Upsert with "Prefer: resolution=merge-duplicates" on specified columns (#1327) (#1432)

Allow query param 'on_conflict=key1,key2,...' to upsert with explicit columns with unique
constraint.

CHANGELOG.md

@@ -11,6 +11,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - #1415, Add support for user defined socket permission via `server-unix-socket-mode` config option - @Dansvidania
 - #1383, Add support for HEAD request - @steve-chavez
 - #1378, Add support for `Prefer: count=planned` and `Prefer: count=estimated` on GET /table - @steve-chavez
+- #1327, Add support for optional query parameter `on_conflict` to upsert with specified keys for POST - @ykst
 
 ### Fixed
 

src/PostgREST/ApiRequest.hs

@@ -87,6 +87,7 @@ data ApiRequest = ApiRequest {
   , iFilters              :: [(Text, Text)]                   -- ^ Filters on the result ("id", "eq.10")
   , iLogic                :: [(Text, Text)]                   -- ^ &and and &or parameters used for complex boolean logic
   , iSelect               :: Maybe Text                       -- ^ &select parameter used to shape the response
+  , iOnConflict           :: Maybe Text                       -- ^ &on_conflict parameter used to upsert on specific unique keys
   , iColumns              :: Maybe Text                       -- ^ &columns parameter used to shape the payload
   , iOrder                :: [(Text, Text)]                   -- ^ &order parameters for each level
   , iCanonicalQS          :: ByteString                       -- ^ Alphabetized (canonical) request query string for response URLs
@@ -122,6 +123,7 @@ userApiRequest schema rootSpec req reqBody
       , iFilters = filters
       , iLogic = [(toS k, toS $ fromJust v) | (k,v) <- qParams, isJust v, endingIn ["and", "or"] k ]
       , iSelect = toS <$> join (lookup "select" qParams)
+      , iOnConflict = toS <$> join (lookup "on_conflict" qParams)
       , iColumns = columns
       , iOrder = [(toS k, toS $ fromJust v) | (k,v) <- qParams, isJust v, endingIn ["order"] k ]
       , iCanonicalQS = toS $ urlEncodeVars

src/PostgREST/App.hs

@@ -169,7 +169,7 @@ app dbStructure proc cols conf apiRequest =
                         else Nothing
                     , Just $ contentRangeH 1 0 $
                         if shouldCount then Just queryTotal else Nothing
-                    , if null pkCols
+                    , if null pkCols && isNothing (iOnConflict apiRequest)
                         then Nothing
                         else (\x -> ("Preference-Applied", show x)) <$> iPreferResolution apiRequest
                     ]

src/PostgREST/DbRequestBuilder.hs

@@ -324,7 +324,11 @@ addProperty f (targetNodeName:remainingPath, a) (Node rn forest) =
 mutateRequest :: Schema -> TableName -> ApiRequest -> S.Set FieldName -> [FieldName] -> ReadRequest -> Either Response MutateRequest
 mutateRequest schema tName apiRequest cols pkCols readReq = mapLeft errorResponseFor $
   case action of
-    ActionCreate -> Right $ Insert qi cols ((,) <$> iPreferResolution apiRequest <*> Just pkCols) [] returnings
+    ActionCreate -> do
+        confCols <- case iOnConflict apiRequest of
+            Nothing    -> pure pkCols
+            Just param -> pRequestOnConflict param
+        pure $ Insert qi cols ((,) <$> iPreferResolution apiRequest <*> Just confCols) [] returnings
     ActionUpdate -> Update qi cols <$> combinedLogic <*> pure returnings
     ActionSingleUpsert ->
       (\flts ->

src/PostgREST/OpenAPI.hs

@@ -133,6 +133,13 @@ makeParamDefs ti =
       & schema .~ ParamOther ((mempty :: ParamOtherSchema)
         & in_ .~ ParamQuery
         & type_ ?~ SwaggerString))
+  , ("on_conflict", (mempty :: Param)
+      & name        .~ "on_conflict"
+      & description ?~ "On Conflict"
+      & required    ?~ False
+      & schema .~ ParamOther ((mempty :: ParamOtherSchema)
+        & in_ .~ ParamQuery
+        & type_ ?~ SwaggerString))
   , ("order", (mempty :: Param)
       & name        .~ "order"
       & description ?~ "Ordering"

src/PostgREST/Parsers.hs

@@ -30,6 +30,10 @@ pRequestSelect :: Text -> Either ApiRequestError [Tree SelectItem]
 pRequestSelect selStr =
   mapError $ parse pFieldForest ("failed to parse select parameter (" <> toS selStr <> ")") (toS selStr)
 
+pRequestOnConflict :: Text -> Either ApiRequestError  [FieldName]
+pRequestOnConflict oncStr =
+  mapError $ parse pColumns ("failed to parse on_conflict parameter (" <> toS oncStr <> ")") (toS oncStr)
+
 pRequestFilter :: (Text, Text) -> Either ApiRequestError (EmbedPath, Filter)
 pRequestFilter (k, v) = mapError $ (,) <$> path <*> (Filter <$> fld <*> oper)
   where

test/Feature/UpsertSpec.hs

@@ -49,6 +49,31 @@ spec =
             [json|[]|] `shouldRespondWith`
             [json|[]|] { matchStatus = 201 , matchHeaders = [matchContentTypeJson] }
 
+        it "INSERTs and UPDATEs rows on single unique key conflict" $
+          request methodPost "/single_unique?on_conflict=unique_key" [("Prefer", "return=representation"), ("Prefer", "resolution=merge-duplicates")]
+            [json| [
+              { "unique_key": 1, "value": "B" },
+              { "unique_key": 2, "value": "C" }
+            ]|] `shouldRespondWith` [json| [
+              { "unique_key": 1, "value": "B" },
+              { "unique_key": 2, "value": "C" }
+            ]|]
+            { matchStatus = 201
+            , matchHeaders = ["Preference-Applied" <:> "resolution=merge-duplicates", matchContentTypeJson]
+            }
+
+        it "INSERTs and UPDATEs rows on compound unique keys conflict" $
+          request methodPost "/compound_unique?on_conflict=key1,key2" [("Prefer", "return=representation"), ("Prefer", "resolution=merge-duplicates")]
+            [json| [
+              { "key1": 1, "key2": 1, "value": "B" },
+              { "key1": 1, "key2": 2, "value": "C" }
+            ]|] `shouldRespondWith` [json| [
+              { "key1": 1, "key2": 1, "value": "B" },
+              { "key1": 1, "key2": 2, "value": "C" }
+            ]|]
+            { matchStatus = 201
+            , matchHeaders = ["Preference-Applied" <:> "resolution=merge-duplicates", matchContentTypeJson]
+            }
 
       context "when Prefer: resolution=ignore-duplicates is specified" $ do
         it "INSERTs and ignores rows on pk conflict" $
@@ -75,6 +100,32 @@ spec =
             , matchHeaders = ["Preference-Applied" <:> "resolution=ignore-duplicates", matchContentTypeJson]
             }
 
+        it "INSERTs and ignores rows on single unique key conflict" $
+          request methodPost "/single_unique?on_conflict=unique_key" [("Prefer", "return=representation"), ("Prefer", "resolution=ignore-duplicates")]
+            [json| [
+              { "unique_key": 1, "value": "B" },
+              { "unique_key": 2, "value": "C" },
+              { "unique_key": 3, "value": "D" }
+            ]|] `shouldRespondWith` [json| [
+              { "unique_key": 3, "value": "D" }
+            ]|]
+            { matchStatus = 201
+            , matchHeaders = ["Preference-Applied" <:> "resolution=ignore-duplicates", matchContentTypeJson]
+            }
+
+        it "INSERTs and UPDATEs rows on compound unique keys conflict" $
+          request methodPost "/compound_unique?on_conflict=key1,key2" [("Prefer", "return=representation"), ("Prefer", "resolution=ignore-duplicates")]
+            [json| [
+              { "key1": 1, "key2": 1, "value": "B" },
+              { "key1": 1, "key2": 2, "value": "C" },
+              { "key1": 1, "key2": 3, "value": "D" }
+            ]|] `shouldRespondWith` [json| [
+              { "key1": 1, "key2": 3, "value": "D" }
+            ]|]
+            { matchStatus = 201
+            , matchHeaders = ["Preference-Applied" <:> "resolution=ignore-duplicates", matchContentTypeJson]
+            }
+
       it "succeeds if the table has only PK cols and no other cols" $ do
         request methodPost "/only_pk" [("Prefer", "return=representation"), ("Prefer", "resolution=ignore-duplicates")]
           [json|[ { "id": 1 }, { "id": 2 }, { "id": 3} ]|]

test/fixtures/data.sql

@@ -344,6 +344,12 @@ INSERT INTO employees VALUES
 TRUNCATE TABLE tiobe_pls CASCADE;
 INSERT INTO tiobe_pls VALUES ('Java', 1), ('C', 2), ('Python', 4);
 
+TRUNCATE TABLE single_unique CASCADE;
+INSERT INTO single_unique (unique_key, value) VALUES (1, 'A');
+
+TRUNCATE TABLE compound_unique CASCADE;
+INSERT INTO compound_unique (key1, key2, value) VALUES (1, 1, 'A');
+
 TRUNCATE TABLE only_pk CASCADE;
 INSERT INTO only_pk VALUES (1), (2);
 

test/fixtures/privileges.sql

@@ -66,6 +66,8 @@ GRANT ALL ON TABLE
     , perf_articles
     , employees
     , tiobe_pls
+    , single_unique
+    , compound_unique
     , only_pk
     , family_tree
     , managers

test/fixtures/schema.sql

@@ -1379,6 +1379,18 @@ create table test.tiobe_pls(
   rank smallint
 );
 
+create table test.single_unique(
+  unique_key integer unique not null,
+  value text
+);
+
+create table test.compound_unique(
+  key1 integer not null,
+  key2 integer not null,
+  value text,
+  unique(key1, key2)
+);
+
 create table test.family_tree (
   id text not null primary key,
   name text not null,