graphql-engine/server/src-lib/Hasura/GraphQL/Parser/Directives.hs
jkachmar 647231b685 Yeet some default-extensions
Manually enables:
* EmptyCase
* ExistentialQuantification
* QuantifiedConstraints
* QuasiQuotes
* TemplateHaskell
* TypeFamilyDependencies

...in the following components:
* 'graphql-engine' library
* 'graphql-engine' 'src-test'
* 'graphql-engine' 'tests/integration'
* 'graphql-engine' tests-hspec'

Additionally, performs some light refactoring and documentation.

PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3991
GitOrigin-RevId: 514477d3466b01f60eca8935d0fef60dd0756838
2022-03-16 00:40:17 +00:00

281 lines
10 KiB
Haskell

{-# LANGUAGE TemplateHaskell #-}
-- | Definition of all supported GraphQL directives.
module Hasura.GraphQL.Parser.Directives
( -- list of directives, for the schema
directivesInfo,
inclusionDirectives,
customDirectives,
-- Custom Directive Types
CachedDirective (..),
DirectiveMap,
-- lookup keys for directives
include,
skip,
cached,
multipleRootFields,
-- parsing utilities
parseDirectives,
withDirective,
-- exposed for tests
Directive (..),
DirectiveKey (..),
skipDirective,
includeDirective,
cachedDirective,
multipleRootFieldsDirective,
)
where
import Data.Dependent.Map qualified as DM
import Data.Dependent.Sum (DSum (..))
import Data.GADT.Compare.Extended
import Data.HashMap.Strict.Extended qualified as M
import Data.HashSet qualified as S
import Data.List.Extended (duplicates)
import Data.Parser.JSONPath
import Data.Text.Extended
import Data.Typeable (eqT)
import Hasura.GraphQL.Parser.Class
import Hasura.GraphQL.Parser.Internal.Input
import Hasura.GraphQL.Parser.Internal.Scalars
import Hasura.GraphQL.Parser.Schema
import Hasura.Prelude
import Language.GraphQL.Draft.Syntax qualified as G
import Type.Reflection (Typeable, typeRep, (:~:) (..))
-- | Returns the schema information for all supported directives, for each of
-- which a @DirectiveDefinition@ will be inserted into the schema.
--
-- To add a new custom directives to the schema, add it to @customDirectives@.
-- Inclusion directives are treated separately, as they are not concerned with
-- altering the result of the parsers, but about whether a given field should be
-- parsed at all (see @collectFields@ for more information).
--
-- Alternatively, you could manually add a @DirectiveInfo@ to this list;
-- however, if you do so, and do not provide a corresponding definition in
-- @customDirectives@, calls to @parseDirectives@ will NOT attempt to parse that
-- new directive: they will only validate that it is used correctly. You can use
-- this option to implement directives that do not match our simple inclusion /
-- custom dichotomy.
--
-- To create a directive definition, you need to create a @Directive@ using
-- @mkDirective@, and export from this module its corresponding @DirectiveKey@
-- (see @skip@ below for an example). Make sure the type in the key matches the
-- type of the parser!
--
-- Directives may be "hidden", in which case they won't advertised in the
-- schema, but silently accepted. This is un-advisable and should only be used
-- when there's no other way around it.
directivesInfo :: forall m. MonadParse m => [DirectiveInfo]
directivesInfo = do
dir <- inclusionDirectives @m <> customDirectives @m
guard $ dAdvertised dir
pure $ dDefinition dir
-- | Not exported, only used internally; identical to 'directivesInfo', but also
-- contains hidden directives.
allDirectives :: forall m. MonadParse m => [DirectiveInfo]
allDirectives = map dDefinition $ inclusionDirectives @m <> customDirectives @m
inclusionDirectives :: forall m. MonadParse m => [Directive m]
inclusionDirectives = [includeDirective @m, skipDirective @m]
customDirectives :: forall m. MonadParse m => [Directive m]
customDirectives = [cachedDirective @m, multipleRootFieldsDirective @m]
-- | Parses directives, given a location. Ensures that all directives are known
-- and match the location; subsequently builds a dependent map of the results,
-- that can be then introspected with @withDirective@. The list of parsers that
-- should be applied is given as an argument: if a valid directive is found, but
-- for which no parser is provided, it will be ignored.
--
-- Example use:
--
-- dMap <- parseDirectives customDirectives (DLExecutable EDLQUERY) directives
-- withDirective dMap cached $ onJust \_ -> tagAsCached
parseDirectives ::
forall m.
MonadParse m =>
[Directive m] ->
G.DirectiveLocation ->
[G.Directive Variable] ->
m DirectiveMap
parseDirectives directiveParsers location givenDirectives = do
result <-
catMaybes <$> for givenDirectives \directive -> do
let name = G._dName directive
-- check the directive has a matching definition
DirectiveInfo {diLocations} <-
find (\di -> diName di == name) (allDirectives @m)
`onNothing` parseError ("directive " <> name <<> " is not defined in the schema")
-- check that it is allowed at the current location
unless (location `elem` diLocations) $
parseError $ "directive " <> name <<> " is not allowed on " <> humanReadable location
-- if we are expecting to parse it now, create a dmap entry
case find (\d -> diName (dDefinition d) == name) directiveParsers of
Nothing -> pure Nothing
Just (Directive {dParser}) -> do
result <- dParser directive
pure $ Just (name, DirectiveKey name :=> pure result)
-- check that the result does not contain duplicates
let dups = duplicates $ fst <$> result
unless (null dups) $
parseError $ "the following directives are used more than once: " <> commaSeparated dups
pure $ DM.fromList $ snd <$> result
where
humanReadable = \case
G.DLExecutable G.EDLQUERY -> "a query"
G.DLExecutable G.EDLMUTATION -> "a mutation"
G.DLExecutable G.EDLSUBSCRIPTION -> "a subscription"
G.DLExecutable G.EDLFIELD -> "a field"
G.DLExecutable G.EDLFRAGMENT_DEFINITION -> "a fragment definition"
G.DLExecutable G.EDLFRAGMENT_SPREAD -> "a fragment spread"
G.DLExecutable G.EDLINLINE_FRAGMENT -> "an inline fragment"
G.DLTypeSystem G.TSDLSCHEMA -> "the schema"
G.DLTypeSystem G.TSDLSCALAR -> "a scalar definition"
G.DLTypeSystem G.TSDLOBJECT -> "an object definition"
G.DLTypeSystem G.TSDLFIELD_DEFINITION -> "a field definition"
G.DLTypeSystem G.TSDLARGUMENT_DEFINITION -> "an argument definition"
G.DLTypeSystem G.TSDLINTERFACE -> "an interface definition"
G.DLTypeSystem G.TSDLUNION -> "an union definition"
G.DLTypeSystem G.TSDLENUM -> "an enum definition"
G.DLTypeSystem G.TSDLENUM_VALUE -> "an enum value definition"
G.DLTypeSystem G.TSDLINPUT_OBJECT -> "an input object definition"
G.DLTypeSystem G.TSDLINPUT_FIELD_DEFINITION -> "an input field definition"
withDirective ::
DirectiveMap ->
DirectiveKey a ->
(Maybe a -> m b) ->
m b
withDirective dmap key callback = callback $ runIdentity <$> DM.lookup key dmap
-- Cached custom directive.
cachedDirective :: forall m. MonadParse m => Directive m
cachedDirective =
mkDirective
$$(G.litName "cached")
(Just "whether this query should be cached (Hasura Cloud only)")
True
[G.DLExecutable G.EDLQUERY]
(CachedDirective <$> ttlArgument <*> forcedArgument)
where
-- Optionally set the cache entry time to live
ttlArgument :: InputFieldsParser m Int
ttlArgument = fieldWithDefault $$(G.litName "ttl") (Just "measured in seconds") (G.VInt 60) $ fromIntegral <$> int
-- Optionally Force a refresh of the cache entry
forcedArgument :: InputFieldsParser m Bool
forcedArgument = fieldWithDefault $$(G.litName "refresh") (Just "refresh the cache entry") (G.VBoolean False) boolean
data CachedDirective = CachedDirective {cdTtl :: Int, cdRefresh :: Bool}
cached :: DirectiveKey CachedDirective
cached = DirectiveKey $$(G.litName "cached")
-- Subscription tests custom directive.
multipleRootFieldsDirective :: forall m. MonadParse m => Directive m
multipleRootFieldsDirective =
mkDirective
$$(G.litName "_multiple_top_level_fields")
(Just "INTERNAL TESTING TOOL DO NOT USE")
False -- not advertised in the schema
[G.DLExecutable G.EDLSUBSCRIPTION]
(pure ())
multipleRootFields :: DirectiveKey ()
multipleRootFields = DirectiveKey $$(G.litName "_multiple_top_level_fields")
-- Built-in inclusion directives
skipDirective :: MonadParse m => Directive m
skipDirective =
mkDirective
$$(G.litName "skip")
(Just "whether this query should be skipped")
True
[ G.DLExecutable G.EDLFIELD,
G.DLExecutable G.EDLFRAGMENT_SPREAD,
G.DLExecutable G.EDLINLINE_FRAGMENT
]
ifArgument
includeDirective :: MonadParse m => Directive m
includeDirective =
mkDirective
$$(G.litName "include")
(Just "whether this query should be included")
True
[ G.DLExecutable G.EDLFIELD,
G.DLExecutable G.EDLFRAGMENT_SPREAD,
G.DLExecutable G.EDLINLINE_FRAGMENT
]
ifArgument
skip :: DirectiveKey Bool
skip = DirectiveKey $$(G.litName "skip")
include :: DirectiveKey Bool
include = DirectiveKey $$(G.litName "include")
ifArgument :: MonadParse m => InputFieldsParser m Bool
ifArgument = field $$(G.litName "if") Nothing boolean
-- Parser type for directives.
data Directive m where
Directive ::
forall m a.
(MonadParse m, Typeable a) =>
{ dDefinition :: DirectiveInfo,
dAdvertised :: Bool,
dParser :: G.Directive Variable -> m a
} ->
Directive m
data DirectiveKey a where
DirectiveKey :: Typeable a => G.Name -> DirectiveKey a
instance GEq DirectiveKey where
geq
(DirectiveKey name1 :: DirectiveKey a1)
(DirectiveKey name2 :: DirectiveKey a2)
| name1 == name2,
Just Refl <- eqT @a1 @a2 =
Just Refl
| otherwise = Nothing
instance GCompare DirectiveKey where
gcompare
(DirectiveKey name1 :: DirectiveKey a1)
(DirectiveKey name2 :: DirectiveKey a2) =
strengthenOrdering (compare name1 name2)
`extendGOrdering` gcompare (typeRep @a1) (typeRep @a2)
`extendGOrdering` GEQ
type DirectiveMap = DM.DMap DirectiveKey Identity
mkDirective ::
(MonadParse m, Typeable a) =>
G.Name ->
Maybe G.Description ->
Bool ->
[G.DirectiveLocation] ->
InputFieldsParser m a ->
Directive m
mkDirective name description advertised location argsParser =
Directive
{ dDefinition = DirectiveInfo name description (ifDefinitions argsParser) location,
dAdvertised = advertised,
dParser = \(G.Directive _name arguments) -> withPath (++ [Key $ G.unName name]) $ do
for_ (M.keys arguments) \argumentName ->
unless (argumentName `S.member` argumentNames) $
parseError $ name <<> " has no argument named " <>> argumentName
withPath (++ [Key "args"]) $ ifParser argsParser $ GraphQLValue <$> arguments
}
where
argumentNames = S.fromList (dName <$> ifDefinitions argsParser)