rest-kit-mapping-options

rest-kit-mapping-options.js

/*
 * RestKit QUESTION
 *
 * What is the correct way to map the following server response variants, and 
 * is there a preferred option?
 *
 * Also, keeping in mind that these responses can represent nested objects that need to
 * be mapped to corresponding object hierarchies on the client side. I can give more 
 * examples of that if needed.
 *
 * Finally, the client side is core-data, so the mappings are managed object mappings.
 *  
 */

// format #1
// named array of objects
// This is the format shown on the RestKit wiki examples

{
  persons: [
    {
      id: 1,
      last_name: "Johnson",
      first_name: "Stephanie",
      gender: "female"
    },
    {
      id: 2,
      last_name: "Black",
      first_name: "Joe",
      gender: "male"
    }
  ]
}

// format #2
// naked array of named objects

[
  {
    person: {
      id: 1,
      last_name: "Johnson",
      first_name: "Stephanie",
      gender: "female"
    }
  },
  {
    person: {
      id: 2,
      last_name: "Black",
      first_name: "Joe",
      gender: "male"
    }
  }
]

// format #3
// naked array of (unnamed) objects

  [
    {
      id: 1,
      last_name: "Johnson",
      first_name: "Stephanie",
      gender: "female"
    },
    {
      id: 2,
      last_name: "Black",
      first_name: "Joe",
      gender: "male",
    }
  ]


// format #4
// named array of named objects

{
  persons: [
    {
      person: {
        id: 1,
        last_name: "Johnson",
        first_name: "Stephanie",
        gender: "female"
      }
    },
    {
      person: {
        id: 2,
        last_name: "Black",
        first_name: "Joe",
        gender: "male"
      }
    }
  ]
}

Posted on google groups at http://groups.google.com/group/restkit/browse_thread/thread/1065c5466ae7a2ec

One way for #3 (maybe not the best) is to follow the RKTwitter example:

- (void)loadTimeline {
    // Load the object model via RestKit    
    RKObjectManager* objectManager = [RKObjectManager sharedManager];

    [objectManager loadObjectsAtResourcePath:@"" delegate:self block:^(RKObjectLoader* loader) {
        // Handle naked array in JSON, so we instruct the loader to user the appropriate object mapping
        if ([objectManager.acceptMIMEType isEqualToString:RKMIMETypeJSON]) {
            loader.objectMapping = [objectManager.mappingProvider objectMappingForClass:[Person class]];
        }
    }];
}

For #1 above is clearly documented in the RK docs. See the article example at https://github.com/RestKit/RestKit/wiki/Object-mapping

For #2, I was able to get to the actual values with mappings like below - but that seems like a big hack and there must be a better way to do it.

mapKeyPathsToAttributes:@"person.first_name",@"firstName",
     @"person.last_name",@"lastName",
     @"person.gender",@"gender",
     nil];

For #4, maybe try something like this?

RKManagedObjectMapping* personMapping = [RKManagedObjectMapping mappingForClass:[Person class]];
[personMapping mapKeyPath:@"person.first_name" toAttribute:@"firstName"];
[personMapping mapKeyPath:@"person.last_name" toAttribute:@"lastName"];
[personMapping mapKeyPath:@"person.gender" toAttribute:@"gender"];
[personMapping mapKeyPath:@"person.id" toAttribute:@"personID"];
personMapping.primaryKeyAttribute = @"personID";
[[RKObjectManager sharedManager].mappingProvider setMapping:personMapping forKeyPath:@"persons"];

Greg, that would definitely work. I am still learning the intricacies of KVC, so not sure if that's the correct way ...

Until we come up with a system of automatic mapping, this is probably as good as we'll get, barring some convenience methods later on Sent from my iPhone.

…

On Sep 15, 2011, at 3:50 PM, ***@***.*** wrote: Greg, that would definitely work. I am still learning the intricacies of KVC, so not sure if that's the correct way ... ## Reply to this email directly or view it on GitHub: https://gist.github.com/1215427