@emartech/faye-redis-sharded/vendor/faye/javascript/transport/xhr.js

Redis backend engine for Faye with support for sharding

Faye.Transport.XHR = Faye.extend(Faye.Class(Faye.Transport, {
  encode: function(envelopes) {
    var messages = Faye.map(envelopes, function(e) { return e.message });
    return Faye.toJSON(messages);
  },

  request: function(envelopes) {
    var href = this.endpoint.href,
        xhr  = Faye.ENV.ActiveXObject ? new ActiveXObject('Microsoft.XMLHTTP') : new XMLHttpRequest(),
        self = this;

    xhr.open('POST', href, true);
    xhr.setRequestHeader('Content-Type', 'application/json');
    xhr.setRequestHeader('Pragma', 'no-cache');
    xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest');

    var headers = this._client.headers;
    for (var key in headers) {
      if (!headers.hasOwnProperty(key)) continue;
      xhr.setRequestHeader(key, headers[key]);
    }

    var abort = function() { xhr.abort() };
    if (Faye.ENV.onbeforeunload !== undefined) Faye.Event.on(Faye.ENV, 'beforeunload', abort);

    xhr.onreadystatechange = function() {
      if (!xhr || xhr.readyState !== 4) return;

      var parsedMessage = null,
          status        = xhr.status,
          text          = xhr.responseText,
          successful    = (status >= 200 && status < 300) || status === 304 || status === 1223;

      if (Faye.ENV.onbeforeunload !== undefined) Faye.Event.detach(Faye.ENV, 'beforeunload', abort);
      xhr.onreadystatechange = function() {};
      xhr = null;

      if (!successful) return self.handleError(envelopes);

      try {
        parsedMessage = JSON.parse(text);
      } catch (e) {}

      if (parsedMessage)
        self.receive(envelopes, parsedMessage);
      else
        self.handleError(envelopes);
    };

    xhr.send(this.encode(envelopes));
    return xhr;
  }
}), {
  isUsable: function(client, endpoint, callback, context) {
    callback.call(context, Faye.URI.isSameOrigin(endpoint));
  }
});

Faye.Transport.register('long-polling', Faye.Transport.XHR);