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JavaScript

/**
* Module dependencies.
*/
var Transport = require('../transport');
var parser = require('engine.io-parser');
var parseqs = require('parseqs');
var inherit = require('component-inherit');
var yeast = require('yeast');
var debug = require('debug')('engine.io-client:websocket');
var BrowserWebSocket, NodeWebSocket;
if (typeof WebSocket !== 'undefined') {
BrowserWebSocket = WebSocket;
} else if (typeof self !== 'undefined') {
BrowserWebSocket = self.WebSocket || self.MozWebSocket;
}
if (typeof window === 'undefined') {
try {
NodeWebSocket = require('ws');
} catch (e) { }
}
/**
* Get either the `WebSocket` or `MozWebSocket` globals
* in the browser or try to resolve WebSocket-compatible
* interface exposed by `ws` for Node-like environment.
*/
var WebSocketImpl = BrowserWebSocket || NodeWebSocket;
/**
* Module exports.
*/
module.exports = WS;
/**
* WebSocket transport constructor.
*
* @api {Object} connection options
* @api public
*/
function WS (opts) {
var forceBase64 = (opts && opts.forceBase64);
if (forceBase64) {
this.supportsBinary = false;
}
this.perMessageDeflate = opts.perMessageDeflate;
this.usingBrowserWebSocket = BrowserWebSocket && !opts.forceNode;
this.protocols = opts.protocols;
if (!this.usingBrowserWebSocket) {
WebSocketImpl = NodeWebSocket;
}
Transport.call(this, opts);
}
/**
* Inherits from Transport.
*/
inherit(WS, Transport);
/**
* Transport name.
*
* @api public
*/
WS.prototype.name = 'websocket';
/*
* WebSockets support binary
*/
WS.prototype.supportsBinary = true;
/**
* Opens socket.
*
* @api private
*/
WS.prototype.doOpen = function () {
if (!this.check()) {
// let probe timeout
return;
}
var uri = this.uri();
var protocols = this.protocols;
var opts = {
agent: this.agent,
perMessageDeflate: this.perMessageDeflate
};
// SSL options for Node.js client
opts.pfx = this.pfx;
opts.key = this.key;
opts.passphrase = this.passphrase;
opts.cert = this.cert;
opts.ca = this.ca;
opts.ciphers = this.ciphers;
opts.rejectUnauthorized = this.rejectUnauthorized;
if (this.extraHeaders) {
opts.headers = this.extraHeaders;
}
if (this.localAddress) {
opts.localAddress = this.localAddress;
}
try {
this.ws =
this.usingBrowserWebSocket && !this.isReactNative
? protocols
? new WebSocketImpl(uri, protocols)
: new WebSocketImpl(uri)
: new WebSocketImpl(uri, protocols, opts);
} catch (err) {
return this.emit('error', err);
}
if (this.ws.binaryType === undefined) {
this.supportsBinary = false;
}
if (this.ws.supports && this.ws.supports.binary) {
this.supportsBinary = true;
this.ws.binaryType = 'nodebuffer';
} else {
this.ws.binaryType = 'arraybuffer';
}
this.addEventListeners();
};
/**
* Adds event listeners to the socket
*
* @api private
*/
WS.prototype.addEventListeners = function () {
var self = this;
this.ws.onopen = function () {
self.onOpen();
};
this.ws.onclose = function () {
self.onClose();
};
this.ws.onmessage = function (ev) {
self.onData(ev.data);
};
this.ws.onerror = function (e) {
self.onError('websocket error', e);
};
};
/**
* Writes data to socket.
*
* @param {Array} array of packets.
* @api private
*/
WS.prototype.write = function (packets) {
var self = this;
this.writable = false;
// encodePacket efficient as it uses WS framing
// no need for encodePayload
var total = packets.length;
for (var i = 0, l = total; i < l; i++) {
(function (packet) {
parser.encodePacket(packet, self.supportsBinary, function (data) {
if (!self.usingBrowserWebSocket) {
// always create a new object (GH-437)
var opts = {};
if (packet.options) {
opts.compress = packet.options.compress;
}
if (self.perMessageDeflate) {
var len = 'string' === typeof data ? Buffer.byteLength(data) : data.length;
if (len < self.perMessageDeflate.threshold) {
opts.compress = false;
}
}
}
// Sometimes the websocket has already been closed but the browser didn't
// have a chance of informing us about it yet, in that case send will
// throw an error
try {
if (self.usingBrowserWebSocket) {
// TypeError is thrown when passing the second argument on Safari
self.ws.send(data);
} else {
self.ws.send(data, opts);
}
} catch (e) {
debug('websocket closed before onclose event');
}
--total || done();
});
})(packets[i]);
}
function done () {
self.emit('flush');
// fake drain
// defer to next tick to allow Socket to clear writeBuffer
setTimeout(function () {
self.writable = true;
self.emit('drain');
}, 0);
}
};
/**
* Called upon close
*
* @api private
*/
WS.prototype.onClose = function () {
Transport.prototype.onClose.call(this);
};
/**
* Closes socket.
*
* @api private
*/
WS.prototype.doClose = function () {
if (typeof this.ws !== 'undefined') {
this.ws.close();
}
};
/**
* Generates uri for connection.
*
* @api private
*/
WS.prototype.uri = function () {
var query = this.query || {};
var schema = this.secure ? 'wss' : 'ws';
var port = '';
// avoid port if default for schema
if (this.port && (('wss' === schema && Number(this.port) !== 443) ||
('ws' === schema && Number(this.port) !== 80))) {
port = ':' + this.port;
}
// append timestamp to URI
if (this.timestampRequests) {
query[this.timestampParam] = yeast();
}
// communicate binary support capabilities
if (!this.supportsBinary) {
query.b64 = 1;
}
query = parseqs.encode(query);
// prepend ? to query
if (query.length) {
query = '?' + query;
}
var ipv6 = this.hostname.indexOf(':') !== -1;
return schema + '://' + (ipv6 ? '[' + this.hostname + ']' : this.hostname) + port + this.path + query;
};
/**
* Feature detection for WebSocket.
*
* @return {Boolean} whether this transport is available.
* @api public
*/
WS.prototype.check = function () {
return !!WebSocketImpl && !('__initialize' in WebSocketImpl && this.name === WS.prototype.name);
};