chushihua

node_modules/sockjs-client/lib/info-receiver.js

@@ -0,0 +1,89 @@
+'use strict';
+
+var EventEmitter = require('events').EventEmitter
+  , inherits = require('inherits')
+  , urlUtils = require('./utils/url')
+  , XDR = require('./transport/sender/xdr')
+  , XHRCors = require('./transport/sender/xhr-cors')
+  , XHRLocal = require('./transport/sender/xhr-local')
+  , XHRFake = require('./transport/sender/xhr-fake')
+  , InfoIframe = require('./info-iframe')
+  , InfoAjax = require('./info-ajax')
+  ;
+
+var debug = function() {};
+if (process.env.NODE_ENV !== 'production') {
+  debug = require('debug')('sockjs-client:info-receiver');
+}
+
+function InfoReceiver(baseUrl, urlInfo) {
+  debug(baseUrl);
+  var self = this;
+  EventEmitter.call(this);
+
+  setTimeout(function() {
+    self.doXhr(baseUrl, urlInfo);
+  }, 0);
+}
+
+inherits(InfoReceiver, EventEmitter);
+
+// TODO this is currently ignoring the list of available transports and the whitelist
+
+InfoReceiver._getReceiver = function(baseUrl, url, urlInfo) {
+  // determine method of CORS support (if needed)
+  if (urlInfo.sameOrigin) {
+    return new InfoAjax(url, XHRLocal);
+  }
+  if (XHRCors.enabled) {
+    return new InfoAjax(url, XHRCors);
+  }
+  if (XDR.enabled && urlInfo.sameScheme) {
+    return new InfoAjax(url, XDR);
+  }
+  if (InfoIframe.enabled()) {
+    return new InfoIframe(baseUrl, url);
+  }
+  return new InfoAjax(url, XHRFake);
+};
+
+InfoReceiver.prototype.doXhr = function(baseUrl, urlInfo) {
+  var self = this
+    , url = urlUtils.addPath(baseUrl, '/info')
+    ;
+  debug('doXhr', url);
+
+  this.xo = InfoReceiver._getReceiver(baseUrl, url, urlInfo);
+
+  this.timeoutRef = setTimeout(function() {
+    debug('timeout');
+    self._cleanup(false);
+    self.emit('finish');
+  }, InfoReceiver.timeout);
+
+  this.xo.once('finish', function(info, rtt) {
+    debug('finish', info, rtt);
+    self._cleanup(true);
+    self.emit('finish', info, rtt);
+  });
+};
+
+InfoReceiver.prototype._cleanup = function(wasClean) {
+  debug('_cleanup');
+  clearTimeout(this.timeoutRef);
+  this.timeoutRef = null;
+  if (!wasClean && this.xo) {
+    this.xo.close();
+  }
+  this.xo = null;
+};
+
+InfoReceiver.prototype.close = function() {
+  debug('close');
+  this.removeAllListeners();
+  this._cleanup(false);
+};
+
+InfoReceiver.timeout = 8000;
+
+module.exports = InfoReceiver;