summaryrefslogtreecommitdiff
path: root/src/Data/GraphQL/Schema.hs
diff options
context:
space:
mode:
Diffstat (limited to 'src/Data/GraphQL/Schema.hs')
-rw-r--r--src/Data/GraphQL/Schema.hs138
1 files changed, 62 insertions, 76 deletions
diff --git a/src/Data/GraphQL/Schema.hs b/src/Data/GraphQL/Schema.hs
index 0ff94f8..919235e 100644
--- a/src/Data/GraphQL/Schema.hs
+++ b/src/Data/GraphQL/Schema.hs
@@ -1,5 +1,5 @@
{-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE LambdaCase #-}
+
-- | This module provides a representation of a @GraphQL@ Schema in addition to
-- functions for defining and manipulating Schemas.
module Data.GraphQL.Schema
@@ -25,12 +25,9 @@ module Data.GraphQL.Schema
, Value(..)
) where
-import Control.Applicative (Alternative(..))
-import Control.Monad (MonadPlus)
+import Control.Monad (MonadPlus(..))
import Control.Monad.Trans.Class (lift)
-import Control.Monad.Trans.State ( get
- , put
- )
+import Control.Monad.Trans.Except (runExceptT)
import Data.Foldable ( find
, fold
)
@@ -42,7 +39,7 @@ import Data.HashMap.Strict (HashMap)
import qualified Data.HashMap.Strict as HashMap
import Data.Text (Text)
import qualified Data.Text as T
-
+import Language.GraphQL.Trans
import Data.GraphQL.AST.Core
-- | A GraphQL schema.
@@ -63,104 +60,93 @@ type Arguments = [Argument]
type Subs = Name -> Maybe Value
-- | Create a new 'Resolver' with the given 'Name' from the given 'Resolver's.
-object :: MonadPlus m => Name -> [Resolver m] -> Resolver m
-object name resolvers = objectA name $ \case
- [] -> resolvers
- _ -> empty
+object :: MonadPlus m => Name -> ActionT m [Resolver m] -> Resolver m
+object name = objectA name . const
-- | Like 'object' but also taking 'Argument's.
-objectA
- :: MonadPlus m
- => Name -> (Arguments -> [Resolver m]) -> Resolver m
-objectA name f = Resolver name go
+objectA :: MonadPlus m
+ => Name -> (Arguments -> ActionT m [Resolver m]) -> Resolver m
+objectA name f = Resolver name $ resolveFieldValue f resolveRight
where
- go fld@(Field _ _ args flds) = withField name (resolve (f args) flds) fld
-
+ resolveRight fld@(Field _ _ _ flds) resolver = withField name (resolve resolver flds) fld
-- | Create a named 'Resolver' from a list of 'Resolver's.
-object' :: MonadPlus m => Name -> m [Resolver m] -> Resolver m
-object' name resolvs = objectA' name $ \case
- [] -> resolvs
- _ -> empty
+object' :: MonadPlus m => Name -> ActionT m [Resolver m] -> Resolver m
+object' name = objectA' name . const
-- | Like 'object'' but also taking 'Argument's.
-objectA'
- :: MonadPlus m
- => Name -> (Arguments -> m [Resolver m]) -> Resolver m
-objectA' name f = Resolver name go
+objectA' :: MonadPlus m
+ => Name -> (Arguments -> ActionT m [Resolver m]) -> Resolver m
+objectA' name f = Resolver name $ resolveFieldValue f resolveRight
where
- go fld@(Field _ _ args flds) = do
- resolvs <- lift $ f args
- withField name (resolve resolvs flds) fld
+ resolveRight fld@(Field _ _ _ flds) resolver = withField name (resolve resolver flds) fld
-- | A scalar represents a primitive value, like a string or an integer.
-scalar :: (MonadPlus m, Aeson.ToJSON a) => Name -> a -> Resolver m
-scalar name s = scalarA name $ \case
- [] -> pure s
- _ -> empty
+scalar :: (MonadPlus m, Aeson.ToJSON a) => Name -> ActionT m a -> Resolver m
+scalar name = scalarA name . const
-- | Like 'scalar' but also taking 'Argument's.
-scalarA
- :: (MonadPlus m, Aeson.ToJSON a)
- => Name -> (Arguments -> m a) -> Resolver m
-scalarA name f = Resolver name go
+scalarA :: (MonadPlus m, Aeson.ToJSON a)
+ => Name -> (Arguments -> ActionT m a) -> Resolver m
+scalarA name f = Resolver name $ resolveFieldValue f resolveRight
where
- go fld@(Field _ _ args []) = withField name (lift $ f args) fld
- go _ = empty
+ resolveRight fld@(Field _ _ _ []) result = withField name (return result) fld
+ resolveRight _ _ = mzero
-array :: MonadPlus m => Name -> [[Resolver m]] -> Resolver m
-array name resolvers = arrayA name $ \case
- [] -> resolvers
- _ -> empty
+array :: MonadPlus m => Name -> ActionT m [[Resolver m]] -> Resolver m
+array name = arrayA name . const
-- | Like 'array' but also taking 'Argument's.
-arrayA
- :: MonadPlus m
- => Name -> (Arguments -> [[Resolver m]]) -> Resolver m
-arrayA name f = Resolver name go
+arrayA :: MonadPlus m
+ => Name -> (Arguments -> ActionT m [[Resolver m]]) -> Resolver m
+arrayA name f = Resolver name $ resolveFieldValue f resolveRight
where
- go fld@(Field _ _ args sels) = withField name (traverse (`resolve` sels) $ f args) fld
+ resolveRight fld@(Field _ _ _ sels) resolver
+ = withField name (traverse (`resolve` sels) resolver) fld
-- | Like 'object'' but taking lists of 'Resolver's instead of a single list.
-array' :: MonadPlus m => Name -> m [[Resolver m]] -> Resolver m
-array' name resolvs = arrayA' name $ \case
- [] -> resolvs
- _ -> empty
+array' :: MonadPlus m => Name -> ActionT m [[Resolver m]] -> Resolver m
+array' name = arrayA' name . const
-- | Like 'array'' but also taking 'Argument's.
-arrayA'
- :: MonadPlus m
- => Name -> (Arguments -> m [[Resolver m]]) -> Resolver m
-arrayA' name f = Resolver name go
+arrayA' :: MonadPlus m
+ => Name -> (Arguments -> ActionT m [[Resolver m]]) -> Resolver m
+arrayA' name f = Resolver name $ resolveFieldValue f resolveRight
where
- go fld@(Field _ _ args sels) = do
- resolvs <- lift $ f args
- withField name (traverse (`resolve` sels) resolvs) fld
+ resolveRight fld@(Field _ _ _ sels) resolver
+ = withField name (traverse (`resolve` sels) resolver) fld
-- | Represents one of a finite set of possible values.
-- Used in place of a 'scalar' when the possible responses are easily enumerable.
-enum :: MonadPlus m => Name -> m [Text] -> Resolver m
-enum name enums = enumA name $ \case
- [] -> enums
- _ -> empty
+enum :: MonadPlus m => Name -> ActionT m [Text] -> Resolver m
+enum name = enumA name . const
-- | Like 'enum' but also taking 'Argument's.
-enumA :: MonadPlus m => Name -> (Arguments -> m [Text]) -> Resolver m
-enumA name f = Resolver name go
+enumA :: MonadPlus m => Name -> (Arguments -> ActionT m [Text]) -> Resolver m
+enumA name f = Resolver name $ resolveFieldValue f resolveRight
where
- go fld@(Field _ _ args []) = withField name (lift $ f args) fld
- go _ = empty
+ resolveRight fld resolver = withField name (return resolver) fld
+
+resolveFieldValue :: MonadPlus m
+ => ([Argument] -> ActionT m a)
+ -> (Field -> a -> CollectErrsT m (HashMap Text Aeson.Value))
+ -> Field
+ -> CollectErrsT m (HashMap Text Aeson.Value)
+resolveFieldValue f resolveRight fld@(Field alias name args _) = do
+ result <- lift $ runExceptT . runActionT $ f args
+ either resolveLeft (resolveRight fld) result
+ where
+ resolveLeft err = do
+ _ <- addErrMsg err
+ return $ HashMap.singleton (fromMaybe name alias) Aeson.Null
-- | Helper function to facilitate 'Argument' handling.
withField :: (MonadPlus m, Aeson.ToJSON a)
- => Name -> CollectErrsT m a -> Field -> CollectErrsT m (HashMap Text Aeson.Value)
-withField name v (Field alias _ _ _) = do
- collection <- HashMap.singleton aliasOrName . Aeson.toJSON <$> runAppendErrs v
- errors <- get
- if null errors
- then return collection
- -- TODO: Report error when Non-Nullable type for field argument.
- else put [] >> return (HashMap.singleton aliasOrName Aeson.Null)
+ => Name -> CollectErrsT m a -> Field -> CollectErrsT m (HashMap Text Aeson.Value)
+withField name v (Field alias _ _ _)
+ = HashMap.singleton aliasOrName . Aeson.toJSON <$> runAppendErrs v
+ {- TODO: Report error when Non-Nullable type for field argument.
+ else return (HashMap.singleton aliasOrName Aeson.Null) -}
where
aliasOrName = fromMaybe name alias
@@ -168,10 +154,10 @@ withField name v (Field alias _ _ _) = do
-- 'Resolver' to each 'Field'. Resolves into a value containing the
-- resolved 'Field', or a null value and error information.
resolve :: MonadPlus m
- => [Resolver m] -> Fields -> CollectErrsT m Aeson.Value
+ => [Resolver m] -> Fields -> CollectErrsT m Aeson.Value
resolve resolvers = fmap (Aeson.toJSON . fold) . traverse tryResolvers
where
- tryResolvers fld = maybe empty (tryResolver fld) (find (compareResolvers fld) resolvers) <|> errmsg fld
+ tryResolvers fld = mplus (maybe mzero (tryResolver fld) $ find (compareResolvers fld) resolvers) $ errmsg fld
compareResolvers (Field _ name _ _) (Resolver name' _) = name == name'
tryResolver fld (Resolver _ resolver) = resolver fld
errmsg (Field alias name _ _) = do
generated by cgit v1.2.3 (git 2.26.2) at 2026-06-26 22:30:22 +0000