AngularJS and complex JSON returned by django tastypie

Question

I have few resources written on AngularJS that access a Tastypie API. Everything works fine, except for a detail: tastypie always encapsulate the actual result inside a objects attribute on a JSON, example:

/api/v1/reminder/:

{
    meta: {
        limit: 20,
        next: null,
        offset: 0,
        previous: null,
        total_count: 3
    },
    objects: [{
        category: {
            color: "#999999",
            id: 1,
            name: "Groceries",
            resource_uri: "/api/v1/category/1"
        },
        description: "",
        due_date: "2010-10-16",
        id: 1,
        repeat: "weekly",
        resource_uri: "/api/v1/reminder/1",
        value: "-50"
    }, {
        category: {
            color: "#999999",
            id: 1,
            name: "Groceries",
            resource_uri: "/api/v1/category/1"
        },
        description: "",
        due_date: "2010-10-17",
        id: 2,
        repeat: "weekly",
        resource_uri: "/api/v1/reminder/2",
        value: "-50"
    }
}

It was wasy to fix using a callback to the get() call:

Reminder.get().$then(function (result) {
    $scope.reminders  = result.data.objects;
});

But I know result.resource is an actual Reminder instance.

.factory('Reminder', ['$resource', function($resource){
    var Reminder = $resource('/api/v1/reminder/:id', {}, {
        get: {
            method: 'GET',
            isArray: false
        }
    });

    Reminder.prototype.TESTE = function () {console.log('asd');};

    return Reminder;
}])

Now I need to implement behavior on my Reminder class, and I need every element on my meta.objects to be an instance of Reminder:

Reminder.get().$then(function (result) {
    $scope.reminders  = result.data.objects;

    result.resource.TESTE(); // -> outputs 'asd'

    o = result.data.objects[0];
    o.TESTE // -> undefined, obvisously
    i = new Reminder(o);
    i.TESTE() // -> outputs 'asd'
});

So, how to I get angularjs to understand that every object on objects is the actual result so it behaves like a list of instances?

The workaround is to creating a new list iterating on the results creating the instances, but it's not optimal...

Suggestions?

Solution by @rtcherry:

As suggested by rtcherry, I used restangular

Configuring the reading of request data:

.config(['RestangularProvider', function(RestangularProvider) {
    RestangularProvider.setBaseUrl("/api/v1");

    RestangularProvider.setResponseExtractor(function(response, operation, what, url) {
        var newResponse;
        if (operation === "getList") {
            newResponse = response.objects;
            newResponse.metadata = response.meta;
        } else {
            newResponse = response.data;
        }
        return newResponse;
    });
}])

Loading the reminders:

function RemindersCtrl ($scope, $rootScope, Reminder) {
    $scope.reminders = Reminder.getList();
}

Adding my custom method to Reminder (not as clean as ngResource, but doable):

.factory('Reminder', ['Restangular', '$filter', function(Restangular, $filter){
    var Reminder = Restangular.all('reminder');

    var remainingDays = function () {
        //do stuff
    };

    // adding custom behavior
    Restangular.addElementTransformer('reminder', false, function (reminder) {
        reminder.remainingDays = remainingDays;
        return reminder;
    });

    return Reminder;
}])

Solution by @moderndegree:

I used pure ngResource:

var tastypieDataTransformer = function ($http) {
    return $http.defaults.transformResponse.concat([
        function (data, headersGetter) {
            var result = data.objects;
            result.meta = data.meta;
            return result;
        }
    ])
};

...

.factory('Reminder', ['$resource', '$http', function($resource, $http){
    var Reminder = $resource('/api/v1/reminder/:id', {}, {
        query: {
            method: 'GET',
            isArray: true,
            transformResponse: tastypieDataTransformer($http)
        }
    });

    Reminder.prototype.remainingDays = function () {
        // doing stuff
    };

    return Reminder;
}])

My controller:

Transaction.query(filter).$then(function (result) {
    $scope.days = [];
    var transactions = result.resource;
    resource[0].remainingDays(); // it works

});

Answer 1

If you wanted to avoid using an additional library, you should be able to do the following:

$resource('/api/v1/reminder/', {}, {
    query: {
        method: 'GET',
        isArray: true,
        transformResponse: $http.defaults.transformResponse.concat([
            function (data, headersGetter) {
                return data.objects;
            }
        ])
    }
});

This will append your transform to $HttpProvider's default transformer.

Note: Correct me if I'm wrong on this one but I believe this feature requires v1.1.2 or greater.

Answer 2

You may want to try something like restangular.

There is some configuration needed to make that work. An example is here.

Answer 3

I ended up doing the following in order to preserve the meta object directly on the results returned by Reminder.query() (expanding on the answer from @moderndegree).

var Reminder = $resource('/api/v1/reminder/', {}, {
  query: {
    method: 'GET',
    isArray: true,
    transformResponse: $http.defaults.transformResponse.concat([
      function (data, headersGetter) {
          return data.objects;
      }
    ]),
    interceptor: {
      response: function(response) {
        response.resource.meta = response.data.meta;
      }
    }
  }
});

That allows you to get the meta value directly on the returned object:

var reminders = Reminder.query(...);
console.log(reminders.meta); // Returns `meta` as expected.

I think it would also be possible to do something similar inside the callback from Reminder.query since the response object is available there as well.