graphql/src/Language/GraphQL/Validate/Validation.hs

51 lines
1.9 KiB
Haskell

{- This Source Code Form is subject to the terms of the Mozilla Public License,
v. 2.0. If a copy of the MPL was not distributed with this file, You can
obtain one at https://mozilla.org/MPL/2.0/. -}
-- | Definitions used by the validation rules and the validator itself.
module Language.GraphQL.Validate.Validation
( Error(..)
, Rule(..)
, RuleT
, Validation(..)
) where
import Control.Monad.Trans.Reader (ReaderT)
import Data.Sequence (Seq)
import Language.GraphQL.AST.DirectiveLocation (DirectiveLocation(..))
import Language.GraphQL.AST.Document
import qualified Language.GraphQL.Type.In as In
import qualified Language.GraphQL.Type.Out as Out
import Language.GraphQL.Type.Schema (Schema)
-- | Validation error.
data Error = Error
{ message :: String
, locations :: [Location]
} deriving (Eq, Show)
-- | Validation rule context.
data Validation m = Validation
{ ast :: Document
, schema :: Schema m
}
-- | 'Rule' assigns a function to each AST node that can be validated. If the
-- validation fails, the function should return an error message, or 'Nothing'
-- otherwise.
data Rule m
= DefinitionRule (Definition -> RuleT m)
| OperationDefinitionRule (OperationDefinition -> RuleT m)
| FragmentDefinitionRule (FragmentDefinition -> RuleT m)
| SelectionRule (Maybe (Out.Type m) -> Selection -> RuleT m)
| FragmentRule (FragmentDefinition -> RuleT m) (InlineFragment -> RuleT m)
| FragmentSpreadRule (FragmentSpread -> RuleT m)
| FieldRule (Maybe (Out.Type m) -> Field -> RuleT m)
| ArgumentsRule (Maybe (Out.Type m) -> Field -> RuleT m) (Directive -> RuleT m)
| DirectivesRule (DirectiveLocation -> [Directive] -> RuleT m)
| VariablesRule ([VariableDefinition] -> RuleT m)
| ValueRule (Maybe In.Type -> Node Value -> RuleT m) (Maybe In.Type -> Node ConstValue -> RuleT m)
-- | Monad transformer used by the rules.
type RuleT m = ReaderT (Validation m) Seq Error