graphql/src/Language/GraphQL.hs

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-- | This module provides the functions to parse and execute @GraphQL@ queries.
module Language.GraphQL where
import Control.Monad.IO.Class (MonadIO)
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import qualified Data.Text as T
import qualified Data.Aeson as Aeson
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import Text.Megaparsec ( errorBundlePretty
, parse
)
import Language.GraphQL.Execute
import Language.GraphQL.Parser
import Language.GraphQL.Schema
import Language.GraphQL.Error
-- | Takes a 'Schema' and text representing a @GraphQL@ request document.
-- If the text parses correctly as a @GraphQL@ query the query is
-- executed according to the given 'Schema'.
--
-- Returns the response as an @Aeson.@'Aeson.Value'.
graphql :: MonadIO m => Schema m -> T.Text -> m Aeson.Value
graphql = flip graphqlSubs $ const Nothing
-- | Takes a 'Schema', a variable substitution function and text
-- representing a @GraphQL@ request document. If the text parses
-- correctly as a @GraphQL@ query the substitution is applied to the
-- query and the query is then executed according to the given 'Schema'.
--
-- Returns the response as an @Aeson.@'Aeson.Value'.
graphqlSubs :: MonadIO m => Schema m -> Subs -> T.Text -> m Aeson.Value
graphqlSubs schema f =
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either (parseError . errorBundlePretty) (execute schema f)
. parse document ""