forked from OSS/graphql
Eugen Wissner
61879fb124
This replaces the most usages of MonadPlus, which is not appropriate for the resolvers, since a resolver is unambiguously chosen by the name (no need for 'mplus'), and the resolvers are often doing IO.
36 lines
1.3 KiB
Haskell
36 lines
1.3 KiB
Haskell
-- | This module provides the functions to parse and execute @GraphQL@ queries.
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module Language.GraphQL where
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import Control.Monad.IO.Class (MonadIO)
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import qualified Data.Text as T
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import qualified Data.Aeson as Aeson
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import Text.Megaparsec ( errorBundlePretty
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, parse
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)
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import Language.GraphQL.Execute
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import Language.GraphQL.Parser
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import Language.GraphQL.Schema
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import Language.GraphQL.Error
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-- | Takes a 'Schema' and text representing a @GraphQL@ request document.
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-- If the text parses correctly as a @GraphQL@ query the query is
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-- executed according to the given 'Schema'.
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--
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-- Returns the response as an @Aeson.@'Aeson.Value'.
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graphql :: MonadIO m => Schema m -> T.Text -> m Aeson.Value
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graphql = flip graphqlSubs $ const Nothing
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-- | Takes a 'Schema', a variable substitution function and text
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-- representing a @GraphQL@ request document. If the text parses
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-- correctly as a @GraphQL@ query the substitution is applied to the
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-- query and the query is then executed according to the given 'Schema'.
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--
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-- Returns the response as an @Aeson.@'Aeson.Value'.
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graphqlSubs :: MonadIO m => Schema m -> Subs -> T.Text -> m Aeson.Value
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graphqlSubs schema f =
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either (parseError . errorBundlePretty) (execute schema f)
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. parse document ""
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