graphql-engine/server/src-lib/Hasura/GraphQL/Schema/Select.hs
Auke Booij c4cdacf989 First attempt at deduplicating permission filters
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3362
Co-authored-by: Chris Parks <592078+cdparks@users.noreply.github.com>
GitOrigin-RevId: 802c099c26ff024e6cf594ea0317480e260486e9
2022-02-03 16:14:44 +00:00

1748 lines
72 KiB
Haskell

{-# LANGUAGE ApplicativeDo #-}
{-# LANGUAGE ViewPatterns #-}
-- | Generate table selection schema both for ordinary Hasura-type and
-- relay-type queries. All schema with "relay" or "connection" in the name is
-- used exclusively by relay.
module Hasura.GraphQL.Schema.Select
( selectTable,
selectTableByPk,
selectTableAggregate,
selectTableConnection,
selectFunction,
selectFunctionAggregate,
selectFunctionConnection,
computedFieldPG,
remoteRelationshipField,
defaultTableArgs,
tableWhereArg,
tableOrderByArg,
tableDistinctArg,
tableLimitArg,
tableOffsetArg,
tablePermissionsInfo,
tableSelectionSet,
tableSelectionList,
nodePG,
nodeField,
)
where
import Control.Lens hiding (index)
import Data.Aeson qualified as J
import Data.Aeson.Extended qualified as J
import Data.Aeson.Internal qualified as J
import Data.Align (align)
import Data.ByteString.Lazy qualified as BL
import Data.Has
import Data.HashMap.Strict.Extended qualified as Map
import Data.Int (Int64)
import Data.List.NonEmpty qualified as NE
import Data.Parser.JSONPath
import Data.Sequence qualified as Seq
import Data.Sequence.NonEmpty qualified as NESeq
import Data.Text qualified as T
import Data.Text.Extended
import Data.These (partitionThese)
import Data.Traversable (mapAccumL)
import Hasura.Backends.Postgres.SQL.Types qualified as PG
import Hasura.Base.Error
import Hasura.GraphQL.Execute.Types qualified as ET
import Hasura.GraphQL.Parser
( FieldParser,
InputFieldsParser,
Kind (..),
Parser,
UnpreparedValue (..),
mkParameter,
)
import Hasura.GraphQL.Parser qualified as P
import Hasura.GraphQL.Parser.Class
( MonadParse (parseErrorWith, withPath),
MonadSchema (..),
MonadTableInfo,
askTableInfo,
parseError,
)
import Hasura.GraphQL.Parser.Internal.Parser qualified as P
import Hasura.GraphQL.Schema.Backend
import Hasura.GraphQL.Schema.BoolExp
import Hasura.GraphQL.Schema.Common
import Hasura.GraphQL.Schema.OrderBy
import {-# SOURCE #-} Hasura.GraphQL.Schema.RemoteRelationship
import Hasura.GraphQL.Schema.Table
import Hasura.Prelude
import Hasura.RQL.IR qualified as IR
import Hasura.RQL.Types
import Hasura.SQL.AnyBackend qualified as AB
import Hasura.Server.Utils (executeJSONPath)
import Language.GraphQL.Draft.Syntax qualified as G
--------------------------------------------------------------------------------
-- Top-level functions.
--
-- Those functions implement parsers for top-level components of the schema,
-- such as querying a table or a function. They are typically used to implement
-- root fields.
-- | Simple table selection.
--
-- The field for the table accepts table selection arguments, and
-- expects a selection of fields
--
-- > table_name(limit: 10) {
-- > col1: col1_type
-- > col2: col2_type
-- > }: [table!]!
selectTable ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
-- | table info
TableInfo b ->
-- | field display name
G.Name ->
-- | field description, if any
Maybe G.Description ->
-- | select permissions of the table
SelPermInfo b ->
m (FieldParser n (SelectExp b))
selectTable sourceName tableInfo fieldName description selectPermissions = memoizeOn 'selectTable (sourceName, tableName, fieldName) do
stringifyNum <- asks $ qcStringifyNum . getter
tableArgsParser <- tableArguments sourceName tableInfo selectPermissions
selectionSetParser <- tableSelectionList sourceName tableInfo selectPermissions
pure $
P.subselection fieldName description tableArgsParser selectionSetParser
<&> \(args, fields) ->
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromTable tableName,
IR._asnPerm = tablePermissionsInfo selectPermissions,
IR._asnArgs = args,
IR._asnStrfyNum = stringifyNum
}
where
tableName = tableInfoName tableInfo
-- | Simple table connection selection.
--
-- The field for the table accepts table connection selection argument, and
-- expects a selection of connection fields
--
-- > table_name_connection(first: 1) {
-- > pageInfo: {
-- > hasNextPage: Boolean!
-- > endCursor: String!
-- > }
-- > edges: {
-- > cursor: String!
-- > node: {
-- > id: ID!
-- > col1: col1_type
-- > col2: col2_type
-- > }
-- > }
-- > }: table_nameConnection!
selectTableConnection ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
-- | table info
TableInfo b ->
-- | field display name
G.Name ->
-- | field description, if any
Maybe G.Description ->
-- | primary key columns
PrimaryKeyColumns b ->
-- | select permissions of the table
SelPermInfo b ->
m (Maybe (FieldParser n (ConnectionSelectExp b)))
selectTableConnection sourceName tableInfo fieldName description pkeyColumns selectPermissions =
for (relayExtension @b) \xRelayInfo -> memoizeOn 'selectTableConnection (sourceName, tableName, fieldName) do
stringifyNum <- asks $ qcStringifyNum . getter
selectArgsParser <- tableConnectionArgs pkeyColumns sourceName tableInfo selectPermissions
selectionSetParser <- P.nonNullableParser <$> tableConnectionSelectionSet sourceName tableInfo selectPermissions
pure $
P.subselection fieldName description selectArgsParser selectionSetParser
<&> \((args, split, slice), fields) ->
IR.ConnectionSelect
{ IR._csXRelay = xRelayInfo,
IR._csPrimaryKeyColumns = pkeyColumns,
IR._csSplit = split,
IR._csSlice = slice,
IR._csSelect =
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromTable tableName,
IR._asnPerm = tablePermissionsInfo selectPermissions,
IR._asnArgs = args,
IR._asnStrfyNum = stringifyNum
}
}
where
tableName = tableInfoName tableInfo
-- | Table selection by primary key.
--
-- > table_name(id: 42) {
-- > col1: col1_type
-- > col2: col2_type
-- > }: table
--
-- Returns Nothing if there's nothing that can be selected with
-- current permissions or if there are primary keys the user
-- doesn't have select permissions for.
selectTableByPk ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
-- | table info
TableInfo b ->
-- | field display name
G.Name ->
-- | field description, if any
Maybe G.Description ->
-- | select permissions of the table
SelPermInfo b ->
m (Maybe (FieldParser n (SelectExp b)))
selectTableByPk sourceName tableInfo fieldName description selectPermissions = runMaybeT do
primaryKeys <- hoistMaybe $ fmap _pkColumns . _tciPrimaryKey . _tiCoreInfo $ tableInfo
guard $ all (\c -> ciColumn c `Map.member` spiCols selectPermissions) primaryKeys
lift $ memoizeOn 'selectTableByPk (sourceName, tableName, fieldName) do
stringifyNum <- asks $ qcStringifyNum . getter
argsParser <-
sequenceA <$> for primaryKeys \columnInfo -> do
field <- columnParser (ciType columnInfo) (G.Nullability $ ciIsNullable columnInfo)
pure $
BoolFld . AVColumn columnInfo . pure . AEQ True . mkParameter
<$> P.field (ciName columnInfo) (ciDescription columnInfo) field
selectionSetParser <- tableSelectionSet sourceName tableInfo selectPermissions
pure $
P.subselection fieldName description argsParser selectionSetParser
<&> \(boolExpr, fields) ->
let defaultPerms = tablePermissionsInfo selectPermissions
-- Do not account permission limit since the result is just a nullable object
permissions = defaultPerms {IR._tpLimit = Nothing}
whereExpr = Just $ BoolAnd $ toList boolExpr
in IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromTable tableName,
IR._asnPerm = permissions,
IR._asnArgs = IR.noSelectArgs {IR._saWhere = whereExpr},
IR._asnStrfyNum = stringifyNum
}
where
tableName = tableInfoName tableInfo
-- | Table aggregation selection
--
-- Parser for an aggregation selection of a table.
-- > table_aggregate(limit: 10) {
-- > aggregate: table_aggregate_fields
-- > nodes: [table!]!
-- > } :: table_aggregate!
--
-- Returns Nothing if there's nothing that can be selected with
-- current permissions.
selectTableAggregate ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
-- | table info
TableInfo b ->
-- | field display name
G.Name ->
-- | field description, if any
Maybe G.Description ->
-- | select permissions of the table
SelPermInfo b ->
m (Maybe (FieldParser n (AggSelectExp b)))
selectTableAggregate sourceName tableInfo fieldName description selectPermissions = runMaybeT $ do
guard $ spiAllowAgg selectPermissions
xNodesAgg <- hoistMaybe $ nodesAggExtension @b
lift $ memoizeOn 'selectTableAggregate (sourceName, tableName, fieldName) do
stringifyNum <- asks $ qcStringifyNum . getter
tableGQLName <- getTableGQLName tableInfo
tableArgsParser <- tableArguments sourceName tableInfo selectPermissions
aggregateParser <- tableAggregationFields sourceName tableInfo selectPermissions
nodesParser <- tableSelectionList sourceName tableInfo selectPermissions
selectionName <- P.mkTypename $ tableGQLName <> $$(G.litName "_aggregate")
let aggregationParser =
P.nonNullableParser $
parsedSelectionsToFields IR.TAFExp
<$> P.selectionSet
selectionName
(Just $ G.Description $ "aggregated selection of " <>> tableName)
[ IR.TAFNodes xNodesAgg <$> P.subselection_ $$(G.litName "nodes") Nothing nodesParser,
IR.TAFAgg <$> P.subselection_ $$(G.litName "aggregate") Nothing aggregateParser
]
pure $
P.subselection fieldName description tableArgsParser aggregationParser
<&> \(args, fields) ->
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromTable tableName,
IR._asnPerm = tablePermissionsInfo selectPermissions,
IR._asnArgs = args,
IR._asnStrfyNum = stringifyNum
}
where
tableName = tableInfoName tableInfo
{- Note [Selectability of tables]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The GraphQL specification requires that if the type of a selected field is an
interface, union, or object, then its subselection set must not be empty
(Section 5.3.3). Since we model database tables by GraphQL objects, this means
that a table can be selected as a GraphQL field only if it has fields that we
can select, such as a column. It is perfectly fine not to allow any selections
of any columns of the table in the database. In that case, the table would not
be selectable as a field in GraphQL.
However, this is not the end of the story. In addition to scalar fields, we
support relationships between tables, so that we may have another table B as a
selected field of this table A. Then the selectability of A depends on the
selectability of B: if we permit selection a column of B, then, as a
consequence, we permit selection of the relationship from A to B, and hence we
permit selection of A, as there would now be valid GraphQL syntax that selects
A. In turn, the selectability of B can depend on the selectability of a further
table C, through a relationship from B to C.
Now consider the case of a table A, whose columns themselves are not selectable,
but which has a relationship with itself. Is A selectable? In fact, if A has
no further relationships with other tables, or any computed fields, A is not
selectable. But as soon as any leaf field in the transitive closure of tables
related to A becomes selectable, A itself becomes selectable.
In summary, figuring out the selectability of a table is a mess. In order to
avoid doing graph theory, for now, we simply pretend that GraphQL did not have
the restriction of only allowing selections of fields of type objects when its
subselection is non-empty. In practice, this white lie is somewhat unlikely to
cause errors on the client side, for the following reasons:
- Introspection of the GraphQL schema is normally provided to aid development of
valid GraphQL schemas, and so any errors in the exposed schema can be caught
at development time: when a developer is building a GraphQL query using schema
introspection, they will eventually find out that the selection they aim to do
is not valid GraphQL. Put differently: exposing a given field through
introspection is not the same as claiming that there is a valid GraphQL query
that selects that field.
- We only support tables that have at least one column (since we require primary
keys), so that the admin role can select every table anyway.
-}
-- | Fields of a table
--
-- > type table{
-- > # table columns
-- > column_1: column1_type
-- > .
-- > column_n: columnn_type
-- >
-- > # table relationships
-- > object_relationship: remote_table
-- > array_relationship: [remote_table!]!
-- >
-- > # computed fields
-- > computed_field: field_type
-- >
-- > # remote relationships
-- > remote_field: field_type
-- > }
tableSelectionSet ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (Parser 'Output n (AnnotatedFields b))
tableSelectionSet sourceName tableInfo selectPermissions = memoizeOn 'tableSelectionSet (sourceName, tableName) do
tableGQLName <- getTableGQLName tableInfo
objectTypename <- P.mkTypename tableGQLName
let xRelay = relayExtension @b
tableFields = Map.elems $ _tciFieldInfoMap tableCoreInfo
tablePkeyColumns = _pkColumns <$> _tciPrimaryKey tableCoreInfo
description =
Just $
mkDescriptionWith (_tciDescription tableCoreInfo) $
"columns and relationships of " <>> tableName
fieldParsers <-
concat <$> for tableFields \fieldInfo ->
fieldSelection sourceName tableName tablePkeyColumns fieldInfo selectPermissions
-- We don't check *here* that the subselection set is non-empty,
-- even though the GraphQL specification requires that it is (see
-- Note [Selectability of tables]). However, the GraphQL parser
-- enforces that a selection set, if present, is non-empty; and our
-- parser later verifies that a selection set is present if
-- required, meaning that not having this check here does not allow
-- for the construction of invalid queries.
queryType <- asks $ qcQueryType . getter
case (queryType, tablePkeyColumns, xRelay) of
-- A relay table
(ET.QueryRelay, Just pkeyColumns, Just xRelayInfo) -> do
let nodeIdFieldParser =
P.selection_ $$(G.litName "id") Nothing P.identifier $> IR.AFNodeId xRelayInfo tableName pkeyColumns
allFieldParsers = fieldParsers <> [nodeIdFieldParser]
nodeInterface <- node @b
pure $
P.selectionSetObject objectTypename description allFieldParsers [nodeInterface]
<&> parsedSelectionsToFields IR.AFExpression
_ ->
pure $
P.selectionSetObject objectTypename description fieldParsers []
<&> parsedSelectionsToFields IR.AFExpression
where
tableName = tableInfoName tableInfo
tableCoreInfo = _tiCoreInfo tableInfo
-- | List of table fields object.
-- Just a @'nonNullableObjectList' wrapper over @'tableSelectionSet'.
-- > table_name: [table!]!
tableSelectionList ::
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (Parser 'Output n (AnnotatedFields b))
tableSelectionList sourceName tableInfo selectPermissions =
nonNullableObjectList <$> tableSelectionSet sourceName tableInfo selectPermissions
-- | Converts an output type parser from object_type to [object_type!]!
nonNullableObjectList :: Parser 'Output m a -> Parser 'Output m a
nonNullableObjectList =
P.nonNullableParser . P.multiple . P.nonNullableParser
-- | Connection fields of a table
--
-- > type tableConnection{
-- > pageInfo: PageInfo!
-- > edges: [tableEdge!]!
-- > }
--
-- > type PageInfo{
-- > startCursor: String!
-- > endCursor: String!
-- > hasNextPage: Boolean!
-- > hasPreviousPage: Boolean!
-- > }
--
-- > type tableEdge{
-- > cursor: String!
-- > node: table!
-- > }
tableConnectionSelectionSet ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (Parser 'Output n (ConnectionFields b))
tableConnectionSelectionSet sourceName tableInfo selectPermissions = memoizeOn 'tableConnectionSelectionSet (sourceName, tableName) do
tableGQLName <- getTableGQLName tableInfo
edgesParser <- tableEdgesSelectionSet tableGQLName
connectionTypeName <- P.mkTypename $ tableGQLName <> $$(G.litName "Connection")
let pageInfo =
P.subselection_
$$(G.litName "pageInfo")
Nothing
pageInfoSelectionSet
<&> IR.ConnectionPageInfo
edges =
P.subselection_
$$(G.litName "edges")
Nothing
edgesParser
<&> IR.ConnectionEdges
connectionDescription = G.Description $ "A Relay connection object on " <>> tableName
pure $
P.nonNullableParser $
P.selectionSet connectionTypeName (Just connectionDescription) [pageInfo, edges]
<&> parsedSelectionsToFields IR.ConnectionTypename
where
tableName = tableInfoName tableInfo
pageInfoSelectionSet :: Parser 'Output n IR.PageInfoFields
pageInfoSelectionSet =
let startCursorField =
P.selection_
$$(G.litName "startCursor")
Nothing
P.string
$> IR.PageInfoStartCursor
endCursorField =
P.selection_
$$(G.litName "endCursor")
Nothing
P.string
$> IR.PageInfoEndCursor
hasNextPageField =
P.selection_
$$(G.litName "hasNextPage")
Nothing
P.boolean
$> IR.PageInfoHasNextPage
hasPreviousPageField =
P.selection_
$$(G.litName "hasPreviousPage")
Nothing
P.boolean
$> IR.PageInfoHasPreviousPage
allFields =
[ startCursorField,
endCursorField,
hasNextPageField,
hasPreviousPageField
]
in P.nonNullableParser $
P.selectionSet $$(G.litName "PageInfo") Nothing allFields
<&> parsedSelectionsToFields IR.PageInfoTypename
tableEdgesSelectionSet ::
G.Name -> m (Parser 'Output n (EdgeFields b))
tableEdgesSelectionSet tableGQLName = do
edgeNodeParser <- P.nonNullableParser <$> tableSelectionSet sourceName tableInfo selectPermissions
edgesType <- P.mkTypename $ tableGQLName <> $$(G.litName "Edge")
let cursor =
P.selection_
$$(G.litName "cursor")
Nothing
P.string
$> IR.EdgeCursor
edgeNode =
P.subselection_
$$(G.litName "node")
Nothing
edgeNodeParser
<&> IR.EdgeNode
pure $
nonNullableObjectList $
P.selectionSet edgesType Nothing [cursor, edgeNode]
<&> parsedSelectionsToFields IR.EdgeTypename
-- | User-defined function (AKA custom function)
selectFunction ::
forall b r m n.
MonadBuildSchema b r m n =>
-- | source name
SourceName ->
-- | SQL function info
FunctionInfo b ->
-- | field description, if any
Maybe G.Description ->
-- | select permissions of the target table
SelPermInfo b ->
m (FieldParser n (SelectExp b))
selectFunction sourceName fi@FunctionInfo {..} description selectPermissions = do
stringifyNum <- asks $ qcStringifyNum . getter
tableInfo <- askTableInfo sourceName _fiReturnType
tableArgsParser <- tableArguments sourceName tableInfo selectPermissions
selectionSetParser <- returnFunctionParser sourceName tableInfo selectPermissions
functionArgsParser <- customSQLFunctionArgs fi _fiGQLName _fiGQLArgsName
let argsParser = liftA2 (,) functionArgsParser tableArgsParser
functionFieldName <- mkRootFieldName _fiGQLName
pure $
P.subselection functionFieldName description argsParser selectionSetParser
<&> \((funcArgs, tableArgs'), fields) ->
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromFunction _fiSQLName funcArgs Nothing,
IR._asnPerm = tablePermissionsInfo selectPermissions,
IR._asnArgs = tableArgs',
IR._asnStrfyNum = stringifyNum
}
where
returnFunctionParser =
case _fiJsonAggSelect of
JASSingleObject -> tableSelectionSet
JASMultipleRows -> tableSelectionList
selectFunctionAggregate ::
forall b r m n.
MonadBuildSchema b r m n =>
-- | source name
SourceName ->
-- | SQL function info
FunctionInfo b ->
-- | field description, if any
Maybe G.Description ->
-- | select permissions of the target table
SelPermInfo b ->
m (Maybe (FieldParser n (AggSelectExp b)))
selectFunctionAggregate sourceName fi@FunctionInfo {..} description selectPermissions = runMaybeT do
guard $ spiAllowAgg selectPermissions
xNodesAgg <- hoistMaybe $ nodesAggExtension @b
tableInfo <- askTableInfo sourceName _fiReturnType
stringifyNum <- asks $ qcStringifyNum . getter
tableGQLName <- getTableGQLName tableInfo
tableArgsParser <- lift $ tableArguments sourceName tableInfo selectPermissions
functionArgsParser <- lift $ customSQLFunctionArgs fi _fiGQLAggregateName _fiGQLArgsName
aggregateParser <- lift $ tableAggregationFields sourceName tableInfo selectPermissions
selectionName <- P.mkTypename =<< lift (pure tableGQLName <&> (<> $$(G.litName "_aggregate")))
nodesParser <- lift $ tableSelectionList sourceName tableInfo selectPermissions
aggregateFieldName <- mkRootFieldName _fiGQLAggregateName
let argsParser = liftA2 (,) functionArgsParser tableArgsParser
aggregationParser =
fmap (parsedSelectionsToFields IR.TAFExp) $
P.nonNullableParser $
P.selectionSet
selectionName
Nothing
[ IR.TAFNodes xNodesAgg <$> P.subselection_ $$(G.litName "nodes") Nothing nodesParser,
IR.TAFAgg <$> P.subselection_ $$(G.litName "aggregate") Nothing aggregateParser
]
pure $
P.subselection aggregateFieldName description argsParser aggregationParser
<&> \((funcArgs, tableArgs'), fields) ->
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromFunction _fiSQLName funcArgs Nothing,
IR._asnPerm = tablePermissionsInfo selectPermissions,
IR._asnArgs = tableArgs',
IR._asnStrfyNum = stringifyNum
}
selectFunctionConnection ::
forall pgKind r m n.
MonadBuildSchema ('Postgres pgKind) r m n =>
-- | source name
SourceName ->
-- | SQL function info
FunctionInfo ('Postgres pgKind) ->
-- | field description, if any
Maybe G.Description ->
-- | primary key columns of the target table
PrimaryKeyColumns ('Postgres pgKind) ->
-- | select permissions of the target table
SelPermInfo ('Postgres pgKind) ->
m (Maybe (FieldParser n (ConnectionSelectExp ('Postgres pgKind))))
selectFunctionConnection sourceName fi@FunctionInfo {..} description pkeyColumns selectPermissions = do
fieldName <- mkRootFieldName $ _fiGQLName <> $$(G.litName "_connection")
for (relayExtension @('Postgres pgKind)) \xRelayInfo -> do
stringifyNum <- asks $ qcStringifyNum . getter
tableInfo <- askTableInfo sourceName _fiReturnType
tableConnectionArgsParser <- tableConnectionArgs pkeyColumns sourceName tableInfo selectPermissions
functionArgsParser <- customSQLFunctionArgs fi _fiGQLName _fiGQLArgsName
selectionSetParser <- tableConnectionSelectionSet sourceName tableInfo selectPermissions
let argsParser = liftA2 (,) functionArgsParser tableConnectionArgsParser
pure $
P.subselection fieldName description argsParser selectionSetParser
<&> \((funcArgs, (args, split, slice)), fields) ->
IR.ConnectionSelect
{ IR._csXRelay = xRelayInfo,
IR._csPrimaryKeyColumns = pkeyColumns,
IR._csSplit = split,
IR._csSlice = slice,
IR._csSelect =
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromFunction _fiSQLName funcArgs Nothing,
IR._asnPerm = tablePermissionsInfo selectPermissions,
IR._asnArgs = args,
IR._asnStrfyNum = stringifyNum
}
}
--------------------------------------------------------------------------------
-- Components
--
-- Those parsers are sub-components of those top-level parsers.
-- | Arguments for a table selection. Default implementation for BackendSchema.
--
-- > distinct_on: [table_select_column!]
-- > limit: Int
-- > offset: Int
-- > order_by: [table_order_by!]
-- > where: table_bool_exp
defaultTableArgs ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (InputFieldsParser n (SelectArgs b))
defaultTableArgs sourceName tableInfo selectPermissions = do
whereParser <- tableWhereArg sourceName tableInfo selectPermissions
orderByParser <- tableOrderByArg sourceName tableInfo selectPermissions
distinctParser <- tableDistinctArg sourceName tableInfo selectPermissions
let result = do
whereArg <- whereParser
orderByArg <- orderByParser
limitArg <- tableLimitArg
offsetArg <- tableOffsetArg
distinctArg <- distinctParser
pure $
IR.SelectArgs
{ IR._saWhere = whereArg,
IR._saOrderBy = orderByArg,
IR._saLimit = limitArg,
IR._saOffset = offsetArg,
IR._saDistinct = distinctArg
}
pure $
result `P.bindFields` \args -> do
sequence_ do
orderBy <- IR._saOrderBy args
distinct <- IR._saDistinct args
Just $ validateArgs orderBy distinct
pure args
where
validateArgs orderByCols distinctCols = do
let colsLen = length distinctCols
initOrderBys = take colsLen $ NE.toList orderByCols
initOrdByCols = flip mapMaybe initOrderBys $ \ob ->
case IR.obiColumn ob of
IR.AOCColumn columnInfo -> Just $ ciColumn columnInfo
_ -> Nothing
isValid =
(colsLen == length initOrdByCols)
&& all (`elem` initOrdByCols) (toList distinctCols)
unless isValid $
parseError
"\"distinct_on\" columns must match initial \"order_by\" columns"
-- | Argument to filter rows returned from table selection
-- > where: table_bool_exp
tableWhereArg ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (InputFieldsParser n (Maybe (IR.AnnBoolExp b (UnpreparedValue b))))
tableWhereArg sourceName tableInfo selectPermissions = do
boolExpParser <- boolExp sourceName tableInfo (Just selectPermissions)
pure $
fmap join $
P.fieldOptional whereName whereDesc $
P.nullable boolExpParser
where
whereName = $$(G.litName "where")
whereDesc = Just $ G.Description "filter the rows returned"
-- | Argument to sort rows returned from table selection
-- > order_by: [table_order_by!]
tableOrderByArg ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (InputFieldsParser n (Maybe (NonEmpty (IR.AnnotatedOrderByItemG b (UnpreparedValue b)))))
tableOrderByArg sourceName tableInfo selectPermissions = do
orderByParser <- orderByExp sourceName tableInfo selectPermissions
pure $ do
maybeOrderByExps <-
fmap join $
P.fieldOptional orderByName orderByDesc $ P.nullable $ P.list orderByParser
pure $ maybeOrderByExps >>= NE.nonEmpty . concat
where
orderByName = $$(G.litName "order_by")
orderByDesc = Just $ G.Description "sort the rows by one or more columns"
-- | Argument to distinct select on columns returned from table selection
-- > distinct_on: [table_select_column!]
tableDistinctArg ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (InputFieldsParser n (Maybe (NonEmpty (Column b))))
tableDistinctArg sourceName tableInfo selectPermissions = do
columnsEnum <- tableSelectColumnsEnum sourceName tableInfo selectPermissions
pure do
maybeDistinctOnColumns <-
join . join
<$> for
columnsEnum
(P.fieldOptional distinctOnName distinctOnDesc . P.nullable . P.list)
pure $ maybeDistinctOnColumns >>= NE.nonEmpty
where
distinctOnName = $$(G.litName "distinct_on")
distinctOnDesc = Just $ G.Description "distinct select on columns"
-- | Argument to limit rows returned from table selection
-- > limit: NonNegativeInt
tableLimitArg ::
forall n.
MonadParse n =>
InputFieldsParser n (Maybe Int)
tableLimitArg =
fmap (fmap fromIntegral . join) $
P.fieldOptional limitName limitDesc $
P.nullable P.nonNegativeInt
where
limitName = $$(G.litName "limit")
limitDesc = Just $ G.Description "limit the number of rows returned"
-- | Argument to skip some rows, in conjunction with order_by
-- > offset: BigInt
tableOffsetArg ::
forall n.
MonadParse n =>
InputFieldsParser n (Maybe Int64)
tableOffsetArg =
fmap join $
P.fieldOptional offsetName offsetDesc $
P.nullable P.bigInt
where
offsetName = $$(G.litName "offset")
offsetDesc = Just $ G.Description "skip the first n rows. Use only with order_by"
-- | Arguments for a table connection selection
--
-- > distinct_on: [table_select_column!]
-- > order_by: [table_order_by!]
-- > where: table_bool_exp
-- > first: Int
-- > last: Int
-- > before: String
-- > after: String
tableConnectionArgs ::
forall b r m n.
MonadBuildSchema b r m n =>
PrimaryKeyColumns b ->
SourceName ->
TableInfo b ->
SelPermInfo b ->
m
( InputFieldsParser
n
( SelectArgs b,
Maybe (NonEmpty (IR.ConnectionSplit b (UnpreparedValue b))),
Maybe IR.ConnectionSlice
)
)
tableConnectionArgs pkeyColumns sourceName tableInfo selectPermissions = do
whereParser <- tableWhereArg sourceName tableInfo selectPermissions
orderByParser <- fmap (fmap appendPrimaryKeyOrderBy) <$> tableOrderByArg sourceName tableInfo selectPermissions
distinctParser <- tableDistinctArg sourceName tableInfo selectPermissions
let maybeFirst = fmap join $ P.fieldOptional $$(G.litName "first") Nothing $ P.nullable P.nonNegativeInt
maybeLast = fmap join $ P.fieldOptional $$(G.litName "last") Nothing $ P.nullable P.nonNegativeInt
maybeAfter = fmap join $ P.fieldOptional $$(G.litName "after") Nothing $ P.nullable base64Text
maybeBefore = fmap join $ P.fieldOptional $$(G.litName "before") Nothing $ P.nullable base64Text
firstAndLast = (,) <$> maybeFirst <*> maybeLast
afterBeforeAndOrderBy = (,,) <$> maybeAfter <*> maybeBefore <*> orderByParser
pure $ do
whereF <- whereParser
orderBy <- orderByParser
distinct <- distinctParser
split <-
afterBeforeAndOrderBy `P.bindFields` \(after, before, orderBy') -> do
rawSplit <- case (after, before) of
(Nothing, Nothing) -> pure Nothing
(Just _, Just _) -> parseError "\"after\" and \"before\" are not allowed at once"
(Just v, Nothing) -> pure $ Just (IR.CSKAfter, v)
(Nothing, Just v) -> pure $ Just (IR.CSKBefore, v)
for rawSplit (uncurry (parseConnectionSplit orderBy'))
slice <-
firstAndLast `P.bindFields` \case
(Nothing, Nothing) -> pure Nothing
(Just _, Just _) -> parseError "\"first\" and \"last\" are not allowed at once"
(Just v, Nothing) -> pure $ Just $ IR.SliceFirst $ fromIntegral v
(Nothing, Just v) -> pure $ Just $ IR.SliceLast $ fromIntegral v
pure
( IR.SelectArgs whereF orderBy Nothing Nothing distinct,
split,
slice
)
where
base64Text = base64Decode <$> P.string
appendPrimaryKeyOrderBy :: NonEmpty (IR.AnnotatedOrderByItemG b v) -> NonEmpty (IR.AnnotatedOrderByItemG b v)
appendPrimaryKeyOrderBy orderBys@(h NE.:| t) =
let orderByColumnNames =
orderBys ^.. traverse . to IR.obiColumn . IR._AOCColumn . to ciColumn
pkeyOrderBys = flip mapMaybe (toList pkeyColumns) $ \columnInfo ->
if ciColumn columnInfo `elem` orderByColumnNames
then Nothing
else Just $ IR.OrderByItemG Nothing (IR.AOCColumn columnInfo) Nothing
in h NE.:| (t <> pkeyOrderBys)
parseConnectionSplit ::
Maybe (NonEmpty (IR.AnnotatedOrderByItemG b (UnpreparedValue b))) ->
IR.ConnectionSplitKind ->
BL.ByteString ->
n (NonEmpty (IR.ConnectionSplit b (UnpreparedValue b)))
parseConnectionSplit maybeOrderBys splitKind cursorSplit = do
cursorValue <- J.eitherDecode cursorSplit `onLeft` const throwInvalidCursor
case maybeOrderBys of
Nothing -> forM (NESeq.toNonEmpty pkeyColumns) $
\columnInfo -> do
let columnJsonPath = [J.Key $ toTxt $ ciColumn columnInfo]
columnType = ciType columnInfo
columnValue <-
iResultToMaybe (executeJSONPath columnJsonPath cursorValue)
`onNothing` throwInvalidCursor
pgValue <- liftQErr $ parseScalarValueColumnType columnType columnValue
let unresolvedValue = UVParameter Nothing $ ColumnValue columnType pgValue
pure $
IR.ConnectionSplit splitKind unresolvedValue $
IR.OrderByItemG Nothing (IR.AOCColumn columnInfo) Nothing
Just orderBys ->
forM orderBys $ \orderBy -> do
let IR.OrderByItemG orderType annObCol nullsOrder = orderBy
columnType = getOrderByColumnType annObCol
orderByItemValue <-
iResultToMaybe (executeJSONPath (getPathFromOrderBy annObCol) cursorValue)
`onNothing` throwInvalidCursor
pgValue <- liftQErr $ parseScalarValueColumnType columnType orderByItemValue
let unresolvedValue = UVParameter Nothing $ ColumnValue columnType pgValue
pure $
IR.ConnectionSplit splitKind unresolvedValue $
IR.OrderByItemG orderType annObCol nullsOrder
where
throwInvalidCursor = parseError "the \"after\" or \"before\" cursor is invalid"
liftQErr = either (parseError . qeError) pure . runExcept
mkAggregateOrderByPath = \case
IR.AAOCount -> [J.Key "count"]
IR.AAOOp t col -> [J.Key t, J.Key $ toTxt $ ciColumn col]
getPathFromOrderBy = \case
IR.AOCColumn columnInfo ->
let pathElement = J.Key $ toTxt $ ciColumn columnInfo
in [pathElement]
IR.AOCObjectRelation relInfo _ obCol ->
let pathElement = J.Key $ relNameToTxt $ riName relInfo
in pathElement : getPathFromOrderBy obCol
IR.AOCArrayAggregation relInfo _ aggOb ->
let fieldName = J.Key $ relNameToTxt (riName relInfo) <> "_aggregate"
in fieldName : mkAggregateOrderByPath aggOb
IR.AOCComputedField cfob ->
let fieldNameText = computedFieldNameToText $ IR._cfobName cfob
in case IR._cfobOrderByElement cfob of
IR.CFOBEScalar _ -> [J.Key fieldNameText]
IR.CFOBETableAggregation _ _ aggOb ->
J.Key (fieldNameText <> "_aggregate") : mkAggregateOrderByPath aggOb
getOrderByColumnType = \case
IR.AOCColumn columnInfo -> ciType columnInfo
IR.AOCObjectRelation _ _ obCol -> getOrderByColumnType obCol
IR.AOCArrayAggregation _ _ aggOb -> aggregateOrderByColumnType aggOb
IR.AOCComputedField cfob ->
case IR._cfobOrderByElement cfob of
IR.CFOBEScalar scalarType -> ColumnScalar scalarType
IR.CFOBETableAggregation _ _ aggOb -> aggregateOrderByColumnType aggOb
where
aggregateOrderByColumnType = \case
IR.AAOCount -> ColumnScalar (aggregateOrderByCountType @b)
IR.AAOOp _ colInfo -> ciType colInfo
-- | Aggregation fields
--
-- > type table_aggregate_fields{
-- > count(distinct: Boolean, columns: [table_select_column!]): Int!
-- > sum: table_sum_fields
-- > avg: table_avg_fields
-- > stddev: table_stddev_fields
-- > stddev_pop: table_stddev_pop_fields
-- > variance: table_variance_fields
-- > var_pop: table_var_pop_fields
-- > max: table_max_fields
-- > min: table_min_fields
-- > }
tableAggregationFields ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (Parser 'Output n (IR.AggregateFields b))
tableAggregationFields sourceName tableInfo selectPermissions = memoizeOn 'tableAggregationFields (sourceName, tableInfoName tableInfo) do
tableGQLName <- getTableGQLName tableInfo
allColumns <- tableSelectColumns sourceName tableInfo selectPermissions
let numericColumns = onlyNumCols allColumns
comparableColumns = onlyComparableCols allColumns
description = G.Description $ "aggregate fields of " <>> tableInfoName tableInfo
selectName <- P.mkTypename $ tableGQLName <> $$(G.litName "_aggregate_fields")
count <- countField
mkTypename <- asks getter
numericAndComparable <-
fmap concat $
sequenceA $
catMaybes
[ -- operators on numeric columns
if null numericColumns
then Nothing
else Just $
for numericAggOperators $ \operator -> do
numFields <- mkNumericAggFields operator numericColumns
pure $ parseAggOperator mkTypename operator tableGQLName numFields,
-- operators on comparable columns
if null comparableColumns
then Nothing
else Just $ do
comparableFields <- traverse mkColumnAggField comparableColumns
pure $
comparisonAggOperators & map \operator ->
parseAggOperator mkTypename operator tableGQLName comparableFields
]
let aggregateFields = count : numericAndComparable
pure $
P.selectionSet selectName (Just description) aggregateFields
<&> parsedSelectionsToFields IR.AFExp
where
mkNumericAggFields :: G.Name -> [ColumnInfo b] -> m [FieldParser n (IR.ColFld b)]
mkNumericAggFields name
| name == $$(G.litName "sum") = traverse mkColumnAggField
| otherwise = traverse \columnInfo ->
pure $
P.selection_
(ciName columnInfo)
(ciDescription columnInfo)
(P.nullable P.float)
$> IR.CFCol (ciColumn columnInfo) (ciType columnInfo)
mkColumnAggField :: ColumnInfo b -> m (FieldParser n (IR.ColFld b))
mkColumnAggField columnInfo = do
field <- columnParser (ciType columnInfo) (G.Nullability True)
pure $
P.selection_
(ciName columnInfo)
(ciDescription columnInfo)
field
$> IR.CFCol (ciColumn columnInfo) (ciType columnInfo)
countField :: m (FieldParser n (IR.AggregateField b))
countField = do
columnsEnum <- tableSelectColumnsEnum sourceName tableInfo selectPermissions
let distinctName = $$(G.litName "distinct")
args = do
distinct <- P.fieldOptional distinctName Nothing P.boolean
mkCountType <- countTypeInput @b columnsEnum
pure $
mkCountType $
maybe
IR.SelectCountNonDistinct -- If "distinct" is "null" or absent, we default to @'SelectCountNonDistinct'
(bool IR.SelectCountNonDistinct IR.SelectCountDistinct)
distinct
pure $ IR.AFCount <$> P.selection $$(G.litName "count") Nothing args P.int
parseAggOperator ::
P.MkTypename ->
G.Name ->
G.Name ->
[FieldParser n (IR.ColFld b)] ->
FieldParser n (IR.AggregateField b)
parseAggOperator mkTypename operator tableGQLName columns =
let opText = G.unName operator
setName = P.runMkTypename mkTypename $ tableGQLName <> $$(G.litName "_") <> operator <> $$(G.litName "_fields")
setDesc = Just $ G.Description $ "aggregate " <> opText <> " on columns"
subselectionParser =
P.selectionSet setName setDesc columns
<&> parsedSelectionsToFields IR.CFExp
in P.subselection_ operator Nothing subselectionParser
<&> IR.AFOp . IR.AggregateOp opText
-- | An individual field of a table
--
-- > field_name(arg_name: arg_type, ...): field_type
fieldSelection ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableName b ->
Maybe (PrimaryKeyColumns b) ->
FieldInfo b ->
SelPermInfo b ->
m [FieldParser n (AnnotatedField b)]
fieldSelection sourceName table maybePkeyColumns fieldInfo selectPermissions = do
case fieldInfo of
FIColumn columnInfo ->
maybeToList <$> runMaybeT do
queryType <- asks $ qcQueryType . getter
let columnName = ciColumn columnInfo
fieldName = ciName columnInfo
if fieldName == $$(G.litName "id") && queryType == ET.QueryRelay
then do
xRelayInfo <- hoistMaybe $ relayExtension @b
pkeyColumns <- hoistMaybe maybePkeyColumns
pure $
P.selection_ fieldName Nothing P.identifier
$> IR.AFNodeId xRelayInfo table pkeyColumns
else do
guard $ columnName `Map.member` spiCols selectPermissions
let caseBoolExp = join $ Map.lookup columnName (spiCols selectPermissions)
let caseBoolExpUnpreparedValue =
(fmap . fmap) partialSQLExpToUnpreparedValue <$> caseBoolExp
let pathArg = jsonPathArg $ ciType columnInfo
-- In an inherited role, when a column is part of all the select
-- permissions which make up the inherited role then the nullability
-- of the field is determined by the nullability of the DB column
-- otherwise it is marked as nullable explicitly, ignoring the column's
-- nullability. We do this because
-- in multiple roles we execute an SQL query like:
--
-- select
-- (case when (P1 or P2) then addr else null end) as addr,
-- (case when P2 then phone else null end) as phone
-- from employee
-- where (P1 or P2)
--
-- In the above example, P(n) is a predicate configured for a role
--
-- NOTE: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/FGALanguageICDE07.pdf
-- The above is the paper which talks about the idea of cell-level
-- authorization and multiple roles. The paper says that we should only
-- allow the case analysis only on nullable columns.
nullability = ciIsNullable columnInfo || isJust caseBoolExp
field <- lift $ columnParser (ciType columnInfo) (G.Nullability nullability)
pure $
P.selection fieldName (ciDescription columnInfo) pathArg field
<&> IR.mkAnnColumnField (ciColumn columnInfo) (ciType columnInfo) caseBoolExpUnpreparedValue
FIRelationship relationshipInfo ->
concat . maybeToList <$> relationshipField sourceName table relationshipInfo
FIComputedField computedFieldInfo ->
maybeToList <$> computedField sourceName computedFieldInfo table selectPermissions
FIRemoteRelationship remoteFieldInfo -> do
relationshipFields <- fromMaybe [] <$> remoteRelationshipField remoteFieldInfo
let lhsFields = _rfiLHS remoteFieldInfo
pure $ map (fmap (IR.AFRemote . IR.RemoteRelationshipSelect lhsFields)) relationshipFields
{- Note [Permission filter deduplication]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1. `T` and `U` are tables.
1. `r` is a relationship on `T` to table `U` with the join condition, `T.c =
U.d` where `c` and `d` are columns on tables `T` and `U` respectively.
1. `s` is a relationship on `U` to table `T` with the join condition, `U.d =
T.c`.
1. `p(T)` and `p(U)` denote the permission filters on table `T` and `U`
respectively for some role `R`.
Consider the SQL that we generate for this query:
```
query {
T {
c
r {
d
}
}
}
```
It would be along these lines:
```sql
SELECT
*
FROM
(
SELECT * FROM T WHERE p(T)
) AS T
LEFT OUTER JOIN LATERAL
(
SELECT * FROM U WHERE T.c = U.d AND p(U)
) AS U
ON TRUE
```
The expression `T.c = U.d` is the join condition for relationship `r`. Note
that we use lateral joins, so the join condition is not expressed using `ON`
but on the where clause of `U`.
Now, let's say `p(U)` is of the form `{ s : p(T) }`.
```sql
SELECT
*
FROM
(
SELECT * FROM T WHERE p(T)
) AS T
LEFT OUTER JOIN LATERAL
(
SELECT * FROM U WHERE T.c = U.d
AND EXISTS (
SELECT 1 FROM T WHERE U.d = T.c AND p(T)
)
) AS U
ON TRUE
```
`p(U)`, i.e, `{ s : p(T) }` got expanded to
```sql
EXISTS (
SELECT 1 FROM T WHERE U.d = T.c AND p(T)
)
```
Now, assuming, in the `WHERE` clause for `U`, that `T.c = U.d` holds, then the
`EXISTS` clause must evaluate to true. The `EXISTS` clause must evaluate to true
because the row from `T` we are joining against is exactly such a row satisfying
`p(T)`. In other words, the row obtained from `T` (as the left-hand side of the
join) satisfies `p(T)`.
-}
-- | Field parsers for a table relationship
relationshipField ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableName b ->
RelInfo b ->
m (Maybe [FieldParser n (AnnotatedField b)])
relationshipField sourceName table ri = runMaybeT do
optimizePermissionFilters <- asks $ qcOptimizePermissionFilters . getter
otherTableInfo <- lift $ askTableInfo sourceName $ riRTable ri
remotePerms <- MaybeT $ tableSelectPermissions otherTableInfo
relFieldName <- lift $ textToName $ relNameToTxt $ riName ri
-- START black magic to deduplicate permission checks
thisTablePerm <-
IR._tpFilter . tablePermissionsInfo
<$> MaybeT (tableSelectPermissions =<< askTableInfo @b sourceName table)
let deduplicatePermissions :: AnnBoolExp b (UnpreparedValue b) -> AnnBoolExp b (UnpreparedValue b)
deduplicatePermissions x =
case (optimizePermissionFilters, x) of
(True, BoolAnd [BoolFld (AVRelationship remoteRI remoteTablePerm)]) ->
-- Here we try to figure out if the "forwards" joining condition
-- from `table` to the related table `riRTable ri` is equal to the
-- "backwards" joining condition from the related table back to
-- `table`. If it is, then we can optimize the row-level permission
-- filters by dropping them here.
if riRTable remoteRI == table
&& riMapping remoteRI `Map.isInverseOf` riMapping ri
&& thisTablePerm == remoteTablePerm
then BoolAnd []
else x
_ -> x
deduplicatePermissions' :: SelectExp b -> SelectExp b
deduplicatePermissions' expr =
let newFilter = deduplicatePermissions (IR._tpFilter (IR._asnPerm expr))
in expr {IR._asnPerm = (IR._asnPerm expr) {IR._tpFilter = newFilter}}
-- END black magic to deduplicate permission checks
case riType ri of
ObjRel -> do
let desc = Just $ G.Description "An object relationship"
selectionSetParser <- lift $ tableSelectionSet sourceName otherTableInfo remotePerms
-- We need to set the correct nullability of our GraphQL field. Manual
-- relationships are always nullable, and so are "reverse" object
-- relationships, i.e. Hasura relationships that are generated from a
-- referenced table to a referencing table. For automatic forward object
-- relationships, i.e. the generated relationship from table1 to table2,
-- where table1 has a foreign key constraint, we have to do some work.
--
-- Specifically, we would like to mark the relationship generated from a
-- foreign key constraint from table1 to table2 to be non-nullable if
-- Postgres enforces that for each row in table1, a corresponding row in
-- table2 exists. From the Postgres manual:
--
-- "Normally, a referencing row need not satisfy the foreign key
-- constraint if any of its referencing columns are null. If MATCH FULL
-- is added to the foreign key declaration, a referencing row escapes
-- satisfying the constraint only if all its referencing columns are null
-- (so a mix of null and non-null values is guaranteed to fail a MATCH
-- FULL constraint)."
--
-- https://www.postgresql.org/docs/9.5/ddl-constraints.html#DDL-CONSTRAINTS-FK
--
-- Since we don't store MATCH FULL in the RQL representation of the
-- database, the closest we can get is to only set the field to be
-- non-nullable if _all_ of the columns that reference the foreign table
-- are non-nullable. Strictly speaking, we could do slightly better by
-- setting the field to be non-nullable also if the foreign key has MATCH
-- FULL set, and _any_ of the columns is non-nullable. But we skip doing
-- this since, as of writing this, the old code used to make the wrong
-- decision about nullability of joint foreign keys entirely, so this is
-- probably not a very widely used mode of use. The impact of this
-- suboptimality is merely that in introspection some fields might get
-- marked nullable which are in fact known to always be non-null.
nullable <- case (riIsManual ri, riInsertOrder ri) of
-- Automatically generated forward relationship
(False, BeforeParent) -> do
tableInfo <- askTableInfo @b sourceName table
let columns = Map.keys $ riMapping ri
fieldInfoMap = _tciFieldInfoMap $ _tiCoreInfo tableInfo
findColumn col = Map.lookup (fromCol @b col) fieldInfoMap ^? _Just . _FIColumn
-- Fetch information about the referencing columns of the foreign key
-- constraint
colInfo <-
traverse findColumn columns
`onNothing` throw500 "could not find column info in schema cache"
pure $ boolToNullable $ any ciIsNullable colInfo
-- Manual or reverse relationships are always nullable
_ -> pure Nullable
pure $
pure $
case nullable of { Nullable -> id; NotNullable -> P.nonNullableField } $
P.subselection_ relFieldName desc selectionSetParser
<&> \fields ->
IR.AFObjectRelation $
IR.AnnRelationSelectG (riName ri) (riMapping ri) $
IR.AnnObjectSelectG fields (riRTable ri) $
deduplicatePermissions $
IR._tpFilter $ tablePermissionsInfo remotePerms
ArrRel -> do
let arrayRelDesc = Just $ G.Description "An array relationship"
otherTableParser <- lift $ selectTable sourceName otherTableInfo relFieldName arrayRelDesc remotePerms
let arrayRelField =
otherTableParser <&> \selectExp ->
IR.AFArrayRelation $
IR.ASSimple $
IR.AnnRelationSelectG (riName ri) (riMapping ri) $
deduplicatePermissions' selectExp
relAggFieldName = relFieldName <> $$(G.litName "_aggregate")
relAggDesc = Just $ G.Description "An aggregate relationship"
remoteAggField <- lift $ selectTableAggregate sourceName otherTableInfo relAggFieldName relAggDesc remotePerms
remoteConnectionField <- runMaybeT $ do
-- Parse array connection field only for relay schema
queryType <- asks $ qcQueryType . getter
guard $ queryType == ET.QueryRelay
xRelayInfo <- hoistMaybe $ relayExtension @b
pkeyColumns <-
MaybeT $
(^? tiCoreInfo . tciPrimaryKey . _Just . pkColumns)
<$> pure otherTableInfo
let relConnectionName = relFieldName <> $$(G.litName "_connection")
relConnectionDesc = Just $ G.Description "An array relationship connection"
MaybeT $ lift $ selectTableConnection sourceName otherTableInfo relConnectionName relConnectionDesc pkeyColumns remotePerms
pure $
catMaybes
[ Just arrayRelField,
fmap (IR.AFArrayRelation . IR.ASAggregate . IR.AnnRelationSelectG (riName ri) (riMapping ri)) <$> remoteAggField,
fmap (IR.AFArrayRelation . IR.ASConnection . IR.AnnRelationSelectG (riName ri) (riMapping ri)) <$> remoteConnectionField
]
-- | Computed field parser
computedFieldPG ::
forall pgKind r m n.
MonadBuildSchema ('Postgres pgKind) r m n =>
SourceName ->
ComputedFieldInfo ('Postgres pgKind) ->
TableName ('Postgres pgKind) ->
SelPermInfo ('Postgres pgKind) ->
m (Maybe (FieldParser n (AnnotatedField ('Postgres pgKind))))
computedFieldPG sourceName ComputedFieldInfo {..} parentTable selectPermissions = runMaybeT do
stringifyNum <- asks $ qcStringifyNum . getter
fieldName <- lift $ textToName $ computedFieldNameToText _cfiName
functionArgsParser <- lift $ computedFieldFunctionArgs _cfiFunction
case _cfiReturnType of
CFRScalar scalarReturnType -> do
caseBoolExpMaybe <-
onNothing
(Map.lookup _cfiName (spiScalarComputedFields selectPermissions))
(hoistMaybe Nothing)
let caseBoolExpUnpreparedValue =
(fmap . fmap) partialSQLExpToUnpreparedValue <$> caseBoolExpMaybe
fieldArgsParser = do
args <- functionArgsParser
colOp <- jsonPathArg $ ColumnScalar scalarReturnType
pure $
IR.AFComputedField
_cfiXComputedFieldInfo
_cfiName
( IR.CFSScalar
( IR.ComputedFieldScalarSelect
{ IR._cfssFunction = _cffName _cfiFunction,
IR._cfssType = scalarReturnType,
IR._cfssColumnOp = colOp,
IR._cfssArguments = args
}
)
caseBoolExpUnpreparedValue
)
dummyParser <- lift $ columnParser @('Postgres pgKind) (ColumnScalar scalarReturnType) (G.Nullability True)
pure $ P.selection fieldName (Just fieldDescription) fieldArgsParser dummyParser
CFRSetofTable tableName -> do
tableInfo <- lift $ askTableInfo sourceName tableName
remotePerms <- MaybeT $ tableSelectPermissions tableInfo
selectArgsParser <- lift $ tableArguments sourceName tableInfo remotePerms
selectionSetParser <- lift $ P.multiple . P.nonNullableParser <$> tableSelectionSet sourceName tableInfo remotePerms
let fieldArgsParser = liftA2 (,) functionArgsParser selectArgsParser
pure $
P.subselection fieldName (Just fieldDescription) fieldArgsParser selectionSetParser
<&> \((functionArgs', args), fields) ->
IR.AFComputedField _cfiXComputedFieldInfo _cfiName $
IR.CFSTable JASMultipleRows $
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromFunction (_cffName _cfiFunction) functionArgs' Nothing,
IR._asnPerm = tablePermissionsInfo remotePerms,
IR._asnArgs = args,
IR._asnStrfyNum = stringifyNum
}
where
fieldDescription =
let defaultDescription = "A computed field, executes function " <>> _cffName _cfiFunction
in mkDescriptionWith (_cffDescription _cfiFunction) defaultDescription
computedFieldFunctionArgs ::
ComputedFieldFunction ('Postgres pgKind) ->
m (InputFieldsParser n (IR.FunctionArgsExpTableRow (UnpreparedValue ('Postgres pgKind))))
computedFieldFunctionArgs ComputedFieldFunction {..} =
functionArgs (FTAComputedField _cfiName sourceName parentTable) (IAUserProvided <$> _cffInputArgs) <&> fmap addTableAndSessionArgument
where
addTableAndSessionArgument args@(IR.FunctionArgsExp positional named) =
let withTable = case _cffTableArgument of
FTAFirst -> IR.FunctionArgsExp (IR.AETableRow : positional) named
FTANamed argName index -> IR.insertFunctionArg argName index IR.AETableRow args
sessionArgVal = IR.AESession UVSession
in case _cffSessionArgument of
Nothing -> withTable
Just (FunctionSessionArgument argName index) ->
IR.insertFunctionArg argName index sessionArgVal withTable
-- | The custom SQL functions' input "args" field parser
-- > function_name(args: function_args)
customSQLFunctionArgs ::
(BackendSchema b, MonadSchema n m, MonadTableInfo r m, Has P.MkTypename r) =>
FunctionInfo b ->
G.Name ->
G.Name ->
m (InputFieldsParser n (IR.FunctionArgsExpTableRow (UnpreparedValue b)))
customSQLFunctionArgs FunctionInfo {..} functionName functionArgsName =
functionArgs
( FTACustomFunction $
CustomFunctionNames
{ cfnFunctionName = functionName,
cfnArgsName = functionArgsName
}
)
_fiInputArgs
-- | Parses the arguments to the underlying sql function of a computed field or
-- a custom function. All arguments to the underlying sql function are parsed
-- as an "args" object. Named arguments are expected in a field with the same
-- name, while positional arguments are expected in an field named "arg_$n".
-- Note that collisions are possible, but ignored for now, if a named argument
-- is also named "arg_$n". (FIXME: link to an issue?)
--
-- If the function requires no argument, or if its only argument is not
-- user-provided (the session argument in the case of custom functions, the
-- table row argument in the case of computed fields), the args object will
-- be omitted.
functionArgs ::
forall b m n r.
( BackendSchema b,
MonadSchema n m,
MonadTableInfo r m,
Has P.MkTypename r
) =>
FunctionTrackedAs b ->
Seq.Seq (FunctionInputArgument b) ->
m (InputFieldsParser n (IR.FunctionArgsExpTableRow (UnpreparedValue b)))
functionArgs functionTrackedAs (toList -> inputArgs) = do
-- First, we iterate through the original sql arguments in order, to find the
-- corresponding graphql names. At the same time, we create the input field
-- parsers, in three groups: session argument, optional arguments, and
-- mandatory arguments. Optional arguments have a default value, mandatory
-- arguments don't.
let (names, session, optional, mandatory) = mconcat $ snd $ mapAccumL splitArguments 1 inputArgs
defaultArguments = IR.FunctionArgsExp (snd <$> session) Map.empty
if
| length session > 1 ->
-- We somehow found more than one session argument; this should never
-- happen and is an error on our side.
throw500 "there shouldn't be more than one session argument"
| null optional && null mandatory ->
-- There are no user-provided arguments to the function: there will be
-- no args field.
pure $ pure defaultArguments
| otherwise -> do
-- There are user-provided arguments: we need to parse an args object.
argumentParsers <- sequenceA $ optional <> mandatory
objectName <-
P.mkTypename
=<< case functionTrackedAs of
FTAComputedField computedFieldName sourceName tableName -> do
tableInfo <- askTableInfo sourceName tableName
computedFieldGQLName <- textToName $ computedFieldNameToText computedFieldName
tableGQLName <- getTableGQLName @b tableInfo
pure $ computedFieldGQLName <> $$(G.litName "_") <> tableGQLName <> $$(G.litName "_args")
FTACustomFunction (CustomFunctionNames {cfnArgsName}) ->
pure cfnArgsName
let fieldName = $$(G.litName "args")
fieldDesc =
case functionTrackedAs of
FTAComputedField computedFieldName _sourceName tableName ->
G.Description $
"input parameters for computed field "
<> computedFieldName <<> " defined on table " <>> tableName
FTACustomFunction (CustomFunctionNames {cfnFunctionName}) ->
G.Description $ "input parameters for function " <>> cfnFunctionName
objectParser =
P.object objectName Nothing (sequenceA argumentParsers) `P.bind` \arguments -> do
-- After successfully parsing, we create a dictionary of the parsed fields
-- and we re-iterate through the original list of sql arguments, now with
-- the knowledge of their graphql name.
let foundArguments = Map.fromList $ catMaybes arguments <> session
argsWithNames = zip names inputArgs
-- All elements (in the orignal sql order) that are found in the result map
-- are treated as positional arguments, whether they were originally named or
-- not.
(positional, left) <- spanMaybeM (\(name, _) -> pure $ Map.lookup name foundArguments) argsWithNames
-- If there are arguments left, it means we found one that was not passed
-- positionally. As a result, any remaining argument will have to be passed
-- by name. We fail with a parse error if we encounter a positional sql
-- argument (that does not have a name in the sql function), as:
-- * only the last positional arguments can be omitted;
-- * it has no name we can use.
-- We also fail if we find a mandatory argument that was not
-- provided by the user.
named <- Map.fromList . catMaybes <$> traverse (namedArgument foundArguments) left
pure $ IR.FunctionArgsExp positional named
pure $ P.field fieldName (Just fieldDesc) objectParser
where
sessionPlaceholder :: IR.ArgumentExp (UnpreparedValue b)
sessionPlaceholder = IR.AEInput P.UVSession
splitArguments ::
Int ->
FunctionInputArgument b ->
( Int,
( [Text], -- graphql names, in order
[(Text, IR.ArgumentExp (UnpreparedValue b))], -- session argument
[m (InputFieldsParser n (Maybe (Text, IR.ArgumentExp (UnpreparedValue b))))], -- optional argument
[m (InputFieldsParser n (Maybe (Text, IR.ArgumentExp (UnpreparedValue b))))] -- mandatory argument
)
)
splitArguments positionalIndex (IASessionVariables name) =
let argName = getFuncArgNameTxt name
in (positionalIndex, ([argName], [(argName, sessionPlaceholder)], [], []))
splitArguments positionalIndex (IAUserProvided arg) =
let (argName, newIndex) = case faName arg of
Nothing -> ("arg_" <> tshow positionalIndex, positionalIndex + 1)
Just name -> (getFuncArgNameTxt name, positionalIndex)
in if unHasDefault $ faHasDefault arg
then (newIndex, ([argName], [], [parseArgument arg argName], []))
else (newIndex, ([argName], [], [], [parseArgument arg argName]))
parseArgument :: FunctionArg b -> Text -> m (InputFieldsParser n (Maybe (Text, IR.ArgumentExp (UnpreparedValue b))))
parseArgument arg name = do
typedParser <- columnParser (ColumnScalar $ functionArgScalarType @b $ faType arg) (G.Nullability True)
fieldName <- textToName name
-- Since all postgres function arguments are nullable, we define the
-- GraphQL fields in nullable types. As explained in Note [When are fields
-- optional?], this implies that they can be omitted. For backwards
-- compatibility reasons, and also to avoid surprises, we prefer to reject
-- the query if a mandatory argument is missing rather than filling the
-- blanks for the user.
--
-- As explained in Note [The value of omitted fields], we can still reject
-- queries when such nullable fields are omitted, and accept them when an
-- explicit value of `null` is used, as long as we don't set a default
-- value, not even `null`.
let argParser = P.fieldOptional fieldName Nothing typedParser
pure $ argParser `mapField` ((name,) . IR.AEInput . mkParameter)
namedArgument ::
HashMap Text (IR.ArgumentExp (UnpreparedValue b)) ->
(Text, FunctionInputArgument b) ->
n (Maybe (Text, IR.ArgumentExp (UnpreparedValue b)))
namedArgument dictionary (name, inputArgument) = case inputArgument of
IASessionVariables _ -> pure $ Just (name, sessionPlaceholder)
IAUserProvided arg -> case Map.lookup name dictionary of
Just parsedValue -> case faName arg of
Just _ -> pure $ Just (name, parsedValue)
Nothing -> parseErrorWith NotSupported "Only last set of positional arguments can be omitted"
Nothing ->
whenMaybe (not $ unHasDefault $ faHasDefault arg) $
parseErrorWith NotSupported "Non default arguments cannot be omitted"
tablePermissionsInfo :: Backend b => SelPermInfo b -> TablePerms b
tablePermissionsInfo selectPermissions =
IR.TablePerm
{ IR._tpFilter = fmap partialSQLExpToUnpreparedValue <$> spiFilter selectPermissions,
IR._tpLimit = spiLimit selectPermissions
}
------------------------ Node interface from Relay ---------------------------
{- Note [Relay Node Id]
~~~~~~~~~~~~~~~~~~~~~~~
The 'Node' interface in Relay schema has exactly one field which returns
a non-null 'ID' value. Each table object type in Relay schema should implement
'Node' interface to provide global object identification.
See https://relay.dev/graphql/objectidentification.htm for more details.
To identify each row in a table, we need to encode the table information
(schema and name) and primary key column values in the 'Node' id.
Node id data:
-------------
We are using JSON format for encoding and decoding the node id. The JSON
schema looks like following
'[<version-integer>, "<table-schema>", "<table-name>", "column-1", "column-2", ... "column-n"]'
It is represented in the type @'NodeId'. The 'version-integer' represents the JSON
schema version to enable any backward compatibility if it is broken in upcoming versions.
The stringified JSON is Base64 encoded and sent to client. Also the same
base64 encoded JSON string is accepted for 'node' field resolver's 'id' input.
-}
data V1NodeId = V1NodeId
{ _nidTable :: !(TableName ('Postgres 'Vanilla)),
_nidColumns :: !(NESeq.NESeq J.Value)
}
deriving (Show, Eq)
-- | The Relay 'Node' inteface's 'id' field value.
-- See Note [Relay Node id].
data NodeId
= NodeIdV1 !V1NodeId
deriving (Show, Eq)
instance J.FromJSON NodeId where
parseJSON v = do
valueList <- J.parseJSON v
case valueList of
[] -> fail "unexpected GUID format, found empty list"
J.Number 1 : rest -> NodeIdV1 <$> parseNodeIdV1 rest
J.Number n : _ -> fail $ "unsupported GUID version: " <> show n
_ -> fail "unexpected GUID format, needs to start with a version number"
where
parseNodeIdV1 (schemaValue : (nameValue : (firstColumn : remainingColumns))) =
V1NodeId
<$> (PG.QualifiedObject <$> J.parseJSON schemaValue <*> J.parseJSON nameValue)
<*> pure (firstColumn NESeq.:<|| Seq.fromList remainingColumns)
parseNodeIdV1 _ = fail "GUID version 1: expecting schema name, table name and at least one column value"
throwInvalidNodeId :: MonadParse n => Text -> n a
throwInvalidNodeId t = parseError $ "the node id is invalid: " <> t
-- | The 'node' root field of a Relay request.
nodePG ::
forall m n r.
MonadBuildSchema ('Postgres 'Vanilla) r m n =>
m
( P.Parser
'Output
n
( HashMap
(TableName ('Postgres 'Vanilla))
( SourceName,
SourceConfig ('Postgres 'Vanilla),
SelPermInfo ('Postgres 'Vanilla),
PrimaryKeyColumns ('Postgres 'Vanilla),
AnnotatedFields ('Postgres 'Vanilla)
)
)
)
nodePG = memoizeOn 'nodePG () do
let idDescription = G.Description "A globally unique identifier"
idField = P.selection_ $$(G.litName "id") (Just idDescription) P.identifier
nodeInterfaceDescription = G.Description "An object with globally unique ID"
sources :: SourceCache <- asks getter
let allTables = Map.fromList $ do
-- FIXME? When source name is used in type generation?
(source, sourceInfo) <- Map.toList sources
tableName <- maybe [] (Map.keys . takeValidTables) $ unsafeSourceTables @('Postgres 'Vanilla) sourceInfo
sourceConfig <- maybeToList $ unsafeSourceConfiguration @('Postgres 'Vanilla) sourceInfo
pure (tableName, (source, sourceConfig, AB.runBackend sourceInfo _siCustomization))
tables <-
Map.mapMaybe id <$> flip Map.traverseWithKey allTables \table (source, sourceConfig, sourceCustomization) -> runMaybeT do
tableInfo <- lift $ askTableInfo source table
tablePkeyColumns <- hoistMaybe $ tableInfo ^? tiCoreInfo . tciPrimaryKey . _Just . pkColumns
selectPermissions <- MaybeT $ tableSelectPermissions tableInfo
annotatedFieldsParser <-
lift $
P.withTypenameCustomization (mkCustomizedTypename $ _scTypeNames sourceCustomization) $
tableSelectionSet source tableInfo selectPermissions
pure $ (source,sourceConfig,selectPermissions,tablePkeyColumns,) <$> annotatedFieldsParser
pure $
P.selectionSetInterface
$$(G.litName "Node")
(Just nodeInterfaceDescription)
[idField]
tables
nodeField ::
forall m n r.
MonadBuildSchema ('Postgres 'Vanilla) r m n =>
m (P.FieldParser n (IR.QueryRootField UnpreparedValue))
nodeField = do
let idDescription = G.Description "A globally unique id"
idArgument = P.field $$(G.litName "id") (Just idDescription) P.identifier
stringifyNum <- asks $ qcStringifyNum . getter
nodeObject <- node
return $
P.subselection $$(G.litName "node") Nothing idArgument nodeObject
`P.bindField` \(ident, parseds) -> do
NodeIdV1 (V1NodeId table columnValues) <- parseNodeId ident
(source, sourceConfig, perms, pkeyColumns, fields) <-
onNothing (Map.lookup table parseds) $
withArgsPath $ throwInvalidNodeId $ "the table " <>> ident
whereExp <- buildNodeIdBoolExp columnValues pkeyColumns
return $
IR.RFDB source $
AB.mkAnyBackend $
IR.SourceConfigWith sourceConfig Nothing $
IR.QDBR $
IR.QDBSingleRow $
IR.AnnSelectG
{ IR._asnFields = fields,
IR._asnFrom = IR.FromTable table,
IR._asnPerm = tablePermissionsInfo perms,
IR._asnArgs =
IR.SelectArgs
{ IR._saWhere = Just whereExp,
IR._saOrderBy = Nothing,
IR._saLimit = Nothing,
IR._saOffset = Nothing,
IR._saDistinct = Nothing
},
IR._asnStrfyNum = stringifyNum
}
where
parseNodeId :: Text -> n NodeId
parseNodeId =
either (withArgsPath . throwInvalidNodeId . T.pack) pure . J.eitherDecode . base64Decode
withArgsPath = withPath (++ [Key "args", Key "id"])
buildNodeIdBoolExp ::
NESeq.NESeq J.Value ->
NESeq.NESeq (ColumnInfo ('Postgres 'Vanilla)) ->
n (IR.AnnBoolExp ('Postgres 'Vanilla) (UnpreparedValue ('Postgres 'Vanilla)))
buildNodeIdBoolExp columnValues pkeyColumns = do
let firstPkColumn NESeq.:<|| remainingPkColumns = pkeyColumns
firstColumnValue NESeq.:<|| remainingColumns = columnValues
(nonAlignedPkColumns, nonAlignedColumnValues, alignedTuples) =
partitionThese $ toList $ align remainingPkColumns remainingColumns
unless (null nonAlignedPkColumns) $
throwInvalidNodeId $
"primary key columns " <> dquoteList (map ciColumn nonAlignedPkColumns) <> " are missing"
unless (null nonAlignedColumnValues) $
throwInvalidNodeId $
"unexpected column values " <> J.encodeToStrictText nonAlignedColumnValues
let allTuples = (firstPkColumn, firstColumnValue) : alignedTuples
flip onLeft (parseErrorWith ParseFailed . qeError) $
runExcept $
fmap IR.BoolAnd $
for allTuples $ \(columnInfo, columnValue) -> do
let modifyErrFn t =
"value of column " <> ciColumn columnInfo
<<> " in node id: " <> t
pgColumnType = ciType columnInfo
pgValue <- modifyErr modifyErrFn $ parseScalarValueColumnType pgColumnType columnValue
let unpreparedValue = UVParameter Nothing $ ColumnValue pgColumnType pgValue
pure $ IR.BoolFld $ IR.AVColumn columnInfo [IR.AEQ True unpreparedValue]