Safe Haskell	Safe-Inferred
Language	Haskell2010

Language.GraphQL.Resolver

Description

Helper functions and exceptions to write resolvers.

Synopsis

data ServerException
- = FieldNotResolvedException !Text
- | ErroneousArgumentTypeException !Text
argument :: (MonadCatch m, FromGraphQL a) => Name -> ReaderT Context m a
defaultResolver :: MonadCatch m => Name -> Resolve m

Documentation

data ServerException Source #

Exceptions thrown by the functions in this module.

Constructors

FieldNotResolvedException !Text
ErroneousArgumentTypeException !Text

Instances

Instances details

Exception ServerException Source #
Instance details Defined in Language.GraphQL.Resolver Methods toException :: ServerException -> SomeException # fromException :: SomeException -> Maybe ServerException # displayException :: ServerException -> String #
Show ServerException Source #
Instance details Defined in Language.GraphQL.Resolver Methods showsPrec :: Int -> ServerException -> ShowS # show :: ServerException -> String # showList :: [ServerException] -> ShowS #

argument :: (MonadCatch m, FromGraphQL a) => Name -> ReaderT Context m a Source #

Takes an argument name, validates that the argument exists, and optionally converts it to a user-defined type.

defaultResolver :: MonadCatch m => Name -> Resolve m Source #

Default resolver expects that the field value is returned by the parent object. If the parent is not an object or it doesn't contain the requested field name, an error is thrown.