@ngdoc overview @name Tutorial: 11 - REST and Custom Services @description In this step, you will improve the way our app fetches data.
The last improvement we will make to our app is to define a custom service that represents a {@link http://en.wikipedia.org/wiki/Representational_State_Transfer RESTful} client. Using this client we can make XHR requests for data in an easier way, without having to deal with the lower-level {@link api/ng.$http $http} API, HTTP methods and URLs. The most important changes are listed below. You can see the full diff on {@link https://github.com/angular/angular-phonecat/compare/step-10...step-11 GitHub}: ## Template The custom service is defined in `app/js/services.js` so we need to include this file in our layout template. Additionally, we also need to load the `angular-resource.js` file, which contains the `ngResource` module and in it the `$resource` service, that we'll soon use: __`app/index.html`.__ 
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## Service __`app/js/services.js`.__ 
angular.module('phonecatServices', ['ngResource']).
    factory('Phone', function($resource){
  return $resource('phones/:phoneId.json', {}, {
    query: {method:'GET', params:{phoneId:'phones'}, isArray:true}
  });
});
We used the module API to register a custom service using a factory function. We passed in the name of the service - 'Phone' - and the factory function. The factory function is similar to a controller's constructor in that both can declare dependencies via function arguments. The Phone service declared a dependency on the `$resource` service. The {@link api/ngResource.$resource `$resource`} service makes it easy to create a {@link http://en.wikipedia.org/wiki/Representational_State_Transfer RESTful} client with just a few lines of code. This client can then be used in our application, instead of the lower-level {@link api/ng.$http $http} service. __`app/js/app.js`.__ 
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angular.module('phonecat', ['phonecatFilters', 'phonecatServices']).
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We need to add 'phonecatServices' to 'phonecat' application's requires array. ## Controller We simplified our sub-controllers (`PhoneListCtrl` and `PhoneDetailCtrl`) by factoring out the lower-level {@link api/ng.$http $http} service, replacing it with a new service called `Phone`. Angular's {@link api/ngResource.$resource `$resource`} service is easier to use than `$http` for interacting with data sources exposed as RESTful resources. It is also easier now to understand what the code in our controllers is doing. __`app/js/controllers.js`.__ 
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function PhoneListCtrl($scope, Phone) {
  $scope.phones = Phone.query();
  $scope.orderProp = 'age';
}

//PhoneListCtrl.$inject = ['$scope', 'Phone'];



function PhoneDetailCtrl($scope, $routeParams, Phone) {
  $scope.phone = Phone.get({phoneId: $routeParams.phoneId}, function(phone) {
    $scope.mainImageUrl = phone.images[0];
  });

  $scope.setImage = function(imageUrl) {
    $scope.mainImageUrl = imageUrl;
  }
}

//PhoneDetailCtrl.$inject = ['$scope', '$routeParams', 'Phone'];
Notice how in `PhoneListCtrl` we replaced: $http.get('phones/phones.json').success(function(data) { $scope.phones = data; }); with: $scope.phones = Phone.query(); This is a simple statement that we want to query for all phones. An important thing to notice in the code above is that we don't pass any callback functions when invoking methods of our Phone service. Although it looks as if the result were returned synchronously, that is not the case at all. What is returned synchronously is a "future" — an object, which will be filled with data when the XHR response returns. Because of the data-binding in Angular, we can use this future and bind it to our template. Then, when the data arrives, the view will automatically update. Sometimes, relying on the future object and data-binding alone is not sufficient to do everything we require, so in these cases, we can add a callback to process the server response. The `PhoneDetailCtrl` controller illustrates this by setting the `mainImageUrl` in a callback. ## Test We have modified our unit tests to verify that our new service is issuing HTTP requests and processing them as expected. The tests also check that our controllers are interacting with the service correctly. The {@link api/ngResource.$resource $resource} service augments the response object with methods for updating and deleting the resource. If we were to use the standard `toEqual` matcher, our tests would fail because the test values would not match the responses exactly. To solve the problem, we use a newly-defined `toEqualData` {@link http://pivotal.github.com/jasmine/jsdoc/symbols/jasmine.Matchers.html Jasmine matcher}. When the `toEqualData` matcher compares two objects, it takes only object properties into account and ignores methods. __`test/unit/controllersSpec.js`:__ 
describe('PhoneCat controllers', function() {

  beforeEach(function(){
    this.addMatchers({
      toEqualData: function(expected) {
        return angular.equals(this.actual, expected);
      }
    });
  });


  beforeEach(module('phonecatServices'));


  describe('PhoneListCtrl', function(){
    var scope, ctrl, $httpBackend;

    beforeEach(inject(function(_$httpBackend_, $rootScope, $controller) {
      $httpBackend = _$httpBackend_;
      $httpBackend.expectGET('phones/phones.json').
          respond([{name: 'Nexus S'}, {name: 'Motorola DROID'}]);

      scope = $rootScope.$new();
      ctrl = $controller(PhoneListCtrl, {$scope: scope});
    }));


    it('should create "phones" model with 2 phones fetched from xhr', function() {
      expect(scope.phones).toEqual([]);
      $httpBackend.flush();

      expect(scope.phones).toEqualData(
          [{name: 'Nexus S'}, {name: 'Motorola DROID'}]);
    });


    it('should set the default value of orderProp model', function() {
      expect(scope.orderProp).toBe('age');
    });
  });


  describe('PhoneDetailCtrl', function(){
    var scope, $httpBackend, ctrl,
        xyzPhoneData = function() {
          return {
            name: 'phone xyz',
                images: ['image/url1.png', 'image/url2.png']
          }
        };


    beforeEach(inject(function(_$httpBackend_, $rootScope, $routeParams, $controller) {
      $httpBackend = _$httpBackend_;
      $httpBackend.expectGET('phones/xyz.json').respond(xyzPhoneData());

      $routeParams.phoneId = 'xyz';
      scope = $rootScope.$new();
      ctrl = $controller(PhoneDetailCtrl, {$scope: scope});
    }));


    it('should fetch phone detail', function() {
      expect(scope.phone).toEqualData({});
      $httpBackend.flush();

      expect(scope.phone).toEqualData(xyzPhoneData());
    });
  });
});
You should now see the following output in the Karma tab: Chrome 22.0: Executed 4 of 4 SUCCESS (0.038 secs / 0.01 secs) # Summary There you have it! We have created a web app in a relatively short amount of time. In the {@link the_end closing notes} we'll cover where to go from here. n128'>128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408