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node_modules/ws/lib/websocket-server.js

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+'use strict';
+
+const EventEmitter = require('events');
+const crypto = require('crypto');
+const http = require('http');
+const url = require('url');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const extension = require('./extension');
+const constants = require('./constants');
+const WebSocket = require('./websocket');
+
+/**
+ * Class representing a WebSocket server.
+ *
+ * @extends EventEmitter
+ */
+class WebSocketServer extends EventEmitter {
+  /**
+   * Create a `WebSocketServer` instance.
+   *
+   * @param {Object} options Configuration options
+   * @param {String} options.host The hostname where to bind the server
+   * @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 An hook to reject connections
+   * @param {Function} options.handleProtocols An hook to handle protocols
+   * @param {String} options.path Accept only connections matching this path
+   * @param {Boolean} options.noServer Enable no server mode
+   * @param {Boolean} options.clientTracking Specifies whether or not to track clients
+   * @param {(Boolean|Object)} options.perMessageDeflate Enable/disable permessage-deflate
+   * @param {Number} options.maxPayload The maximum allowed message size
+   * @param {Function} callback A listener for the `listening` event
+   */
+  constructor (options, callback) {
+    super();
+
+    options = Object.assign({
+      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 = http.createServer((req, res) => {
+        const body = http.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) {
+      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, (ws) => {
+            this.emit('connection', ws, req);
+          });
+        }
+      });
+    }
+
+    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) {
+    //
+    // 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) return server.close(cb);
+    }
+
+    if (cb) cb();
+  }
+
+  /**
+   * 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 && url.parse(req.url).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 version = +req.headers['sec-websocket-version'];
+    const extensions = {};
+
+    if (
+      req.method !== 'GET' || req.headers.upgrade.toLowerCase() !== 'websocket' ||
+      !req.headers['sec-websocket-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 = extension.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.connection.authorized || req.connection.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(extensions, req, socket, head, cb);
+        });
+        return;
+      }
+
+      if (!this.options.verifyClient(info)) return abortHandshake(socket, 401);
+    }
+
+    this.completeUpgrade(extensions, req, socket, head, cb);
+  }
+
+  /**
+   * Upgrade the connection to WebSocket.
+   *
+   * @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
+   * @private
+   */
+  completeUpgrade (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();
+
+    const key = crypto.createHash('sha1')
+      .update(req.headers['sec-websocket-key'] + constants.GUID, 'binary')
+      .digest('base64');
+
+    const headers = [
+      'HTTP/1.1 101 Switching Protocols',
+      'Upgrade: websocket',
+      'Connection: Upgrade',
+      `Sec-WebSocket-Accept: ${key}`
+    ];
+
+    const ws = new WebSocket(null);
+    var protocol = req.headers['sec-websocket-protocol'];
+
+    if (protocol) {
+      protocol = protocol.trim().split(/ *, */);
+
+      //
+      // 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 = extension.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);
+  }
+}
+
+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]);
+    }
+  };
+}
+
+/**
+ * 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 || http.STATUS_CODES[code];
+    headers = Object.assign({
+      'Connection': 'close',
+      'Content-type': 'text/html',
+      'Content-Length': Buffer.byteLength(message)
+    }, headers);
+
+    socket.write(
+      `HTTP/1.1 ${code} ${http.STATUS_CODES[code]}\r\n` +
+      Object.keys(headers).map(h => `${h}: ${headers[h]}`).join('\r\n') +
+      '\r\n\r\n' +
+      message
+    );
+  }
+
+  socket.removeListener('error', socketOnError);
+  socket.destroy();
+}