twitst4tz

twitter statistics web application
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polling-xhr.js (1239B)

      1 
      2 /**
      3  * Module dependencies.
      4  */
      5 
      6 var Polling = require('./polling');
      7 var util = require('util');
      8 
      9 /**
     10  * Module exports.
     11  */
     12 
     13 module.exports = XHR;
     14 
     15 /**
     16  * Ajax polling transport.
     17  *
     18  * @api public
     19  */
     20 
     21 function XHR (req) {
     22   Polling.call(this, req);
     23 }
     24 
     25 /**
     26  * Inherits from Polling.
     27  */
     28 
     29 util.inherits(XHR, Polling);
     30 
     31 /**
     32  * Overrides `onRequest` to handle `OPTIONS`..
     33  *
     34  * @param {http.IncomingMessage}
     35  * @api private
     36  */
     37 
     38 XHR.prototype.onRequest = function (req) {
     39   if ('OPTIONS' === req.method) {
     40     var res = req.res;
     41     var headers = this.headers(req);
     42     headers['Access-Control-Allow-Headers'] = 'Content-Type';
     43     res.writeHead(200, headers);
     44     res.end();
     45   } else {
     46     Polling.prototype.onRequest.call(this, req);
     47   }
     48 };
     49 
     50 /**
     51  * Returns headers for a response.
     52  *
     53  * @param {http.IncomingMessage} request
     54  * @param {Object} extra headers
     55  * @api private
     56  */
     57 
     58 XHR.prototype.headers = function (req, headers) {
     59   headers = headers || {};
     60 
     61   if (req.headers.origin) {
     62     headers['Access-Control-Allow-Credentials'] = 'true';
     63     headers['Access-Control-Allow-Origin'] = req.headers.origin;
     64   } else {
     65     headers['Access-Control-Allow-Origin'] = '*';
     66   }
     67 
     68   return Polling.prototype.headers.call(this, req, headers);
     69 };