Removing single column limit from join table M2M mapping detection. (#1593)

CHANGELOG.md

@@ -17,7 +17,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #1607, Enable embedding through multiple views recursively - @wolfgangwalther
 
 ### Fixed
-
+ 
+ - #1592, Removed single column restriction to allow composite foreign keys in join tables - @goteguru
  - #1530, Fix how the PostgREST version is shown in the help text when the `.git` directory is not available - @monacoremo
  - #1094, Fix expired JWTs starting an empty transaction on the db - @steve-chavez
  - #1162, Fix location header for POST request with select= without PK - @wolfgangwalther

src/PostgREST/DbStructure.hs

@@ -358,9 +358,9 @@ addO2MRels = concatMap (\rel@(Relation t c cn ft fc _ _) -> [rel, Relation ft fc
 addM2MRels :: [Relation] -> [Relation]
 addM2MRels rels = rels ++ addMirrorRel (mapMaybe junction2Rel junctions)
   where
-    junctions = join $ map (combinations 2) $ filter (not . null) $ groupWith groupFn $ filter ( (==M2O). relType) rels
-    groupFn :: Relation -> Text
-    groupFn Relation{relTable=Table{tableSchema=s, tableName=t}} = s <> "_" <> t
+    junctions = join $ map (combinations 2) $ groupWith groupFn $ filter ( (==M2O). relType) rels
+    groupFn :: Relation -> (Text,Text)
+    groupFn Relation{relTable=Table{tableSchema=s, tableName=t}} = (s,t)
     -- Reference : https://wiki.haskell.org/99_questions/Solutions/26
     combinations :: Int -> [a] -> [[a]]
     combinations 0 _  = [ [] ]
@@ -370,7 +370,7 @@ addM2MRels rels = rels ++ addMirrorRel (mapMaybe junction2Rel junctions)
       Relation{relTable=jt, relColumns=jc1, relConstraint=const1, relFTable=t,  relFColumns=c},
       Relation{             relColumns=jc2, relConstraint=const2, relFTable=ft, relFColumns=fc}
       ]
-      | jc1 /= jc2 && length jc1 == 1 && length jc2 == 1 = Just $ Relation t c Nothing ft fc M2M (Just $ Junction jt const1 jc1 const2 jc2)
+      | jc1 /= jc2 = Just $ Relation t c Nothing ft fc M2M (Just $ Junction jt const1 jc1 const2 jc2)
       | otherwise = Nothing
     junction2Rel _ = Nothing
     addMirrorRel = concatMap (\rel@(Relation t c _ ft fc _ (Just (Junction jt const1 jc1 const2 jc2))) ->

test/Feature/QuerySpec.hs

@@ -351,6 +351,21 @@ spec actualPgVersion = do
         [json|[{"id":1,"tasks":[{"id":1},{"id":2},{"id":3},{"id":4}]},{"id":2,"tasks":[{"id":5},{"id":6},{"id":7}]},{"id":3,"tasks":[{"id":1},{"id":5}]}]|]
         { matchHeaders = [matchContentTypeJson] }
 
+    it "requesting many<->many relation using composite key" $
+      get "/files?filename=eq.autoexec.bat&project_id=eq.1&select=filename,users_tasks(user_id,task_id)" `shouldRespondWith`
+        [json|[{"filename":"autoexec.bat","users_tasks":[{"user_id":1,"task_id":1},{"user_id":3,"task_id":1}]}]|]
+        { matchHeaders = [matchContentTypeJson] }
+
+    it "requesting data using many<->many relation defined by composite keys" $
+      get "/users_tasks?user_id=eq.1&task_id=eq.1&select=user_id,files(filename,content)" `shouldRespondWith`
+        [json|[{"user_id":1,"files":[{"filename":"command.com","content":"#include <unix.h>"},{"filename":"autoexec.bat","content":"@ECHO OFF"},{"filename":"README.md","content":"# make $$$!"}]}]|]
+        { matchHeaders = [matchContentTypeJson] }
+
+    it "requesting data using many<->many (composite keys) relation using hint" $
+      get "/users_tasks?user_id=eq.1&task_id=eq.1&select=user_id,files!touched_files(filename,content)" `shouldRespondWith`
+        [json|[{"user_id":1,"files":[{"filename":"command.com","content":"#include <unix.h>"},{"filename":"autoexec.bat","content":"@ECHO OFF"},{"filename":"README.md","content":"# make $$$!"}]}]|]
+        { matchHeaders = [matchContentTypeJson] }
+
     it "requesting children with composite key" $
       get "/users_tasks?user_id=eq.2&task_id=eq.6&select=*, comments(content)" `shouldRespondWith`
         [json|[{"user_id":2,"task_id":6,"comments":[{"content":"Needs to be delivered ASAP"}]}]|]

test/fixtures/data.sql

@@ -140,6 +140,26 @@ INSERT INTO users_tasks VALUES (3, 5);
 TRUNCATE TABLE comments CASCADE;
 INSERT INTO comments VALUES (1, 1, 2, 6, 'Needs to be delivered ASAP');
 
+--
+-- Data for Name: files; Type: TABLE DATA; Schema: test; Owner: -
+--
+
+TRUNCATE TABLE files CASCADE;
+INSERT INTO files VALUES
+	 (1, 'command.com', '#include <unix.h>')
+	,(1, 'autoexec.bat', '@ECHO OFF')
+	,(1, 'io.sys', 'TODO')
+	,(2, 'README.md', '# make $$$!')
+	,(2, 'marketing.key', '$-$')
+	;
+
+TRUNCATE TABLE touched_files CASCADE;
+INSERT INTO touched_files VALUES
+	 (1, 1, 1, 'command.com')
+	,(1, 1, 1, 'autoexec.bat')
+	,(1, 1, 2, 'README.md')
+	,(3, 1, 1, 'autoexec.bat')
+	;
 
 --
 -- Data for Name: complex_items; Type: TABLE DATA; Schema: test; Owner: -

test/fixtures/privileges.sql

@@ -43,6 +43,8 @@ GRANT ALL ON TABLE
     , users
     , users_projects
     , users_tasks
+    , files
+    , touched_files
     , "Escap3e;"
     , "ghostBusters"
     , "withUnique"

test/fixtures/schema.sql

@@ -697,6 +697,28 @@ alter table only comments
     add constraint "user" foreign key (commenter_id) references users(id),
     add constraint comments_task_id_fkey foreign key (task_id, user_id) references users_tasks(task_id, user_id);
 
+CREATE TABLE files (
+    project_id integer NOT NULL,
+    filename text NOT NULL,
+    content text NOT NULL,
+    PRIMARY KEY (project_id, filename)
+);
+
+CREATE TABLE touched_files (
+    user_id integer NOT NULL,
+    task_id integer NOT NULL,
+    project_id integer NOT NULL,
+    filename text NOT NULL,
+    CONSTRAINT fk_users_tasks
+	FOREIGN KEY (user_id, task_id)
+	REFERENCES users_tasks (user_id, task_id)
+	ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT fk_upload
+	FOREIGN KEY (project_id, filename)
+	REFERENCES files (project_id,filename)
+	ON DELETE CASCADE ON UPDATE CASCADE
+);
+
 create table private.articles (
     id integer primary key,
     body text,