47 lines
1.7 KiB
Haskell
47 lines
1.7 KiB
Haskell
{-# LANGUAGE RecordWildCards #-}
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-- | This module provides the functions to parse and execute @GraphQL@ queries.
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module Language.GraphQL
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( graphql
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) where
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import Control.Monad.Catch (MonadCatch)
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import Data.HashMap.Strict (HashMap)
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import qualified Data.Sequence as Seq
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import Data.Text (Text)
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import qualified Data.Text as Text
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import qualified Language.GraphQL.AST as Full
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import Language.GraphQL.Error
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import Language.GraphQL.Execute
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import qualified Language.GraphQL.Validate as Validate
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import Language.GraphQL.Type.Schema (Schema)
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import Prelude hiding (null)
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import Text.Megaparsec (parse)
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-- | If the text parses correctly as a @GraphQL@ query the query is
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-- executed using the given 'Schema'.
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--
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-- An operation name can be given if the document contains multiple operations.
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graphql :: (MonadCatch m, VariableValue a, Serialize b)
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=> Schema m -- ^ Resolvers.
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-> Maybe Text -- ^ Operation name.
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-> HashMap Full.Name a -- ^ Variable substitution function.
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-> Text -- ^ Text representing a @GraphQL@ request document.
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-> m (Either (ResponseEventStream m b) (Response b)) -- ^ Response.
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graphql schema operationName variableValues document' =
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case parse Full.document "" document' of
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Left errorBundle -> pure <$> parseError errorBundle
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Right parsed ->
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case validate parsed of
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Seq.Empty -> execute schema operationName variableValues parsed
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errors -> pure $ pure
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$ Response null
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$ fromValidationError <$> errors
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where
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validate = Validate.document schema Validate.specifiedRules
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fromValidationError Validate.Error{..} = Error
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{ message = Text.pack message
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, locations = locations
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, path = []
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}
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