resource.js

'use strict';

/**
 * @ngdoc overview
 * @name ngResource
 * @description
 */

/**
 * @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 $http} service.
 *
 * @param {string} url A parameterized URL template with parameters prefixed by `:` as in
 *   `/user/:username`. If you are using a URL with a port number (e.g. 
 *   `http://example.com:8080/api`), you'll need to escape the colon character before the port
 *   number, like this: `$resource('http://example.com\\:8080/api')`.
 *
 * @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 overriden).
 *
 *   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 following format:
 *
 *       {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 overriden).
 *   - isArray – {boolean=} – If true then the returned object for this action is an array, see
 *     `returns` section.
 *   - `headers` – {Object=} – Optional HTTP headers to send
 *
 * @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.$http} with the specified http method,
 *   destination and parameters. When the data is returned from the server then the object is an
 *   instance of the resource class `save`, `remove` and `delete` actions are available on it as
 *   methods with the `$` 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])`
 *
 *
 * @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', '$parse', function($http, $parse) {
    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 becuase encodeURIComponent is too agressive 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((pctEncodeSpaces ? null : /%20/g), '+');
    }

    function Route(template, defaults) {
      this.template = template = template + '#';
      this.defaults = defaults || {};
      var urlParams = this.urlParams = {};
      forEach(template.split(/\W/), function(param){
        if (param && template.match(new RegExp("[^\\\\]:" + param + "\\W"))) {
          urlParams[param] = true;
        }
      });
      this.template = template.replace(/\\:/g, ':');
    }

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

        params = params || {};
        forEach(this.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"), '$1');
          }
        });
        url = url.replace(/\/?#$/, '');
        var query = [];
        forEach(params, function(value, key){
          if (!self.urlParams[key]) {
            query.push(encodeUriQuery(key) + '=' + encodeUriQuery(value));
          }
        });
        query.sort();
        url = url.replace(/\/*$/, '');
        return url + (query.length ? '?' + query.join('&') : '');
      }
    };


    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.charAt && value.charAt(0) == '@' ? getter(data, value.substr(1)) : value;
        });
        return ids;
      }

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

      forEach(actions, function(action, name) {
        action.method = angular.uppercase(action.method);
        var hasBody = action.method == 'POST' || action.method == 'PUT' || action.method == 'PATCH';
        Resource[name] = function(a1, a2, a3, a4) {
          var params = {};
          var data;
          var success = noop;
          var error = null;
          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 "Expected between 0-4 arguments [params, data, success, error], got " +
              arguments.length + " arguments.";
          }

          var value = this instanceof Resource ? this : (action.isArray ? [] : new Resource(data));
          $http({
            method: action.method,
            url: route.url(extend({}, extractParams(data, action.params || {}), params)),
            data: data,
            headers: extend({}, action.headers || {})
          }).then(function(response) {
              var data = response.data;

              if (data) {
                if (action.isArray) {
                  value.length = 0;
                  forEach(data, function(item) {
                    value.push(new Resource(item));
                  });
                } else {
                  copy(data, value);
                }
              }
              (success||noop)(value, response.headers);
            }, error);

          return value;
        };


        Resource.prototype['$' + name] = function(a1, a2, a3) {
          var params = extractParams(this),
              success = noop,
              error;

          switch(arguments.length) {
          case 3: params = a1; success = a2; error = a3; break;
          case 2:
          case 1:
            if (isFunction(a1)) {
              success = a1;
              error = a2;
            } else {
              params = a1;
              success = a2 || noop;
            }
          case 0: break;
          default:
            throw "Expected between 1-3 arguments [params, success, error], got " +
              arguments.length + " arguments.";
          }
          var data = hasBody ? this : undefined;
          Resource[name].call(this, params, data, success, error);
        };
      });

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

      return Resource;
    }

    return ResourceFactory;
  }]);