInfo -> pure $ FragmentTyUnion tyInfo
+    _ -> throwVE "fragments can only be defined on object/interface/union types"

server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs

@@ -0,0 +1,550 @@
+{-# LANGUAGE RecordWildCards        #-}
+{-# LANGUAGE TypeFamilyDependencies #-}
+module Hasura.GraphQL.Validate.SelectionSet
+  ( ArgsMap
+  , Field(..)
+  , AliasedFields(..)
+  , SelectionSet(..)
+  , ObjectSelectionSet(..)
+  , traverseObjectSelectionSet
+  , InterfaceSelectionSet
+  , UnionSelectionSet
+  , RootSelectionSet(..)
+  , parseObjectSelectionSet
+  , asObjectSelectionSet
+  , asInterfaceSelectionSet
+  , getMemberSelectionSet
+  ) where
+
+import           Hasura.Prelude
+
+import qualified Data.HashMap.Strict                 as Map
+import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
+import qualified Data.HashSet                        as Set
+import qualified Data.List                           as L
+import qualified Data.Sequence.NonEmpty              as NE
+import qualified Data.Text                           as T
+import qualified Language.GraphQL.Draft.Syntax       as G
+
+import           Hasura.GraphQL.NormalForm
+import           Hasura.GraphQL.Validate.Context
+import           Hasura.GraphQL.Validate.InputValue
+import           Hasura.GraphQL.Validate.Types
+import           Hasura.RQL.Types
+import           Hasura.SQL.Value
+
+class HasSelectionSet a where
+
+  getTypename :: a -> G.NamedType
+  getMemberTypes :: a -> Set.HashSet G.NamedType
+
+  fieldToSelectionSet
+    :: G.Alias -> NormalizedField a -> NormalizedSelectionSet a
+
+  parseField_
+    :: ( MonadReader ValidationCtx m
+       , MonadError QErr m
+       , MonadReusability m
+       , MonadState [G.Name] m
+       )
+    => a
+    -> G.Field
+    -> m (Maybe (NormalizedField a))
+
+  mergeNormalizedSelectionSets
+    :: ( MonadReader ValidationCtx m
+       , MonadError QErr m
+       , MonadReusability m
+       )
+    => [NormalizedSelectionSet a]
+    -> m (NormalizedSelectionSet a)
+
+  fromObjectSelectionSet
+    :: G.NamedType
+    -- ^ parent typename
+    -> G.NamedType
+    -- ^ fragment typename
+    -> Set.HashSet G.NamedType
+    -- ^ common types
+    -> NormalizedSelectionSet ObjTyInfo
+    -> NormalizedSelectionSet a
+
+  fromInterfaceSelectionSet
+    :: G.NamedType
+    -- ^ parent typename
+    -> G.NamedType
+    -- ^ fragment typename
+    -> Set.HashSet G.NamedType
+    -> NormalizedSelectionSet IFaceTyInfo
+    -> NormalizedSelectionSet a
+
+  fromUnionSelectionSet
+    :: G.NamedType
+    -- ^ parent typename
+    -> G.NamedType
+    -- ^ fragment typename
+    -> Set.HashSet G.NamedType
+    -- ^ common types
+    -> NormalizedSelectionSet UnionTyInfo
+    -> NormalizedSelectionSet a
+
+parseObjectSelectionSet
+  :: ( MonadError QErr m
+     , MonadReusability m
+     )
+  => ValidationCtx
+  -> ObjTyInfo
+  -> G.SelectionSet
+  -> m ObjectSelectionSet
+parseObjectSelectionSet validationCtx objectTypeInfo selectionSet =
+  flip evalStateT [] $ flip runReaderT validationCtx $
+    parseSelectionSet objectTypeInfo selectionSet
+
+selectionToSelectionSet
+  :: HasSelectionSet a
+  => NormalizedSelection a -> NormalizedSelectionSet a
+selectionToSelectionSet = \case
+  SelectionField alias fld -> fieldToSelectionSet alias fld
+  SelectionInlineFragmentSpread selectionSet -> selectionSet
+  SelectionFragmentSpread _ selectionSet -> selectionSet
+
+parseSelectionSet
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , HasSelectionSet a
+     , MonadState [G.Name] m
+     )
+  => a
+  -> G.SelectionSet
+  -> m (NormalizedSelectionSet a)
+parseSelectionSet fieldTypeInfo selectionSet = do
+  visitedFragments <- get
+  withPathK "selectionSet" $ do
+    -- The visited fragments state shouldn't accumulate over a selection set.
+    normalizedSelections <-
+      catMaybes <$> mapM (parseSelection visitedFragments fieldTypeInfo) selectionSet
+    mergeNormalizedSelections normalizedSelections
+  where
+    mergeNormalizedSelections = mergeNormalizedSelectionSets . map selectionToSelectionSet
+
+-- | While interfaces and objects have fields, unions do not, so
+-- this is a specialized function for every Object type
+parseSelection
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , HasSelectionSet a
+     )
+  => [G.Name]
+  -> a -- parent type info
+  -> G.Selection
+  -> m (Maybe (NormalizedSelection a))
+parseSelection visitedFragments parentTypeInfo =
+  flip evalStateT visitedFragments . \case
+    G.SelectionField fld -> withPathK (G.unName $ G._fName fld) $ do
+      let fieldName = G._fName fld
+          fieldAlias = fromMaybe (G.Alias fieldName) $ G._fAlias fld
+      fmap (SelectionField fieldAlias) <$> parseField_ parentTypeInfo fld
+    G.SelectionFragmentSpread (G.FragmentSpread name directives) -> do
+      FragDef _ fragmentTyInfo fragmentSelectionSet <- getFragmentInfo name
+      withPathK (G.unName name) $
+        fmap (SelectionFragmentSpread name) <$>
+        parseFragment parentTypeInfo fragmentTyInfo directives fragmentSelectionSet
+    G.SelectionInlineFragment G.InlineFragment{..} -> do
+      let fragmentType = fromMaybe (getTypename parentTypeInfo) _ifTypeCondition
+      fragmentTyInfo <- getFragmentTyInfo fragmentType
+      withPathK "inlineFragment" $ fmap SelectionInlineFragmentSpread <$>
+        parseFragment parentTypeInfo fragmentTyInfo _ifDirectives _ifSelectionSet
+
+parseFragment
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , MonadState [G.Name] m
+     , HasSelectionSet a
+     )
+  => a
+  -> FragmentTypeInfo
+  -> [G.Directive]
+  -> G.SelectionSet
+  -> m (Maybe (NormalizedSelectionSet a))
+parseFragment parentTyInfo fragmentTyInfo directives fragmentSelectionSet = do
+  commonTypes <- validateSpread
+  case fragmentTyInfo of
+    FragmentTyObject objTyInfo ->
+      withDirectives directives $
+      fmap (fromObjectSelectionSet parentType fragmentType commonTypes) $
+      parseSelectionSet objTyInfo fragmentSelectionSet
+    FragmentTyInterface interfaceTyInfo ->
+      withDirectives directives $
+      fmap (fromInterfaceSelectionSet parentType fragmentType commonTypes) $
+      parseSelectionSet interfaceTyInfo fragmentSelectionSet
+    FragmentTyUnion unionTyInfo ->
+      withDirectives directives $
+      fmap (fromUnionSelectionSet parentType fragmentType commonTypes) $
+      parseSelectionSet unionTyInfo fragmentSelectionSet
+  where
+    validateSpread = do
+      let commonTypes = parentTypeMembers `Set.intersection` fragmentTypeMembers
+      if null commonTypes then
+          -- TODO: better error location by capturing the fragment source -
+          -- named or otherwise
+          -- throwVE $ "cannot spread fragment " <> showName name <> " defined on " <>
+          throwVE $ "cannot spread fragment  defined on " <> showNamedTy fragmentType
+          <> " when selecting fields of type " <> showNamedTy parentType
+         else pure commonTypes
+
+    parentType = getTypename parentTyInfo
+    parentTypeMembers = getMemberTypes parentTyInfo
+
+    fragmentType = case fragmentTyInfo of
+      FragmentTyObject tyInfo    -> getTypename tyInfo
+      FragmentTyInterface tyInfo -> getTypename tyInfo
+      FragmentTyUnion tyInfo     -> getTypename tyInfo
+    fragmentTypeMembers = case fragmentTyInfo of
+      FragmentTyObject tyInfo    -> getMemberTypes tyInfo
+      FragmentTyInterface tyInfo -> getMemberTypes tyInfo
+      FragmentTyUnion tyInfo     -> getMemberTypes tyInfo
+
+class IsField f => MergeableField f where
+
+  checkFieldMergeability
+    :: (MonadError QErr m) => G.Alias -> NE.NESeq f -> m f
+
+instance MergeableField Field where
+
+  checkFieldMergeability alias fields = do
+    let groupedFlds = toList $ NE.toSeq fields
+        fldNames = L.nub $ map getFieldName groupedFlds
+        args = L.nub $ map getFieldArguments groupedFlds
+    when (length fldNames > 1) $
+      throwVE $ "cannot merge different fields under the same alias ("
+      <> showName (G.unAlias alias) <> "): "
+      <> showNames fldNames
+    when (length args > 1) $
+      throwVE $ "cannot merge fields with different arguments"
+      <> " under the same alias: "
+      <> showName (G.unAlias alias)
+    let fld = NE.head fields
+    mergedGroupSelectionSet <- mergeSelectionSets $ fmap _fSelSet fields
+    return $ fld { _fSelSet = mergedGroupSelectionSet }
+
+instance MergeableField Typename where
+
+  checkFieldMergeability _ fields = pure $ NE.head fields
+
+parseArguments
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     )
+  => ParamMap
+  -> [G.Argument]
+  -> m ArgsMap
+parseArguments fldParams argsL = do
+
+  args <- onLeft (mkMapWith G._aName argsL) $ \dups ->
+    throwVE $ "the following arguments are defined more than once: " <>
+    showNames dups
+
+  let requiredParams = Map.filter (G.isNotNull . _iviType) fldParams
+
+  inpArgs <- forM args $ \(G.Argument argName argVal) ->
+    withPathK (G.unName argName) $ do
+      argTy <- getArgTy argName
+      validateInputValue valueParser argTy argVal
+
+  forM_ requiredParams $ \argDef -> do
+    let param = _iviName argDef
+    onNothing (Map.lookup param inpArgs) $ throwVE $ mconcat
+      [ "the required argument ", showName param, " is missing"]
+
+  return inpArgs
+
+  where
+    getArgTy argName =
+      onNothing (_iviType <$> Map.lookup argName fldParams) $ throwVE $
+      "no such argument " <> showName argName <> " is expected"
+
+mergeFields
+  :: ( MonadError QErr m
+     , MergeableField f
+     )
+  -- => Seq.Seq Field
+  => [AliasedFields f]
+  -> m (AliasedFields f)
+mergeFields flds =
+  AliasedFields <$> OMap.traverseWithKey checkFieldMergeability groups
+  where
+    groups = foldr (OMap.unionWith (<>)) mempty $
+             map (fmap NE.init . unAliasedFields) flds
+
+appendSelectionSets
+  :: (MonadError QErr m) => SelectionSet -> SelectionSet -> m SelectionSet
+appendSelectionSets = curry \case
+  (SelectionSetObject s1, SelectionSetObject s2) ->
+    SelectionSetObject <$> mergeObjectSelectionSets [s1, s2]
+  (SelectionSetInterface s1, SelectionSetInterface s2) ->
+    SelectionSetInterface <$> appendScopedSelectionSet s1 s2
+  (SelectionSetUnion s1, SelectionSetUnion s2) ->
+    SelectionSetUnion <$> appendScopedSelectionSet s1 s2
+  (SelectionSetNone, SelectionSetNone) -> pure SelectionSetNone
+  (_, _) -> throw500 $ "mergeSelectionSets: 'same kind' assertion failed"
+
+
+-- query q {
+--    author {
+--      id
+--    }
+--    author {
+--      name
+--    }
+-- }
+--
+-- | When we are merging two selection sets down two different trees they
+-- should be of the same type, however, as it is not enforced in the type
+-- system, an internal error is thrown when this assumption is violated
+mergeSelectionSets
+  :: (MonadError QErr m) => NE.NESeq SelectionSet -> m SelectionSet
+-- mergeSelectionSets = curry $ \case
+mergeSelectionSets selectionSets =
+  foldM appendSelectionSets (NE.head selectionSets) $ NE.tail selectionSets
+
+mergeObjectSelectionSets
+  :: (MonadError QErr m) => [ObjectSelectionSet] -> m ObjectSelectionSet
+mergeObjectSelectionSets =
+  fmap ObjectSelectionSet . mergeFields . map unObjectSelectionSet
+
+mergeObjectSelectionSetMaps
+  :: (MonadError QErr m) => [ObjectSelectionSetMap] -> m ObjectSelectionSetMap
+mergeObjectSelectionSetMaps selectionSetMaps =
+  traverse mergeObjectSelectionSets $
+    foldr (Map.unionWith (<>)) mempty $ map (fmap (:[])) selectionSetMaps
+
+appendScopedSelectionSet
+  :: (MonadError QErr m, MergeableField f)
+  => ScopedSelectionSet f -> ScopedSelectionSet f -> m (ScopedSelectionSet f)
+appendScopedSelectionSet s1 s2 =
+  ScopedSelectionSet
+  <$> mergeFields [_sssBaseSelectionSet s1, _sssBaseSelectionSet s2]
+  <*> mergeObjectSelectionSetMaps [s1MembersUnified, s2MembersUnified]
+
+  where
+    s1Base = fmap toField $ _sssBaseSelectionSet s1
+    s2Base = fmap toField $ _sssBaseSelectionSet s2
+
+    s1MembersUnified =
+      (_sssMemberSelectionSets s1)
+      <> fmap (const (ObjectSelectionSet s1Base)) (_sssMemberSelectionSets s2)
+
+    s2MembersUnified =
+      (_sssMemberSelectionSets s2)
+      <> fmap (const (ObjectSelectionSet s2Base)) (_sssMemberSelectionSets s1)
+
+mergeScopedSelectionSets
+  :: (MonadError QErr m, MergeableField f)
+  => [ScopedSelectionSet f] -> m (ScopedSelectionSet f)
+mergeScopedSelectionSets selectionSets =
+  foldM appendScopedSelectionSet emptyScopedSelectionSet selectionSets
+
+withDirectives
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     )
+  => [G.Directive]
+  -> m a
+  -> m (Maybe a)
+withDirectives dirs act = do
+  procDirs <- withPathK "directives" $ do
+    dirDefs <- onLeft (mkMapWith G._dName dirs) $ \dups ->
+      throwVE $ "the following directives are used more than once: " <>
+      showNames dups
+
+    flip Map.traverseWithKey dirDefs $ \name dir ->
+      withPathK (G.unName name) $ do
+        dirInfo <- onNothing (Map.lookup (G._dName dir) defDirectivesMap) $
+                   throwVE $ "unexpected directive: " <> showName name
+        procArgs <- withPathK "args" $ parseArguments (_diParams dirInfo)
+                    (G._dArguments dir)
+        getIfArg procArgs
+
+  let shouldSkip    = fromMaybe False $ Map.lookup "skip" procDirs
+      shouldInclude = fromMaybe True $ Map.lookup "include" procDirs
+
+  if not shouldSkip && shouldInclude
+    then Just <$> act
+    else return Nothing
+
+  where
+    getIfArg m = do
+      val <- onNothing (Map.lookup "if" m) $ throw500
+              "missing if argument in the directive"
+      when (isJust $ _aivVariable val) markNotReusable
+      case _aivValue val of
+        AGScalar _ (Just (PGValBoolean v)) -> return v
+        _ -> throw500 "did not find boolean scalar for if argument"
+
+getFragmentInfo
+  :: (MonadReader ValidationCtx m, MonadError QErr m, MonadState [G.Name] m)
+  => G.Name
+  -- ^ fragment name
+  -> m FragDef
+getFragmentInfo name = do
+  -- check for cycles
+  visitedFragments <- get
+  if name `elem` visitedFragments
+    then throwVE $ "cannot spread fragment " <> showName name
+         <> " within itself via "
+         <> T.intercalate "," (map G.unName visitedFragments)
+    else put $ name:visitedFragments
+  fragInfo <- Map.lookup name <$> asks _vcFragDefMap
+  onNothing fragInfo $ throwVE $ "fragment '" <> G.unName name <> "' not found"
+
+denormalizeField
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , MonadState [G.Name] m
+     )
+  => ObjFldInfo
+  -> G.Field
+  -> m (Maybe Field)
+denormalizeField fldInfo (G.Field _ name args dirs selSet) = do
+
+  let fldTy = _fiTy fldInfo
+      fldBaseTy = getBaseTy fldTy
+
+  fldTyInfo <- getTyInfo fldBaseTy
+
+  argMap <- withPathK "args" $ parseArguments (_fiParams fldInfo) args
+
+  fields <- case (fldTyInfo, selSet) of
+
+    (TIObj _, [])  ->
+      throwVE $ "field " <> showName name <> " of type "
+      <> G.showGT fldTy <> " must have a selection of subfields"
+
+    (TIObj objTyInfo, _) ->
+      SelectionSetObject <$> parseSelectionSet objTyInfo selSet
+
+    (TIIFace _, [])  ->
+      throwVE $ "field " <> showName name <> " of type "
+      <> G.showGT fldTy <> " must have a selection of subfields"
+
+    (TIIFace interfaceTyInfo, _) ->
+      SelectionSetInterface <$> parseSelectionSet interfaceTyInfo selSet
+
+    (TIUnion _, [])  ->
+      throwVE $ "field " <> showName name <> " of type "
+      <> G.showGT fldTy <> " must have a selection of subfields"
+
+    (TIUnion unionTyInfo, _) ->
+      SelectionSetUnion <$> parseSelectionSet unionTyInfo selSet
+
+    (TIScalar _, []) -> return SelectionSetNone
+    -- when scalar/enum and no empty set
+    (TIScalar _, _) ->
+      throwVE $ "field " <> showName name <> " must not have a "
+      <> "selection since type " <> G.showGT fldTy <> " has no subfields"
+
+    (TIEnum _, []) -> return SelectionSetNone
+    (TIEnum _, _) ->
+      throwVE $ "field " <> showName name <> " must not have a "
+      <> "selection since type " <> G.showGT fldTy <> " has no subfields"
+
+    (TIInpObj _, _) ->
+      throwVE $ "internal error: unexpected input type for field: "
+      <> showName name
+
+  withDirectives dirs $ pure $ Field  name fldBaseTy argMap fields
+
+type instance NormalizedSelectionSet ObjTyInfo = ObjectSelectionSet
+type instance NormalizedField ObjTyInfo = Field
+
+instance HasSelectionSet ObjTyInfo where
+
+  getTypename = _otiName
+  getMemberTypes = Set.singleton . _otiName
+
+  parseField_ objTyInfo field = do
+    fieldInfo <- getFieldInfo (_otiName objTyInfo) (_otiFields objTyInfo) $ G._fName field
+    denormalizeField fieldInfo field
+
+  fieldToSelectionSet alias fld =
+    ObjectSelectionSet $ AliasedFields $ OMap.singleton alias fld
+
+  mergeNormalizedSelectionSets = mergeObjectSelectionSets
+
+  fromObjectSelectionSet _ _ _ objectSelectionSet =
+    objectSelectionSet
+
+  fromInterfaceSelectionSet parentType _ _ interfaceSelectionSet =
+      getMemberSelectionSet parentType interfaceSelectionSet
+
+  fromUnionSelectionSet parentType _ _ unionSelectionSet =
+      getMemberSelectionSet parentType unionSelectionSet
+
+type instance NormalizedSelectionSet IFaceTyInfo = InterfaceSelectionSet
+type instance NormalizedField IFaceTyInfo = Field
+
+instance HasSelectionSet IFaceTyInfo where
+
+  getTypename = _ifName
+  getMemberTypes = _ifMemberTypes
+
+  parseField_ interfaceTyInfo field = do
+    fieldInfo <- getFieldInfo (_ifName interfaceTyInfo) (_ifFields interfaceTyInfo)
+                 $ G._fName field
+    denormalizeField fieldInfo field
+
+  fieldToSelectionSet alias field =
+    ScopedSelectionSet (AliasedFields $ OMap.singleton alias field) mempty
+
+  mergeNormalizedSelectionSets = mergeScopedSelectionSets
+
+  fromObjectSelectionSet _ fragmentType _ objectSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.singleton fragmentType objectSelectionSet
+
+  fromInterfaceSelectionSet _ _ commonTypes interfaceSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType interfaceSelectionSet)
+
+  fromUnionSelectionSet _ _ commonTypes unionSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType unionSelectionSet)
+
+type instance NormalizedSelectionSet UnionTyInfo = UnionSelectionSet
+type instance NormalizedField UnionTyInfo = Typename
+
+instance HasSelectionSet UnionTyInfo where
+
+  getTypename = _utiName
+  getMemberTypes = _utiMemberTypes
+
+  parseField_ unionTyInfo field = do
+    let fieldMap = Map.singleton (_fiName typenameFld) typenameFld
+    fieldInfo <- getFieldInfo (_utiName unionTyInfo) fieldMap $ G._fName field
+    fmap (const Typename) <$> denormalizeField fieldInfo field
+
+  fieldToSelectionSet alias field =
+    ScopedSelectionSet (AliasedFields $ OMap.singleton alias field) mempty
+
+  mergeNormalizedSelectionSets = mergeScopedSelectionSets
+
+  fromObjectSelectionSet _ fragmentType _ objectSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.singleton fragmentType objectSelectionSet
+
+  fromInterfaceSelectionSet _ _ commonTypes interfaceSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType interfaceSelectionSet)
+
+  fromUnionSelectionSet _ _ commonTypes unionSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType unionSelectionSet)

server/src-lib/Hasura/GraphQL/Validate/Types.hs

@@ -0,0 +1,812 @@
+{-# LANGUAGE GADTs #-}
+module Hasura.GraphQL.Validate.Types
+  ( InpValInfo(..)
+  , ParamMap
+
+  , typenameFld
+  , ObjFldInfo(..)
+  , mkHsraObjFldInfo
+  , ObjFieldMap
+
+  -- Don't expose 'ObjTyInfo' constructor. Instead use 'mkObjTyInfo' or 'mkHsraObjTyInfo'
+  -- which will auto-insert the compulsory '__typename' field.
+  , ObjTyInfo
+  , _otiDesc
+  , _otiName
+  , _otiImplIFaces
+  , _otiFields
+  , mkObjTyInfo
+  , mkHsraObjTyInfo
+
+  -- Don't expose 'IFaceTyInfo' constructor. Instead use 'mkIFaceTyInfo'
+  -- which will auto-insert the compulsory '__typename' field.
+  , IFaceTyInfo
+  , _ifDesc
+  , _ifName
+  , _ifFields
+  , _ifMemberTypes
+  , mkIFaceTyInfo
+
+  , IFacesSet
+  , UnionTyInfo(..)
+  , FragDef(..)
+  , FragmentTypeInfo(..)
+  , FragDefMap
+  , AnnVarVals
+  , AnnInpVal(..)
+
+  , EnumTyInfo(..)
+  , mkHsraEnumTyInfo
+
+  , EnumValuesInfo(..)
+  , normalizeEnumValues
+  , EnumValInfo(..)
+  , InpObjFldMap
+  , InpObjTyInfo(..)
+  , mkHsraInpTyInfo
+
+  , ScalarTyInfo(..)
+  , fromScalarTyDef
+  , mkHsraScalarTyInfo
+
+  , DirectiveInfo(..)
+  , AsObjType(..)
+  , defaultDirectives
+  , defDirectivesMap
+  , defaultSchema
+  , TypeInfo(..)
+  , isObjTy
+  , isIFaceTy
+  , getPossibleObjTypes
+  , getObjTyM
+  , getUnionTyM
+  , mkScalarTy
+  , pgColTyToScalar
+  , getNamedTy
+  , mkTyInfoMap
+  , fromTyDef
+  , fromSchemaDoc
+  , fromSchemaDocQ
+  , TypeMap
+  , TypeLoc (..)
+  , typeEq
+  , AnnGValue(..)
+  , AnnGEnumValue(..)
+  , AnnGObject
+  , hasNullVal
+  , getAnnInpValKind
+  , stripTypenames
+
+  , ReusableVariableTypes(..)
+  , ReusableVariableValues
+
+  , QueryReusability(..)
+  , _Reusable
+  , _NotReusable
+  , MonadReusability(..)
+  , ReusabilityT
+  , runReusabilityT
+  , runReusabilityTWith
+  , evalReusabilityT
+
+  , module Hasura.GraphQL.Utils
+  ) where
+
+import           Hasura.Prelude
+
+import qualified Data.Aeson                    as J
+import qualified Data.Aeson.Casing             as J
+import qualified Data.Aeson.TH                 as J
+import qualified Data.HashMap.Strict           as Map
+import qualified Data.HashSet                  as Set
+import qualified Data.Text                     as T
+import qualified Language.GraphQL.Draft.Syntax as G
+import qualified Language.GraphQL.Draft.TH     as G
+import qualified Language.Haskell.TH.Syntax    as TH
+
+import           Control.Lens                  (makePrisms)
+
+import qualified Hasura.RQL.Types.Column       as RQL
+
+import           Hasura.GraphQL.NormalForm
+import           Hasura.GraphQL.Utils
+import           Hasura.RQL.Instances          ()
+import           Hasura.RQL.Types.Common
+import           Hasura.RQL.Types.RemoteSchema (RemoteSchemaInfo, RemoteSchemaName)
+import           Hasura.SQL.Types
+import           Hasura.SQL.Value
+
+typeEq :: (EquatableGType a, Eq (EqProps a)) => a -> a -> Bool
+typeEq a b = getEqProps a == getEqProps b
+
+data EnumValInfo
+  = EnumValInfo
+  { _eviDesc         :: !(Maybe G.Description)
+  , _eviVal          :: !G.EnumValue
+  , _eviIsDeprecated :: !Bool
+  } deriving (Show, Eq, TH.Lift)
+
+fromEnumValDef :: G.EnumValueDefinition -> EnumValInfo
+fromEnumValDef (G.EnumValueDefinition descM val _) =
+  EnumValInfo descM val False
+
+data EnumValuesInfo
+  = EnumValuesSynthetic !(Map.HashMap G.EnumValue EnumValInfo)
+  -- ^ Values for an enum that exists only in the GraphQL schema and does not
+  -- have any external source of truth.
+  | EnumValuesReference !RQL.EnumReference
+  -- ^ Values for an enum that is backed by an enum table reference (see
+  -- "Hasura.RQL.Schema.Enum").
+  deriving (Show, Eq, TH.Lift)
+
+normalizeEnumValues :: EnumValuesInfo -> Map.HashMap G.EnumValue EnumValInfo
+normalizeEnumValues = \case
+  EnumValuesSynthetic values -> values
+  EnumValuesReference (RQL.EnumReference _ values) ->
+    mapFromL _eviVal . flip map (Map.toList values) $
+      \(RQL.EnumValue name, RQL.EnumValueInfo maybeDescription) -> EnumValInfo
+        { _eviVal = G.EnumValue $ G.Name name
+        , _eviDesc = G.Description <$> maybeDescription
+        , _eviIsDeprecated = False }
+
+data EnumTyInfo
+  = EnumTyInfo
+  { _etiDesc   :: !(Maybe G.Description)
+  , _etiName   :: !G.NamedType
+  , _etiValues :: !EnumValuesInfo
+  , _etiLoc    :: !TypeLoc
+  } deriving (Show, Eq, TH.Lift)
+
+instance EquatableGType EnumTyInfo where
+  type EqProps EnumTyInfo = (G.NamedType, Map.HashMap G.EnumValue EnumValInfo)
+  getEqProps ety = (,) (_etiName ety) (normalizeEnumValues $ _etiValues ety)
+
+fromEnumTyDef :: G.EnumTypeDefinition -> TypeLoc -> EnumTyInfo
+fromEnumTyDef (G.EnumTypeDefinition descM n _ valDefs) loc =
+  EnumTyInfo descM (G.NamedType n) (EnumValuesSynthetic enumVals) loc
+  where
+    enumVals = Map.fromList
+      [(G._evdName valDef, fromEnumValDef valDef) | valDef <- valDefs]
+
+mkHsraEnumTyInfo
+  :: Maybe G.Description
+  -> G.NamedType
+  -> EnumValuesInfo
+  -> EnumTyInfo
+mkHsraEnumTyInfo descM ty enumVals =
+  EnumTyInfo descM ty enumVals TLHasuraType
+
+fromInpValDef :: G.InputValueDefinition -> InpValInfo
+fromInpValDef (G.InputValueDefinition descM n ty defM) =
+  InpValInfo descM n defM ty
+
+type ParamMap = Map.HashMap G.Name InpValInfo
+
+-- | location of the type: a hasura type or a remote type
+data TypeLoc
+  = TLHasuraType
+  | TLRemoteType !RemoteSchemaName !RemoteSchemaInfo
+  | TLCustom
+  deriving (Show, Eq, TH.Lift, Generic)
+
+$(J.deriveJSON
+  J.defaultOptions { J.constructorTagModifier = J.snakeCase . drop 2
+                   , J.sumEncoding = J.TaggedObject "type" "detail"
+                   }
+  ''TypeLoc)
+
+instance Hashable TypeLoc
+
+data ObjFldInfo
+  = ObjFldInfo
+  { _fiDesc   :: !(Maybe G.Description)
+  , _fiName   :: !G.Name
+  , _fiParams :: !ParamMap
+  , _fiTy     :: !G.GType
+  , _fiLoc    :: !TypeLoc
+  } deriving (Show, Eq, TH.Lift)
+
+instance EquatableGType ObjFldInfo where
+  type EqProps ObjFldInfo = (G.Name, G.GType, ParamMap)
+  getEqProps o = (,,) (_fiName o) (_fiTy o) (_fiParams o)
+
+fromFldDef :: G.FieldDefinition -> TypeLoc -> ObjFldInfo
+fromFldDef (G.FieldDefinition descM n args ty _) loc =
+  ObjFldInfo descM n params ty loc
+  where
+    params = Map.fromList [(G._ivdName arg, fromInpValDef arg) | arg <- args]
+
+mkHsraObjFldInfo
+  :: Maybe G.Description
+  -> G.Name
+  -> ParamMap
+  -> G.GType
+  -> ObjFldInfo
+mkHsraObjFldInfo descM name params ty =
+  ObjFldInfo descM name params ty TLHasuraType
+
+type ObjFieldMap = Map.HashMap G.Name ObjFldInfo
+
+type IFacesSet = Set.HashSet G.NamedType
+
+data ObjTyInfo
+  = ObjTyInfo
+  { _otiDesc       :: !(Maybe G.Description)
+  , _otiName       :: !G.NamedType
+  , _otiImplIFaces :: !IFacesSet
+  , _otiFields     :: !ObjFieldMap
+  } deriving (Show, Eq, TH.Lift)
+
+instance EquatableGType ObjTyInfo where
+  type EqProps ObjTyInfo =
+    (G.NamedType, Set.HashSet G.NamedType,  Map.HashMap G.Name (G.Name, G.GType, ParamMap))
+  getEqProps a = (,,) (_otiName a) (_otiImplIFaces a) (Map.map getEqProps (_otiFields a))
+
+instance Monoid ObjTyInfo where
+  mempty = ObjTyInfo Nothing (G.NamedType "") Set.empty Map.empty
+
+instance Semigroup ObjTyInfo where
+  objA <> objB =
+    objA { _otiFields = Map.union (_otiFields objA) (_otiFields objB)
+         , _otiImplIFaces = _otiImplIFaces objA `Set.union` _otiImplIFaces objB
+         }
+
+mkObjTyInfo
+  :: Maybe G.Description -> G.NamedType
+  -> IFacesSet -> ObjFieldMap -> TypeLoc -> ObjTyInfo
+mkObjTyInfo descM ty iFaces flds _ =
+  ObjTyInfo descM ty iFaces $ Map.insert (_fiName newFld) newFld flds
+  where newFld = typenameFld
+
+mkHsraObjTyInfo
+  :: Maybe G.Description
+  -> G.NamedType
+  -> IFacesSet
+  -> ObjFieldMap
+  -> ObjTyInfo
+mkHsraObjTyInfo descM ty implIFaces flds =
+  mkObjTyInfo descM ty implIFaces flds TLHasuraType
+
+mkIFaceTyInfo
+  :: Maybe G.Description -> G.NamedType
+  -> Map.HashMap G.Name ObjFldInfo -> MemberTypes -> IFaceTyInfo
+mkIFaceTyInfo descM ty flds =
+  IFaceTyInfo descM ty $ Map.insert (_fiName newFld) newFld flds
+  where
+    newFld = typenameFld
+
+typenameFld :: ObjFldInfo
+typenameFld =
+  ObjFldInfo (Just desc) "__typename" Map.empty
+    (G.toGT $ G.toNT $ G.NamedType "String") TLHasuraType
+  where
+    desc = "The name of the current Object type at runtime"
+
+fromObjTyDef :: G.ObjectTypeDefinition -> TypeLoc -> ObjTyInfo
+fromObjTyDef (G.ObjectTypeDefinition descM n ifaces _ flds) loc =
+  mkObjTyInfo descM (G.NamedType n) (Set.fromList ifaces) fldMap loc
+  where
+    fldMap = Map.fromList [(G._fldName fld, fromFldDef fld loc) | fld <- flds]
+
+data IFaceTyInfo
+  = IFaceTyInfo
+  { _ifDesc        :: !(Maybe G.Description)
+  , _ifName        :: !G.NamedType
+  , _ifFields      :: !ObjFieldMap
+  , _ifMemberTypes :: !MemberTypes
+  } deriving (Show, Eq, TH.Lift)
+
+instance EquatableGType IFaceTyInfo where
+  type EqProps IFaceTyInfo =
+    (G.NamedType, Map.HashMap G.Name (G.Name, G.GType, ParamMap))
+  getEqProps a = (,) (_ifName a) (Map.map getEqProps (_ifFields a))
+
+instance Semigroup IFaceTyInfo where
+  objA <> objB =
+    objA { _ifFields = Map.union (_ifFields objA) (_ifFields objB)
+         }
+
+fromIFaceDef
+  :: InterfaceImplementations -> G.InterfaceTypeDefinition -> TypeLoc -> IFaceTyInfo
+fromIFaceDef interfaceImplementations (G.InterfaceTypeDefinition descM n _ flds) loc =
+  mkIFaceTyInfo descM (G.NamedType n) fldMap implementations
+  where
+    fldMap = Map.fromList [(G._fldName fld, fromFldDef fld loc) | fld <- flds]
+    implementations = fromMaybe mempty $ Map.lookup (G.NamedType n) interfaceImplementations
+
+type MemberTypes = Set.HashSet G.NamedType
+
+data UnionTyInfo
+  = UnionTyInfo
+  { _utiDesc        :: !(Maybe G.Description)
+  , _utiName        :: !G.NamedType
+  , _utiMemberTypes :: !MemberTypes
+  } deriving (Show, Eq, TH.Lift)
+
+instance EquatableGType UnionTyInfo where
+  type EqProps UnionTyInfo =
+    (G.NamedType, Set.HashSet G.NamedType)
+  getEqProps a = (,) (_utiName a) (_utiMemberTypes a)
+
+instance Monoid UnionTyInfo where
+  mempty = UnionTyInfo Nothing (G.NamedType "") Set.empty
+
+instance Semigroup UnionTyInfo where
+  objA <> objB =
+    objA { _utiMemberTypes = Set.union (_utiMemberTypes objA) (_utiMemberTypes objB)
+         }
+
+fromUnionTyDef :: G.UnionTypeDefinition -> UnionTyInfo
+fromUnionTyDef (G.UnionTypeDefinition descM n _ mt) = UnionTyInfo descM (G.NamedType n) $ Set.fromList mt
+
+type InpObjFldMap = Map.HashMap G.Name InpValInfo
+
+data InpObjTyInfo
+  = InpObjTyInfo
+  { _iotiDesc   :: !(Maybe G.Description)
+  , _iotiName   :: !G.NamedType
+  , _iotiFields :: !InpObjFldMap
+  , _iotiLoc    :: !TypeLoc
+  } deriving (Show, Eq, TH.Lift)
+
+instance EquatableGType InpObjTyInfo where
+  type EqProps InpObjTyInfo = (G.NamedType, Map.HashMap G.Name (G.Name, G.GType))
+  getEqProps a = (,) (_iotiName a) (Map.map getEqProps $ _iotiFields a)
+
+fromInpObjTyDef :: G.InputObjectTypeDefinition -> TypeLoc -> InpObjTyInfo
+fromInpObjTyDef (G.InputObjectTypeDefinition descM n _ inpFlds) loc =
+  InpObjTyInfo descM (G.NamedType n) fldMap loc
+  where
+    fldMap = Map.fromList
+      [(G._ivdName inpFld, fromInpValDef inpFld) | inpFld <- inpFlds]
+
+mkHsraInpTyInfo
+  :: Maybe G.Description
+  -> G.NamedType
+  -> InpObjFldMap
+  -> InpObjTyInfo
+mkHsraInpTyInfo descM ty flds =
+  InpObjTyInfo descM ty flds TLHasuraType
+
+data ScalarTyInfo
+  = ScalarTyInfo
+  { _stiDesc :: !(Maybe G.Description)
+  , _stiName :: !G.Name
+  , _stiType :: !PGScalarType
+  , _stiLoc  :: !TypeLoc
+  } deriving (Show, Eq, TH.Lift)
+
+mkHsraScalarTyInfo :: PGScalarType -> ScalarTyInfo
+mkHsraScalarTyInfo ty =
+  ScalarTyInfo Nothing (G.Name $ pgColTyToScalar ty) ty TLHasuraType
+
+instance EquatableGType ScalarTyInfo where
+  type EqProps ScalarTyInfo = PGScalarType
+  getEqProps = _stiType
+
+fromScalarTyDef
+  :: G.ScalarTypeDefinition
+  -> TypeLoc
+  -> ScalarTyInfo
+fromScalarTyDef (G.ScalarTypeDefinition descM n _) =
+  ScalarTyInfo descM n ty
+  where
+    ty = case n of
+      "Int"     -> PGInteger
+      "Float"   -> PGFloat
+      "String"  -> PGText
+      "Boolean" -> PGBoolean
+      "ID"      -> PGText
+      _         -> textToPGScalarType $ G.unName n
+
+data TypeInfo
+  = TIScalar !ScalarTyInfo
+  | TIObj !ObjTyInfo
+  | TIEnum !EnumTyInfo
+  | TIInpObj !InpObjTyInfo
+  | TIIFace !IFaceTyInfo
+  | TIUnion !UnionTyInfo
+  deriving (Show, Eq, TH.Lift)
+
+instance J.ToJSON TypeInfo where
+  toJSON _ = J.String "toJSON not implemented for TypeInfo"
+
+data AsObjType
+  = AOTIFace IFaceTyInfo
+  | AOTUnion UnionTyInfo
+
+getPossibleObjTypes :: TypeMap -> AsObjType -> Map.HashMap G.NamedType ObjTyInfo
+getPossibleObjTypes tyMap = \case
+  (AOTIFace i) ->
+    toObjMap $ mapMaybe (extrObjTyInfoM tyMap) $ Set.toList $ _ifMemberTypes i
+  (AOTUnion u) ->
+    toObjMap $ mapMaybe (extrObjTyInfoM tyMap) $ Set.toList $ _utiMemberTypes u
+  -- toObjMap $ mapMaybe previewImplTypeM $ Map.elems tyMap
+  -- where
+  --   previewImplTypeM = \case
+  --     TIObj objTyInfo -> bool Nothing (Just objTyInfo) $
+  --        _ifName i `elem` _otiImplIFaces objTyInfo
+  --     _               -> Nothing
+
+
+toObjMap :: [ObjTyInfo] -> Map.HashMap G.NamedType ObjTyInfo
+toObjMap = foldr (\o -> Map.insert (_otiName o) o) Map.empty
+
+
+isObjTy :: TypeInfo -> Bool
+isObjTy = \case
+  (TIObj _) -> True
+  _         -> False
+
+getObjTyM :: TypeInfo -> Maybe ObjTyInfo
+getObjTyM = \case
+  (TIObj t) -> return t
+  _         -> Nothing
+
+getUnionTyM :: TypeInfo -> Maybe UnionTyInfo
+getUnionTyM = \case
+  (TIUnion u) -> return u
+  _         -> Nothing
+
+isIFaceTy :: TypeInfo -> Bool
+isIFaceTy = \case
+  (TIIFace _) -> True
+  _         -> False
+
+data SchemaPath
+  = SchemaPath
+  { _spTypeName :: !(Maybe G.NamedType)
+  , _spFldName  :: !(Maybe G.Name)
+  , _spArgName  :: !(Maybe G.Name)
+  , _spType     :: !(Maybe T.Text)
+  }
+
+setFldNameSP :: SchemaPath -> G.Name -> SchemaPath
+setFldNameSP sp fn = sp { _spFldName = Just fn}
+
+setArgNameSP :: SchemaPath -> G.Name -> SchemaPath
+setArgNameSP sp an = sp { _spArgName = Just an}
+
+showSP :: SchemaPath -> Text
+showSP (SchemaPath t f a _) = maybe "" (\x -> showNamedTy x <> fN) t
+  where
+    fN = maybe "" (\x -> "." <> showName x <> aN) f
+    aN = maybe "" showArg a
+    showArg x = "(" <> showName x <> ":)"
+
+showSPTxt' :: SchemaPath -> Text
+showSPTxt' (SchemaPath _ f a t)  = maybe "" (<> " "<> fld) t
+  where
+    fld = maybe "" (const $ "field " <> arg) f
+    arg = maybe "" (const "argument ") a
+
+showSPTxt :: SchemaPath -> Text
+showSPTxt p = showSPTxt' p <> showSP p
+
+validateIFace :: MonadError Text f => IFaceTyInfo -> f ()
+validateIFace (IFaceTyInfo _ n flds _) =
+  when (isFldListEmpty flds) $ throwError $ "List of fields cannot be empty for interface " <> showNamedTy n
+
+validateObj :: TypeMap -> ObjTyInfo -> Either Text ()
+validateObj tyMap objTyInfo@(ObjTyInfo _ n _ flds) = do
+  when (isFldListEmpty flds) $ throwError $ "List of fields cannot be empty for " <> objTxt
+  mapM_ (extrIFaceTyInfo' >=> validateIFaceImpl objTyInfo) $ _otiImplIFaces objTyInfo
+  where
+    extrIFaceTyInfo' t = withObjTxt $ extrIFaceTyInfo tyMap t
+    withObjTxt x = x `catchError` \e -> throwError $ e <> " implemented by " <> objTxt
+    objTxt = "Object type " <> showNamedTy n
+    validateIFaceImpl = implmntsIFace tyMap
+
+isFldListEmpty :: ObjFieldMap -> Bool
+isFldListEmpty = Map.null . Map.delete "__typename"
+
+validateUnion :: MonadError Text m => TypeMap -> UnionTyInfo -> m ()
+validateUnion tyMap (UnionTyInfo _ un mt) = do
+  when (Set.null mt) $ throwError $ "List of member types cannot be empty for union type " <> showNamedTy un
+  mapM_ valIsObjTy $ Set.toList mt
+  where
+    valIsObjTy mn = case Map.lookup mn tyMap of
+      Just (TIObj t) -> return t
+      Nothing -> throwError $ "Could not find type " <> showNamedTy mn <> ", which is defined as a member type of Union " <> showNamedTy un
+      _ -> throwError $ "Union type " <> showNamedTy un <> " can only include object types. It cannot include " <> showNamedTy mn
+
+implmntsIFace :: TypeMap -> ObjTyInfo -> IFaceTyInfo -> Either Text ()
+implmntsIFace tyMap objTyInfo iFaceTyInfo = do
+  let path =
+        ( SchemaPath (Just $ _otiName objTyInfo) Nothing Nothing (Just "Object")
+        , SchemaPath  (Just $ _ifName iFaceTyInfo) Nothing Nothing (Just "Interface")
+        )
+  mapM_ (includesIFaceFld path) $ _ifFields iFaceTyInfo
+  where
+    includesIFaceFld (spO,spIF) ifFld = do
+      let pathA@(spOA, spIFA) = (spO, setFldNameSP spIF $ _fiName ifFld)
+      objFld <- sameNameFld pathA ifFld
+      let pathB = (setFldNameSP spOA $ _fiName objFld, spIFA)
+      validateIsSubType' pathB (_fiTy objFld) (_fiTy ifFld)
+      hasAllArgs pathB objFld ifFld
+      isExtraArgsNullable pathB objFld ifFld
+
+    validateIsSubType' (spO,spIF) oFld iFld = validateIsSubType tyMap oFld iFld `catchError` \_ ->
+      throwError $ "The type of " <> showSPTxt spO <> " (" <> G.showGT oFld <>
+      ") is not the same type/sub type of " <> showSPTxt spIF <> " (" <> G.showGT iFld <> ")"
+
+    sameNameFld (spO, spIF) ifFld = do
+      let spIFN = setFldNameSP spIF $ _fiName ifFld
+      onNothing (Map.lookup (_fiName ifFld) objFlds)
+        $ throwError $ showSPTxt spIFN <> " expected, but " <> showSP spO <> " does not provide it"
+
+    hasAllArgs (spO, spIF) objFld ifFld = forM_ (_fiParams ifFld) $ \ifArg -> do
+      objArg <- sameNameArg ifArg
+      let (spON, spIFN) = (setArgNameSP spO $ _iviName objArg, setArgNameSP spIF $ _iviName ifArg)
+      unless (_iviType objArg == _iviType ifArg) $ throwError $
+        showSPTxt spIFN <> " expects type " <> G.showGT (_iviType ifArg) <> ", but " <>
+        showSP spON <> " has type " <> G.showGT (_iviType objArg)
+      where
+        sameNameArg ivi = do
+          let spIFN = setArgNameSP spIF $ _iviName ivi
+          onNothing (Map.lookup (_iviName ivi) objArgs) $ throwError $ showSPTxt spIFN <> " required, but " <>
+            showSPTxt spO <> " does not provide it"
+        objArgs = _fiParams objFld
+
+    isExtraArgsNullable (spO, spIF) objFld ifFld = forM_ extraArgs isInpValNullable
+      where
+        extraArgs = Map.difference (_fiParams objFld) (_fiParams ifFld)
+        isInpValNullable ivi = unless (G.isNullable $ _iviType ivi) $ throwError $
+          showSPTxt (setArgNameSP spO $ _iviName ivi) <> " is of required type "
+          <> G.showGT (_iviType ivi) <> ", but is not provided by " <> showSPTxt spIF
+
+    objFlds =  _otiFields objTyInfo
+
+extrTyInfo :: TypeMap -> G.NamedType -> Either Text TypeInfo
+extrTyInfo tyMap tn = maybe
+  (throwError $ "Could not find type with name " <> showNamedTy tn)
+  return
+  $ Map.lookup tn tyMap
+
+extrIFaceTyInfo :: MonadError Text m => Map.HashMap G.NamedType TypeInfo -> G.NamedType -> m IFaceTyInfo
+extrIFaceTyInfo tyMap tn = case Map.lookup tn tyMap of
+  Just (TIIFace i) -> return i
+  _                -> throwError $ "Could not find interface " <> showNamedTy tn
+
+extrObjTyInfoM :: TypeMap -> G.NamedType -> Maybe ObjTyInfo
+extrObjTyInfoM tyMap tn = case Map.lookup tn tyMap of
+  Just (TIObj o) -> return o
+  _              -> Nothing
+
+validateIsSubType :: Map.HashMap G.NamedType TypeInfo -> G.GType -> G.GType -> Either Text ()
+validateIsSubType tyMap subFldTy supFldTy = do
+  checkNullMismatch subFldTy supFldTy
+  case (subFldTy,supFldTy) of
+    (G.TypeNamed _ subTy, G.TypeNamed _ supTy) -> do
+      subTyInfo <- extrTyInfo tyMap subTy
+      supTyInfo <- extrTyInfo tyMap supTy
+      isSubTypeBase subTyInfo supTyInfo
+    (G.TypeList _ (G.ListType sub), G.TypeList _ (G.ListType sup) ) ->
+      validateIsSubType tyMap sub sup
+    _ -> throwError $ showIsListTy subFldTy <> " Type " <> G.showGT subFldTy <>
+      " cannot be a sub-type of " <> showIsListTy supFldTy <> " Type " <> G.showGT supFldTy
+  where
+    checkNullMismatch subTy supTy = when (G.isNotNull supTy && G.isNullable subTy ) $
+      throwError $ "Nullable Type " <> G.showGT subFldTy <> " cannot be a sub-type of Non-Null Type " <> G.showGT supFldTy
+    showIsListTy = \case
+      G.TypeList  {} -> "List"
+      G.TypeNamed {} -> "Named"
+
+-- TODO Should we check the schema location as well?
+isSubTypeBase :: (MonadError Text m) => TypeInfo -> TypeInfo -> m ()
+isSubTypeBase subTyInfo supTyInfo = case (subTyInfo,supTyInfo) of
+  (TIObj obj, TIIFace iFace) -> unless (_ifName iFace `elem` _otiImplIFaces obj) notSubTyErr
+  _                          -> unless (subTyInfo == supTyInfo) notSubTyErr
+  where
+    showTy = showNamedTy . getNamedTy
+    notSubTyErr = throwError $ "Type " <> showTy subTyInfo <> " is not a sub type of " <> showTy supTyInfo
+
+-- map postgres types to builtin scalars
+pgColTyToScalar :: PGScalarType -> Text
+pgColTyToScalar = \case
+  PGInteger -> "Int"
+  PGBoolean -> "Boolean"
+  PGFloat   -> "Float"
+  PGText    -> "String"
+  PGVarchar -> "String"
+  t         -> toSQLTxt t
+
+mkScalarTy :: PGScalarType -> G.NamedType
+mkScalarTy =
+  G.NamedType . G.Name . pgColTyToScalar
+
+getNamedTy :: TypeInfo -> G.NamedType
+getNamedTy = \case
+  TIScalar t -> G.NamedType $ _stiName t
+  TIObj t -> _otiName t
+  TIIFace i -> _ifName i
+  TIEnum t -> _etiName t
+  TIInpObj t -> _iotiName t
+  TIUnion u -> _utiName u
+
+mkTyInfoMap :: [TypeInfo] -> TypeMap
+mkTyInfoMap tyInfos =
+  Map.fromList [(getNamedTy tyInfo, tyInfo) | tyInfo <- tyInfos]
+
+fromTyDef :: InterfaceImplementations -> TypeLoc -> G.TypeDefinition -> TypeInfo
+fromTyDef interfaceImplementations loc tyDef = case tyDef of
+  G.TypeDefinitionScalar t      -> TIScalar $ fromScalarTyDef t loc
+  G.TypeDefinitionObject t      -> TIObj $ fromObjTyDef t loc
+  G.TypeDefinitionInterface t   -> TIIFace $ fromIFaceDef interfaceImplementations t loc
+  G.TypeDefinitionUnion t       -> TIUnion $ fromUnionTyDef t
+  G.TypeDefinitionEnum t        -> TIEnum $ fromEnumTyDef t loc
+  G.TypeDefinitionInputObject t -> TIInpObj $ fromInpObjTyDef t loc
+
+type InterfaceImplementations = Map.HashMap G.NamedType MemberTypes
+
+fromSchemaDoc :: G.SchemaDocument -> TypeLoc -> Either Text TypeMap
+fromSchemaDoc (G.SchemaDocument tyDefs) loc = do
+  let tyMap = mkTyInfoMap $ map (fromTyDef interfaceImplementations loc) tyDefs
+  validateTypeMap tyMap
+  return tyMap
+  where
+    interfaceImplementations :: InterfaceImplementations
+    interfaceImplementations =
+      foldr (Map.unionWith (<>)) mempty $ flip mapMaybe tyDefs $ \case
+        G.TypeDefinitionObject objectDefinition ->
+          Just $ Map.fromList $ zip
+            (G._otdImplementsInterfaces objectDefinition)
+            (repeat $ Set.singleton $ G.NamedType $ G._otdName objectDefinition)
+        _ -> Nothing
+
+validateTypeMap :: TypeMap -> Either Text ()
+validateTypeMap tyMap =  mapM_ validateTy $ Map.elems tyMap
+  where
+    validateTy (TIObj o)   = validateObj tyMap o
+    validateTy (TIUnion u) = validateUnion tyMap u
+    validateTy (TIIFace i) = validateIFace i
+    validateTy _           = return ()
+
+fromSchemaDocQ :: G.SchemaDocument -> TypeLoc -> TH.Q TH.Exp
+fromSchemaDocQ sd loc = case fromSchemaDoc sd loc of
+  Left e      -> fail $ T.unpack e
+  Right tyMap -> TH.ListE <$> mapM TH.lift (Map.elems tyMap)
+
+defaultSchema :: G.SchemaDocument
+defaultSchema = $(G.parseSchemaDocQ "src-rsr/schema.graphql")
+
+-- fromBaseSchemaFileQ :: FilePath -> TH.Q TH.Exp
+-- fromBaseSchemaFileQ fp =
+--   fromSchemaDocQ $(G.parseSchemaDocQ fp)
+
+type TypeMap = Map.HashMap G.NamedType TypeInfo
+
+data DirectiveInfo
+  = DirectiveInfo
+  { _diDescription :: !(Maybe G.Description)
+  , _diName        :: !G.Name
+  , _diParams      :: !ParamMap
+  , _diLocations   :: ![G.DirectiveLocation]
+  } deriving (Show, Eq)
+
+-- TODO: generate this from template haskell once we have a parser for directive defs
+-- directive @skip(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
+defaultDirectives :: [DirectiveInfo]
+defaultDirectives =
+  [mkDirective "skip", mkDirective "include"]
+  where
+    mkDirective n = DirectiveInfo Nothing n args dirLocs
+    args = Map.singleton "if" $ InpValInfo Nothing "if" Nothing $
+           G.TypeNamed (G.Nullability False) $ mkScalarTy PGBoolean
+    dirLocs = map G.DLExecutable
+              [G.EDLFIELD, G.EDLFRAGMENT_SPREAD, G.EDLINLINE_FRAGMENT]
+
+defDirectivesMap :: Map.HashMap G.Name DirectiveInfo
+defDirectivesMap = mapFromL _diName defaultDirectives
+
+data FragDef
+  = FragDef
+  { _fdName   :: !G.Name
+  , _fdTyInfo :: !FragmentTypeInfo
+  , _fdSelSet :: !G.SelectionSet
+  } deriving (Show, Eq)
+
+data FragmentTypeInfo
+  = FragmentTyObject !ObjTyInfo
+  | FragmentTyInterface !IFaceTyInfo
+  | FragmentTyUnion !UnionTyInfo
+  deriving (Show, Eq)
+
+type FragDefMap = Map.HashMap G.Name FragDef
+
+type AnnVarVals =
+  Map.HashMap G.Variable AnnInpVal
+
+stripTypenames :: [G.ExecutableDefinition] -> [G.ExecutableDefinition]
+stripTypenames = map filterExecDef
+  where
+    filterExecDef = \case
+      G.ExecutableDefinitionOperation opDef  ->
+        G.ExecutableDefinitionOperation $ filterOpDef opDef
+      G.ExecutableDefinitionFragment fragDef ->
+        let newSelset = filterSelSet $ G._fdSelectionSet fragDef
+        in G.ExecutableDefinitionFragment fragDef{G._fdSelectionSet = newSelset}
+
+    filterOpDef  = \case
+      G.OperationDefinitionTyped typeOpDef ->
+        let newSelset = filterSelSet $ G._todSelectionSet typeOpDef
+        in G.OperationDefinitionTyped typeOpDef{G._todSelectionSet = newSelset}
+      G.OperationDefinitionUnTyped selset ->
+        G.OperationDefinitionUnTyped $ filterSelSet selset
+
+    filterSelSet = mapMaybe filterSel
+    filterSel s = case s of
+      G.SelectionField f ->
+        if G._fName f == "__typename"
+        then Nothing
+        else
+          let newSelset = filterSelSet $ G._fSelectionSet f
+          in Just $ G.SelectionField  f{G._fSelectionSet = newSelset}
+      _                  -> Just s
+
+-- | Used by 'Hasura.GraphQL.Validate.validateVariablesForReuse' to parse new sets of variables for
+-- reusable query plans; see also 'QueryReusability'.
+newtype ReusableVariableTypes
+  = ReusableVariableTypes { unReusableVarTypes :: Map.HashMap G.Variable RQL.PGColumnType }
+  deriving (Show, Eq, Semigroup, Monoid, J.ToJSON)
+type ReusableVariableValues = Map.HashMap G.Variable (WithScalarType PGScalarValue)
+
+-- | Tracks whether or not a query is /reusable/. Reusable queries are nice, since we can cache
+-- their resolved ASTs and avoid re-resolving them if we receive an identical query. However, we
+-- can’t always safely reuse queries if they have variables, since some variable values can affect
+-- the generated SQL. For example, consider the following query:
+--
+-- > query users_where($condition: users_bool_exp!) {
+-- >   users(where: $condition) {
+-- >     id
+-- >   }
+-- > }
+--
+-- Different values for @$condition@ will produce completely different queries, so we can’t reuse
+-- its plan (unless the variable values were also all identical, of course, but we don’t bother
+-- caching those).
+--
+-- If a query does turn out to be reusable, we build up a 'ReusableVariableTypes' value that maps
+-- variable names to their types so that we can use a fast path for validating new sets of
+-- variables (namely 'Hasura.GraphQL.Validate.validateVariablesForReuse').
+data QueryReusability
+  = Reusable !ReusableVariableTypes
+  | NotReusable
+  deriving (Show, Eq)
+$(makePrisms ''QueryReusability)
+
+instance Semigroup QueryReusability where
+  Reusable a <> Reusable b = Reusable (a <> b)
+  _          <> _          = NotReusable
+instance Monoid QueryReusability where
+  mempty = Reusable mempty
+
+class (Monad m) => MonadReusability m where
+  recordVariableUse :: G.Variable -> RQL.PGColumnType -> m ()
+  markNotReusable :: m ()
+
+instance (MonadReusability m) => MonadReusability (ReaderT r m) where
+  recordVariableUse a b = lift $ recordVariableUse a b
+  markNotReusable = lift markNotReusable
+
+instance (MonadReusability m) => MonadReusability (StateT s m) where
+  recordVariableUse a b = lift $ recordVariableUse a b
+  markNotReusable = lift markNotReusable
+
+newtype ReusabilityT m a = ReusabilityT { unReusabilityT :: StateT QueryReusability m a }
+  deriving (Functor, Applicative, Monad, MonadError e, MonadReader r, MonadIO)
+
+instance (Monad m) => MonadReusability (ReusabilityT m) where
+  recordVariableUse varName varType = ReusabilityT $
+    modify' (<> Reusable (ReusableVariableTypes $ Map.singleton varName varType))
+  markNotReusable = ReusabilityT $ put NotReusable
+
+runReusabilityT :: ReusabilityT m a -> m (a, QueryReusability)
+runReusabilityT = runReusabilityTWith mempty
+
+-- | Like 'runReusabilityT', but starting from an existing 'QueryReusability' state.
+runReusabilityTWith :: QueryReusability -> ReusabilityT m a -> m (a, QueryReusability)
+runReusabilityTWith initialReusability = flip runStateT initialReusability . unReusabilityT
+
+evalReusabilityT :: (Monad m) => ReusabilityT m a -> m a
+evalReusabilityT = flip evalStateT mempty . unReusabilityT

server/src-lib/Hasura/RQL/DDL/RemoteSchema.hs

@@ -10,6 +10,9 @@ module Hasura.RQL.DDL.RemoteSchema
   ) where
 
 import           Hasura.EncJSON
+-- import           Hasura.GraphQL.NormalForm
+import           Hasura.GraphQL.RemoteServer
+-- import           Hasura.GraphQL.Schema.Merge
 import           Hasura.Prelude
 
 import qualified Data.Aeson                  as J
@@ -121,3 +124,34 @@ fetchRemoteSchemas =
   where
     fromRow (name, Q.AltJ def, comment) =
       AddRemoteSchemaQuery name def comment
+
+-- runIntrospectRemoteSchema
+--   :: (CacheRM m, QErrM m) => RemoteSchemaNameQuery -> m EncJSON
+-- runIntrospectRemoteSchema (RemoteSchemaNameQuery rsName) = do
+--   sc <- askSchemaCache
+--   rGCtx <-
+--     case Map.lookup rsName (scRemoteSchemas sc) of
+--       Nothing ->
+--         throw400 NotExists $
+--         "remote schema: " <> remoteSchemaNameToTxt rsName <> " not found"
+--       Just rCtx -> mergeGCtx (rscGCtx rCtx) GC.emptyGCtx
+--       -- merge with emptyGCtx to get default query fields
+--   queryParts <- flip runReaderT rGCtx $ VQ.getQueryParts introspectionQuery
+--   (rootSelSet, _) <- flip runReaderT rGCtx $ VT.runReusabilityT $ VQ.validateGQ queryParts
+--   schemaField <-
+--     case rootSelSet of
+--       VQ.RQuery selSet -> getSchemaField $ toList $ unAliasedFields $
+--                           unObjectSelectionSet selSet
+--       _                -> throw500 "expected query for introspection"
+--   (introRes, _) <- flip runReaderT rGCtx $ VT.runReusabilityT $ RI.schemaR schemaField
+--   pure $ wrapInSpecKeys introRes
+--   where
+--     wrapInSpecKeys introObj =
+--       encJFromAssocList
+--         [ ( T.pack "data"
+--           , encJFromAssocList [(T.pack "__schema", encJFromJValue introObj)])
+--         ]
+--     getSchemaField = \case
+--         []  -> throw500 "found empty when looking for __schema field"
+--         [f] -> pure f
+--         _   -> throw500 "expected __schema field, found many fields"

server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs

@@ -47,6 +47,7 @@ import           Hasura.RQL.DDL.CustomTypes
 import           Hasura.RQL.DDL.Deps
 import           Hasura.RQL.DDL.EventTrigger
 import           Hasura.RQL.DDL.RemoteSchema
+-- import           Hasura.RQL.DDL.ScheduledTrigger
 import           Hasura.RQL.DDL.Schema.Cache.Common
 import           Hasura.RQL.DDL.Schema.Cache.Dependencies
 import           Hasura.RQL.DDL.Schema.Cache.Fields
@@ -192,6 +193,9 @@ buildSchemaCacheRule = proc (catalogMetadata, invalidationKeys) -> do
 
 
 
+  -- Step 4: Build the relay GraphQL schema
+  -- relayGQLSchema <- bindA -< Relay.mkRelayGCtxMap (_boTables resolvedOutputs) (_boFunctions resolvedOutputs)
+
   returnA -< SchemaCache
     { scTables = _boTables resolvedOutputs
     , scActions = _boActions resolvedOutputs

server/src-lib/Hasura/RQL/DML/Mutation.hs

@@ -71,7 +71,7 @@ mutateAndFetchCols qt cols (cte, p) strfyNum =
     tabFrom = FromIden aliasIden
     tabPerm = TablePerm annBoolExpTrue Nothing
     selFlds = flip map cols $
-              \ci -> (fromPGCol $ pgiColumn ci, mkAnnColFieldAsText ci)
+              \ci -> (fromPGCol $ pgiColumn ci, mkAnnColumnFieldAsText ci)
 
     sql = toSQL selectWith
     selectWith = S.SelectWith [(S.Alias aliasIden, cte)] select
@@ -87,7 +87,7 @@ mutateAndFetchCols qt cols (cte, p) strfyNum =
       , S.selFrom = Just $ S.FromExp [S.FIIden aliasIden]
       }
     colSel = S.SESelect $ mkSQLSelect JASMultipleRows $
-             AnnSelG selFlds tabFrom tabPerm noTableArgs strfyNum
+             AnnSelectG selFlds tabFrom tabPerm noSelectArgs strfyNum
 
 -- | Note:- Using sorted columns is necessary to enable casting the rows returned by VALUES expression to table type.
 -- For example, let's consider the table, `CREATE TABLE test (id serial primary key, name text not null, age int)`.

server/src-lib/Hasura/RQL/DML/RemoteJoin.hs

@@ -12,23 +12,20 @@ import           Hasura.Prelude
 
 import           Control.Lens
 import           Data.List                              (nub)
-import           Data.Validation
 import           Data.Scientific                        (toBoundedInteger, toRealFloat)
+import           Data.Validation
 
 import           Hasura.EncJSON
+import           Hasura.GraphQL.Parser
 import           Hasura.GraphQL.RemoteServer            (execRemoteGQ')
 import           Hasura.GraphQL.Transport.HTTP.Protocol
-import           Hasura.GraphQL.Utils
-import           Hasura.GraphQL.Parser
-import           Hasura.GraphQL.Execute.Resolve
 import           Hasura.RQL.DML.Internal
-import           Hasura.RQL.DML.Returning
 import           Hasura.RQL.DML.Returning.Types
 import           Hasura.RQL.DML.Select.Types
 import           Hasura.RQL.Types
 import           Hasura.Server.Version                  (HasVersion)
-import           Hasura.SQL.Types                       ((<<>))
 import           Hasura.Session
+import           Hasura.SQL.Types                       ((<<>))
 
 import qualified Hasura.SQL.DML                         as S
 
@@ -45,8 +42,6 @@ import qualified Language.GraphQL.Draft.Printer.Text    as G
 import qualified Language.GraphQL.Draft.Syntax          as G
 import qualified Network.HTTP.Client                    as HTTP
 import qualified Network.HTTP.Types                     as N
-import qualified Data.ByteString.Lazy                   as BL
-import qualified Network.Wreq                           as Wreq
 
 -- | Executes given query and fetch response JSON from Postgres. Substitutes remote relationship fields.
 executeQueryWithRemoteJoins
@@ -106,7 +101,7 @@ pathToAlias path counter = do
   parseGraphQLName $ T.intercalate "_" (map getFieldNameTxt $ unFieldPath path)
                  <> "__" <> (T.pack . show . unCounter) counter
 
--- | A 'RemoteJoin' represents the context of remote relationship to be extracted from 'AnnFldG's.
+-- | A 'RemoteJoin' represents the context of remote relationship to be extracted from 'AnnFieldG's.
 data RemoteJoin
   = RemoteJoin
   { _rjName          :: !FieldName -- ^ The remote join field name.
@@ -139,14 +134,14 @@ transformSelect path sel = do
   pure sel{_asnFields = transformedFields}
 
 -- | Traverse through @'AnnAggregateSelect' and collect remote join fields (if any).
-getRemoteJoinsAggregateSelect :: AnnAggSel -> (AnnAggSel, Maybe RemoteJoins)
+getRemoteJoinsAggregateSelect :: AnnAggregateSelect -> (AnnAggregateSelect, Maybe RemoteJoins)
 getRemoteJoinsAggregateSelect =
   second mapToNonEmpty . flip runState mempty . transformAggregateSelect mempty
 
 transformAggregateSelect
   :: FieldPath
-  -> AnnAggSel
-  -> State RemoteJoinMap AnnAggSel
+  -> AnnAggregateSelect
+  -> State RemoteJoinMap AnnAggregateSelect
 transformAggregateSelect path sel = do
   let aggFields = _asnFields sel
   transformedFields <- forM aggFields $ \(fieldName, aggField) ->
@@ -156,32 +151,32 @@ transformAggregateSelect path sel = do
       TAFExp t           -> pure $ TAFExp t
   pure sel{_asnFields = transformedFields}
 
--- -- | Traverse through @'ConnectionSelect' and collect remote join fields (if any).
--- getRemoteJoinsConnectionSelect :: ConnectionSelect S.SQLExp -> (ConnectionSelect S.SQLExp, Maybe RemoteJoins)
--- getRemoteJoinsConnectionSelect =
---   second mapToNonEmpty . flip runState mempty . transformConnectionSelect mempty
+-- | Traverse through @'ConnectionSelect' and collect remote join fields (if any).
+getRemoteJoinsConnectionSelect :: ConnectionSelect S.SQLExp -> (ConnectionSelect S.SQLExp, Maybe RemoteJoins)
+getRemoteJoinsConnectionSelect =
+  second mapToNonEmpty . flip runState mempty . transformConnectionSelect mempty
 
--- transformConnectionSelect
---   :: FieldPath
---   -> ConnectionSelect S.SQLExp
---   -> State RemoteJoinMap (ConnectionSelect S.SQLExp)
--- transformConnectionSelect path ConnectionSelect{..} = do
---   let connectionFields = _asnFields _csSelect
---   transformedFields <- forM connectionFields $ \(fieldName, field) ->
---     (fieldName,) <$> case field of
---       ConnectionTypename t -> pure $ ConnectionTypename t
---       ConnectionPageInfo p -> pure $ ConnectionPageInfo p
---       ConnectionEdges edges -> ConnectionEdges <$> transformEdges (appendPath fieldName path) edges
---   let select = _csSelect{_asnFields = transformedFields}
---   pure $ ConnectionSelect _csPrimaryKeyColumns _csSplit _csSlice select
---   where
---     transformEdges edgePath edgeFields =
---       forM edgeFields $ \(fieldName, edgeField) ->
---       (fieldName,) <$> case edgeField of
---         EdgeTypename t -> pure $ EdgeTypename t
---         EdgeCursor -> pure EdgeCursor
---         EdgeNode annFields ->
---           EdgeNode <$> transformAnnFields (appendPath fieldName edgePath) annFields
+transformConnectionSelect
+  :: FieldPath
+  -> ConnectionSelect S.SQLExp
+  -> State RemoteJoinMap (ConnectionSelect S.SQLExp)
+transformConnectionSelect path ConnectionSelect{..} = do
+  let connectionFields = _asnFields _csSelect
+  transformedFields <- forM connectionFields $ \(fieldName, field) ->
+    (fieldName,) <$> case field of
+      ConnectionTypename t -> pure $ ConnectionTypename t
+      ConnectionPageInfo p -> pure $ ConnectionPageInfo p
+      ConnectionEdges edges -> ConnectionEdges <$> transformEdges (appendPath fieldName path) edges
+  let select = _csSelect{_asnFields = transformedFields}
+  pure $ ConnectionSelect _csPrimaryKeyColumns _csSplit _csSlice select
+  where
+    transformEdges edgePath edgeFields =
+      forM edgeFields $ \(fieldName, edgeField) ->
+      (fieldName,) <$> case edgeField of
+        EdgeTypename t -> pure $ EdgeTypename t
+        EdgeCursor -> pure EdgeCursor
+        EdgeNode annFields ->
+          EdgeNode <$> transformAnnFields (appendPath fieldName edgePath) annFields
 
 -- | Traverse through 'MutationOutput' and collect remote join fields (if any)
 getRemoteJoinsMutationOutput :: MutationOutput -> (MutationOutput, Maybe RemoteJoins)
@@ -203,10 +198,10 @@ getRemoteJoinsMutationOutput =
             MExp t         -> pure $ MExp t
             MRet annFields -> MRet <$> transformAnnFields fieldPath annFields
 
-transformAnnFields :: FieldPath -> AnnFlds -> State RemoteJoinMap AnnFlds
+transformAnnFields :: FieldPath -> AnnFields -> State RemoteJoinMap AnnFields
 transformAnnFields path fields = do
-  let pgColumnFields = map fst $ getFields _FCol fields
-      remoteSelects = getFields _FRemote fields
+  let pgColumnFields = map fst $ getFields _AFColumn fields
+      remoteSelects = getFields _AFRemote fields
       remoteJoins = flip map remoteSelects $ \(fieldName, remoteSelect) ->
         let RemoteSelect argsMap selSet hasuraColumns remoteFields rsi = remoteSelect
             hasuraColumnL = toList hasuraColumns
@@ -217,44 +212,46 @@ transformAnnFields path fields = do
   transformedFields <- forM fields $ \(fieldName, field') -> do
     let fieldPath = appendPath fieldName path
     (fieldName,) <$> case field' of
-      FCol c -> pure $ FCol c
-      FObj annRel ->
-        FObj <$> transformAnnRelation fieldPath annRel
-      FArr (ASSimple annRel) ->
-        FArr . ASSimple <$> transformAnnRelation fieldPath annRel
-      FArr (ASAgg aggRel) ->
-        FArr . ASAgg <$> transformAnnAggregateRelation fieldPath aggRel
-      -- AFArrayRelation (ASConnection annRel) ->
-      --   AFArrayRelation . ASConnection <$> transformArrayConnection fieldPath annRel
-      FComputedField computedField ->
-        FComputedField <$> case computedField of
+      AFNodeId qt pkeys -> pure $ AFNodeId qt pkeys
+      AFColumn c -> pure $ AFColumn c
+      AFObjectRelation annRel ->
+        AFObjectRelation <$> transformAnnRelation fieldPath annRel
+      AFArrayRelation (ASSimple annRel) ->
+        AFArrayRelation . ASSimple <$> transformAnnRelation fieldPath annRel
+      AFArrayRelation (ASAggregate aggRel) ->
+        AFArrayRelation . ASAggregate <$> transformAnnAggregateRelation fieldPath aggRel
+      AFArrayRelation (ASConnection annRel) ->
+        AFArrayRelation . ASConnection <$> transformArrayConnection fieldPath annRel
+      AFComputedField computedField ->
+        AFComputedField <$> case computedField of
           CFSScalar _         -> pure computedField
           CFSTable jas annSel -> CFSTable jas <$> transformSelect fieldPath annSel
-      FRemote rs -> pure $ FRemote rs
+      AFRemote rs -> pure $ AFRemote rs
+      AFExpression t     -> pure $ AFExpression t
 
   case NE.nonEmpty remoteJoins of
     Nothing -> pure transformedFields
     Just nonEmptyRemoteJoins -> do
-      let phantomColumns = map (\ci -> (fromPGCol $ pgiColumn ci, FCol $ AnnColField ci False Nothing)) $
+      let phantomColumns = map (\ci -> (fromPGCol $ pgiColumn ci, AFColumn $ AnnColumnField ci False Nothing)) $
                            concatMap _rjPhantomFields remoteJoins
       modify (Map.insert path nonEmptyRemoteJoins)
       pure $ transformedFields <> phantomColumns
     where
       getFields f = mapMaybe (sequence . second (^? f))
       transformAnnRelation fieldPath annRel = do
-        let annSel = aarAnnSel annRel
+        let annSel = aarAnnSelect annRel
         transformedSel <- transformSelect fieldPath annSel
-        pure annRel{aarAnnSel = transformedSel}
+        pure annRel{aarAnnSelect = transformedSel}
 
       transformAnnAggregateRelation fieldPath annRel = do
-        let annSel = aarAnnSel annRel
+        let annSel = aarAnnSelect annRel
         transformedSel <- transformAggregateSelect fieldPath annSel
-        pure annRel{aarAnnSel = transformedSel}
+        pure annRel{aarAnnSelect = transformedSel}
 
-      -- transformArrayConnection fieldPath annRel = do
-      --   let connectionSelect = aarAnnSelect annRel
-      --   transformedConnectionSelect <- transformConnectionSelect fieldPath connectionSelect
-      --   pure annRel{aarAnnSelect = transformedConnectionSelect}
+      transformArrayConnection fieldPath annRel = do
+        let connectionSelect = aarAnnSelect annRel
+        transformedConnectionSelect <- transformConnectionSelect fieldPath connectionSelect
+        pure annRel{aarAnnSelect = transformedConnectionSelect}
 
 type CompositeObject a = OMap.InsOrdHashMap Text (CompositeValue a)
 
@@ -338,7 +335,7 @@ traverseQueryResponseJSON rjm =
                   A.Number val ->
                     case (toBoundedInteger val) of
                       Just intVal -> pure $  G.VInt intVal
-                      Nothing -> pure $  G.VFloat $ toRealFloat val
+                      Nothing     -> pure $  G.VFloat $ toRealFloat val
                   A.Array vals -> G.VList <$> traverse go (toList vals)
                   A.Object vals ->
                     G.VObject . Map.fromList <$> for (Map.toList vals) \(key, val) -> do

server/src-lib/Hasura/RQL/DML/Returning.hs

@@ -10,7 +10,6 @@ import           Hasura.SQL.Types
 import qualified Data.Text                      as T
 import qualified Hasura.SQL.DML                 as S
 
-
 traverseMutFld
   :: (Applicative f)
   => (a -> f b)
@@ -19,8 +18,7 @@ traverseMutFld
 traverseMutFld f = \case
   MCount    -> pure MCount
   MExp t    -> pure $ MExp t
-  MRet flds -> MRet <$> traverse (traverse (traverseAnnFld f)) flds
-
+  MRet flds -> MRet <$> traverse (traverse (traverseAnnField f)) flds
 
 traverseMutationOutput
   :: (Applicative f)
@@ -30,7 +28,7 @@ traverseMutationOutput f = \case
   MOutMultirowFields mutationFields ->
     MOutMultirowFields <$> traverse (traverse (traverseMutFld f)) mutationFields
   MOutSinglerowObject annFields ->
-    MOutSinglerowObject <$> traverseAnnFlds f annFields
+    MOutSinglerowObject <$> traverseAnnFields f annFields
 
 traverseMutFlds
   :: (Applicative f)
@@ -43,15 +41,15 @@ traverseMutFlds f =
 hasNestedFld :: MutationOutputG a -> Bool
 hasNestedFld = \case
   MOutMultirowFields flds -> any isNestedMutFld flds
-  MOutSinglerowObject annFlds -> any isNestedAnnFld annFlds
+  MOutSinglerowObject annFlds -> any isNestedAnnField annFlds
   where
     isNestedMutFld (_, mutFld) = case mutFld of
-      MRet annFlds -> any isNestedAnnFld annFlds
+      MRet annFlds -> any isNestedAnnField annFlds
       _            -> False
-    isNestedAnnFld (_, annFld) = case annFld of
-      FObj _ -> True
-      FArr _ -> True
-      _      -> False
+    isNestedAnnField (_, annFld) = case annFld of
+      AFObjectRelation _ -> True
+      AFArrayRelation _  -> True
+      _                  -> False
 
 pgColsFromMutFld :: MutFld -> [(PGCol, PGColumnType)]
 pgColsFromMutFld = \case
@@ -59,16 +57,16 @@ pgColsFromMutFld = \case
   MExp _ -> []
   MRet selFlds ->
     flip mapMaybe selFlds $ \(_, annFld) -> case annFld of
-    FCol (AnnColField (PGColumnInfo col _ _ colTy _ _) _ _) -> Just (col, colTy)
-    _                                                       -> Nothing
+    AFColumn (AnnColumnField (PGColumnInfo col _ _ colTy _ _) _ _) -> Just (col, colTy)
+    _                                                              -> Nothing
 
 pgColsFromMutFlds :: MutFlds -> [(PGCol, PGColumnType)]
 pgColsFromMutFlds = concatMap (pgColsFromMutFld . snd)
 
-pgColsToSelFlds :: [PGColumnInfo] -> [(FieldName, AnnFld)]
+pgColsToSelFlds :: [PGColumnInfo] -> [(FieldName, AnnField)]
 pgColsToSelFlds cols =
   flip map cols $
-  \pgColInfo -> (fromPGCol $ pgiColumn pgColInfo, mkAnnColField pgColInfo Nothing)
+  \pgColInfo -> (fromPGCol $ pgiColumn pgColInfo, mkAnnColumnField pgColInfo Nothing)
 
 mkDefaultMutFlds :: Maybe [PGColumnInfo] -> MutationOutput
 mkDefaultMutFlds = MOutMultirowFields . \case
@@ -95,7 +93,7 @@ mkMutFldExp qt preCalAffRows strfyNum = \case
     let tabFrom = FromIden cteAlias
         tabPerm = TablePerm annBoolExpTrue Nothing
     in S.SESelect $ mkSQLSelect JASMultipleRows $
-       AnnSelG selFlds tabFrom tabPerm noTableArgs strfyNum
+       AnnSelectG selFlds tabFrom tabPerm noSelectArgs strfyNum
   where
     cteAlias = qualTableToAliasIden qt
 
@@ -117,7 +115,7 @@ mkMutationOutputExp qt preCalAffRows cte mutOutput strfyNum =
         let tabFrom = FromIden cteAlias
             tabPerm = TablePerm annBoolExpTrue Nothing
         in S.SESelect $ mkSQLSelect JASSingleObject $
-           AnnSelG annFlds tabFrom tabPerm noTableArgs strfyNum
+           AnnSelectG annFlds tabFrom tabPerm noSelectArgs strfyNum
 
 
 checkRetCols

server/src-lib/Hasura/RQL/DML/Returning/Types.hs

@@ -12,7 +12,7 @@ import           Hasura.RQL.DML.Select.Types
 data MutFldG v
   = MCount
   | MExp !T.Text
-  | MRet !(AnnFldsG v)
+  | MRet !(AnnFieldsG v)
   deriving (Show, Eq)
 
 type MutFld = MutFldG S.SQLExp
@@ -21,7 +21,7 @@ type MutFldsG v = Fields (MutFldG v)
 
 data MutationOutputG v
   = MOutMultirowFields !(MutFldsG v)
-  | MOutSinglerowObject !(AnnFldsG v)
+  | MOutSinglerowObject !(AnnFieldsG v)
   deriving (Show, Eq)
 
 type MutationOutput = MutationOutputG S.SQLExp

server/src-lib/Hasura/RQL/DML/Select.hs

@@ -1,11 +1,11 @@
 module Hasura.RQL.DML.Select
   ( selectP2
-  , selectQuerySQL
-  , selectAggQuerySQL
   , convSelectQuery
   , asSingleRowJsonResp
-  , module Hasura.RQL.DML.Select.Internal
   , runSelect
+  , selectQuerySQL
+  , selectAggregateQuerySQL
+  , module Hasura.RQL.DML.Select.Internal
   )
 where
 
@@ -105,7 +105,7 @@ convOrderByElem
   => SessVarBldr m
   -> (FieldInfoMap FieldInfo, SelPermInfo)
   -> OrderByCol
-  -> m AnnObCol
+  -> m (AnnOrderByElement S.SQLExp)
 convOrderByElem sessVarBldr (flds, spi) = \case
   OCPG fldName -> do
     fldInfo <- askFieldInfo flds fldName
@@ -118,7 +118,7 @@ convOrderByElem sessVarBldr (flds, spi) = \case
            [ fldName <<> " has type 'geometry'"
            , " and cannot be used in order_by"
            ]
-          else return $ AOCPG $ pgiColumn colInfo
+          else return $ AOCColumn colInfo
       FIRelationship _ -> throw400 UnexpectedPayload $ mconcat
         [ fldName <<> " is a"
         , " relationship and should be expanded"
@@ -149,7 +149,7 @@ convOrderByElem sessVarBldr (flds, spi) = \case
           ]
         (relFim, relSpi) <- fetchRelDet (riName relInfo) (riRTable relInfo)
         resolvedSelFltr <- convAnnBoolExpPartialSQL sessVarBldr $ spiFilter relSpi
-        AOCObj relInfo resolvedSelFltr <$>
+        AOCObjectRelation relInfo resolvedSelFltr <$>
           convOrderByElem sessVarBldr (relFim, relSpi) rest
       FIRemoteRelationship {} ->
         throw400 UnexpectedPayload (mconcat [ fldName <<> " is a remote field" ])
@@ -168,12 +168,12 @@ convSelectQ fieldInfoMap selPermInfo selQ sessVarBldr prepValBldr = do
     indexedForM (sqColumns selQ) $ \case
     (ECSimple pgCol) -> do
       colInfo <- convExtSimple fieldInfoMap selPermInfo pgCol
-      return (fromPGCol pgCol, mkAnnColField colInfo Nothing)
+      return (fromPGCol pgCol, mkAnnColumnField colInfo Nothing)
     (ECRel relName mAlias relSelQ) -> do
       annRel <- convExtRel fieldInfoMap relName mAlias
                 relSelQ sessVarBldr prepValBldr
       return ( fromRel $ fromMaybe relName mAlias
-             , either FObj FArr annRel
+             , either AFObjectRelation AFArrayRelation annRel
              )
 
   -- let spiT = spiTable selPermInfo
@@ -198,11 +198,11 @@ convSelectQ fieldInfoMap selPermInfo selQ sessVarBldr prepValBldr = do
 
   let tabFrom = FromTable $ spiTable selPermInfo
       tabPerm = TablePerm resolvedSelFltr mPermLimit
-      tabArgs = TableArgs wClause annOrdByM mQueryLimit
+      tabArgs = SelectArgs wClause annOrdByM mQueryLimit
                 (S.intToSQLExp <$> mQueryOffset) Nothing
 
   strfyNum <- stringifyNum <$> askSQLGenCtx
-  return $ AnnSelG annFlds tabFrom tabPerm tabArgs strfyNum
+  return $ AnnSelectG annFlds tabFrom tabPerm tabArgs strfyNum
 
   where
     mQueryOffset = sqOffset selQ
@@ -229,7 +229,7 @@ convExtRel
   -> SelectQExt
   -> SessVarBldr m
   -> (PGColumnType -> Value -> m S.SQLExp)
-  -> m (Either ObjSel ArrSel)
+  -> m (Either ObjectRelationSelect ArraySelect)
 convExtRel fieldInfoMap relName mAlias selQ sessVarBldr prepValBldr = do
   -- Point to the name key
   relInfo <- withPathK "name" $
@@ -240,9 +240,9 @@ convExtRel fieldInfoMap relName mAlias selQ sessVarBldr prepValBldr = do
   case relTy of
     ObjRel -> do
       when misused $ throw400 UnexpectedPayload objRelMisuseMsg
-      return $ Left $ AnnRelG (fromMaybe relName mAlias) colMapping annSel
+      return $ Left $ AnnRelationSelectG (fromMaybe relName mAlias) colMapping annSel
     ArrRel ->
-      return $ Right $ ASSimple $ AnnRelG (fromMaybe relName mAlias)
+      return $ Right $ ASSimple $ AnnRelationSelectG (fromMaybe relName mAlias)
                colMapping annSel
   where
     pgWhenRelErr = "only relationships can be expanded"
@@ -270,8 +270,7 @@ convSelectQuery sessVarBldr prepArgBuilder (DMLQuery qt selQ) = do
   let fieldInfo = _tciFieldInfoMap $ _tiCoreInfo tabInfo
   extSelQ <- resolveStar fieldInfo selPermInfo selQ
   validateHeaders $ spiRequiredHeaders selPermInfo
-  convSelectQ fieldInfo selPermInfo
-    extSelQ sessVarBldr prepArgBuilder
+  convSelectQ fieldInfo selPermInfo extSelQ sessVarBldr prepArgBuilder
 
 selectP2 :: JsonAggSelect -> (AnnSimpleSel, DS.Seq Q.PrepArg) -> Q.TxE QErr EncJSON
 selectP2 jsonAggSelect (sel, p) =
@@ -284,9 +283,9 @@ selectQuerySQL :: JsonAggSelect -> AnnSimpleSel -> Q.Query
 selectQuerySQL jsonAggSelect sel =
   Q.fromBuilder $ toSQL $ mkSQLSelect jsonAggSelect sel
 
-selectAggQuerySQL :: AnnAggSel -> Q.Query
-selectAggQuerySQL =
-  Q.fromBuilder . toSQL . mkAggSelect
+selectAggregateQuerySQL :: AnnAggregateSelect -> Q.Query
+selectAggregateQuerySQL =
+  Q.fromBuilder . toSQL . mkAggregateSelect
 
 asSingleRowJsonResp :: Q.Query -> [Q.PrepArg] -> Q.TxE QErr EncJSON
 asSingleRowJsonResp query args =

server/src-lib/Hasura/RQL/DML/Select/Types.hs

@@ -3,19 +3,19 @@
 
 module Hasura.RQL.DML.Select.Types where
 
+import           Control.Lens.TH                     (makeLenses, makePrisms)
 import           Data.Aeson.Types
-import           Language.Haskell.TH.Syntax   (Lift)
-import           Control.Lens.TH              (makePrisms)
+import           Language.Haskell.TH.Syntax          (Lift)
 
-import qualified Data.HashMap.Strict           as HM
-import qualified Data.List.NonEmpty            as NE
-import qualified Data.Sequence                 as Seq
-import qualified Data.Text                     as T
-import qualified Data.Aeson                    as J
-import qualified Language.GraphQL.Draft.Syntax as G
+import qualified Data.Aeson                          as J
+import qualified Data.HashMap.Strict                 as HM
+import qualified Data.List.NonEmpty                  as NE
+import qualified Data.Sequence                       as Seq
+import qualified Data.Text                           as T
+import qualified Language.GraphQL.Draft.Syntax       as G
 
-import           Hasura.Prelude
 import           Hasura.GraphQL.Parser.Schema
+import           Hasura.Prelude
 import           Hasura.RQL.Types.BoolExp
 import           Hasura.RQL.Types.Column
 import           Hasura.RQL.Types.Common
@@ -23,7 +23,7 @@ import           Hasura.RQL.Types.DML
 import           Hasura.RQL.Types.Function
 import           Hasura.RQL.Types.RemoteRelationship
 import           Hasura.RQL.Types.RemoteSchema
-import qualified Hasura.SQL.DML             as S
+import qualified Hasura.SQL.DML                      as S
 import           Hasura.SQL.Types
 
 type SelectQExt = SelectG ExtCol BoolExp Int
@@ -31,7 +31,8 @@ type SelectQExt = SelectG ExtCol BoolExp Int
 data JsonAggSelect
   = JASMultipleRows
   | JASSingleObject
-  deriving (Show, Eq)
+  deriving (Show, Eq, Generic)
+instance Hashable JsonAggSelect
 
 -- Columns in RQL
 data ExtCol
@@ -60,118 +61,129 @@ instance FromJSON ExtCol where
     , "object (relationship)"
     ]
 
-data AnnAggOrdBy
+data AnnAggregateOrderBy
   = AAOCount
-  | AAOOp !T.Text !PGCol
-  deriving (Show, Eq)
+  | AAOOp !T.Text !PGColumnInfo
+  deriving (Show, Eq, Generic)
+instance Hashable AnnAggregateOrderBy
 
-data AnnObColG v
-  = AOCPG !PGCol
-  | AOCObj !RelInfo !(AnnBoolExp v) !(AnnObColG v)
-  | AOCAgg !RelInfo !(AnnBoolExp v) !AnnAggOrdBy
-  deriving (Show, Eq)
+data AnnOrderByElementG v
+  = AOCColumn !PGColumnInfo
+  | AOCObjectRelation !RelInfo !v !(AnnOrderByElementG v)
+  | AOCArrayAggregation !RelInfo !v !AnnAggregateOrderBy
+  deriving (Show, Eq, Generic, Functor)
+instance (Hashable v) => Hashable (AnnOrderByElementG v)
 
-traverseAnnObCol
+type AnnOrderByElement v = AnnOrderByElementG (AnnBoolExp v)
+
+traverseAnnOrderByElement
   :: (Applicative f)
-  => (a -> f b) -> AnnObColG a -> f (AnnObColG b)
-traverseAnnObCol f = \case
-  AOCPG pgColInfo -> pure $ AOCPG pgColInfo
-  AOCObj relInfo annBoolExp annObCol ->
-    AOCObj relInfo
+  => (a -> f b) -> AnnOrderByElement a -> f (AnnOrderByElement b)
+traverseAnnOrderByElement f = \case
+  AOCColumn pgColInfo -> pure $ AOCColumn pgColInfo
+  AOCObjectRelation relInfo annBoolExp annObCol ->
+    AOCObjectRelation relInfo
     <$> traverseAnnBoolExp f annBoolExp
-    <*> traverseAnnObCol f annObCol
-  AOCAgg relInfo annBoolExp annAggOb ->
-    AOCAgg relInfo
+    <*> traverseAnnOrderByElement f annObCol
+  AOCArrayAggregation relInfo annBoolExp annAggOb ->
+    AOCArrayAggregation relInfo
     <$> traverseAnnBoolExp f annBoolExp
     <*> pure annAggOb
 
-type AnnObCol = AnnObColG S.SQLExp
-
-type AnnOrderByItemG v = OrderByItemG (AnnObColG v)
+type AnnOrderByItemG v = OrderByItemG (AnnOrderByElement v)
 
 traverseAnnOrderByItem
   :: (Applicative f)
   => (a -> f b) -> AnnOrderByItemG a -> f (AnnOrderByItemG b)
 traverseAnnOrderByItem f =
-  traverse (traverseAnnObCol f)
+  traverse (traverseAnnOrderByElement f)
 
 type AnnOrderByItem = AnnOrderByItemG S.SQLExp
 
-data AnnRelG a
-  = AnnRelG
-  { aarName    :: !RelName -- Relationship name
-  , aarMapping :: !(HashMap PGCol PGCol) -- Column of left table to join with
-  , aarAnnSel  :: !a -- Current table. Almost ~ to SQL Select
+type OrderByItemExp =
+  OrderByItemG (AnnOrderByElement S.SQLExp, (S.Alias, S.SQLExp))
+
+data AnnRelationSelectG a
+  = AnnRelationSelectG
+  { aarRelationshipName :: !RelName -- Relationship name
+  , aarColumnMapping    :: !(HashMap PGCol PGCol) -- Column of left table to join with
+  , aarAnnSelect        :: !a -- Current table. Almost ~ to SQL Select
   } deriving (Show, Eq, Functor, Foldable, Traversable)
 
-type ObjSelG v = AnnRelG (AnnSimpleSelG v)
-type ObjSel = ObjSelG S.SQLExp
+type ObjectRelationSelectG v = AnnRelationSelectG (AnnSimpleSelG v)
+type ObjectRelationSelect = ObjectRelationSelectG S.SQLExp
 
-type ArrRelG v = AnnRelG (AnnSimpleSelG v)
-type ArrRelAggG v = AnnRelG (AnnAggSelG v)
-type ArrRelAgg = ArrRelAggG S.SQLExp
+type ArrayRelationSelectG v = AnnRelationSelectG (AnnSimpleSelG v)
+type ArrayAggregateSelectG v = AnnRelationSelectG (AnnAggregateSelectG v)
+type ArrayConnectionSelect v = AnnRelationSelectG (ConnectionSelect v)
+type ArrayAggregateSelect = ArrayAggregateSelectG S.SQLExp
 
-data ComputedFieldScalarSel v
-  = ComputedFieldScalarSel
+data ComputedFieldScalarSelect v
+  = ComputedFieldScalarSelect
   { _cfssFunction  :: !QualifiedFunction
   , _cfssArguments :: !(FunctionArgsExpTableRow v)
   , _cfssType      :: !PGScalarType
-  , _cfssColumnOp  :: !(Maybe ColOp)
+  , _cfssColumnOp  :: !(Maybe ColumnOp)
   } deriving (Show, Eq, Functor, Foldable, Traversable)
 
-data ComputedFieldSel v
-  = CFSScalar !(ComputedFieldScalarSel v)
+data ComputedFieldSelect v
+  = CFSScalar !(ComputedFieldScalarSelect v)
   | CFSTable !JsonAggSelect !(AnnSimpleSelG v)
   deriving (Show, Eq)
 
-traverseComputedFieldSel
+traverseComputedFieldSelect
   :: (Applicative f)
   => (v -> f w)
-  -> ComputedFieldSel v -> f (ComputedFieldSel w)
-traverseComputedFieldSel fv = \case
+  -> ComputedFieldSelect v -> f (ComputedFieldSelect w)
+traverseComputedFieldSelect fv = \case
   CFSScalar scalarSel -> CFSScalar <$> traverse fv scalarSel
-  CFSTable b tableSel -> CFSTable b <$> traverseAnnSimpleSel fv tableSel
+  CFSTable b tableSel -> CFSTable b <$> traverseAnnSimpleSelect fv tableSel
 
 type Fields a = [(FieldName, a)]
 
-data ArrSelG v
-  = ASSimple !(ArrRelG v)
-  | ASAgg !(ArrRelAggG v)
+data ArraySelectG v
+  = ASSimple !(ArrayRelationSelectG v)
+  | ASAggregate !(ArrayAggregateSelectG v)
+  | ASConnection !(ArrayConnectionSelect v)
   deriving (Show, Eq)
 
-traverseArrSel
+traverseArraySelect
   :: (Applicative f)
   => (a -> f b)
-  -> ArrSelG a
-  -> f (ArrSelG b)
-traverseArrSel f = \case
-  ASSimple arrRel -> ASSimple <$> traverse (traverseAnnSimpleSel f) arrRel
-  ASAgg arrRelAgg -> ASAgg <$> traverse (traverseAnnAggSel f) arrRelAgg
+  -> ArraySelectG a
+  -> f (ArraySelectG b)
+traverseArraySelect f = \case
+  ASSimple arrRel ->
+    ASSimple <$> traverse (traverseAnnSimpleSelect f) arrRel
+  ASAggregate arrRelAgg ->
+    ASAggregate <$> traverse (traverseAnnAggregateSelect f) arrRelAgg
+  ASConnection relConnection ->
+    ASConnection <$> traverse (traverseConnectionSelect f) relConnection
 
-type ArrSel = ArrSelG S.SQLExp
+type ArraySelect = ArraySelectG S.SQLExp
 
-type ArrSelFldsG v = Fields (ArrSelG v)
+type ArraySelectFieldsG v = Fields (ArraySelectG v)
 
-data ColOp
-  = ColOp
+data ColumnOp
+  = ColumnOp
   { _colOp  :: S.SQLOp
   , _colExp :: S.SQLExp
   } deriving (Show, Eq)
 
-data AnnColField
-  = AnnColField
+data AnnColumnField
+  = AnnColumnField
   { _acfInfo   :: !PGColumnInfo
   , _acfAsText :: !Bool
   -- ^ If this field is 'True', columns are explicitly casted to @text@ when fetched, which avoids
   -- an issue that occurs because we don’t currently have proper support for array types. See
   -- https://github.com/hasura/graphql-engine/pull/3198 for more details.
-  , _acfOp     :: !(Maybe ColOp)
+  , _acfOp     :: !(Maybe ColumnOp)
   } deriving (Show, Eq)
 
 data RemoteFieldArgument
   = RemoteFieldArgument
-  { _rfaName :: !G.Name
-  , _rfaValue :: !(G.Value Variable)
+  { _rfaName     :: !G.Name
+  , _rfaValue    :: !(G.Value Variable)
   , _rfaVariable :: !(Maybe [(G.VariableDefinition,J.Value)])
   } deriving (Eq,Show)
 
@@ -184,50 +196,53 @@ data RemoteSelect
   , _rselRemoteSchema  :: !RemoteSchemaInfo
   } deriving (Show,Eq)
 
-data AnnFldG v
-  = FCol !AnnColField
-  | FObj !(ObjSelG v)
-  | FArr !(ArrSelG v)
-  | FComputedField !(ComputedFieldSel v)
-  | FExp !T.Text
-  | FRemote !RemoteSelect
-  deriving (Show,Eq)
+data AnnFieldG v
+  = AFColumn !AnnColumnField
+  | AFObjectRelation !(ObjectRelationSelectG v)
+  | AFArrayRelation !(ArraySelectG v)
+  | AFComputedField !(ComputedFieldSelect v)
+  | AFRemote !RemoteSelect
+  | AFNodeId !QualifiedTable !(NonEmpty PGColumnInfo)
+  | AFExpression !T.Text
+  deriving (Show, Eq)
 
-mkAnnColField :: PGColumnInfo -> Maybe ColOp -> AnnFldG v
-mkAnnColField ci colOpM =
-  FCol $ AnnColField ci False colOpM
+mkAnnColumnField :: PGColumnInfo -> Maybe ColumnOp -> AnnFieldG v
+mkAnnColumnField ci colOpM =
+  AFColumn $ AnnColumnField ci False colOpM
 
-mkAnnColFieldAsText :: PGColumnInfo -> AnnFldG v
-mkAnnColFieldAsText ci =
-  FCol $ AnnColField ci True Nothing
+mkAnnColumnFieldAsText :: PGColumnInfo -> AnnFieldG v
+mkAnnColumnFieldAsText ci =
+  AFColumn $ AnnColumnField ci True Nothing
 
-traverseAnnFld
+traverseAnnField
   :: (Applicative f)
-  => (a -> f b) -> AnnFldG a -> f (AnnFldG b)
-traverseAnnFld f = \case
-  FCol colFld -> pure $ FCol colFld
-  FObj sel -> FObj <$> traverse (traverseAnnSimpleSel f) sel
-  FArr sel -> FArr <$> traverseArrSel f sel
-  FComputedField sel -> FComputedField <$> traverseComputedFieldSel f sel
-  FExp t -> FExp <$> pure t
-  FRemote s -> pure $ FRemote s
+  => (a -> f b) -> AnnFieldG a -> f (AnnFieldG b)
+traverseAnnField f = \case
+  AFColumn colFld -> pure $ AFColumn colFld
+  AFObjectRelation sel -> AFObjectRelation <$> traverse (traverseAnnSimpleSelect f) sel
+  AFArrayRelation sel -> AFArrayRelation <$> traverseArraySelect f sel
+  AFComputedField sel -> AFComputedField <$> traverseComputedFieldSelect f sel
+  AFRemote s -> pure $ AFRemote s
+  AFNodeId qt pKeys -> pure $ AFNodeId qt pKeys
+  AFExpression t -> AFExpression <$> pure t
 
-type AnnFld = AnnFldG S.SQLExp
+type AnnField = AnnFieldG S.SQLExp
 
-data TableArgsG v
-  = TableArgs
-  { _taWhere    :: !(Maybe (AnnBoolExp v))
-  , _taOrderBy  :: !(Maybe (NE.NonEmpty (AnnOrderByItemG v)))
-  , _taLimit    :: !(Maybe Int)
-  , _taOffset   :: !(Maybe S.SQLExp)
-  , _taDistCols :: !(Maybe (NE.NonEmpty PGCol))
-  } deriving (Show, Eq)
+data SelectArgsG v
+  = SelectArgs
+  { _saWhere    :: !(Maybe (AnnBoolExp v))
+  , _saOrderBy  :: !(Maybe (NE.NonEmpty (AnnOrderByItemG v)))
+  , _saLimit    :: !(Maybe Int)
+  , _saOffset   :: !(Maybe S.SQLExp)
+  , _saDistinct :: !(Maybe (NE.NonEmpty PGCol))
+  } deriving (Show, Eq, Generic)
+instance (Hashable v) => Hashable (SelectArgsG v)
 
-traverseTableArgs
+traverseSelectArgs
   :: (Applicative f)
-  => (a -> f b) -> TableArgsG a -> f (TableArgsG b)
-traverseTableArgs f (TableArgs wh ordBy lmt ofst distCols) =
-  TableArgs
+  => (a -> f b) -> SelectArgsG a -> f (SelectArgsG b)
+traverseSelectArgs f (SelectArgs wh ordBy lmt ofst distCols) =
+  SelectArgs
   <$> traverse (traverseAnnBoolExp f) wh
   -- traversing through maybe -> nonempty -> annorderbyitem
   <*> traverse (traverse (traverseAnnOrderByItem f)) ordBy
@@ -235,62 +250,103 @@ traverseTableArgs f (TableArgs wh ordBy lmt ofst distCols) =
   <*> pure ofst
   <*> pure distCols
 
-type TableArgs = TableArgsG S.SQLExp
+type SelectArgs = SelectArgsG S.SQLExp
 
-noTableArgs :: TableArgsG v
-noTableArgs = TableArgs Nothing Nothing Nothing Nothing Nothing
+noSelectArgs :: SelectArgsG v
+noSelectArgs = SelectArgs Nothing Nothing Nothing Nothing Nothing
 
 data PGColFld
   = PCFCol !PGCol
   | PCFExp !T.Text
   deriving (Show, Eq)
 
-type ColFlds = Fields PGColFld
+type ColumnFields = Fields PGColFld
 
-data AggOp
-  = AggOp
-  { _aoOp   :: !T.Text
-  , _aoFlds :: !ColFlds
+data AggregateOp
+  = AggregateOp
+  { _aoOp     :: !T.Text
+  , _aoFields :: !ColumnFields
   } deriving (Show, Eq)
 
-data AggFld
+data AggregateField
   = AFCount !S.CountType
-  | AFOp !AggOp
+  | AFOp !AggregateOp
   | AFExp !T.Text
   deriving (Show, Eq)
 
-type AggFlds = Fields AggFld
-type AnnFldsG v = Fields (AnnFldG v)
+type AggregateFields = Fields AggregateField
+type AnnFieldsG v = Fields (AnnFieldG v)
 
-traverseAnnFlds
+traverseAnnFields
   :: (Applicative f)
-  => (a -> f b) -> AnnFldsG a -> f (AnnFldsG b)
-traverseAnnFlds f = traverse (traverse (traverseAnnFld f))
+  => (a -> f b) -> AnnFieldsG a -> f (AnnFieldsG b)
+traverseAnnFields f = traverse (traverse (traverseAnnField f))
 
-type AnnFlds = AnnFldsG S.SQLExp
+type AnnFields = AnnFieldsG S.SQLExp
 
-data TableAggFldG v
-  = TAFAgg !AggFlds
-  | TAFNodes !(AnnFldsG v)
+data TableAggregateFieldG v
+  = TAFAgg !AggregateFields
+  | TAFNodes !(AnnFieldsG v)
   | TAFExp !T.Text
   deriving (Show, Eq)
 
-traverseTableAggFld
+data PageInfoField
+  = PageInfoTypename !Text
+  | PageInfoHasNextPage
+  | PageInfoHasPreviousPage
+  | PageInfoStartCursor
+  | PageInfoEndCursor
+  deriving (Show, Eq)
+type PageInfoFields = Fields PageInfoField
+
+data EdgeField v
+  = EdgeTypename !Text
+  | EdgeCursor
+  | EdgeNode !(AnnFieldsG v)
+  deriving (Show, Eq)
+type EdgeFields v = Fields (EdgeField v)
+
+traverseEdgeField
   :: (Applicative f)
-  => (a -> f b) -> TableAggFldG a -> f (TableAggFldG b)
-traverseTableAggFld f = \case
+  => (a -> f b) -> EdgeField a -> f (EdgeField b)
+traverseEdgeField f = \case
+  EdgeTypename t  -> pure $ EdgeTypename t
+  EdgeCursor      -> pure EdgeCursor
+  EdgeNode fields -> EdgeNode <$> traverseAnnFields f fields
+
+data ConnectionField v
+  = ConnectionTypename !Text
+  | ConnectionPageInfo !PageInfoFields
+  | ConnectionEdges !(EdgeFields v)
+  deriving (Show, Eq)
+type ConnectionFields v = Fields (ConnectionField v)
+
+traverseConnectionField
+  :: (Applicative f)
+  => (a -> f b) -> ConnectionField a -> f (ConnectionField b)
+traverseConnectionField f = \case
+  ConnectionTypename t -> pure $ ConnectionTypename t
+  ConnectionPageInfo fields -> pure $ ConnectionPageInfo fields
+  ConnectionEdges fields ->
+    ConnectionEdges <$> traverse (traverse (traverseEdgeField f)) fields
+
+traverseTableAggregateField
+  :: (Applicative f)
+  => (a -> f b) -> TableAggregateFieldG a -> f (TableAggregateFieldG b)
+traverseTableAggregateField f = \case
   TAFAgg aggFlds -> pure $ TAFAgg aggFlds
-  TAFNodes annFlds -> TAFNodes <$> traverseAnnFlds f annFlds
+  TAFNodes annFlds -> TAFNodes <$> traverseAnnFields f annFlds
   TAFExp t -> pure $ TAFExp t
 
-type TableAggFld = TableAggFldG S.SQLExp
-type TableAggFldsG v = Fields (TableAggFldG v)
-type TableAggFlds = TableAggFldsG S.SQLExp
+type TableAggregateField = TableAggregateFieldG S.SQLExp
+type TableAggregateFieldsG v = Fields (TableAggregateFieldG v)
+type TableAggregateFields = TableAggregateFieldsG S.SQLExp
 
 data ArgumentExp a
   = AETableRow !(Maybe Iden) -- ^ table row accessor
   | AEInput !a
-  deriving (Show, Eq, Functor, Foldable, Traversable)
+  deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
+instance (Hashable v) => Hashable (ArgumentExp v)
 
 type FunctionArgsExpTableRow v = FunctionArgsExpG (ArgumentExp v)
 
@@ -299,8 +355,10 @@ data SelectFromG v
   | FromIden !Iden
   | FromFunction !QualifiedFunction
                  !(FunctionArgsExpTableRow v)
+                 -- a definition list
                  !(Maybe [(PGCol, PGScalarType)])
-  deriving (Show, Eq, Functor, Foldable, Traversable)
+  deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
+instance (Hashable v) => Hashable (SelectFromG v)
 
 type SelectFrom = SelectFromG S.SQLExp
 
@@ -308,7 +366,8 @@ data TablePermG v
   = TablePerm
   { _tpFilter :: !(AnnBoolExp v)
   , _tpLimit  :: !(Maybe Int)
-  } deriving (Eq, Show)
+  } deriving (Eq, Show, Generic)
+instance (Hashable v) => Hashable (TablePermG v)
 
 traverseTablePerm
   :: (Applicative f)
@@ -326,62 +385,105 @@ noTablePermissions =
 
 type TablePerm = TablePermG S.SQLExp
 
-data AnnSelG a v
-  = AnnSelG
+data AnnSelectG a v
+  = AnnSelectG
   { _asnFields   :: !a
   , _asnFrom     :: !(SelectFromG v)
   , _asnPerm     :: !(TablePermG v)
-  , _asnArgs     :: !(TableArgsG v)
+  , _asnArgs     :: !(SelectArgsG v)
   , _asnStrfyNum :: !Bool
   } deriving (Show, Eq)
 
-getPermLimit :: AnnSelG a v -> Maybe Int
-getPermLimit = _tpLimit . _asnPerm
-
-traverseAnnSimpleSel
+traverseAnnSimpleSelect
   :: (Applicative f)
   => (a -> f b)
   -> AnnSimpleSelG a -> f (AnnSimpleSelG b)
-traverseAnnSimpleSel f = traverseAnnSel (traverseAnnFlds f) f
+traverseAnnSimpleSelect f = traverseAnnSelect (traverseAnnFields f) f
 
-traverseAnnAggSel
+traverseAnnAggregateSelect
   :: (Applicative f)
   => (a -> f b)
-  -> AnnAggSelG a -> f (AnnAggSelG b)
-traverseAnnAggSel f =
-  traverseAnnSel (traverse (traverse (traverseTableAggFld f))) f
+  -> AnnAggregateSelectG a -> f (AnnAggregateSelectG b)
+traverseAnnAggregateSelect f =
+  traverseAnnSelect (traverse (traverse (traverseTableAggregateField f))) f
 
-traverseAnnSel
+traverseAnnSelect
   :: (Applicative f)
   => (a -> f b) -> (v -> f w)
-  -> AnnSelG a v -> f (AnnSelG b w)
-traverseAnnSel f1 f2 (AnnSelG flds tabFrom perm args strfyNum) =
-  AnnSelG
+  -> AnnSelectG a v -> f (AnnSelectG b w)
+traverseAnnSelect f1 f2 (AnnSelectG flds tabFrom perm args strfyNum) =
+  AnnSelectG
   <$> f1 flds
   <*> traverse f2 tabFrom
   <*> traverseTablePerm f2 perm
-  <*> traverseTableArgs f2 args
+  <*> traverseSelectArgs f2 args
   <*> pure strfyNum
 
-type AnnSimpleSelG v = AnnSelG (AnnFldsG v) v
+type AnnSimpleSelG v = AnnSelectG (AnnFieldsG v) v
 type AnnSimpleSel = AnnSimpleSelG S.SQLExp
 
-type AnnAggSelG v = AnnSelG (TableAggFldsG v) v
-type AnnAggSel = AnnAggSelG S.SQLExp
+type AnnAggregateSelectG v = AnnSelectG (TableAggregateFieldsG v) v
+type AnnAggregateSelect = AnnAggregateSelectG S.SQLExp
+
+data ConnectionSlice
+  = SliceFirst !Int
+  | SliceLast !Int
+  deriving (Show, Eq, Generic)
+instance Hashable ConnectionSlice
+
+data ConnectionSplitKind
+  = CSKBefore
+  | CSKAfter
+  deriving (Show, Eq, Generic)
+instance Hashable ConnectionSplitKind
+
+data ConnectionSplit v
+  = ConnectionSplit
+  { _csKind    :: !ConnectionSplitKind
+  , _csValue   :: !v
+  , _csOrderBy :: !(OrderByItemG (AnnOrderByElementG ()))
+  } deriving (Show, Eq, Functor, Generic, Foldable, Traversable)
+instance (Hashable v) => Hashable (ConnectionSplit v)
+
+traverseConnectionSplit
+  :: (Applicative f)
+  => (a -> f b) -> ConnectionSplit a -> f (ConnectionSplit b)
+traverseConnectionSplit f (ConnectionSplit k v ob) =
+  ConnectionSplit k <$> f v <*> pure ob
+
+data ConnectionSelect v
+  = ConnectionSelect
+  { _csPrimaryKeyColumns :: !(NE.NonEmpty PGColumnInfo)
+  , _csSplit             :: !(Maybe (NE.NonEmpty (ConnectionSplit v)))
+  , _csSlice             :: !(Maybe ConnectionSlice)
+  , _csSelect            :: !(AnnSelectG (ConnectionFields v) v)
+  } deriving (Show, Eq)
+
+traverseConnectionSelect
+  :: (Applicative f)
+  => (a -> f b)
+  -> ConnectionSelect a -> f (ConnectionSelect b)
+traverseConnectionSelect f (ConnectionSelect pkCols cSplit cSlice sel) =
+  ConnectionSelect pkCols
+  <$> traverse (traverse (traverseConnectionSplit f)) cSplit
+  <*> pure cSlice
+  <*> traverseAnnSelect (traverse (traverse (traverseConnectionField f))) f sel
 
 data FunctionArgsExpG a
   = FunctionArgsExp
   { _faePositional :: ![a]
   , _faeNamed      :: !(HM.HashMap Text a)
-  } deriving (Show, Eq, Functor, Foldable, Traversable)
+  } deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
+instance (Hashable a) => Hashable (FunctionArgsExpG a)
 
 emptyFunctionArgsExp :: FunctionArgsExpG a
 emptyFunctionArgsExp = FunctionArgsExp [] HM.empty
 
 type FunctionArgExp = FunctionArgsExpG S.SQLExp
 
--- | If argument positional index is less than or equal to length of 'positional' arguments then
--- insert the value in 'positional' arguments else insert the value with argument name in 'named' arguments
+-- | If argument positional index is less than or equal to length of
+-- 'positional' arguments then insert the value in 'positional' arguments else
+-- insert the value with argument name in 'named' arguments
 insertFunctionArg
   :: FunctionArgName
   -> Int
@@ -396,113 +498,106 @@ insertFunctionArg argName index value (FunctionArgsExp positional named) =
   where
     insertAt i a = toList . Seq.insertAt i a . Seq.fromList
 
-data BaseNode
-  = BaseNode
-  { _bnPrefix              :: !Iden
-  , _bnDistinct            :: !(Maybe S.DistinctExpr)
-  , _bnFrom                :: !S.FromItem
-  , _bnWhere               :: !S.BoolExp
-  , _bnOrderBy             :: !(Maybe S.OrderByExp)
-  , _bnLimit               :: !(Maybe Int)
-  , _bnOffset              :: !(Maybe S.SQLExp)
+data SourcePrefixes
+  = SourcePrefixes
+  { _pfThis :: !Iden -- ^ Current source prefix
+  , _pfBase :: !Iden
+  -- ^ Base table source row identifier to generate
+  -- the table's column identifiers for computed field
+  -- function input parameters
+  } deriving (Show, Eq, Generic)
+instance Hashable SourcePrefixes
 
-  , _bnExtrs               :: !(HM.HashMap S.Alias S.SQLExp)
-  , _bnObjs                :: !(HM.HashMap RelName ObjNode)
-  , _bnArrs                :: !(HM.HashMap S.Alias ArrNode)
-  , _bnComputedFieldTables :: !(HM.HashMap FieldName CFTableNode)
+data SelectSource
+  = SelectSource
+  { _ssPrefix   :: !Iden
+  , _ssFrom     :: !S.FromItem
+  , _ssDistinct :: !(Maybe S.DistinctExpr)
+  , _ssWhere    :: !S.BoolExp
+  , _ssOrderBy  :: !(Maybe S.OrderByExp)
+  , _ssLimit    :: !(Maybe Int)
+  , _ssOffset   :: !(Maybe S.SQLExp)
+  } deriving (Show, Eq, Generic)
+instance Hashable SelectSource
+
+data SelectNode
+  = SelectNode
+  { _snExtractors :: !(HM.HashMap S.Alias S.SQLExp)
+  , _snJoinTree   :: !JoinTree
   } deriving (Show, Eq)
 
-mergeBaseNodes :: BaseNode -> BaseNode -> BaseNode
-mergeBaseNodes lNodeDet rNodeDet =
-  BaseNode pfx dExp f whr ordBy limit offset
-  (HM.union lExtrs rExtrs)
-  (HM.unionWith mergeObjNodes lObjs rObjs)
-  (HM.unionWith mergeArrNodes lArrs rArrs)
-  (HM.unionWith mergeCFTableNodes lCFTables rCFTables)
-  where
-    BaseNode pfx dExp f whr ordBy limit offset lExtrs lObjs lArrs lCFTables
-      = lNodeDet
-    BaseNode _   _    _ _   _     _     _      rExtrs rObjs rArrs rCFTables
-      = rNodeDet
+instance Semigroup SelectNode where
+  SelectNode lExtrs lJoinTree <> SelectNode rExtrs rJoinTree =
+    SelectNode (lExtrs <> rExtrs) (lJoinTree <> rJoinTree)
 
-data OrderByNode
-  = OBNNothing
-  | OBNObjNode !RelName !ObjNode
-  | OBNArrNode !S.Alias !ArrNode
+data ObjectRelationSource
+  = ObjectRelationSource
+  { _orsRelationshipName :: !RelName
+  , _orsRelationMapping  :: !(HM.HashMap PGCol PGCol)
+  , _orsSelectSource     :: !SelectSource
+  } deriving (Show, Eq, Generic)
+instance Hashable ObjectRelationSource
+
+data ArrayRelationSource
+  = ArrayRelationSource
+  { _arsAlias           :: !S.Alias
+  , _arsRelationMapping :: !(HM.HashMap PGCol PGCol)
+  , _arsSelectSource    :: !SelectSource
+  } deriving (Show, Eq, Generic)
+instance Hashable ArrayRelationSource
+
+data ArraySelectNode
+  = ArraySelectNode
+  { _asnTopExtractors :: ![S.Extractor]
+  , _asnSelectNode    :: !SelectNode
+  } deriving (Show, Eq)
+
+instance Semigroup ArraySelectNode where
+  ArraySelectNode lTopExtrs lSelNode <> ArraySelectNode rTopExtrs rSelNode =
+    ArraySelectNode (lTopExtrs <> rTopExtrs) (lSelNode <> rSelNode)
+
+data ComputedFieldTableSetSource
+  = ComputedFieldTableSetSource
+  { _cftssFieldName    :: !FieldName
+  , _cftssSelectType   :: !JsonAggSelect
+  , _cftssSelectSource :: !SelectSource
+  } deriving (Show, Eq, Generic)
+instance Hashable ComputedFieldTableSetSource
+
+data ArrayConnectionSource
+  = ArrayConnectionSource
+  { _acsAlias           :: !S.Alias
+  , _acsRelationMapping :: !(HM.HashMap PGCol PGCol)
+  , _acsSplitFilter     :: !(Maybe S.BoolExp)
+  , _acsSlice           :: !(Maybe ConnectionSlice)
+  , _acsSource          :: !SelectSource
+  } deriving (Show, Eq, Generic)
+
+instance Hashable ArrayConnectionSource
+
+data JoinTree
+  = JoinTree
+  { _jtObjectRelations        :: !(HM.HashMap ObjectRelationSource SelectNode)
+  , _jtArrayRelations         :: !(HM.HashMap ArrayRelationSource ArraySelectNode)
+  , _jtArrayConnections       :: !(HM.HashMap ArrayConnectionSource ArraySelectNode)
+  , _jtComputedFieldTableSets :: !(HM.HashMap ComputedFieldTableSetSource SelectNode)
+  } deriving (Show, Eq)
+
+instance Semigroup JoinTree where
+  JoinTree lObjs lArrs lArrConns lCfts <> JoinTree rObjs rArrs rArrConns rCfts =
+    JoinTree (HM.unionWith (<>) lObjs rObjs)
+             (HM.unionWith (<>) lArrs rArrs)
+             (HM.unionWith (<>) lArrConns rArrConns)
+             (HM.unionWith (<>) lCfts rCfts)
+
+instance Monoid JoinTree where
+  mempty = JoinTree mempty mempty mempty mempty
+
+data PermissionLimitSubQuery
+  = PLSQRequired !Int -- ^ Permission limit
+  | PLSQNotRequired
   deriving (Show, Eq)
 
-data ArrRelCtxG v
-  = ArrRelCtx
-  { aacFields    :: !(ArrSelFldsG v)
-  , aacAggOrdBys :: ![RelName]
-  } deriving (Show, Eq)
-
-type ArrRelCtx = ArrRelCtxG S.SQLExp
-
-emptyArrRelCtx :: ArrRelCtxG a
-emptyArrRelCtx = ArrRelCtx [] []
-
-data ArrNodeItemG v
-  = ANIField !(FieldName, ArrSelG v)
-  | ANIAggOrdBy !RelName
-  deriving (Show, Eq)
-
-type ArrNodeItem = ArrNodeItemG S.SQLExp
-
-data ObjNode
-  = ObjNode
-  { _rnRelMapping :: !(HashMap PGCol PGCol)
-  , _rnNodeDet    :: !BaseNode
-  } deriving (Show, Eq)
-
-mergeObjNodes :: ObjNode -> ObjNode -> ObjNode
-mergeObjNodes lNode rNode =
-  ObjNode colMapping $ mergeBaseNodes lBN rBN
-  where
-    ObjNode colMapping lBN = lNode
-    ObjNode _          rBN = rNode
-
--- simple array select, aggregate select and order by
--- nodes differ in extractors
-data ArrNode
-  = ArrNode
-  { _anExtr       :: ![S.Extractor]
-  , _anRelMapping :: !(HashMap PGCol PGCol)
-  , _anNodeDet    :: !BaseNode
-  } deriving (Show, Eq)
-
-mergeArrNodes :: ArrNode -> ArrNode -> ArrNode
-mergeArrNodes lNode rNode =
-  ArrNode (lExtrs `union` rExtrs) colMapping $
-  mergeBaseNodes lBN rBN
-  where
-    ArrNode lExtrs colMapping lBN = lNode
-    ArrNode rExtrs _          rBN = rNode
-
-data ArrNodeInfo
-  = ArrNodeInfo
-  { _aniAlias            :: !S.Alias
-  , _aniPrefix           :: !Iden
-  , _aniSubQueryRequired :: !Bool
-  } deriving (Show, Eq)
-
--- | Node for computed field returning setof <table>
-data CFTableNode
-  = CFTableNode
-  { _ctnSelectType :: !JsonAggSelect
-  , _ctnNode       :: !BaseNode
-  } deriving (Show, Eq)
-
-mergeCFTableNodes :: CFTableNode -> CFTableNode -> CFTableNode
-mergeCFTableNodes lNode rNode =
-  CFTableNode
-  (_ctnSelectType rNode)
-  (mergeBaseNodes (_ctnNode lNode) (_ctnNode rNode))
-
-data Prefixes
-  = Prefixes
-  { _pfThis :: !Iden -- Current node prefix
-  , _pfBase :: !Iden -- Base table row identifier for computed field function
-  } deriving (Show, Eq)
-
-$(makePrisms ''AnnFldG)
+$(makeLenses ''AnnSelectG)
+$(makePrisms ''AnnFieldG)
+$(makePrisms ''AnnOrderByElementG)

server/src-lib/Hasura/RQL/Types/Action.hs

@@ -55,9 +55,9 @@ import           Hasura.RQL.DDL.Headers
 import           Hasura.RQL.DML.Select.Types
 import           Hasura.RQL.Types.CustomTypes
 import           Hasura.RQL.Types.Permission
+import           Hasura.Session
 import           Hasura.SQL.Types
 import           Language.Haskell.TH.Syntax    (Lift)
-import           Hasura.Session
 
 import qualified Data.Aeson                    as J
 import qualified Data.Aeson.Casing             as J
@@ -273,7 +273,7 @@ data AnnActionExecution v
   = AnnActionExecution
   { _aaeName                 :: !ActionName
   , _aaeOutputType           :: !GraphQLType -- ^ output type
-  , _aaeFields               :: !(AnnFldsG v) -- ^ output selection
+  , _aaeFields               :: !(AnnFieldsG v) -- ^ output selection
   , _aaePayload              :: !J.Value -- ^ jsonified input arguments
   , _aaeOutputFields         :: !ActionOutputFields
   -- ^ to validate the response fields from webhook
@@ -292,7 +292,7 @@ data AnnActionMutationAsync
 
 data AsyncActionQueryFieldG v
   = AsyncTypename !Text
-  | AsyncOutput !(AnnFldsG v)
+  | AsyncOutput !(AnnFieldsG v)
   | AsyncId
   | AsyncCreatedAt
   | AsyncErrors

server/src-lib/Hasura/RQL/Types/BoolExp.hs

@@ -66,6 +66,7 @@ data GExists a
 instance (NFData a) => NFData (GExists a)
 instance (Data a) => Plated (GExists a)
 instance (Cacheable a) => Cacheable (GExists a)
+instance (Hashable a) => Hashable (GExists a)
 
 gExistsToJSON :: (a -> (Text, Value)) -> GExists a -> Value
 gExistsToJSON f (GExists qt wh) =
@@ -92,6 +93,7 @@ data GBoolExp a
 instance (NFData a) => NFData (GBoolExp a)
 instance (Data a) => Plated (GBoolExp a)
 instance (Cacheable a) => Cacheable (GBoolExp a)
+instance (Hashable a) => Hashable (GBoolExp a)
 
 gBoolExpTrue :: GBoolExp a
 gBoolExpTrue = BoolAnd []
@@ -143,6 +145,7 @@ data DWithinGeomOp a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (DWithinGeomOp a)
 instance (Cacheable a) => Cacheable (DWithinGeomOp a)
+instance (Hashable a) => Hashable (DWithinGeomOp a)
 $(deriveJSON (aesonDrop 6 snakeCase) ''DWithinGeomOp)
 
 data DWithinGeogOp a =
@@ -153,6 +156,7 @@ data DWithinGeogOp a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (DWithinGeogOp a)
 instance (Cacheable a) => Cacheable (DWithinGeogOp a)
+instance (Hashable a) => Hashable (DWithinGeogOp a)
 $(deriveJSON (aesonDrop 6 snakeCase) ''DWithinGeogOp)
 
 data STIntersectsNbandGeommin a =
@@ -162,6 +166,7 @@ data STIntersectsNbandGeommin a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (STIntersectsNbandGeommin a)
 instance (Cacheable a) => Cacheable (STIntersectsNbandGeommin a)
+instance (Hashable a) => Hashable (STIntersectsNbandGeommin a)
 $(deriveJSON (aesonDrop 4 snakeCase) ''STIntersectsNbandGeommin)
 
 data STIntersectsGeomminNband a =
@@ -171,6 +176,7 @@ data STIntersectsGeomminNband a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (STIntersectsGeomminNband a)
 instance (Cacheable a) => Cacheable (STIntersectsGeomminNband a)
+instance (Hashable a) => Hashable (STIntersectsGeomminNband a)
 $(deriveJSON (aesonDrop 4 snakeCase) ''STIntersectsGeomminNband)
 
 type CastExp a = M.HashMap PGScalarType [OpExpG a]
@@ -230,6 +236,7 @@ data OpExpG a
   deriving (Eq, Show, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (OpExpG a)
 instance (Cacheable a) => Cacheable (OpExpG a)
+instance (Hashable a) => Hashable (OpExpG a)
 
 opExpDepCol :: OpExpG a -> Maybe PGCol
 opExpDepCol = \case
@@ -303,6 +310,7 @@ data AnnBoolExpFld a
   deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
 instance (NFData a) => NFData (AnnBoolExpFld a)
 instance (Cacheable a) => Cacheable (AnnBoolExpFld a)
+instance (Hashable a) => Hashable (AnnBoolExpFld a)
 
 type AnnBoolExp a
   = GBoolExp (AnnBoolExpFld a)

server/src-lib/Hasura/RQL/Types/Common.hs

@@ -143,6 +143,7 @@ data RelInfo
   } deriving (Show, Eq, Generic)
 instance NFData RelInfo
 instance Cacheable RelInfo
+instance Hashable RelInfo
 $(deriveToJSON (aesonDrop 2 snakeCase) ''RelInfo)
 
 newtype FieldName
@@ -150,6 +151,7 @@ newtype FieldName
   deriving ( Show, Eq, Ord, Hashable, FromJSON, ToJSON
            , FromJSONKey, ToJSONKey, Lift, Data, Generic
            , IsString, Arbitrary, NFData, Cacheable
+           , Semigroup
            )
 
 instance IsIden FieldName where
@@ -212,7 +214,7 @@ data PrimaryKey a
   = PrimaryKey
   { _pkConstraint :: !Constraint
   , _pkColumns    :: !(NESeq a)
-  } deriving (Show, Eq, Generic)
+  } deriving (Show, Eq, Generic, Foldable)
 instance (NFData a) => NFData (PrimaryKey a)
 instance (Cacheable a) => Cacheable (PrimaryKey a)
 $(makeLenses ''PrimaryKey)

server/src-lib/Hasura/RQL/Types/DML.hs

@@ -101,6 +101,7 @@ instance (FromJSON a) => FromJSON (DMLQuery a) where
 newtype OrderType
   = OrderType { unOrderType :: S.OrderType }
   deriving (Show, Eq, Lift, Generic)
+instance Hashable OrderType
 
 instance FromJSON OrderType where
   parseJSON =
@@ -112,6 +113,7 @@ instance FromJSON OrderType where
 newtype NullsOrder
   = NullsOrder { unNullsOrder :: S.NullsOrder }
   deriving (Show, Eq, Lift, Generic)
+instance Hashable NullsOrder
 
 instance FromJSON NullsOrder where
   parseJSON =
@@ -176,7 +178,8 @@ data OrderByItemG a
   { obiType   :: !(Maybe OrderType)
   , obiColumn :: !a
   , obiNulls  :: !(Maybe NullsOrder)
-  } deriving (Show, Eq, Lift, Functor, Foldable, Traversable)
+  } deriving (Show, Eq, Lift, Functor, Foldable, Traversable, Generic)
+instance (Hashable a) => Hashable (OrderByItemG a)
 
 type OrderByItem = OrderByItemG OrderByCol
 

server/src-lib/Hasura/RQL/Types/SchemaCache.hs

@@ -133,8 +133,8 @@ import           Hasura.RQL.Types.QueryCollection
 import           Hasura.RQL.Types.RemoteSchema
 import           Hasura.RQL.Types.SchemaCacheTypes
 import           Hasura.RQL.Types.Table
-import           Hasura.SQL.Types
 import           Hasura.Session
+import           Hasura.SQL.Types
 
 import           Data.Aeson
 import           Data.Aeson.Casing
@@ -198,18 +198,18 @@ type ActionCache = M.HashMap ActionName ActionInfo -- info of all actions
 
 data SchemaCache
   = SchemaCache
-  { scTables           :: !TableCache
-  , scActions          :: !ActionCache
-  , scFunctions        :: !FunctionCache
-  , scRemoteSchemas    :: !RemoteSchemaMap
-  , scAllowlist        :: !(HS.HashSet GQLQuery)
-  , scGQLContext       :: !(HashMap RoleName GQLContext)
-  , scUnauthenticatedGQLContext :: !GQLContext
-  , scRelayContext     :: !(HashMap RoleName GQLContext)
+  { scTables                      :: !TableCache
+  , scActions                     :: !ActionCache
+  , scFunctions                   :: !FunctionCache
+  , scRemoteSchemas               :: !RemoteSchemaMap
+  , scAllowlist                   :: !(HS.HashSet GQLQuery)
+  , scGQLContext                  :: !(HashMap RoleName GQLContext)
+  , scUnauthenticatedGQLContext   :: !GQLContext
+  , scRelayContext                :: !(HashMap RoleName GQLContext)
   , scUnauthenticatedRelayContext :: !GQLContext
   -- , scCustomTypes       :: !(NonObjectTypeMap, AnnotatedObjects)
-  , scDepMap           :: !DepMap
-  , scInconsistentObjs :: ![InconsistentMetadata]
+  , scDepMap                      :: !DepMap
+  , scInconsistentObjs            :: ![InconsistentMetadata]
   }
 $(deriveToJSON (aesonDrop 2 snakeCase) ''SchemaCache)
 

server/src-lib/Hasura/SQL/DML.hs

@@ -35,6 +35,7 @@ data Select
     } deriving (Show, Eq, Generic, Data)
 instance NFData Select
 instance Cacheable Select
+instance Hashable Select
 
 mkSelect :: Select
 mkSelect = Select Nothing [] Nothing
@@ -43,7 +44,7 @@ mkSelect = Select Nothing [] Nothing
 
 newtype LimitExp
   = LimitExp SQLExp
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL LimitExp where
   toSQL (LimitExp se) =
@@ -51,15 +52,15 @@ instance ToSQL LimitExp where
 
 newtype OffsetExp
   = OffsetExp SQLExp
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL OffsetExp where
   toSQL (OffsetExp se) =
     "OFFSET" <-> toSQL se
 
 newtype OrderByExp
-  = OrderByExp [OrderByItem]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  = OrderByExp (NonEmpty OrderByItem)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 data OrderByItem
   = OrderByItem
@@ -69,6 +70,7 @@ data OrderByItem
     } deriving (Show, Eq, Generic, Data)
 instance NFData OrderByItem
 instance Cacheable OrderByItem
+instance Hashable OrderByItem
 
 instance ToSQL OrderByItem where
   toSQL (OrderByItem e ot no) =
@@ -78,6 +80,7 @@ data OrderType = OTAsc | OTDesc
   deriving (Show, Eq, Lift, Generic, Data)
 instance NFData OrderType
 instance Cacheable OrderType
+instance Hashable OrderType
 
 instance ToSQL OrderType where
   toSQL OTAsc  = "ASC"
@@ -89,6 +92,7 @@ data NullsOrder
   deriving (Show, Eq, Lift, Generic, Data)
 instance NFData NullsOrder
 instance Cacheable NullsOrder
+instance Hashable NullsOrder
 
 instance ToSQL NullsOrder where
   toSQL NFirst = "NULLS FIRST"
@@ -96,11 +100,11 @@ instance ToSQL NullsOrder where
 
 instance ToSQL OrderByExp where
   toSQL (OrderByExp l) =
-    "ORDER BY" <-> (", " <+> l)
+    "ORDER BY" <-> (", " <+> toList l)
 
 newtype GroupByExp
   = GroupByExp [SQLExp]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL GroupByExp where
   toSQL (GroupByExp idens) =
@@ -108,7 +112,7 @@ instance ToSQL GroupByExp where
 
 newtype FromExp
   = FromExp [FromItem]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL FromExp where
   toSQL (FromExp items) =
@@ -148,7 +152,7 @@ mkRowExp extrs = let
 
 newtype HavingExp
   = HavingExp BoolExp
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL HavingExp where
   toSQL (HavingExp be) =
@@ -156,7 +160,7 @@ instance ToSQL HavingExp where
 
 newtype WhereFrag
   = WhereFrag { getWFBoolExp :: BoolExp }
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL WhereFrag where
   toSQL (WhereFrag be) =
@@ -188,6 +192,7 @@ data Qual
   deriving (Show, Eq, Generic, Data)
 instance NFData Qual
 instance Cacheable Qual
+instance Hashable Qual
 
 mkQual :: QualifiedTable -> Qual
 mkQual = QualTable
@@ -205,6 +210,7 @@ data QIden
   deriving (Show, Eq, Generic, Data)
 instance NFData QIden
 instance Cacheable QIden
+instance Hashable QIden
 
 instance ToSQL QIden where
   toSQL (QIden qual iden) =
@@ -212,7 +218,7 @@ instance ToSQL QIden where
 
 newtype SQLOp
   = SQLOp {sqlOpTxt :: T.Text}
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 incOp :: SQLOp
 incOp = SQLOp "+"
@@ -234,7 +240,7 @@ jsonbDeleteAtPathOp = SQLOp "#-"
 
 newtype TypeAnn
   = TypeAnn { unTypeAnn :: T.Text }
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL TypeAnn where
   toSQL (TypeAnn ty) = "::" <> TB.text ty
@@ -260,6 +266,9 @@ jsonTypeAnn = mkTypeAnn $ PGTypeScalar PGJSON
 jsonbTypeAnn :: TypeAnn
 jsonbTypeAnn = mkTypeAnn $ PGTypeScalar PGJSONB
 
+boolTypeAnn :: TypeAnn
+boolTypeAnn = mkTypeAnn $ PGTypeScalar PGBoolean
+
 data CountType
   = CTStar
   | CTSimple ![PGCol]
@@ -267,6 +276,7 @@ data CountType
   deriving (Show, Eq, Generic, Data)
 instance NFData CountType
 instance Cacheable CountType
+instance Hashable CountType
 
 instance ToSQL CountType where
   toSQL CTStar            = "*"
@@ -277,7 +287,7 @@ instance ToSQL CountType where
 
 newtype TupleExp
   = TupleExp [SQLExp]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL TupleExp where
   toSQL (TupleExp exps) =
@@ -302,6 +312,7 @@ data SQLExp
   | SEBool !BoolExp
   | SEExcluded !Iden
   | SEArray ![SQLExp]
+  | SEArrayIndex !SQLExp !SQLExp
   | SETuple !TupleExp
   | SECount !CountType
   | SENamedArg !Iden !SQLExp
@@ -309,6 +320,7 @@ data SQLExp
   deriving (Show, Eq, Generic, Data)
 instance NFData SQLExp
 instance Cacheable SQLExp
+instance Hashable SQLExp
 
 withTyAnn :: PGScalarType -> SQLExp -> SQLExp
 withTyAnn colTy v = SETyAnn v . mkTypeAnn $ PGTypeScalar colTy
@@ -318,7 +330,7 @@ instance J.ToJSON SQLExp where
 
 newtype Alias
   = Alias { getAlias :: Iden }
-  deriving (Show, Eq, NFData, Hashable, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance IsIden Alias where
   toIden (Alias iden) = iden
@@ -370,6 +382,9 @@ instance ToSQL SQLExp where
                          <> toSQL i
   toSQL (SEArray exps) = "ARRAY" <> TB.char '['
                          <> (", " <+> exps) <> TB.char ']'
+  toSQL (SEArrayIndex arrayExp indexExp) =
+    paren (toSQL arrayExp)
+    <> TB.char '[' <> toSQL indexExp <> TB.char ']'
   toSQL (SETuple tup) = toSQL tup
   toSQL (SECount ty) = "COUNT" <> paren (toSQL ty)
   -- https://www.postgresql.org/docs/current/sql-syntax-calling-funcs.html
@@ -384,6 +399,7 @@ data Extractor = Extractor !SQLExp !(Maybe Alias)
   deriving (Show, Eq, Generic, Data)
 instance NFData Extractor
 instance Cacheable Extractor
+instance Hashable Extractor
 
 mkSQLOpExp
   :: SQLOp
@@ -431,6 +447,7 @@ data DistinctExpr
   deriving (Show, Eq, Generic, Data)
 instance NFData DistinctExpr
 instance Cacheable DistinctExpr
+instance Hashable DistinctExpr
 
 instance ToSQL DistinctExpr where
   toSQL DistinctSimple    = "DISTINCT"
@@ -444,6 +461,7 @@ data FunctionArgs
   } deriving (Show, Eq, Generic, Data)
 instance NFData FunctionArgs
 instance Cacheable FunctionArgs
+instance Hashable FunctionArgs
 
 instance ToSQL FunctionArgs where
   toSQL (FunctionArgs positionalArgs namedArgsMap) =
@@ -458,6 +476,7 @@ data DefinitionListItem
   } deriving (Show, Eq, Data, Generic)
 instance NFData DefinitionListItem
 instance Cacheable DefinitionListItem
+instance Hashable DefinitionListItem
 
 instance ToSQL DefinitionListItem where
   toSQL (DefinitionListItem column columnType) =
@@ -470,6 +489,7 @@ data FunctionAlias
   } deriving (Show, Eq, Data, Generic)
 instance NFData FunctionAlias
 instance Cacheable FunctionAlias
+instance Hashable FunctionAlias
 
 mkSimpleFunctionAlias :: Iden -> FunctionAlias
 mkSimpleFunctionAlias identifier =
@@ -494,6 +514,7 @@ data FunctionExp
   } deriving (Show, Eq, Generic, Data)
 instance NFData FunctionExp
 instance Cacheable FunctionExp
+instance Hashable FunctionExp
 
 instance ToSQL FunctionExp where
   toSQL (FunctionExp qf args alsM) =
@@ -505,11 +526,13 @@ data FromItem
   | FIFunc !FunctionExp
   | FIUnnest ![SQLExp] !Alias ![SQLExp]
   | FISelect !Lateral !Select !Alias
+  | FISelectWith !Lateral !(SelectWithG Select) !Alias
   | FIValues !ValuesExp !Alias !(Maybe [PGCol])
   | FIJoin !JoinExpr
   deriving (Show, Eq, Generic, Data)
 instance NFData FromItem
 instance Cacheable FromItem
+instance Hashable FromItem
 
 mkSelFromItem :: Select -> Alias -> FromItem
 mkSelFromItem = FISelect (Lateral False)
@@ -532,6 +555,8 @@ instance ToSQL FromItem where
     "UNNEST" <> paren (", " <+> args) <-> toSQL als <> paren (", " <+> cols)
   toSQL (FISelect mla sel al) =
     toSQL mla <-> paren (toSQL sel) <-> toSQL al
+  toSQL (FISelectWith mla selWith al) =
+    toSQL mla <-> paren (toSQL selWith) <-> toSQL al
   toSQL (FIValues valsExp al mCols) =
     paren (toSQL valsExp) <-> toSQL al
     <-> toSQL (toColTupExp <$> mCols)
@@ -539,7 +564,7 @@ instance ToSQL FromItem where
     toSQL je
 
 newtype Lateral = Lateral Bool
-  deriving (Show, Eq, Data, NFData, Cacheable)
+  deriving (Show, Eq, Data, NFData, Cacheable, Hashable)
 
 instance ToSQL Lateral where
   toSQL (Lateral True)  = "LATERAL"
@@ -554,6 +579,7 @@ data JoinExpr
   } deriving (Show, Eq, Generic, Data)
 instance NFData JoinExpr
 instance Cacheable JoinExpr
+instance Hashable JoinExpr
 
 instance ToSQL JoinExpr where
   toSQL je =
@@ -570,6 +596,7 @@ data JoinType
   deriving (Eq, Show, Generic, Data)
 instance NFData JoinType
 instance Cacheable JoinType
+instance Hashable JoinType
 
 instance ToSQL JoinType where
   toSQL Inner      = "INNER JOIN"
@@ -583,6 +610,7 @@ data JoinCond
   deriving (Show, Eq, Generic, Data)
 instance NFData JoinCond
 instance Cacheable JoinCond
+instance Hashable JoinCond
 
 instance ToSQL JoinCond where
   toSQL (JoinOn be) =
@@ -606,6 +634,7 @@ data BoolExp
   deriving (Show, Eq, Generic, Data)
 instance NFData BoolExp
 instance Cacheable BoolExp
+instance Hashable BoolExp
 
 -- removes extraneous 'AND true's
 simplifyBoolExp :: BoolExp -> BoolExp
@@ -661,6 +690,7 @@ data BinOp = AndOp | OrOp
   deriving (Show, Eq, Generic, Data)
 instance NFData BinOp
 instance Cacheable BinOp
+instance Hashable BinOp
 
 instance ToSQL BinOp where
   toSQL AndOp = "AND"
@@ -689,6 +719,7 @@ data CompareOp
   deriving (Eq, Generic, Data)
 instance NFData CompareOp
 instance Cacheable CompareOp
+instance Hashable CompareOp
 
 instance Show CompareOp where
   show = \case
@@ -835,7 +866,7 @@ instance ToSQL SQLConflict where
 
 newtype ValuesExp
   = ValuesExp [TupleExp]
-  deriving (Show, Eq, Data, NFData, Cacheable)
+  deriving (Show, Eq, Data, NFData, Cacheable, Hashable)
 
 instance ToSQL ValuesExp where
   toSQL (ValuesExp tuples) =
@@ -874,14 +905,20 @@ instance ToSQL CTE where
     CTEUpdate q -> toSQL q
     CTEDelete q -> toSQL q
 
-data SelectWith
+data SelectWithG v
   = SelectWith
-  { swCTEs   :: [(Alias, CTE)]
+  { swCTEs   :: ![(Alias, v)]
   , swSelect :: !Select
-  } deriving (Show, Eq)
+  } deriving (Show, Eq, Generic, Data)
 
-instance ToSQL SelectWith where
+instance (NFData v) => NFData (SelectWithG v)
+instance (Cacheable v) => Cacheable (SelectWithG v)
+instance (Hashable v) => Hashable (SelectWithG v)
+
+instance (ToSQL v) => ToSQL (SelectWithG v) where
   toSQL (SelectWith ctes sel) =
     "WITH " <> (", " <+> map f ctes) <-> toSQL sel
     where
       f (Alias al, q) = toSQL al <-> "AS" <-> paren (toSQL q)
+
+type SelectWith = SelectWithG CTE

server/src-lib/Hasura/SQL/Rewrite.hs

@@ -1,5 +1,6 @@
 module Hasura.SQL.Rewrite
   ( prefixNumToAliases
+  , prefixNumToAliasesSelectWith
   ) where
 
 import qualified Data.HashMap.Strict as Map
@@ -20,6 +21,11 @@ prefixNumToAliases :: S.Select -> S.Select
 prefixNumToAliases s =
   uSelect s `evalState` UniqSt 0 Map.empty
 
+prefixNumToAliasesSelectWith
+  :: S.SelectWithG S.Select -> S.SelectWithG S.Select
+prefixNumToAliasesSelectWith s =
+  uSelectWith s `evalState` UniqSt 0 Map.empty
+
 type Rewrite a = State a
 
 data UniqSt
@@ -56,6 +62,12 @@ restoringIdens action = do
   modify' $ \s -> s { _uqIdens = idens }
   return res
 
+uSelectWith :: S.SelectWithG S.Select -> Uniq (S.SelectWithG S.Select)
+uSelectWith (S.SelectWith ctes baseSelect) =
+  S.SelectWith
+    <$> forM ctes (\(als, sel) -> (als,) <$> restoringIdens (uSelect sel))
+    <*> uSelect baseSelect
+
 uSelect :: S.Select -> Uniq S.Select
 uSelect sel = do
   -- this has to be the first thing to process
@@ -113,6 +125,10 @@ uFromItem fromItem = case fromItem of
     newSel <- restoringIdens $ uSelect sel
     newAls <- addAlias al
     return $ S.FISelect isLateral newSel newAls
+  S.FISelectWith isLateral selectWith al -> do
+    newSelectWith <- uSelectWith selectWith
+    newAls <- addAlias al
+    return $ S.FISelectWith isLateral newSelectWith newAls
   S.FIValues (S.ValuesExp tups) als mCols -> do
     newValExp <- fmap S.ValuesExp $
                  forM tups $ \(S.TupleExp ts) ->
@@ -196,8 +212,10 @@ uSqlExp = restoringIdens . \case
     S.SEExcluded <$> return t
   S.SEArray l                   ->
     S.SEArray <$> mapM uSqlExp l
+  S.SEArrayIndex arrayExp indexExp ->
+    S.SEArrayIndex <$> uSqlExp arrayExp <*> uSqlExp indexExp
   S.SETuple (S.TupleExp l)      ->
-    S.SEArray <$> mapM uSqlExp l
+    S.SETuple . S.TupleExp <$> mapM uSqlExp l
   S.SECount cty                 -> return $ S.SECount cty
   S.SENamedArg arg val          -> S.SENamedArg arg <$> uSqlExp val
   S.SEFunction funcExp          -> S.SEFunction <$> uFunctionExp funcExp

server/src-lib/Hasura/Server/App.hs

@@ -3,68 +3,68 @@
 module Hasura.Server.App where
 
 import           Control.Concurrent.MVar.Lifted
-import           Control.Exception                      (IOException, try)
-import           Control.Lens                           (view, _2)
+import           Control.Exception                         (IOException, try)
+import           Control.Lens                              (view, _2)
 import           Control.Monad.Stateless
-import           Control.Monad.Trans.Control            (MonadBaseControl)
-import           Data.Aeson                             hiding (json)
-import           Data.Either                            (isRight)
-import           Data.Int                               (Int64)
+import           Control.Monad.Trans.Control               (MonadBaseControl)
+import           Data.Aeson                                hiding (json)
+import           Data.Either                               (isRight)
+import           Data.Int                                  (Int64)
 import           Data.IORef
-import           Data.Time.Clock                        (UTCTime)
-import           Data.Time.Clock.POSIX                  (getPOSIXTime)
-import           Network.Mime                           (defaultMimeLookup)
-import           System.Exit                            (exitFailure)
-import           System.FilePath                        (joinPath, takeFileName)
-import           Web.Spock.Core                         ((<//>))
+import           Data.Time.Clock                           (UTCTime)
+import           Data.Time.Clock.POSIX                     (getPOSIXTime)
+import           Network.Mime                              (defaultMimeLookup)
+import           System.Exit                               (exitFailure)
+import           System.FilePath                           (joinPath, takeFileName)
+import           Web.Spock.Core                            ((<//>))
 
-import qualified Control.Concurrent.Async.Lifted.Safe   as LA
-import qualified Data.ByteString.Lazy                   as BL
-import qualified Data.CaseInsensitive                   as CI
-import qualified Data.HashMap.Strict                    as M
-import qualified Data.HashSet                           as S
-import qualified Data.Text                              as T
-import qualified Database.PG.Query                      as Q
-import qualified Network.HTTP.Client                    as HTTP
-import qualified Network.HTTP.Types                     as HTTP
-import qualified Network.Wai                            as Wai
-import qualified Network.Wai.Handler.WebSockets         as WS
-import qualified Network.WebSockets                     as WS
-import qualified System.Metrics                         as EKG
-import qualified System.Metrics.Json                    as EKG
-import qualified Text.Mustache                          as M
-import qualified Web.Spock.Core                         as Spock
+import qualified Control.Concurrent.Async.Lifted.Safe      as LA
+import qualified Data.ByteString.Lazy                      as BL
+import qualified Data.CaseInsensitive                      as CI
+import qualified Data.HashMap.Strict                       as M
+import qualified Data.HashSet                              as S
+import qualified Data.Text                                 as T
+import qualified Database.PG.Query                         as Q
+import qualified Network.HTTP.Client                       as HTTP
+import qualified Network.HTTP.Types                        as HTTP
+import qualified Network.Wai                               as Wai
+import qualified Network.Wai.Handler.WebSockets            as WS
+import qualified Network.WebSockets                        as WS
+import qualified System.Metrics                            as EKG
+import qualified System.Metrics.Json                       as EKG
+import qualified Text.Mustache                             as M
+import qualified Web.Spock.Core                            as Spock
 
 import           Hasura.EncJSON
 -- import           Hasura.GraphQL.Resolve.Action
 import           Hasura.GraphQL.Logging                    (MonadQueryLog (..))
 import           Hasura.HTTP
-import           Hasura.Prelude                         hiding (get, put)
+import           Hasura.Prelude                            hiding (get, put)
 import           Hasura.RQL.DDL.Schema
 import           Hasura.RQL.Types
 import           Hasura.RQL.Types.Run
-import           Hasura.Server.API.Config               (runGetConfig)
+import           Hasura.Server.API.Config                  (runGetConfig)
 import           Hasura.Server.API.Query
-import           Hasura.Server.Auth                     (AuthMode (..), UserAuthentication (..))
+import           Hasura.Server.Auth                        (AuthMode (..), UserAuthentication (..))
 import           Hasura.Server.Compression
 import           Hasura.Server.Cors
 import           Hasura.Server.Init
 import           Hasura.Server.Logging
-import           Hasura.Server.Middleware               (corsMiddleware)
+import           Hasura.Server.Middleware                  (corsMiddleware)
 import           Hasura.Server.Utils
 import           Hasura.Server.Version
-import           Hasura.SQL.Types
 import           Hasura.Session
+import           Hasura.SQL.Types
 
-import qualified Hasura.GraphQL.Execute                 as E
-import qualified Hasura.GraphQL.Execute.LiveQuery       as EL
+import qualified Hasura.GraphQL.Execute                    as E
+import qualified Hasura.GraphQL.Execute.LiveQuery          as EL
 -- import qualified Hasura.GraphQL.Explain                 as GE
-import qualified Hasura.GraphQL.Transport.HTTP          as GH
-import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
-import qualified Hasura.GraphQL.Transport.WebSocket     as WS
+import qualified Hasura.GraphQL.Transport.HTTP             as GH
+import qualified Hasura.GraphQL.Transport.HTTP.Protocol    as GH
+import qualified Hasura.GraphQL.Transport.WebSocket        as WS
 import qualified Hasura.GraphQL.Transport.WebSocket.Server as WS
-import qualified Hasura.Logging                         as L
-import qualified Hasura.Server.API.PGDump               as PGD
+import qualified Hasura.Logging                            as L
+import qualified Hasura.Server.API.PGDump                  as PGD
 import qualified Network.Wai.Handler.WebSockets.Custom     as WSC
 
 
@@ -350,7 +350,8 @@ v1Alpha1GQHandler queryType query = do
 
 v1GQHandler
   :: (HasVersion, MonadIO m)
-  => GH.GQLBatchedReqs GH.GQLQueryText -> Handler m (HttpResponse EncJSON)
+  => GH.GQLBatchedReqs GH.GQLQueryText
+  -> Handler m (HttpResponse EncJSON)
 v1GQHandler = v1Alpha1GQHandler E.QueryHasura
 
 v1GQRelayHandler

server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_1.yaml

@@ -0,0 +1,49 @@
+description: Get last page of articles with 3 items
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        last: 3
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiA0fQ==
+        endCursor: eyJpZCIgOiA2fQ==
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJpZCIgOiA0fQ==
+        node:
+          title: Article 4
+          content: Sample article content 4
+          author_id: 2
+      - cursor: eyJpZCIgOiA1fQ==
+        node:
+          title: Article 5
+          content: Sample article content 5
+          author_id: 2
+      - cursor: eyJpZCIgOiA2fQ==
+        node:
+          title: Article 6
+          content: Sample article content 6
+          author_id: 3

server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_2.yaml

@@ -0,0 +1,45 @@
+description: Get last page of articles with 2 items before 'Article 4'
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        last: 2
+        before: "eyJpZCIgOiA0fQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiAyfQ==
+        endCursor: eyJpZCIgOiAzfQ==
+        hasPreviousPage: true
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiAyfQ==
+        node:
+          title: Article 2
+          content: Sample article content 2
+          author_id: 1
+      - cursor: eyJpZCIgOiAzfQ==
+        node:
+          title: Article 3
+          content: Sample article content 3
+          author_id: 1

server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_3.yaml

@@ -0,0 +1,40 @@
+description: Get last page of articles before 'Article 2'
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        last: 2
+        before: "eyJpZCIgOiAyfQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiAxfQ==
+        endCursor: eyJpZCIgOiAxfQ==
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiAxfQ==
+        node:
+          title: Article 1
+          content: Sample article content 1
+          author_id: 1

server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_1.yaml

@@ -0,0 +1,49 @@
+description: Get 1st page of articles with 3 items
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        first: 3
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiAxfQ==
+        endCursor: eyJpZCIgOiAzfQ==
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiAxfQ==
+        node:
+          title: Article 1
+          content: Sample article content 1
+          author_id: 1
+      - cursor: eyJpZCIgOiAyfQ==
+        node:
+          title: Article 2
+          content: Sample article content 2
+          author_id: 1
+      - cursor: eyJpZCIgOiAzfQ==
+        node:
+          title: Article 3
+          content: Sample article content 3
+          author_id: 1

server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_2.yaml

@@ -0,0 +1,45 @@
+description: Get 2nd page of articles with 2 items
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        first: 2
+        after: "eyJpZCIgOiAzfQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiA0fQ==
+        endCursor: eyJpZCIgOiA1fQ==
+        hasPreviousPage: true
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiA0fQ==
+        node:
+          title: Article 4
+          content: Sample article content 4
+          author_id: 2
+      - cursor: eyJpZCIgOiA1fQ==
+        node:
+          title: Article 5
+          content: Sample article content 5
+          author_id: 2

server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_3.yaml

@@ -0,0 +1,40 @@
+description: Get 3rd page of articles
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        first: 3
+        after: "eyJpZCIgOiA1fQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiA2fQ==
+        endCursor: eyJpZCIgOiA2fQ==
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJpZCIgOiA2fQ==
+        node:
+          title: Article 6
+          content: Sample article content 6
+          author_id: 3

server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_1.yaml

@@ -0,0 +1,44 @@
+description: Fetch 1st page from last of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        last: 1
+        order_by: {articles_aggregate: {count: asc}}
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        node:
+          name: Author 1
+          articles_aggregate:
+            aggregate:
+              count: 3

server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_2.yaml

@@ -0,0 +1,51 @@
+description: Fetch 2nd page from last of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        last: 2
+        order_by: {articles_aggregate: {count: asc}}
+        before: "eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9"
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        hasPreviousPage: true
+        hasNextPage: true
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        node:
+          name: Author 3
+          articles_aggregate:
+            aggregate:
+              count: 1
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        node:
+          name: Author 2
+          articles_aggregate:
+            aggregate:
+              count: 2

server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_3.yaml

@@ -0,0 +1,45 @@
+description: Fetch 3rd page from last of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        last: 1
+        order_by: {articles_aggregate: {count: asc}}
+        before: "eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9"
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        node:
+          name: Author 4
+          articles_aggregate:
+            aggregate:
+              count: 0

server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_1.yaml

@@ -0,0 +1,50 @@
+description: Fetch 1st page of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        first: 2
+        order_by: {articles_aggregate: {count: asc}}
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        node:
+          name: Author 4
+          articles_aggregate:
+            aggregate:
+              count: 0
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        node:
+          name: Author 3
+          articles_aggregate:
+            aggregate:
+              count: 1

server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_2.yaml

@@ -0,0 +1,51 @@
+description: Fetch 2nd page of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        first: 2
+        order_by: {articles_aggregate: {count: asc}}
+        after: "eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9"
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        node:
+          name: Author 2
+          articles_aggregate:
+            aggregate:
+              count: 2
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        node:
+          name: Author 1
+          articles_aggregate:
+            aggregate:
+              count: 3

server/tests-py/queries/graphql_query/relay/basic/invalid_node_id.yaml

@@ -0,0 +1,19 @@
+description: Query node interface with invalid node id
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      node(id: "eyJpZCIgOiA0fQ=="){
+        __typename
+        ... on author{
+          name
+        }
+      }
+    }
+response:
+  errors:
+  - extensions:
+      path: "$.selectionSet.node"
+      code: validation-failed
+    message: the node id is invalid

server/tests-py/queries/graphql_query/relay/pagination_errors/after_and_before.yaml

@@ -0,0 +1,21 @@
+description: Use after and before arguments in the same query
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+       after: "eyJpZCIgOiAyfQ=="
+       before: "eyJpZCIgOiA0fQ=="
+      ){
+        edges{
+          cursor
+        }
+      }
+    }
+response:
+  errors:
+  - extensions:
+      path: "$.selectionSet.author_connection"
+      code: validation-failed
+    message: '"after" and "before" are not allowed at once'

server/tests-py/queries/graphql_query/relay/pagination_errors/first_and_last.yaml

@@ -0,0 +1,21 @@
+description: Use first and last arguments in the same query
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        first: 1
+        last: 2
+      ){
+        edges{
+          cursor
+        }
+      }
+    }
+response:
+  errors:
+  - extensions:
+      path: "$.selectionSet.author_connection"
+      code: validation-failed
+    message: '"first" and "last" are not allowed at once'

server/tests-py/queries/graphql_query/relay/setup.yaml

@@ -0,0 +1,79 @@
+type: bulk
+args:
+- type: run_sql
+  args:
+    sql: |
+      CREATE TABLE author(
+          id SERIAL PRIMARY KEY,
+          name TEXT UNIQUE NOT NULL
+      );
+
+      INSERT INTO author (name)
+      VALUES ('Author 1'), ('Author 2'), ('Author 3'), ('Author 4');
+
+      CREATE TABLE article (
+        id SERIAL PRIMARY KEY,
+        title TEXT,
+        content TEXT,
+        author_id INTEGER REFERENCES author(id)
+      );
+
+      INSERT INTO article (title, content, author_id)
+      VALUES
+      (
+        'Article 1',
+        'Sample article content 1',
+        1
+      ),
+      (
+        'Article 2',
+        'Sample article content 2',
+        1
+      ),
+      (
+        'Article 3',
+        'Sample article content 3',
+        1
+      ),
+      (
+        'Article 4',
+        'Sample article content 4',
+        2
+      ),
+      (
+        'Article 5',
+        'Sample article content 5',
+        2
+      ),
+      (
+        'Article 6',
+        'Sample article content 6',
+        3
+      );
+
+# Track tables and define relationships
+- type: track_table
+  args:
+    name: author
+    schema: public
+
+- type: track_table
+  args:
+    name: article
+    schema: public
+
+- type: create_object_relationship
+  args:
+    table: article
+    name: author
+    using:
+      foreign_key_constraint_on: author_id
+
+- type: create_array_relationship
+  args:
+    table: author
+    name: articles
+    using:
+      foreign_key_constraint_on:
+        table: article
+        column: author_id

server/tests-py/queries/graphql_query/relay/teardown.yaml

@@ -0,0 +1,8 @@
+type: bulk
+args:
+- type: run_sql
+  args:
+    cascade: true
+    sql: |
+      DROP TABLE article;
+      DROP TABLE author;