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   1  /*
   2  YUI 3.17.2 (build 9c3c78e)
   3  Copyright 2014 Yahoo! Inc. All rights reserved.
   4  Licensed under the BSD License.
   5  http://yuilibrary.com/license/
   6  */
   7  
   8  YUI.add('jsonp', function (Y, NAME) {
   9  
  10  var isFunction = Y.Lang.isFunction;
  11  
  12  /**
  13   * <p>Provides a JSONPRequest class for repeated JSONP calls, and a convenience
  14   * method Y.jsonp(url, callback) to instantiate and send a JSONP request.</p>
  15   *
  16   * <p>Both the constructor as well as the convenience function take two
  17   * parameters: a url string and a callback.</p>
  18   *
  19   * <p>The url provided must include the placeholder string
  20   * &quot;{callback}&quot; which will be replaced by a dynamically
  21   * generated routing function to pass the data to your callback function.
  22   * An example url might look like
  23   * &quot;http://example.com/service?callback={callback}&quot;.</p>
  24   *
  25   * <p>The second parameter can be a callback function that accepts the JSON
  26   * payload as its argument, or a configuration object supporting the keys:</p>
  27   * <ul>
  28   *   <li>on - map of callback subscribers
  29   *      <ul>
  30   *         <li>success - function handler for successful transmission</li>
  31   *         <li>failure - function handler for failed transmission</li>
  32   *         <li>timeout - function handler for transactions that timeout</li>
  33   *      </ul>
  34   *  </li>
  35   *  <li>format  - override function for inserting the proxy name in the url</li>
  36   *  <li>timeout - the number of milliseconds to wait before giving up</li>
  37   *  <li>context - becomes <code>this</code> in the callbacks</li>
  38   *  <li>args    - array of subsequent parameters to pass to the callbacks</li>
  39   *  <li>allowCache - use the same proxy name for all requests? (boolean)</li>
  40   * </ul>
  41   *
  42   * @module jsonp
  43   * @class JSONPRequest
  44   * @constructor
  45   * @param url {String} the url of the JSONP service
  46   * @param callback {Object|Function} the default callback configuration or
  47   *                                   success handler
  48   */
  49  function JSONPRequest() {
  50      this._init.apply(this, arguments);
  51  }
  52  
  53  JSONPRequest.prototype = {
  54      /**
  55       * Set up the success and failure handlers and the regex pattern used
  56       * to insert the temporary callback name in the url.
  57       *
  58       * @method _init
  59       * @param url {String} the url of the JSONP service
  60       * @param callback {Object|Function} Optional success callback or config
  61       *                  object containing success and failure functions and
  62       *                  the url regex.
  63       * @protected
  64       */
  65      _init : function (url, callback) {
  66          this.url = url;
  67  
  68          /**
  69           * Map of the number of requests currently pending responses per
  70           * generated proxy.  Used to ensure the proxy is not flushed if the
  71           * request times out and there is a timeout handler and success
  72           * handler, and used by connections configured to allowCache to make
  73           * sure the proxy isn't deleted until the last response has returned.
  74           *
  75           * @property _requests
  76           * @private
  77           * @type {Object}
  78           */
  79          this._requests = {};
  80  
  81          /**
  82           * Map of the number of timeouts received from the destination url
  83           * by generated proxy.  Used to ensure the proxy is not flushed if the
  84           * request times out and there is a timeout handler and success
  85           * handler, and used by connections configured to allowCache to make
  86           * sure the proxy isn't deleted until the last response has returned.
  87           *
  88           * @property _timeouts
  89           * @private
  90           * @type {Object}
  91           */
  92          this._timeouts = {};
  93  
  94          // Accept a function, an object, or nothing
  95          callback = (isFunction(callback)) ?
  96              { on: { success: callback } } :
  97              callback || {};
  98  
  99          var subs = callback.on || {};
 100  
 101          if (!subs.success) {
 102              subs.success = this._defaultCallback(url, callback);
 103          }
 104  
 105          // Apply defaults and store
 106          this._config = Y.merge({
 107                  context: this,
 108                  args   : [],
 109                  format : this._format,
 110                  allowCache: false
 111              }, callback, { on: subs });
 112      },
 113  
 114      /**
 115       * Override this method to provide logic to default the success callback if
 116       * it is not provided at construction.  This is overridden by jsonp-url to
 117       * parse the callback from the url string.
 118       *
 119       * @method _defaultCallback
 120       * @param url {String} the url passed at construction
 121       * @param config {Object} (optional) the config object passed at
 122       *                        construction
 123       * @return {Function}
 124       */
 125      _defaultCallback: function () {},
 126  
 127      /**
 128       * Issues the JSONP request.
 129       *
 130       * @method send
 131       * @param args* {any} any additional arguments to pass to the url formatter
 132       *              beyond the base url and the proxy function name
 133       * @chainable
 134       */
 135      send : function () {
 136          var self   = this,
 137              args   = Y.Array(arguments, 0, true),
 138              config = self._config,
 139              proxy  = self._proxy || Y.guid(),
 140              url;
 141  
 142          // TODO: support allowCache as time value
 143          if (config.allowCache) {
 144              self._proxy = proxy;
 145          }
 146  
 147          if (self._requests[proxy] === undefined) {
 148              self._requests[proxy] = 0;
 149          }
 150          if (self._timeouts[proxy] === undefined) {
 151              self._timeouts[proxy] = 0;
 152          }
 153          self._requests[proxy]++;
 154  
 155  
 156          args.unshift(self.url, 'YUI.Env.JSONP.' + proxy);
 157          url = config.format.apply(self, args);
 158  
 159          if (!config.on.success) {
 160              return self;
 161          }
 162  
 163          function wrap(fn, isTimeout) {
 164              return (isFunction(fn)) ?
 165                  function (data) {
 166                      var execute = true,
 167                          counter = '_requests';
 168  
 169                      //if (config.allowCache) {
 170                          // A lot of wrangling to make sure timeouts result in
 171                          // fewer success callbacks, but the proxy is properly
 172                          // cleaned up.
 173                          if (isTimeout) {
 174                              ++self._timeouts[proxy];
 175                              --self._requests[proxy];
 176                          } else {
 177                              if (!self._requests[proxy]) {
 178                                  execute = false;
 179                                  counter = '_timeouts';
 180                              }
 181                              --self[counter][proxy];
 182                          }
 183                      //}
 184  
 185                      if (!self._requests[proxy] && !self._timeouts[proxy]) {
 186                          delete YUI.Env.JSONP[proxy];
 187                      }
 188  
 189                      if (execute) {
 190                          fn.apply(config.context, [data].concat(config.args));
 191                      }
 192                  } :
 193                  null;
 194          }
 195  
 196          // Temporary un-sandboxed function alias
 197          // TODO: queuing
 198          YUI.Env.JSONP[proxy] = wrap(config.on.success);
 199  
 200          // Y.Get transactions block each other by design, but can easily
 201          //  be made non-blocking by just calling execute() on the transaction.
 202          // https://github.com/yui/yui3/pull/393#issuecomment-11961608
 203          Y.Get.js(url, {
 204              onFailure : wrap(config.on.failure),
 205              onTimeout : wrap(config.on.timeout, true),
 206              timeout   : config.timeout,
 207              charset   : config.charset,
 208              attributes: config.attributes,
 209              async     : config.async
 210          }).execute();
 211  
 212          return self;
 213      },
 214  
 215      /**
 216       * Default url formatter.  Looks for callback= in the url and appends it
 217       * if not present.  The supplied proxy name will be assigned to the query
 218       * param.  Override this method by passing a function as the
 219       * &quot;format&quot; property in the config object to the constructor.
 220       *
 221       * @method _format
 222       * @param url { String } the original url
 223       * @param proxy {String} the function name that will be used as a proxy to
 224       *      the configured callback methods.
 225       * @param args* {any} additional args passed to send()
 226       * @return {String} fully qualified JSONP url
 227       * @protected
 228       */
 229      _format: function (url, proxy) {
 230          return url.replace(/\{callback\}/, proxy);
 231      }
 232  };
 233  
 234  Y.JSONPRequest = JSONPRequest;
 235  
 236  /**
 237   *
 238   * @method jsonp
 239   * @param url {String} the url of the JSONP service with the {callback}
 240   *          placeholder where the callback function name typically goes.
 241   * @param c {Function|Object} Callback function accepting the JSON payload
 242   *          as its argument, or a configuration object (see above).
 243   * @param args* {any} additional arguments to pass to send()
 244   * @return {JSONPRequest}
 245   * @static
 246   * @for YUI
 247   */
 248  Y.jsonp = function (url,c) {
 249      var req = new Y.JSONPRequest(url,c);
 250      return req.send.apply(req, Y.Array(arguments, 2, true));
 251  };
 252  
 253  if (!YUI.Env.JSONP) {
 254      YUI.Env.JSONP = {};
 255  }
 256  
 257  
 258  }, '3.17.2', {"requires": ["get", "oop"]});