twitst4tz

polling-jsonp.js (4896B)

---

 /**
  * Module requirements.
  */
 
 var Polling = require('./polling');
 var inherit = require('component-inherit');
 var globalThis = require('../globalThis');
 
 /**
  * Module exports.
  */
 
 module.exports = JSONPPolling;
 
 /**
  * Cached regular expressions.
  */
 
 var rNewline = /\n/g;
 var rEscapedNewline = /\\n/g;
 
 /**
  * Global JSONP callbacks.
  */
 
 var callbacks;
 
 /**
  * Noop.
  */
 
 function empty () { }
 
 /**
  * JSONP Polling constructor.
  *
  * @param {Object} opts.
  * @api public
  */
 
 function JSONPPolling (opts) {
   Polling.call(this, opts);
 
   this.query = this.query || {};
 
   // define global callbacks array if not present
   // we do this here (lazily) to avoid unneeded global pollution
   if (!callbacks) {
     // we need to consider multiple engines in the same page
     callbacks = globalThis.___eio = (globalThis.___eio || []);
   }
 
   // callback identifier
   this.index = callbacks.length;
 
   // add callback to jsonp global
   var self = this;
   callbacks.push(function (msg) {
     self.onData(msg);
   });
 
   // append to query string
   this.query.j = this.index;
 
   // prevent spurious errors from being emitted when the window is unloaded
   if (typeof addEventListener === 'function') {
     addEventListener('beforeunload', function () {
       if (self.script) self.script.onerror = empty;
     }, false);
   }
 }
 
 /**
  * Inherits from Polling.
  */
 
 inherit(JSONPPolling, Polling);
 
 /*
  * JSONP only supports binary as base64 encoded strings
  */
 
 JSONPPolling.prototype.supportsBinary = false;
 
 /**
  * Closes the socket.
  *
  * @api private
  */
 
 JSONPPolling.prototype.doClose = function () {
   if (this.script) {
     this.script.parentNode.removeChild(this.script);
     this.script = null;
   }
 
   if (this.form) {
     this.form.parentNode.removeChild(this.form);
     this.form = null;
     this.iframe = null;
   }
 
   Polling.prototype.doClose.call(this);
 };
 
 /**
  * Starts a poll cycle.
  *
  * @api private
  */
 
 JSONPPolling.prototype.doPoll = function () {
   var self = this;
   var script = document.createElement('script');
 
   if (this.script) {
     this.script.parentNode.removeChild(this.script);
     this.script = null;
   }
 
   script.async = true;
   script.src = this.uri();
   script.onerror = function (e) {
     self.onError('jsonp poll error', e);
   };
 
   var insertAt = document.getElementsByTagName('script')[0];
   if (insertAt) {
     insertAt.parentNode.insertBefore(script, insertAt);
   } else {
     (document.head || document.body).appendChild(script);
   }
   this.script = script;
 
   var isUAgecko = 'undefined' !== typeof navigator && /gecko/i.test(navigator.userAgent);
 
   if (isUAgecko) {
     setTimeout(function () {
       var iframe = document.createElement('iframe');
       document.body.appendChild(iframe);
       document.body.removeChild(iframe);
     }, 100);
   }
 };
 
 /**
  * Writes with a hidden iframe.
  *
  * @param {String} data to send
  * @param {Function} called upon flush.
  * @api private
  */
 
 JSONPPolling.prototype.doWrite = function (data, fn) {
   var self = this;
 
   if (!this.form) {
     var form = document.createElement('form');
     var area = document.createElement('textarea');
     var id = this.iframeId = 'eio_iframe_' + this.index;
     var iframe;
 
     form.className = 'socketio';
     form.style.position = 'absolute';
     form.style.top = '-1000px';
     form.style.left = '-1000px';
     form.target = id;
     form.method = 'POST';
     form.setAttribute('accept-charset', 'utf-8');
     area.name = 'd';
     form.appendChild(area);
     document.body.appendChild(form);
 
     this.form = form;
     this.area = area;
   }
 
   this.form.action = this.uri();
 
   function complete () {
     initIframe();
     fn();
   }
 
   function initIframe () {
     if (self.iframe) {
       try {
         self.form.removeChild(self.iframe);
       } catch (e) {
         self.onError('jsonp polling iframe removal error', e);
       }
     }
 
     try {
       // ie6 dynamic iframes with target="" support (thanks Chris Lambacher)
       var html = '<iframe src="javascript:0" name="' + self.iframeId + '">';
       iframe = document.createElement(html);
     } catch (e) {
       iframe = document.createElement('iframe');
       iframe.name = self.iframeId;
       iframe.src = 'javascript:0';
     }
 
     iframe.id = self.iframeId;
 
     self.form.appendChild(iframe);
     self.iframe = iframe;
   }
 
   initIframe();
 
   // escape \n to prevent it from being converted into \r\n by some UAs
   // double escaping is required for escaped new lines because unescaping of new lines can be done safely on server-side
   data = data.replace(rEscapedNewline, '\\\n');
   this.area.value = data.replace(rNewline, '\\n');
 
   try {
     this.form.submit();
   } catch (e) {}
 
   if (this.iframe.attachEvent) {
     this.iframe.onreadystatechange = function () {
       if (self.iframe.readyState === 'complete') {
         complete();
       }
     };
   } else {
     this.iframe.onload = complete;
   }
 };