forked from OSS/graphql
5390c4ca1e
One AST is meant to be a target parser and tries to adhere as much as possible to the spec. The other is a simplified version of that AST meant for execution. Also newtypes have been replaced by type synonyms and NonEmpty lists are being used where it makes sense.
58 lines
2.4 KiB
Haskell
58 lines
2.4 KiB
Haskell
-- | This module provides the function to execute a @GraphQL@ request --
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-- according to a 'Schema'.
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module Data.GraphQL.Execute (execute) where
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import Control.Applicative (Alternative)
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import Data.Maybe (catMaybes)
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import qualified Data.Aeson as Aeson
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import Data.GraphQL.AST
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import Data.GraphQL.Schema (Schema(..))
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import qualified Data.GraphQL.Schema as Schema
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import Data.GraphQL.Error
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-- | Takes a 'Schema', a variable substitution function ('Schema.Subs'), and a
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-- @GraphQL@ 'document'. The substitution is applied to the document using
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-- 'rootFields', and the 'Schema''s resolvers are applied to the resulting fields.
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--
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-- Returns the result of the query against the 'Schema' wrapped in a /data/ field, or
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-- errors wrapped in an /errors/ field.
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execute :: Alternative f
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=> Schema.Schema f -> Schema.Subs -> Document -> f Aeson.Value
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execute resolvers subs doc = undefined -- resolver resolvs $ rootFields subs doc
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-- | Takes a variable substitution function and a @GraphQL@ document.
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-- If the document contains one query (and no other definitions)
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-- it applies the substitution to the query's set of selections
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-- and then returns their fields.
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-- rootFields :: Schema.Subs -> Document -> [Field]
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-- rootFields subs (Document [DefinitionOperation (Query (Node _varDefs _ _ sels))]) =
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-- Schema.fields $ substitute subs <$> sels
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-- rootFields _ _ = []
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-- | Takes a variable substitution function and a selection. If the
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-- selection is a field it applies the substitution to the field's
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-- arguments using 'subsArg', and recursively applies the substitution to
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-- the arguments of fields nested in the primary field.
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-- substitute :: Schema.Subs -> Selection -> Selection
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-- substitute subs (SelectionField (Field alias name args directives sels)) =
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-- SelectionField $ Field
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-- alias
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-- name
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-- -- TODO: Get rid of `catMaybes`, invalid arguments should raise an error
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-- (catMaybes $ subsArg subs <$> args)
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-- directives
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-- (substitute subs <$> sels)
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-- substitute _ sel = sel
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-- TODO: Support different value types
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-- | Takes a variable substitution function and an argument. If the
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-- argument's value is a variable the substitution is applied to the
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-- variable's name.
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-- subsArg :: Schema.Subs -> Argument -> Maybe Argument
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-- subsArg subs (Argument n (ValueVariable (Variable v))) =
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-- Argument n . ValueString <$> subs v
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-- subsArg _ arg = Just arg
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