websocket.js
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'use strict';
var utils = require('../utils/event')
, urlUtils = require('../utils/url')
, inherits = require('inherits')
, EventEmitter = require('events').EventEmitter
, WebsocketDriver = require('./driver/websocket')
;
var debug = function() {};
if (process.env.NODE_ENV !== 'production') {
debug = require('debug')('sockjs-client:websocket');
}
function WebSocketTransport(transUrl, ignore, options) {
if (!WebSocketTransport.enabled()) {
throw new Error('Transport created when disabled');
}
EventEmitter.call(this);
debug('constructor', transUrl);
var self = this;
var url = urlUtils.addPath(transUrl, '/websocket');
if (url.slice(0, 5) === 'https') {
url = 'wss' + url.slice(5);
} else {
url = 'ws' + url.slice(4);
}
this.url = url;
this.ws = new WebsocketDriver(this.url, [], options);
this.ws.onmessage = function(e) {
debug('message event', e.data);
self.emit('message', e.data);
};
// Firefox has an interesting bug. If a websocket connection is
// created after onunload, it stays alive even when user
// navigates away from the page. In such situation let's lie -
// let's not open the ws connection at all. See:
// https://github.com/sockjs/sockjs-client/issues/28
// https://bugzilla.mozilla.org/show_bug.cgi?id=696085
this.unloadRef = utils.unloadAdd(function() {
debug('unload');
self.ws.close();
});
this.ws.onclose = function(e) {
debug('close event', e.code, e.reason);
self.emit('close', e.code, e.reason);
self._cleanup();
};
this.ws.onerror = function(e) {
debug('error event', e);
self.emit('close', 1006, 'WebSocket connection broken');
self._cleanup();
};
}
inherits(WebSocketTransport, EventEmitter);
WebSocketTransport.prototype.send = function(data) {
var msg = '[' + data + ']';
debug('send', msg);
this.ws.send(msg);
};
WebSocketTransport.prototype.close = function() {
debug('close');
var ws = this.ws;
this._cleanup();
if (ws) {
ws.close();
}
};
WebSocketTransport.prototype._cleanup = function() {
debug('_cleanup');
var ws = this.ws;
if (ws) {
ws.onmessage = ws.onclose = ws.onerror = null;
}
utils.unloadDel(this.unloadRef);
this.unloadRef = this.ws = null;
this.removeAllListeners();
};
WebSocketTransport.enabled = function() {
debug('enabled');
return !!WebsocketDriver;
};
WebSocketTransport.transportName = 'websocket';
// In theory, ws should require 1 round trip. But in chrome, this is
// not very stable over SSL. Most likely a ws connection requires a
// separate SSL connection, in which case 2 round trips are an
// absolute minumum.
WebSocketTransport.roundTrips = 2;
module.exports = WebSocketTransport;