Mapping your Core Data objects with your JSON providing backend has never been this easy.

{
  "first_name": "John",
  "last_name": "Hyperseed"
}

NSDictionary *values = [JSON valueForKey:@"user"];
[user hyp_fillWithDictionary:values];

Your Core Data entities should match your backend models but in camelCase. Your attributes should match their JSON counterparts. For example first_name maps to firstName, address to address.

There are two exceptions to this rule:

• ids should match remoteID
• Reserved attributes should be prefixed with the entityName (type becomes userType, description becomes userDescription and so on). In the JSON they don't need to change, you can keep type and description for example. A full list of reserved attributes can be found here

If you want to map your Core Data attribute with a JSON attribute that has different naming, you can do by adding hyper.remoteKey in the user info box with the value you want to map.

For mapping for arrays and dictionaries just set attributes as Binary Data on the Core Data modeler

We went for just supporting ISO8601 out of the box because that's the most common format when parsing dates, also we have a quite performant way to parse this strings which overcomes the performance issues of using NSDateFormatter.

NSDictionary *values = @{@"created_at" : @"2014-01-01T00:00:00+00:00",
                         @"updated_at" : @"2014-01-02",
                         @"number_of_attendes": @20};

[managedObject hyp_fillWithDictionary:values];

NSDate *createdAt = [managedObject valueForKey:@"createdAt"];
// ==> "2014-01-01 00:00:00 +00:00" 

NSDate *updatedAt = [managedObject valueForKey:@"updatedAt"];
// ==> "2014-01-02 00:00:00 +00:00" 

NSDictionary *values = @{@"hobbies" : @[@"football",
                                        @"soccer",
                                        @"code"]};

[managedObject hyp_fillWithDictionary:values];

NSArray *hobbies = [NSKeyedUnarchiver unarchiveObjectWithData:managedObject.hobbies];
// ==> "football", "soccer", "code" 

NSDictionary *values = @{@"expenses" : @{@"cake" : @12.50,
                                         @"juice" : @0.50}};

[managedObject hyp_fillWithDictionary:values];

NSDictionary *expenses = [NSKeyedUnarchiver unarchiveObjectWithData:managedObject.expenses];
// ==> "cake" : 12.50, "juice" : 0.50

UserManagedObject *user;
[user setValue:@"John" forKey:@"firstName"];
[user setValue:@"Hyperseed" forKey:@"lastName"];

NSDictionary *userValues = [user hyp_dictionary];

That's it, that's all you have to do, the keys will be magically transformed into a snake_case convention.

{
  "first_name": "John",
  "last_name": "Hyperseed"
}

It supports relationships too, and we complain to the Rails rule accepts_nested_attributes_for, for example for a user that has many notes:

"first_name": "John",
"last_name": "Hyperseed",
"notes_attributes": [
  {
    "0": {
      "id": 0,
      "text": "This is the text for the note A"
    },
    "1": {
      "id": 1,
      "text": "This is the text for the note B"
    }
  }
]

NSManagedObject-HYPPropertyMapper is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'NSManagedObject-HYPPropertyMapper'

Please check our playbook for guidelines on contributing.

Hyper made this. We're a digital communications agency with a passion for good code, and if you're using this library we probably want to hire you.

NSManagedObject-HYPPropertyMapper is available under the MIT license. See the LICENSE file for more info.