Current File : //lib/node_modules/pm2/node_modules/ws/lib/websocket-server.js
'use strict';
const EventEmitter = require('events');
const { createHash } = require('crypto');
const { createServer, STATUS_CODES } = require('http');
const PerMessageDeflate = require('./permessage-deflate');
const WebSocket = require('./websocket');
const { format, parse } = require('./extension');
const { GUID, kWebSocket } = require('./constants');
const keyRegex = /^[+/0-9A-Za-z]{22}==$/;
/**
* Class representing a WebSocket server.
*
* @extends EventEmitter
*/
class WebSocketServer extends EventEmitter {
/**
* Create a `WebSocketServer` instance.
*
* @param {Object} options Configuration options
* @param {Number} [options.backlog=511] The maximum length of the queue of
* pending connections
* @param {Boolean} [options.clientTracking=true] Specifies whether or not to
* track clients
* @param {Function} [options.handleProtocols] A hook to handle protocols
* @param {String} [options.host] The hostname where to bind the server
* @param {Number} [options.maxPayload=104857600] The maximum allowed message
* size
* @param {Boolean} [options.noServer=false] Enable no server mode
* @param {String} [options.path] Accept only connections matching this path
* @param {(Boolean|Object)} [options.perMessageDeflate=false] Enable/disable
* permessage-deflate
* @param {Number} [options.port] The port where to bind the server
* @param {http.Server} [options.server] A pre-created HTTP/S server to use
* @param {Function} [options.verifyClient] A hook to reject connections
* @param {Function} [callback] A listener for the `listening` event
*/
constructor(options, callback) {
super();
options = {
maxPayload: 100 * 1024 * 1024,
perMessageDeflate: false,
handleProtocols: null,
clientTracking: true,
verifyClient: null,
noServer: false,
backlog: null, // use default (511 as implemented in net.js)
server: null,
host: null,
path: null,
port: null,
...options
};
if (options.port == null && !options.server && !options.noServer) {
throw new TypeError(
'One of the "port", "server", or "noServer" options must be specified'
);
}
if (options.port != null) {
this._server = createServer((req, res) => {
const body = STATUS_CODES[426];
res.writeHead(426, {
'Content-Length': body.length,
'Content-Type': 'text/plain'
});
res.end(body);
});
this._server.listen(
options.port,
options.host,
options.backlog,
callback
);
} else if (options.server) {
this._server = options.server;
}
if (this._server) {
const emitConnection = this.emit.bind(this, 'connection');
this._removeListeners = addListeners(this._server, {
listening: this.emit.bind(this, 'listening'),
error: this.emit.bind(this, 'error'),
upgrade: (req, socket, head) => {
this.handleUpgrade(req, socket, head, emitConnection);
}
});
}
if (options.perMessageDeflate === true) options.perMessageDeflate = {};
if (options.clientTracking) this.clients = new Set();
this.options = options;
}
/**
* Returns the bound address, the address family name, and port of the server
* as reported by the operating system if listening on an IP socket.
* If the server is listening on a pipe or UNIX domain socket, the name is
* returned as a string.
*
* @return {(Object|String|null)} The address of the server
* @public
*/
address() {
if (this.options.noServer) {
throw new Error('The server is operating in "noServer" mode');
}
if (!this._server) return null;
return this._server.address();
}
/**
* Close the server.
*
* @param {Function} [cb] Callback
* @public
*/
close(cb) {
if (cb) this.once('close', cb);
//
// Terminate all associated clients.
//
if (this.clients) {
for (const client of this.clients) client.terminate();
}
const server = this._server;
if (server) {
this._removeListeners();
this._removeListeners = this._server = null;
//
// Close the http server if it was internally created.
//
if (this.options.port != null) {
server.close(() => this.emit('close'));
return;
}
}
process.nextTick(emitClose, this);
}
/**
* See if a given request should be handled by this server instance.
*
* @param {http.IncomingMessage} req Request object to inspect
* @return {Boolean} `true` if the request is valid, else `false`
* @public
*/
shouldHandle(req) {
if (this.options.path) {
const index = req.url.indexOf('?');
const pathname = index !== -1 ? req.url.slice(0, index) : req.url;
if (pathname !== this.options.path) return false;
}
return true;
}
/**
* Handle a HTTP Upgrade request.
*
* @param {http.IncomingMessage} req The request object
* @param {net.Socket} socket The network socket between the server and client
* @param {Buffer} head The first packet of the upgraded stream
* @param {Function} cb Callback
* @public
*/
handleUpgrade(req, socket, head, cb) {
socket.on('error', socketOnError);
const key =
req.headers['sec-websocket-key'] !== undefined
? req.headers['sec-websocket-key'].trim()
: false;
const version = +req.headers['sec-websocket-version'];
const extensions = {};
if (
req.method !== 'GET' ||
req.headers.upgrade.toLowerCase() !== 'websocket' ||
!key ||
!keyRegex.test(key) ||
(version !== 8 && version !== 13) ||
!this.shouldHandle(req)
) {
return abortHandshake(socket, 400);
}
if (this.options.perMessageDeflate) {
const perMessageDeflate = new PerMessageDeflate(
this.options.perMessageDeflate,
true,
this.options.maxPayload
);
try {
const offers = parse(req.headers['sec-websocket-extensions']);
if (offers[PerMessageDeflate.extensionName]) {
perMessageDeflate.accept(offers[PerMessageDeflate.extensionName]);
extensions[PerMessageDeflate.extensionName] = perMessageDeflate;
}
} catch (err) {
return abortHandshake(socket, 400);
}
}
//
// Optionally call external client verification handler.
//
if (this.options.verifyClient) {
const info = {
origin:
req.headers[`${version === 8 ? 'sec-websocket-origin' : 'origin'}`],
secure: !!(req.socket.authorized || req.socket.encrypted),
req
};
if (this.options.verifyClient.length === 2) {
this.options.verifyClient(info, (verified, code, message, headers) => {
if (!verified) {
return abortHandshake(socket, code || 401, message, headers);
}
this.completeUpgrade(key, extensions, req, socket, head, cb);
});
return;
}
if (!this.options.verifyClient(info)) return abortHandshake(socket, 401);
}
this.completeUpgrade(key, extensions, req, socket, head, cb);
}
/**
* Upgrade the connection to WebSocket.
*
* @param {String} key The value of the `Sec-WebSocket-Key` header
* @param {Object} extensions The accepted extensions
* @param {http.IncomingMessage} req The request object
* @param {net.Socket} socket The network socket between the server and client
* @param {Buffer} head The first packet of the upgraded stream
* @param {Function} cb Callback
* @throws {Error} If called more than once with the same socket
* @private
*/
completeUpgrade(key, extensions, req, socket, head, cb) {
//
// Destroy the socket if the client has already sent a FIN packet.
//
if (!socket.readable || !socket.writable) return socket.destroy();
if (socket[kWebSocket]) {
throw new Error(
'server.handleUpgrade() was called more than once with the same ' +
'socket, possibly due to a misconfiguration'
);
}
const digest = createHash('sha1')
.update(key + GUID)
.digest('base64');
const headers = [
'HTTP/1.1 101 Switching Protocols',
'Upgrade: websocket',
'Connection: Upgrade',
`Sec-WebSocket-Accept: ${digest}`
];
const ws = new WebSocket(null);
let protocol = req.headers['sec-websocket-protocol'];
if (protocol) {
protocol = protocol.split(',').map(trim);
//
// Optionally call external protocol selection handler.
//
if (this.options.handleProtocols) {
protocol = this.options.handleProtocols(protocol, req);
} else {
protocol = protocol[0];
}
if (protocol) {
headers.push(`Sec-WebSocket-Protocol: ${protocol}`);
ws._protocol = protocol;
}
}
if (extensions[PerMessageDeflate.extensionName]) {
const params = extensions[PerMessageDeflate.extensionName].params;
const value = format({
[PerMessageDeflate.extensionName]: [params]
});
headers.push(`Sec-WebSocket-Extensions: ${value}`);
ws._extensions = extensions;
}
//
// Allow external modification/inspection of handshake headers.
//
this.emit('headers', headers, req);
socket.write(headers.concat('\r\n').join('\r\n'));
socket.removeListener('error', socketOnError);
ws.setSocket(socket, head, this.options.maxPayload);
if (this.clients) {
this.clients.add(ws);
ws.on('close', () => this.clients.delete(ws));
}
cb(ws, req);
}
}
module.exports = WebSocketServer;
/**
* Add event listeners on an `EventEmitter` using a map of <event, listener>
* pairs.
*
* @param {EventEmitter} server The event emitter
* @param {Object.<String, Function>} map The listeners to add
* @return {Function} A function that will remove the added listeners when
* called
* @private
*/
function addListeners(server, map) {
for (const event of Object.keys(map)) server.on(event, map[event]);
return function removeListeners() {
for (const event of Object.keys(map)) {
server.removeListener(event, map[event]);
}
};
}
/**
* Emit a `'close'` event on an `EventEmitter`.
*
* @param {EventEmitter} server The event emitter
* @private
*/
function emitClose(server) {
server.emit('close');
}
/**
* Handle premature socket errors.
*
* @private
*/
function socketOnError() {
this.destroy();
}
/**
* Close the connection when preconditions are not fulfilled.
*
* @param {net.Socket} socket The socket of the upgrade request
* @param {Number} code The HTTP response status code
* @param {String} [message] The HTTP response body
* @param {Object} [headers] Additional HTTP response headers
* @private
*/
function abortHandshake(socket, code, message, headers) {
if (socket.writable) {
message = message || STATUS_CODES[code];
headers = {
Connection: 'close',
'Content-Type': 'text/html',
'Content-Length': Buffer.byteLength(message),
...headers
};
socket.write(
`HTTP/1.1 ${code} ${STATUS_CODES[code]}\r\n` +
Object.keys(headers)
.map((h) => `${h}: ${headers[h]}`)
.join('\r\n') +
'\r\n\r\n' +
message
);
}
socket.removeListener('error', socketOnError);
socket.destroy();
}
/**
* Remove whitespace characters from both ends of a string.
*
* @param {String} str The string
* @return {String} A new string representing `str` stripped of whitespace
* characters from both its beginning and end
* @private
*/
function trim(str) {
return str.trim();
}
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