resource.js

'use strict';

var $resourceMinErr = angular.$$minErr('$resource');

/**
 * @ngdoc overview
 * @name ngResource
 * @description
 *
 * # ngResource
 *
 * `ngResource` is the name of the optional Angular module that adds support for interacting with
 * [RESTful](http://en.wikipedia.org/wiki/Representational_State_Transfer) server-side data sources.
 * `ngReource` provides the {@link ngResource.$resource `$resource`} serivce.
 *
 * {@installModule resource}
 *
 * See {@link ngResource.$resource `$resource`} for usage.
 */

/**
 * @ngdoc object
 * @name ngResource.$resource
 * @requires $http
 *
 * @description
 * A factory which creates a resource object that lets you interact with
 * [RESTful](http://en.wikipedia.org/wiki/Representational_State_Transfer) server-side data sources.
 *
 * The returned resource object has action methods which provide high-level behaviors without
 * the need to interact with the low level {@link ng.$http $http} service.
 *
 * Requires the {@link ngResource `ngResource`} module to be installed.
 *
 * @param {string} url A parametrized URL template with parameters prefixed by `:` as in
 *   `/user/:username`. If you are using a URL with a port number (e.g.
 *   `http://example.com:8080/api`), it will be respected.
 *
 *   If you are using a url with a suffix, just add the suffix, like this:
 *   `$resource('http://example.com/resource.json')` or `$resource('http://example.com/:id.json')`
 *   or even `$resource('http://example.com/resource/:resource_id.:format')`
 *   If the parameter before the suffix is empty, :resource_id in this case, then the `/.` will be
 *   collapsed down to a single `.`.  If you need this sequence to appear and not collapse then you
 *   can escape it with `/\.`.
 *
 * @param {Object=} paramDefaults Default values for `url` parameters. These can be overridden in
 *   `actions` methods. If any of the parameter value is a function, it will be executed every time
 *   when a param value needs to be obtained for a request (unless the param was overridden).
 *
 *   Each key value in the parameter object is first bound to url template if present and then any
 *   excess keys are appended to the url search query after the `?`.
 *
 *   Given a template `/path/:verb` and parameter `{verb:'greet', salutation:'Hello'}` results in
 *   URL `/path/greet?salutation=Hello`.
 *
 *   If the parameter value is prefixed with `@` then the value of that parameter is extracted from
 *   the data object (useful for non-GET operations).
 *
 * @param {Object.<Object>=} actions Hash with declaration of custom action that should extend the
 *   default set of resource actions. The declaration should be created in the format of {@link
 *   ng.$http#Parameters $http.config}:
 *
 *       {action1: {method:?, params:?, isArray:?, headers:?, ...},
 *        action2: {method:?, params:?, isArray:?, headers:?, ...},
 *        ...}
 *
 *   Where:
 *
 *   - **`action`** – {string} – The name of action. This name becomes the name of the method on your
 *     resource object.
 *   - **`method`** – {string} – HTTP request method. Valid methods are: `GET`, `POST`, `PUT`, `DELETE`,
 *     and `JSONP`.
 *   - **`params`** – {Object=} – Optional set of pre-bound parameters for this action. If any of the
 *     parameter value is a function, it will be executed every time when a param value needs to be
 *     obtained for a request (unless the param was overridden).
 *   - **`url`** – {string} – action specific `url` override. The url templating is supported just like
 *     for the resource-level urls.
 *   - **`isArray`** – {boolean=} – If true then the returned object for this action is an array, see
 *     `returns` section.
 *   - **`transformRequest`** – `{function(data, headersGetter)|Array.<function(data, headersGetter)>}` –
 *     transform function or an array of such functions. The transform function takes the http
 *     request body and headers and returns its transformed (typically serialized) version.
 *   - **`transformResponse`** – `{function(data, headersGetter)|Array.<function(data, headersGetter)>}` –
 *     transform function or an array of such functions. The transform function takes the http
 *     response body and headers and returns its transformed (typically deserialized) version.
 *   - **`cache`** – `{boolean|Cache}` – If true, a default $http cache will be used to cache the
 *     GET request, otherwise if a cache instance built with
 *     {@link ng.$cacheFactory $cacheFactory}, this cache will be used for
 *     caching.
 *   - **`timeout`** – `{number|Promise}` – timeout in milliseconds, or {@link ng.$q promise} that
 *     should abort the request when resolved.
 *   - **`withCredentials`** - `{boolean}` - whether to to set the `withCredentials` flag on the
 *     XHR object. See {@link https://developer.mozilla.org/en/http_access_control#section_5
 *     requests with credentials} for more information.
 *   - **`responseType`** - `{string}` - see {@link
 *     https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest#responseType requestType}.
 *   - **`interceptor`** - `{Object=}` - The interceptor object has two optional methods -
 *     `response` and `responseError`. Both `response` and `responseError` interceptors get called
 *     with `http response` object. See {@link ng.$http $http interceptors}.
 *
 * @returns {Object} A resource "class" object with methods for the default set of resource actions
 *   optionally extended with custom `actions`. The default set contains these actions:
 *
 *       { 'get':    {method:'GET'},
 *         'save':   {method:'POST'},
 *         'query':  {method:'GET', isArray:true},
 *         'remove': {method:'DELETE'},
 *         'delete': {method:'DELETE'} };
 *
 *   Calling these methods invoke an {@link ng.$http} with the specified http method,
 *   destination and parameters. When the data is returned from the server then the object is an
 *   instance of the resource class. The actions `save`, `remove` and `delete` are available on it
 *   as  methods with the `$` prefix. This allows you to easily perform CRUD operations (create,
 *   read, update, delete) on server-side data like this:
 *   <pre>
        var User = $resource('/user/:userId', {userId:'@id'});
        var user = User.get({userId:123}, function() {
          user.abc = true;
          user.$save();
        });
     </pre>
 *
 *   It is important to realize that invoking a $resource object method immediately returns an
 *   empty reference (object or array depending on `isArray`). Once the data is returned from the
 *   server the existing reference is populated with the actual data. This is a useful trick since
 *   usually the resource is assigned to a model which is then rendered by the view. Having an empty
 *   object results in no rendering, once the data arrives from the server then the object is
 *   populated with the data and the view automatically re-renders itself showing the new data. This
 *   means that in most case one never has to write a callback function for the action methods.
 *
 *   The action methods on the class object or instance object can be invoked with the following
 *   parameters:
 *
 *   - HTTP GET "class" actions: `Resource.action([parameters], [success], [error])`
 *   - non-GET "class" actions: `Resource.action([parameters], postData, [success], [error])`
 *   - non-GET instance actions:  `instance.$action([parameters], [success], [error])`
 *
 *   Success callback is called with (value, responseHeaders) arguments. Error callback is called
 *   with (httpResponse) argument.
 *
 *   Class actions return empty instance (with additional properties below).
 *   Instance actions return promise of the action.
 *
 *   The Resource instances and collection have these additional properties:
 *
 *   - `$promise`: the {@link ng.$q promise} of the original server interaction that created this
 *     instance or collection.
 *
 *     On success, the promise is resolved with the same resource instance or collection object,
 *     updated with data from server. This makes it easy to use in
 *     {@link ngRoute.$routeProvider resolve section of $routeProvider.when()} to defer view rendering
 *     until the resource(s) are loaded.
 *
 *     On failure, the promise is resolved with the {@link ng.$http http response} object,
 *     without the `resource` property.
 *
 *   - `$resolved`: `true` after first server interaction is completed (either with success or rejection),
 *     `false` before that. Knowing if the Resource has been resolved is useful in data-binding.
 *
 * @example
 *
 * # Credit card resource
 *
 * <pre>
     // Define CreditCard class
     var CreditCard = $resource('/user/:userId/card/:cardId',
      {userId:123, cardId:'@id'}, {
       charge: {method:'POST', params:{charge:true}}
      });

     // We can retrieve a collection from the server
     var cards = CreditCard.query(function() {
       // GET: /user/123/card
       // server returns: [ {id:456, number:'1234', name:'Smith'} ];

       var card = cards[0];
       // each item is an instance of CreditCard
       expect(card instanceof CreditCard).toEqual(true);
       card.name = "J. Smith";
       // non GET methods are mapped onto the instances
       card.$save();
       // POST: /user/123/card/456 {id:456, number:'1234', name:'J. Smith'}
       // server returns: {id:456, number:'1234', name: 'J. Smith'};

       // our custom method is mapped as well.
       card.$charge({amount:9.99});
       // POST: /user/123/card/456?amount=9.99&charge=true {id:456, number:'1234', name:'J. Smith'}
     });

     // we can create an instance as well
     var newCard = new CreditCard({number:'0123'});
     newCard.name = "Mike Smith";
     newCard.$save();
     // POST: /user/123/card {number:'0123', name:'Mike Smith'}
     // server returns: {id:789, number:'01234', name: 'Mike Smith'};
     expect(newCard.id).toEqual(789);
 * </pre>
 *
 * The object returned from this function execution is a resource "class" which has "static" method
 * for each action in the definition.
 *
 * Calling these methods invoke `$http` on the `url` template with the given `method`, `params` and `headers`.
 * When the data is returned from the server then the object is an instance of the resource type and
 * all of the non-GET methods are available with `$` prefix. This allows you to easily support CRUD
 * operations (create, read, update, delete) on server-side data.

   <pre>
     var User = $resource('/user/:userId', {userId:'@id'});
     var user = User.get({userId:123}, function() {
       user.abc = true;
       user.$save();
     });
   </pre>
 *
 * It's worth noting that the success callback for `get`, `query` and other method gets passed
 * in the response that came from the server as well as $http header getter function, so one
 * could rewrite the above example and get access to http headers as:
 *
   <pre>
     var User = $resource('/user/:userId', {userId:'@id'});
     User.get({userId:123}, function(u, getResponseHeaders){
       u.abc = true;
       u.$save(function(u, putResponseHeaders) {
         //u => saved user object
         //putResponseHeaders => $http header getter
       });
     });
   </pre>

 * # Buzz client

   Let's look at what a buzz client created with the `$resource` service looks like:
    <doc:example>
      <doc:source jsfiddle="false">
       <script>
         function BuzzController($resource) {
           this.userId = 'googlebuzz';
           this.Activity = $resource(
             'https://www.googleapis.com/buzz/v1/activities/:userId/:visibility/:activityId/:comments',
             {alt:'json', callback:'JSON_CALLBACK'},
             {get:{method:'JSONP', params:{visibility:'@self'}}, replies: {method:'JSONP', params:{visibility:'@self', comments:'@comments'}}}
           );
         }

         BuzzController.prototype = {
           fetch: function() {
             this.activities = this.Activity.get({userId:this.userId});
           },
           expandReplies: function(activity) {
             activity.replies = this.Activity.replies({userId:this.userId, activityId:activity.id});
           }
         };
         BuzzController.$inject = ['$resource'];
       </script>

       <div ng-controller="BuzzController">
         <input ng-model="userId"/>
         <button ng-click="fetch()">fetch</button>
         <hr/>
         <div ng-repeat="item in activities.data.items">
           <h1 style="font-size: 15px;">
             <img src="{{item.actor.thumbnailUrl}}" style="max-height:30px;max-width:30px;"/>
             <a href="{{item.actor.profileUrl}}">{{item.actor.name}}</a>
             <a href ng-click="expandReplies(item)" style="float: right;">Expand replies: {{item.links.replies[0].count}}</a>
           </h1>
           {{item.object.content | html}}
           <div ng-repeat="reply in item.replies.data.items" style="margin-left: 20px;">
             <img src="{{reply.actor.thumbnailUrl}}" style="max-height:30px;max-width:30px;"/>
             <a href="{{reply.actor.profileUrl}}">{{reply.actor.name}}</a>: {{reply.content | html}}
           </div>
         </div>
       </div>
      </doc:source>
      <doc:scenario>
      </doc:scenario>
    </doc:example>
 */
angular.module('ngResource', ['ng']).
  factory('$resource', ['$http', '$parse', '$q', function($http, $parse, $q) {
    var DEFAULT_ACTIONS = {
      'get':    {method:'GET'},
      'save':   {method:'POST'},
      'query':  {method:'GET', isArray:true},
      'remove': {method:'DELETE'},
      'delete': {method:'DELETE'}
    };
    var noop = angular.noop,
        forEach = angular.forEach,
        extend = angular.extend,
        copy = angular.copy,
        isFunction = angular.isFunction,
        getter = function(obj, path) {
          return $parse(path)(obj);
        };

    /**
     * We need our custom method because encodeURIComponent is too aggressive and doesn't follow
     * http://www.ietf.org/rfc/rfc3986.txt with regards to the character set (pchar) allowed in path
     * segments:
     *    segment       = *pchar
     *    pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"
     *    pct-encoded   = "%" HEXDIG HEXDIG
     *    unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
     *    sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
     *                     / "*" / "+" / "," / ";" / "="
     */
    function encodeUriSegment(val) {
      return encodeUriQuery(val, true).
        replace(/%26/gi, '&').
        replace(/%3D/gi, '=').
        replace(/%2B/gi, '+');
    }


    /**
     * This method is intended for encoding *key* or *value* parts of query component. We need a custom
     * method because encodeURIComponent is too aggressive and encodes stuff that doesn't have to be
     * encoded per http://tools.ietf.org/html/rfc3986:
     *    query       = *( pchar / "/" / "?" )
     *    pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"
     *    unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
     *    pct-encoded   = "%" HEXDIG HEXDIG
     *    sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
     *                     / "*" / "+" / "," / ";" / "="
     */
    function encodeUriQuery(val, pctEncodeSpaces) {
      return encodeURIComponent(val).
        replace(/%40/gi, '@').
        replace(/%3A/gi, ':').
        replace(/%24/g, '$').
        replace(/%2C/gi, ',').
        replace(/%20/g, (pctEncodeSpaces ? '%20' : '+'));
    }

    function Route(template, defaults) {
      this.template = template;
      this.defaults = defaults || {};
      this.urlParams = {};
    }

    Route.prototype = {
      setUrlParams: function(config, params, actionUrl) {
        var self = this,
            url = actionUrl || self.template,
            val,
            encodedVal;

        var urlParams = self.urlParams = {};
        forEach(url.split(/\W/), function(param){
          if (!(new RegExp("^\\d+$").test(param)) && param && (new RegExp("(^|[^\\\\]):" + param + "(\\W|$)").test(url))) {
              urlParams[param] = true;
          }
        });
        url = url.replace(/\\:/g, ':');

        params = params || {};
        forEach(self.urlParams, function(_, urlParam){
          val = params.hasOwnProperty(urlParam) ? params[urlParam] : self.defaults[urlParam];
          if (angular.isDefined(val) && val !== null) {
            encodedVal = encodeUriSegment(val);
            url = url.replace(new RegExp(":" + urlParam + "(\\W|$)", "g"), encodedVal + "$1");
          } else {
            url = url.replace(new RegExp("(\/?):" + urlParam + "(\\W|$)", "g"), function(match,
                leadingSlashes, tail) {
              if (tail.charAt(0) == '/') {
                return tail;
              } else {
                return leadingSlashes + tail;
              }
            });
          }
        });

        // strip trailing slashes and set the url
        url = url.replace(/\/+$/, '');
        // then replace collapse `/.` if found in the last URL path segment before the query
        // E.g. `http://url.com/id./format?q=x` becomes `http://url.com/id.format?q=x`
        url = url.replace(/\/\.(?=\w+($|\?))/, '.');
        // replace escaped `/\.` with `/.`
        config.url = url.replace(/\/\\\./, '/.');


        // set params - delegate param encoding to $http
        forEach(params, function(value, key){
          if (!self.urlParams[key]) {
            config.params = config.params || {};
            config.params[key] = value;
          }
        });
      }
    };


    function ResourceFactory(url, paramDefaults, actions) {
      var route = new Route(url);

      actions = extend({}, DEFAULT_ACTIONS, actions);

      function extractParams(data, actionParams){
        var ids = {};
        actionParams = extend({}, paramDefaults, actionParams);
        forEach(actionParams, function(value, key){
          if (isFunction(value)) { value = value(); }
          ids[key] = value && value.charAt && value.charAt(0) == '@' ? getter(data, value.substr(1)) : value;
        });
        return ids;
      }

      function defaultResponseInterceptor(response) {
        return response.resource;
      }

      function Resource(value){
        copy(value || {}, this);
      }

      forEach(actions, function(action, name) {
        var hasBody = /^(POST|PUT|PATCH)$/i.test(action.method);

        Resource[name] = function(a1, a2, a3, a4) {
          var params = {}, data, success, error;

          switch(arguments.length) {
          case 4:
            error = a4;
            success = a3;
            //fallthrough
          case 3:
          case 2:
            if (isFunction(a2)) {
              if (isFunction(a1)) {
                success = a1;
                error = a2;
                break;
              }

              success = a2;
              error = a3;
              //fallthrough
            } else {
              params = a1;
              data = a2;
              success = a3;
              break;
            }
          case 1:
            if (isFunction(a1)) success = a1;
            else if (hasBody) data = a1;
            else params = a1;
            break;
          case 0: break;
          default:
            throw $resourceMinErr('badargs',
              "Expected up to 4 arguments [params, data, success, error], got {0} arguments", arguments.length);
          }

          var isInstanceCall = data instanceof Resource;
          var value = isInstanceCall ? data : (action.isArray ? [] : new Resource(data));
          var httpConfig = {};
          var responseInterceptor = action.interceptor && action.interceptor.response || defaultResponseInterceptor;
          var responseErrorInterceptor = action.interceptor && action.interceptor.responseError || undefined;

          forEach(action, function(value, key) {
            if (key != 'params' && key != 'isArray' && key != 'interceptor') {
              httpConfig[key] = copy(value);
            }
          });

          httpConfig.data = data;
          route.setUrlParams(httpConfig, extend({}, extractParams(data, action.params || {}), params), action.url);

          var promise = $http(httpConfig).then(function(response) {
            var data = response.data,
                promise = value.$promise;

            if (data) {
              if ( angular.isArray(data) != !!action.isArray ) {
                throw $resourceMinErr('badcfg', 'Error in resource configuration. Expected response' +
                  ' to contain an {0} but got an {1}',
                  action.isArray?'array':'object', angular.isArray(data)?'array':'object');
              }
              if (action.isArray) {
                value.length = 0;
                forEach(data, function(item) {
                  value.push(new Resource(item));
                });
              } else {
                copy(data, value);
                value.$promise = promise;
              }
            }

            value.$resolved = true;

            response.resource = value;

            response = (responseInterceptor)(response);

            (success||noop)(response, response.headers);

            return response;
          }, function(response) {
            value.$resolved = true;

            (error||noop)(response);

            return $q.reject(response);
          }).then(responseInterceptor, responseErrorInterceptor);


          if (!isInstanceCall) {
            // we are creating instance / collection
            // - set the initial promise
            // - return the instance / collection
            value.$promise = promise;
            value.$resolved = false;

            return value;
          }

          // instance call
          return promise;
        };


        Resource.prototype['$' + name] = function(params, success, error) {
          if (isFunction(params)) {
            error = success; success = params; params = {};
          }
          var result = Resource[name](params, this, success, error);
          return result.$promise || result;
        };
      });

      Resource.bind = function(additionalParamDefaults){
        return ResourceFactory(url, extend({}, paramDefaults, additionalParamDefaults), actions);
      };

      return Resource;
    }

    return ResourceFactory;
  }]);