Copy subscription code

This commit is contained in:
Eugen Wissner 2021-08-31 14:03:15 +02:00
parent f808d0664f
commit c7e586a125
2 changed files with 144 additions and 58 deletions

View File

@ -38,7 +38,6 @@ library
Language.GraphQL.Error
Language.GraphQL.Execute
Language.GraphQL.Execute.Coerce
Language.GraphQL.Executor
Language.GraphQL.Execute.OrderedMap
Language.GraphQL.Type
Language.GraphQL.Type.In
@ -52,6 +51,7 @@ library
Language.GraphQL.Execute.Internal
Language.GraphQL.Execute.Subscribe
Language.GraphQL.Execute.Transform
Language.GraphQL.Executor
Language.GraphQL.Type.Definition
Language.GraphQL.Type.Internal
Language.GraphQL.Validate.Rules

View File

@ -11,12 +11,14 @@
module Language.GraphQL.Executor
( Error(..)
, Operation(..)
, QueryError(..)
, Path(..)
, ResponseEventStream
, Response(..)
, Segment(..)
, executeRequest
, execute
) where
import Conduit (ConduitT, mapMC, (.|))
import Control.Arrow (left)
import Control.Monad.Catch
( Exception(..)
, MonadCatch(..)
@ -54,6 +56,7 @@ import qualified Language.GraphQL.Type as Type
import qualified Language.GraphQL.Type.Internal as Type.Internal
import Language.GraphQL.Type.Schema (Schema, Type)
import qualified Language.GraphQL.Type.Schema as Schema
import Language.GraphQL.Error (Error(..), Response(..), Path(..))
data Replacement m = Replacement
{ variableValues :: Type.Subs
@ -87,7 +90,7 @@ instance MonadCatch m => MonadCatch (TransformT m) where
TransformT $ catch stack $ runTransformT . handler
newtype ExecutorT m a = ExecutorT
{ runExecutorT :: ReaderT (HashMap Full.Name (Type m)) (WriterT [Error] m) a
{ runExecutorT :: ReaderT (HashMap Full.Name (Type m)) (WriterT (Seq Error) m) a
}
instance Functor m => Functor (ExecutorT m) where
@ -161,19 +164,6 @@ instance Exception FieldException where
toException = graphQLExceptionToException
fromException = graphQLExceptionFromException
data Segment = Segment String | Index Int
data Error = Error
{ message :: String
, locations :: [Full.Location]
, path :: [Segment]
}
data Response a = Response
{ data' :: a
, errors :: [Error]
}
data QueryError
= OperationNameRequired
| OperationNotFound String
@ -187,32 +177,33 @@ queryError :: QueryError -> Error
queryError OperationNameRequired =
Error{ message = "Operation name is required.", locations = [], path = [] }
queryError (OperationNotFound operationName) =
let queryErrorMessage = concat
let queryErrorMessage = Text.concat
[ "Operation \""
, operationName
, Text.pack operationName
, "\" not found."
]
in Error{ message = queryErrorMessage, locations = [], path = [] }
queryError (CoercionError variableDefinition) =
let Full.VariableDefinition variableName _ _ location = variableDefinition
queryErrorMessage = concat
queryErrorMessage = Text.concat
[ "Failed to coerce the variable \""
, Text.unpack variableName
, variableName
, "\"."
]
in Error{ message = queryErrorMessage, locations = [location], path = [] }
queryError (UnknownInputType variableDefinition) =
let Full.VariableDefinition variableName variableTypeName _ location = variableDefinition
queryErrorMessage = concat
queryErrorMessage = Text.concat
[ "Variable \""
, Text.unpack variableName
, variableName
, "\" has unknown type \""
, show variableTypeName
, Text.pack $ show variableTypeName
, "\"."
]
in Error{ message = queryErrorMessage, locations = [location], path = [] }
data Operation m = Operation Full.OperationType (Seq (Selection m))
data Operation m
= Operation Full.OperationType (Seq (Selection m)) Full.Location
data Selection m
= FieldSelection (Field m)
@ -252,12 +243,12 @@ document = foldr filterOperation ([], HashMap.empty)
filterOperation _ accumulator = accumulator -- Type system definitions.
transform :: Monad m => Full.OperationDefinition -> TransformT m (Operation m)
transform (Full.OperationDefinition operationType _ _ _ selectionSet' _) = do
transform (Full.OperationDefinition operationType _ _ _ selectionSet' operationLocation) = do
transformedSelections <- selectionSet selectionSet'
pure $ Operation operationType transformedSelections
transform (Full.SelectionSet selectionSet' _) = do
pure $ Operation operationType transformedSelections operationLocation
transform (Full.SelectionSet selectionSet' operationLocation) = do
transformedSelections <- selectionSet selectionSet'
pure $ Operation Full.Query transformedSelections
pure $ Operation Full.Query transformedSelections operationLocation
selectionSet :: Monad m => Full.SelectionSet -> TransformT m (Seq (Selection m))
selectionSet = selectionSetOpt . NonEmpty.toList
@ -413,24 +404,34 @@ node :: Monad m => Full.Node Full.Value -> TransformT m (Maybe (Full.Node Input)
node Full.Node{node = node', ..} =
traverse Full.Node <$> input node' <*> pure location
execute :: (MonadCatch m, Coerce.VariableValue a, Coerce.Serialize b)
=> Schema m -- ^ Resolvers.
-> Maybe Text -- ^ Operation name.
-> HashMap Full.Name a -- ^ Variable substitution function.
-> Full.Document -- @GraphQL@ document.
-> m (Either (ResponseEventStream m b) (Response b))
execute schema' operationName subs document' =
executeRequest schema' document' (Text.unpack <$> operationName) subs
executeRequest :: (MonadCatch m, Coerce.Serialize a, Coerce.VariableValue b)
=> Schema m
-> Full.Document
-> Maybe String
-> HashMap Full.Name b
-> m (Response a)
-> m (Either (ResponseEventStream m a) (Response a))
executeRequest schema sourceDocument operationName variableValues = do
operationAndVariables <- sequence buildOperation
case operationAndVariables of
Left queryError' -> pure
$ Right
$ Response Coerce.null $ pure $ queryError queryError'
Right operation
| Operation Full.Query topSelections <- operation ->
executeQuery topSelections schema
| Operation Full.Mutation topSelections <- operation ->
executeMutation topSelections schema
| Operation Full.Subscription topSelections <- operation ->
subscribe topSelections schema
| Operation Full.Query topSelections _operationLocation <- operation ->
Right <$> executeQuery topSelections schema
| Operation Full.Mutation topSelections operationLocation <- operation ->
Right <$> executeMutation topSelections schema operationLocation
| Operation Full.Subscription topSelections operationLocation <- operation ->
either rightErrorResponse Left <$> subscribe topSelections schema operationLocation
where
schemaTypes = Schema.types schema
(operationDefinitions, fragmentDefinitions') = document sourceDocument
@ -450,6 +451,9 @@ executeRequest schema sourceDocument operationName variableValues = do
$ runTransformT
$ transform operationDefinition
rightErrorResponse :: Coerce.Serialize b => forall a. Error -> Either a (Response b)
rightErrorResponse = Right . Response Coerce.null . pure
getOperation :: [Full.OperationDefinition] -> Maybe String -> Either QueryError Full.OperationDefinition
getOperation [operation] Nothing = Right operation
getOperation operations (Just givenOperationName)
@ -470,36 +474,31 @@ executeQuery topSelections schema = do
(data', errors) <- runWriterT
$ flip runReaderT (Schema.types schema)
$ runExecutorT
$ executeSelectionSet topSelections queryType Type.Null []
$ executeSelectionSet topSelections queryType Type.Null []
pure $ Response data' errors
executeMutation :: (MonadCatch m, Coerce.Serialize a)
=> Seq (Selection m)
-> Schema m
-> Full.Location
-> m (Response a)
executeMutation topSelections schema
executeMutation topSelections schema operationLocation
| Just mutationType <- Schema.mutation schema = do
(data', errors) <- runWriterT
$ flip runReaderT (Schema.types schema)
$ runExecutorT
$ executeSelectionSet topSelections mutationType Type.Null []
$ executeSelectionSet topSelections mutationType Type.Null []
pure $ Response data' errors
| otherwise = pure $ Response Coerce.null
[Error "Schema doesn't define a mutation type." [] []]
-- TODO: Subscribe.
subscribe :: (MonadCatch m, Coerce.Serialize a)
=> Seq (Selection m)
-> Schema m
-> m (Response a)
subscribe _operation _schema =
pure $ Response Coerce.null mempty
| otherwise = pure
$ Response Coerce.null
$ Seq.singleton
$ Error "Schema doesn't support mutations." [operationLocation] []
executeSelectionSet :: (MonadCatch m, Coerce.Serialize a)
=> Seq (Selection m)
-> Out.ObjectType m
-> Type.Value
-> [Segment]
-> [Path]
-> ExecutorT m a
executeSelectionSet selections objectType objectValue errorPath = do
let groupedFieldSet = collectFields objectType selections
@ -512,15 +511,15 @@ executeSelectionSet selections objectType objectValue errorPath = do
go fields@(Field _ fieldName _ _ _ :| _) =
traverse (executeField' fields) $ HashMap.lookup fieldName resolvers
fieldsSegment :: forall m. NonEmpty (Field m) -> Segment
fieldsSegment :: forall m. NonEmpty (Field m) -> Path
fieldsSegment (Field alias fieldName _ _ _ :| _) =
Segment (Text.unpack $ fromMaybe fieldName alias)
Segment (fromMaybe fieldName alias)
executeField :: (MonadCatch m, Coerce.Serialize a)
=> Type.Value
-> NonEmpty (Field m)
-> Out.Resolver m
-> [Segment]
-> [Path]
-> ExecutorT m a
executeField objectValue fields resolver errorPath =
let Field _ fieldName inputArguments _ fieldLocation :| _ = fields
@ -531,8 +530,8 @@ executeField objectValue fields resolver errorPath =
-> GraphQLException
-> ExecutorT m a
exceptionHandler fieldLocation e =
let newError = Error (displayException e) [fieldLocation] errorPath
in ExecutorT (lift $ tell [newError]) >> pure Coerce.null
let newError = Error (Text.pack $ displayException e) [fieldLocation] errorPath
in ExecutorT (lift $ tell $ Seq.singleton newError) >> pure Coerce.null
go fieldName inputArguments = do
let (Out.Field _ fieldType argumentTypes, resolveFunction) =
resolverField resolver
@ -577,7 +576,7 @@ resolveAbstractType abstractType values'
completeValue :: (MonadCatch m, Coerce.Serialize a)
=> Out.Type m
-> NonEmpty (Field m)
-> [Segment]
-> [Path]
-> Type.Value
-> ExecutorT m a
completeValue outputType _ _ Type.Null
@ -648,7 +647,7 @@ throwFieldError = throwM . FieldException
coerceArgumentValues :: MonadCatch m
=> HashMap Full.Name In.Argument
-> HashMap Full.Name (Full.Node Input)
-> ExecutorT m Type.Subs
-> m Type.Subs
coerceArgumentValues argumentDefinitions argumentValues =
HashMap.foldrWithKey c pure argumentDefinitions mempty
where
@ -759,3 +758,90 @@ constValue (Full.ConstObject o) =
where
constObjectField Full.ObjectField{value = value', ..} =
(name, constValue $ Full.node value')
type ResponseEventStream m a = ConduitT () (Response a) m ()
subscribe :: (MonadCatch m, Coerce.Serialize a)
=> Seq (Selection m)
-> Schema m
-> Full.Location
-> m (Either Error (ResponseEventStream m a))
subscribe fields schema objectLocation
| Just objectType <- Schema.subscription schema = do
let types' = Schema.types schema
sourceStream <-
createSourceEventStream types' objectType objectLocation fields
let traverser =
mapSourceToResponseEvent types' objectType fields
traverse traverser sourceStream
| otherwise = pure $ Left
$ Error "Schema doesn't support subscriptions." [] []
mapSourceToResponseEvent :: (MonadCatch m, Coerce.Serialize a)
=> HashMap Full.Name (Type m)
-> Out.ObjectType m
-> Seq (Selection m)
-> Out.SourceEventStream m
-> m (ResponseEventStream m a)
mapSourceToResponseEvent types' subscriptionType fields sourceStream
= pure
$ sourceStream
.| mapMC (executeSubscriptionEvent types' subscriptionType fields)
createSourceEventStream :: MonadCatch m
=> HashMap Full.Name (Type m)
-> Out.ObjectType m
-> Full.Location
-> Seq (Selection m)
-> m (Either Error (Out.SourceEventStream m))
createSourceEventStream _types subscriptionType objectLocation fields
| [fieldGroup] <- OrderedMap.elems groupedFieldSet
, Field _ fieldName arguments' _ errorLocation <- NonEmpty.head fieldGroup
, Out.ObjectType _ _ _ fieldTypes <- subscriptionType
, resolverT <- fieldTypes HashMap.! fieldName
, Out.EventStreamResolver fieldDefinition _ resolver <- resolverT
, Out.Field _ _fieldType argumentDefinitions <- fieldDefinition =
case coerceArgumentValues argumentDefinitions arguments' of
Left _ -> pure
$ Left
$ Error "Argument coercion failed." [errorLocation] []
Right argumentValues -> left (singleError' [errorLocation])
<$> resolveFieldEventStream Type.Null argumentValues resolver
| otherwise = pure
$ Left
$ Error "Subscription contains more than one field." [objectLocation] []
where
groupedFieldSet = collectFields subscriptionType fields
singleError' :: [Full.Location] -> String -> Error
singleError' errorLocations message = Error (Text.pack message) errorLocations []
resolveFieldEventStream :: MonadCatch m
=> Type.Value
-> Type.Subs
-> Out.Subscribe m
-> m (Either String (Out.SourceEventStream m))
resolveFieldEventStream result args resolver =
catch (Right <$> runReaderT resolver context) handleEventStreamError
where
handleEventStreamError :: MonadCatch m
=> ResolverException
-> m (Either String (Out.SourceEventStream m))
handleEventStreamError = pure . Left . displayException
context = Type.Context
{ Type.arguments = Type.Arguments args
, Type.values = result
}
executeSubscriptionEvent :: (MonadCatch m, Coerce.Serialize a)
=> HashMap Full.Name (Type m)
-> Out.ObjectType m
-> Seq (Selection m)
-> Type.Value
-> m (Response a)
executeSubscriptionEvent types' objectType fields initialValue = do
(data', errors) <- runWriterT
$ flip runReaderT types'
$ runExecutorT
$ executeSelectionSet fields objectType initialValue []
pure $ Response data' errors