summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--src/Data/GraphQL/Schema.hs91
-rw-r--r--stack.yaml2
-rw-r--r--stack.yaml.lock8
-rw-r--r--tests/Test/StarWars/Schema.hs9
4 files changed, 63 insertions, 47 deletions
diff --git a/src/Data/GraphQL/Schema.hs b/src/Data/GraphQL/Schema.hs
index 919235e..ad47cef 100644
--- a/src/Data/GraphQL/Schema.hs
+++ b/src/Data/GraphQL/Schema.hs
@@ -6,16 +6,16 @@ module Data.GraphQL.Schema
( Schema
, Resolver
, Subs
+ , nullableArray
+ , nullableEnum
+ , nullableObject
+ , nullableScalar
, object
- , object'
, objectA
- , objectA'
, scalar
, scalarA
, array
- , array'
, arrayA
- , arrayA'
, enum
, enumA
, resolve
@@ -68,18 +68,16 @@ objectA :: MonadPlus m
=> Name -> (Arguments -> ActionT m [Resolver m]) -> Resolver m
objectA name f = Resolver name $ resolveFieldValue f resolveRight
where
- resolveRight fld@(Field _ _ _ flds) resolver = withField name (resolve resolver flds) fld
+ resolveRight fld@(Field _ _ _ flds) resolver = withField (resolve resolver flds) fld
--- | Create a named 'Resolver' from a list of 'Resolver's.
-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 -> ActionT m [Resolver m]) -> Resolver m
-objectA' name f = Resolver name $ resolveFieldValue f resolveRight
+-- | Like 'object' but can be null.
+nullableObject :: MonadPlus m
+ => Name -> (Arguments -> ActionT m (Maybe [Resolver m])) -> Resolver m
+nullableObject name f = Resolver name $ resolveFieldValue f resolveRight
where
- resolveRight fld@(Field _ _ _ flds) resolver = withField name (resolve resolver flds) fld
+ resolveRight fld@(Field _ _ _ flds) (Just resolver) = withField (resolve resolver flds) fld
+ resolveRight fld Nothing
+ = return $ HashMap.singleton (aliasOrName fld) Aeson.Null
-- | A scalar represents a primitive value, like a string or an integer.
scalar :: (MonadPlus m, Aeson.ToJSON a) => Name -> ActionT m a -> Resolver m
@@ -90,9 +88,20 @@ scalarA :: (MonadPlus m, Aeson.ToJSON a)
=> Name -> (Arguments -> ActionT m a) -> Resolver m
scalarA name f = Resolver name $ resolveFieldValue f resolveRight
where
- resolveRight fld@(Field _ _ _ []) result = withField name (return result) fld
+ resolveRight fld@(Field _ _ _ []) result = withField (return result) fld
resolveRight _ _ = mzero
+-- | Lika 'scalar' but can be null.
+nullableScalar :: (MonadPlus m, Aeson.ToJSON a)
+ => Name -> (Arguments -> ActionT m (Maybe a)) -> Resolver m
+nullableScalar name f = Resolver name $ resolveFieldValue f resolveRight
+ where
+ resolveRight fld@(Field _ _ _ []) (Just result) = withField (return result) fld
+ resolveRight fld Nothing
+ = return $ HashMap.singleton (aliasOrName fld) Aeson.Null
+ resolveRight _ _ = mzero
+
+-- | Creates a list of 'Resolver's.
array :: MonadPlus m => Name -> ActionT m [[Resolver m]] -> Resolver m
array name = arrayA name . const
@@ -102,19 +111,17 @@ arrayA :: MonadPlus m
arrayA name f = Resolver name $ resolveFieldValue f resolveRight
where
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 -> ActionT m [[Resolver m]] -> Resolver m
-array' name = arrayA' name . const
+ = withField (traverse (`resolve` sels) resolver) fld
--- | Like 'array'' but also taking 'Argument's.
-arrayA' :: MonadPlus m
- => Name -> (Arguments -> ActionT m [[Resolver m]]) -> Resolver m
-arrayA' name f = Resolver name $ resolveFieldValue f resolveRight
+-- | Like 'array' but can be null.
+nullableArray :: MonadPlus m
+ => Name -> (Arguments -> ActionT m (Maybe [[Resolver m]])) -> Resolver m
+nullableArray name f = Resolver name $ resolveFieldValue f resolveRight
where
- resolveRight fld@(Field _ _ _ sels) resolver
- = withField name (traverse (`resolve` sels) resolver) fld
+ resolveRight fld@(Field _ _ _ sels) (Just resolver)
+ = withField (traverse (`resolve` sels) resolver) fld
+ resolveRight fld Nothing
+ = return $ HashMap.singleton (aliasOrName fld) Aeson.Null
-- | Represents one of a finite set of possible values.
-- Used in place of a 'scalar' when the possible responses are easily enumerable.
@@ -125,7 +132,16 @@ enum name = enumA name . const
enumA :: MonadPlus m => Name -> (Arguments -> ActionT m [Text]) -> Resolver m
enumA name f = Resolver name $ resolveFieldValue f resolveRight
where
- resolveRight fld resolver = withField name (return resolver) fld
+ resolveRight fld resolver = withField (return resolver) fld
+
+-- | Like 'array'' but also taking 'Argument's.
+nullableEnum :: MonadPlus m
+ => Name -> (Arguments -> ActionT m (Maybe [Text])) -> Resolver m
+nullableEnum name f = Resolver name $ resolveFieldValue f resolveRight
+ where
+ resolveRight fld (Just resolver) = withField (return resolver) fld
+ resolveRight fld Nothing
+ = return $ HashMap.singleton (aliasOrName fld) Aeson.Null
resolveFieldValue :: MonadPlus m
=> ([Argument] -> ActionT m a)
@@ -138,17 +154,13 @@ resolveFieldValue f resolveRight fld@(Field alias name args _) = do
where
resolveLeft err = do
_ <- addErrMsg err
- return $ HashMap.singleton (fromMaybe name alias) Aeson.Null
+ return $ HashMap.singleton (aliasOrName fld) 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 _ _ _)
- = HashMap.singleton aliasOrName . Aeson.toJSON <$> runAppendErrs v
- {- TODO: Report error when Non-Nullable type for field argument.
- else return (HashMap.singleton aliasOrName Aeson.Null) -}
- where
- aliasOrName = fromMaybe name alias
+ => CollectErrsT m a -> Field -> CollectErrsT m (HashMap Text Aeson.Value)
+withField v fld
+ = HashMap.singleton (aliasOrName fld) . Aeson.toJSON <$> runAppendErrs v
-- | Takes a list of 'Resolver's and a list of 'Field's and applies each
-- 'Resolver' to each 'Field'. Resolves into a value containing the
@@ -160,8 +172,9 @@ resolve resolvers = fmap (Aeson.toJSON . fold) . traverse tryResolvers
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
+ errmsg fld@(Field alias name _ _) = do
addErrMsg $ T.unwords ["field", name, "not resolved."]
- return $ HashMap.singleton aliasOrName Aeson.Null
- where
- aliasOrName = fromMaybe name alias
+ return $ HashMap.singleton (aliasOrName fld) Aeson.Null
+
+aliasOrName :: Field -> Text
+aliasOrName (Field alias name _ _) = fromMaybe name alias
diff --git a/stack.yaml b/stack.yaml
index df7e3f1..5909cb4 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,4 +1,4 @@
-resolver: lts-13.26
+resolver: lts-13.27
packages:
- '.'
extra-deps: []
diff --git a/stack.yaml.lock b/stack.yaml.lock
index ea480aa..7fb2c31 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -6,7 +6,7 @@
packages: []
snapshots:
- completed:
- size: 499889
- url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/13/26.yaml
- sha256: ecb02ee16829df8d7219e7d7fe6c310819820bf335b0b9534bce84d3ea896684
- original: lts-13.26
+ size: 500539
+ url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/13/27.yaml
+ sha256: 690db832392afe55733b4c7023fd29b1b1c660ee42f1fb505b86b07394ca994e
+ original: lts-13.27
diff --git a/tests/Test/StarWars/Schema.hs b/tests/Test/StarWars/Schema.hs
index 0abda7b..daa000e 100644
--- a/tests/Test/StarWars/Schema.hs
+++ b/tests/Test/StarWars/Schema.hs
@@ -24,15 +24,18 @@ schema = hero :| [human, droid]
hero :: MonadPlus m => Resolver m
hero = Schema.objectA "hero" $ \case
[] -> character artoo
- [Argument "episode" (ValueInt n)] -> character . getHero $ fromIntegral n
[Argument "episode" (ValueEnum "NEWHOPE")] -> character $ getHero 4
[Argument "episode" (ValueEnum "EMPIRE" )] -> character $ getHero 5
[Argument "episode" (ValueEnum "JEDI" )] -> character $ getHero 6
_ -> ActionT $ throwE "Invalid arguments."
human :: MonadPlus m => Resolver m
-human = Schema.objectA "human" $ \case
- [Argument "id" (ValueString i)] -> character =<< lift (getHuman i)
+human = Schema.nullableObject "human" $ \case
+ [Argument "id" (ValueString i)] -> do
+ humanCharacter <- lift $ return $ getHuman i >>= Just
+ case humanCharacter of
+ Nothing -> return Nothing
+ Just e -> Just <$> character e
_ -> ActionT $ throwE "Invalid arguments."
droid :: MonadPlus m => Resolver m
generated by cgit v1.2.3 (git 2.26.2) at 2026-06-26 22:20:26 +0000