fix: Return 204 No Content without Content-Type for RPCs returning VOID

Resolves #2001

BREAKING CHANGE: Previously, those RPCs would return "null" as a body with Content-Type: application/json.

CHANGELOG.md

@@ -33,6 +33,11 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #2135, Remove trigger functions from schema cache and OpenAPI output, because they can't be called directly anyway. - @wolfgangwalther
  - #2145, Fix accessing json array fields with -> and ->> in ?select= and ?order=. - @wolfgangwalther
 
+### Changed
+
+ - #2001, Return 204 No Content without Content-Type for RPCs returning VOID - @wolfgangwalther
+   + Previously, those RPCs would return "null" as a body with Content-Type: application/json.
+
 ## [9.0.0] - 2021-11-25
 
 ### Added

src/PostgREST/App.hs

@@ -469,6 +469,9 @@ handleInvoke invMethod proc context@RequestContext{..} = do
       RangeQuery.rangeStatusHeader iTopLevelRange queryTotal tableTotal
 
   failNotSingular iAcceptContentType queryTotal $
+    if Proc.procReturnsVoid proc then
+      response HTTP.status204 [contentRange] mempty
+    else
       response status
         (contentTypeHeaders context ++ [contentRange])
         (if invMethod == InvHead then mempty else LBS.fromStrict body)

src/PostgREST/DbStructure.hs

@@ -202,6 +202,7 @@ decodeProcs =
                   <$> column HD.text
                   <*> column HD.text
                   <*> column HD.bool
+                  <*> column HD.bool
                   <*> column HD.bool)
               <*> (parseVolatility <$> column HD.char)
               <*> column HD.bool
@@ -209,10 +210,11 @@ decodeProcs =
     addKey :: ProcDescription -> (QualifiedIdentifier, ProcDescription)
     addKey pd = (QualifiedIdentifier (pdSchema pd) (pdName pd), pd)
 
-    parseRetType :: Text -> Text -> Bool -> Bool -> RetType
+    parseRetType :: Text -> Text -> Bool -> Bool -> Bool -> Maybe RetType
-    parseRetType schema name isSetOf isComposite
+    parseRetType schema name isSetOf isComposite isVoid
-      | isSetOf   = SetOf pgType
+      | isVoid    = Nothing
-      | otherwise = Single pgType
+      | isSetOf   = Just (SetOf pgType)
+      | otherwise = Just (Single pgType)
       where
         qi = QualifiedIdentifier schema name
         pgType
@@ -287,6 +289,7 @@ procsSqlQuery = [q|
      -- if any TABLE, INOUT or OUT arguments present, treat as composite
      or COALESCE(proargmodes::text[] && '{t,b,o}', false)
     ) AS rettype_is_composite,
+    ('pg_catalog.void'::regtype = t.oid) AS rettype_is_void,
     p.provolatile,
     p.provariadic > 0 as hasvariadic
   FROM pg_proc p

src/PostgREST/DbStructure/Proc.hs

@@ -10,6 +10,7 @@ module PostgREST.DbStructure.Proc
   , RetType(..)
   , procReturnsScalar
   , procReturnsSingle
+  , procReturnsVoid
   , procTableName
   ) where
 
@@ -42,7 +43,7 @@ data ProcDescription = ProcDescription
   , pdName        :: Text
   , pdDescription :: Maybe Text
   , pdParams      :: [ProcParam]
-  , pdReturnType  :: RetType
+  , pdReturnType  :: Maybe RetType
   , pdVolatility  :: ProcVolatility
   , pdHasVariadic :: Bool
   }
@@ -69,17 +70,22 @@ type ProcsMap = M.HashMap QualifiedIdentifier [ProcDescription]
 
 procReturnsScalar :: ProcDescription -> Bool
 procReturnsScalar proc = case proc of
-  ProcDescription{pdReturnType = (Single Scalar)} -> True
+  ProcDescription{pdReturnType = Just (Single Scalar)} -> True
-  ProcDescription{pdReturnType = (SetOf Scalar)}  -> True
+  ProcDescription{pdReturnType = Just (SetOf Scalar)}  -> True
   _                                                    -> False
 
 procReturnsSingle :: ProcDescription -> Bool
 procReturnsSingle proc = case proc of
-  ProcDescription{pdReturnType = (Single _)} -> True
+  ProcDescription{pdReturnType = Just (Single _)} -> True
+  _                                               -> False
+
+procReturnsVoid :: ProcDescription -> Bool
+procReturnsVoid proc = case proc of
+  ProcDescription{pdReturnType = Nothing} -> True
   _                                       -> False
 
 procTableName :: ProcDescription -> Maybe TableName
 procTableName proc = case pdReturnType proc of
-  SetOf  (Composite qi) -> Just $ qiName qi
+  Just (SetOf  (Composite qi)) -> Just $ qiName qi
-  Single (Composite qi) -> Just $ qiName qi
+  Just (Single (Composite qi)) -> Just $ qiName qi
   _                            -> Nothing

test/io/test_io.py

@@ -630,7 +630,7 @@ def test_jwt_secret_external_file_reload(tmp_path, defaultenv):
 
         # reload config and external file with NOTIFY
         response = postgrest.session.post("/rpc/reload_pgrst_config")
-        assert response.status_code == 200
+        assert response.status_code == 204
         time.sleep(0.1)
 
         response = postgrest.session.get("/authors_only", headers=headers)
@@ -685,7 +685,7 @@ def test_db_schema_notify_reload(defaultenv):
 
         # reset db-schemas config on the db
         response = postgrest.session.post("/rpc/reset_db_schema_config")
-        assert response.status_code == 200
+        assert response.status_code == 204
 
 
 def test_max_rows_reload(defaultenv):
@@ -714,7 +714,7 @@ def test_max_rows_reload(defaultenv):
 
         # reset max-rows config on the db
         response = postgrest.session.post("/rpc/reset_max_rows_config")
-        assert response.status_code == 200
+        assert response.status_code == 204
 
 
 def test_max_rows_notify_reload(defaultenv):
@@ -744,7 +744,7 @@ def test_max_rows_notify_reload(defaultenv):
 
         # reset max-rows config on the db
         response = postgrest.session.post("/rpc/reset_max_rows_config")
-        assert response.status_code == 200
+        assert response.status_code == 204
 
 
 def test_invalid_role_claim_key_notify_reload(defaultenv):
@@ -770,7 +770,7 @@ def test_invalid_role_claim_key_notify_reload(defaultenv):
         assert "failed to parse role-claim-key value" in output.decode()
 
         response = postgrest.session.post("/rpc/reset_invalid_role_claim_key")
-        assert response.status_code == 200
+        assert response.status_code == 204
 
 
 def test_db_prepared_statements_enable(defaultenv):
@@ -835,7 +835,7 @@ def test_admin_ready_includes_schema_cache_state(defaultenv):
         response = postgrest.session.post(
             "/rpc/no_schema_cache_for_limited_authenticator"
         )
-        assert response.status_code == 200
+        assert response.status_code == 204
 
         # force a reconnection so the new role setting is picked up
         postgrest.process.send_signal(signal.SIGUSR1)

test/spec/Feature/Query/InsertSpec.hs

@@ -179,7 +179,10 @@ spec actualPgVersion = do
               [("Prefer", "tx=commit")]
               [json|{"name": "auto_incrementing_pk_id_seq", "value": 2}|]
             `shouldRespondWith`
-              [json|""|]
+              ""
+              { matchStatus = 204
+              , matchHeaders = [ matchHeaderAbsent hContentType ]
+              }
 
           request methodPost "/auto_incrementing_pk"
               [("Prefer", "return=headers-only")]
@@ -357,7 +360,10 @@ spec actualPgVersion = do
             [("Prefer", "tx=commit")]
             [json|{"name": "items2_id_seq", "value": 20}|]
           `shouldRespondWith`
-            [json|""|]
+            ""
+            { matchStatus = 204
+            , matchHeaders = [ matchHeaderAbsent hContentType ]
+            }
 
         request methodPost "/items2"
             [("Prefer", "return=representation")]
@@ -372,7 +378,10 @@ spec actualPgVersion = do
             [("Prefer", "tx=commit")]
             [json|{"name": "items3_id_seq", "value": 20}|]
           `shouldRespondWith`
-            [json|""|]
+            ""
+            { matchStatus = 204
+            , matchHeaders = [ matchHeaderAbsent hContentType ]
+            }
 
         request methodPost "/items3?select=id"
             [("Prefer", "return=representation")]

test/spec/Feature/Query/RpcSpec.hs

@@ -329,18 +329,20 @@ spec actualPgVersion =
           `shouldRespondWith`
             [json|{"id": 2}|]
 
-      it "returns null for void" $
+      it "returns 204, no Content-Type header and no content for void" $
         post "/rpc/ret_void"
             [json|{}|]
           `shouldRespondWith`
-            [json|null|]
+            ""
+            { matchStatus = 204
+            , matchHeaders = [matchHeaderAbsent hContentType]
+            }
 
       it "returns null for an integer with null value" $
         post "/rpc/ret_null"
             [json|{}|]
           `shouldRespondWith`
-            "null"
+            [json|null|]
-            { matchHeaders = [matchContentTypeJson] }
 
       context "different types when overloaded" $ do
         it "returns composite type" $
@@ -527,7 +529,10 @@ spec actualPgVersion =
           [("Prefer", "tx=commit")]
           [json|{"name": "callcounter_count", "value": 1}|]
         `shouldRespondWith`
-          [json|""|]
+          ""
+          { matchStatus = 204
+          , matchHeaders = [ matchHeaderAbsent hContentType ]
+          }
 
       -- now the test
       post "/rpc/callcounter"
@@ -1074,10 +1079,12 @@ spec actualPgVersion =
       it "can set the same http header twice" $
         get "/rpc/set_cookie_twice"
           `shouldRespondWith`
-            "null"
+            ""
-            { matchHeaders = [ matchContentTypeJson
+            { matchStatus = 204
+            , matchHeaders = [ matchHeaderAbsent hContentType
                              , "Set-Cookie" <:> "sessionid=38afes7a8; HttpOnly; Path=/"
-                             , "Set-Cookie" <:> "id=a3fWa; Expires=Wed, 21 Oct 2015 07:28:00 GMT; Secure; HttpOnly" ]}
+                             , "Set-Cookie" <:> "id=a3fWa; Expires=Wed, 21 Oct 2015 07:28:00 GMT; Secure; HttpOnly" ]
+            }
 
       it "can override the Location header on a trigger" $
         post "/stuff"