Fix 1-to-many relationships serialization according to JSON API v1.0

Classes/JSONAPIResourceParser.m

@@ -121,8 +121,8 @@ + (NSDictionary*)dictionaryFor:(NSObject <JSONAPIResource>*)resource {
                             [dictionaryArray addObject:[self link:valueElement from:resource withKey:[property jsonName]]];
                         }
 
-                        [linkage setValue:dictionaryArray forKey:[property jsonName]];
-
+                        NSDictionary *dataDictionary = @{@"data" : dictionaryArray};
+                        [linkage setValue:dataDictionary forKey:[property jsonName]];
                     } else {
                         NSFormatter *format = [property formatter];
 
@@ -366,10 +366,15 @@ + (NSDictionary*)link:(NSObject <JSONAPIResource>*)resource from:(NSObject <JSON
     }
 
     if (resource.ID) {
-        [reference setValue:@{
-                              @"type" : descriptor.type,
-                              @"id"   : resource.ID
-                              } forKey:@"data"];
+        NSDictionary *referenceObject = @{
+                                          @"type" : descriptor.type,
+                                          @"id"   : resource.ID
+                                          };
+        if ([[owner valueForKey:key] isKindOfClass:[NSArray class]]) {
+            reference = referenceObject.mutableCopy;
+        } else {
+            [reference setValue:referenceObject forKey:@"data"];
+        }
     }
 
     return reference;

Project/JSONAPITests/JSONAPITests.m

@@ -151,16 +151,21 @@ - (void)testSerializeComplex {
     newAuthor.firstName = @"Karl";
     newAuthor.lastName = @"Armstrong";
 
-    CommentResource *newComment = [[CommentResource alloc] init];
-    newComment.ID = [NSUUID UUID];
-    newComment.author = newAuthor;
-    newComment.text = @"First!";
+    CommentResource *firstComment = [[CommentResource alloc] init];
+    firstComment.ID = [NSUUID UUID];
+    firstComment.author = newAuthor;
+    firstComment.text = @"First!";
+
+    CommentResource *secondComment = [[CommentResource alloc] init];
+    secondComment.ID = [NSUUID UUID];
+    secondComment.author = newAuthor;
+    secondComment.text = @"Second!";
 
     ArticleResource *newArticle = [[ArticleResource alloc] init];
     newArticle.title = @"Title";
     newArticle.author = newAuthor;
     newArticle.date = [NSDate date];
-    newArticle.comments = [[NSArray alloc] initWithObjects:newComment, nil];
+    newArticle.comments = [[NSArray alloc] initWithObjects:firstComment, secondComment, nil];
 
     NSDictionary *json = [JSONAPIResourceParser dictionaryFor:newArticle];
     XCTAssertEqualObjects(json[@"type"], @"articles", @"Did not create Article!");
@@ -171,8 +176,8 @@ - (void)testSerializeComplex {
     XCTAssertNil(json[@"relationships"][@"author"][@"first-name"], @"Bad link!");
 
     XCTAssertNotNil(json[@"relationships"][@"comments"], @"Did not create links!");
-    XCTAssertTrue([json[@"relationships"][@"comments"] isKindOfClass:[NSArray class]], @"Comments should be array!.");
-    XCTAssertEqual([json[@"relationships"][@"comments"] count], 1, @"Comments should have 1 element!.");
+    XCTAssertTrue([json[@"relationships"][@"comments"][@"data"] isKindOfClass:[NSArray class]], @"Comments data should be array!.");
+    XCTAssertEqual([json[@"relationships"][@"comments"][@"data"] count], 2, @"Comments should have 2 elements!.");
 }
 
 - (void)testCreate {
@@ -226,11 +231,11 @@ - (void)testGenericSerialization {
     NSDictionary *serializedFirstPost = [JSONAPIResourceParser dictionaryFor:posts.firstObject];
     NSDictionary *serializedSecondPost = [JSONAPIResourceParser dictionaryFor:posts.lastObject];
 
-    XCTAssertNotNil(serializedFirstPost[@"relationships"][@"attachments"][0], @"Media attachment should not be nil");
-    XCTAssertNotNil(serializedFirstPost[@"relationships"][@"attachments"][1], @"Web page url attachment should not be nil");
+    XCTAssertNotNil(serializedFirstPost[@"relationships"][@"attachments"][@"data"][0], @"Media attachment should not be nil");
+    XCTAssertNotNil(serializedFirstPost[@"relationships"][@"attachments"][@"data"][1], @"Web page url attachment should not be nil");
 
-    XCTAssertEqualObjects(serializedFirstPost[@"relationships"][@"attachments"][0][@"data"][@"id"], @15, @"Media id should be '15'");
-    XCTAssertEqualObjects(serializedFirstPost[@"relationships"][@"attachments"][0][@"data"][@"type"], @"Media", @"Media type should be 'Media'");
+    XCTAssertEqualObjects(serializedFirstPost[@"relationships"][@"attachments"][@"data"][0][@"id"], @15, @"Media id should be '15'");
+    XCTAssertEqualObjects(serializedFirstPost[@"relationships"][@"attachments"][@"data"][0][@"type"], @"Media", @"Media type should be 'Media'");
 
     XCTAssertEqualObjects(serializedFirstPost[@"relationships"][@"publisher"][@"data"][@"id"], @45, @"User id should be '45'");
     XCTAssertEqualObjects(serializedFirstPost[@"relationships"][@"publisher"][@"data"][@"type"], @"User", @"User type should be 'User'");