Method handleUpgrade

lib/websocket-server.js:244–357

* Handle a HTTP Upgrade request. * * @param {http.IncomingMessage} req The request object * @param {Duplex} socket The network socket between the server and client * @param {Buffer} head The first packet of the upgraded stream * @param {Function} cb Callback * @public

(req, socket, head, cb)

   * @public
   */
  handleUpgrade(req, socket, head, cb) {
    socket.on('error', socketOnError);

    const key = req.headers['sec-websocket-key'];
    const upgrade = req.headers.upgrade;
    const version = +req.headers['sec-websocket-version'];

    if (req.method !== 'GET') {
      const message = 'Invalid HTTP method';
      abortHandshakeOrEmitwsClientError(this, req, socket, 405, message);
      return;
    }

    if (upgrade === undefined || upgrade.toLowerCase() !== 'websocket') {
      const message = 'Invalid Upgrade header';
      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
      return;
    }

    if (key === undefined || !keyRegex.test(key)) {
      const message = 'Missing or invalid Sec-WebSocket-Key header';
      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
      return;
    }

    if (version !== 13 && version !== 8) {
      const message = 'Missing or invalid Sec-WebSocket-Version header';
      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message, {
        'Sec-WebSocket-Version': '13, 8'
      });
      return;
    }

    if (!this.shouldHandle(req)) {
      abortHandshake(socket, 400);
      return;
    }

    const secWebSocketProtocol = req.headers['sec-websocket-protocol'];
    let protocols = new Set();

    if (secWebSocketProtocol !== undefined) {
      try {
        protocols = subprotocol.parse(secWebSocketProtocol);
      } catch (err) {
        const message = 'Invalid Sec-WebSocket-Protocol header';
        abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
        return;
      }
    }

    const secWebSocketExtensions = req.headers['sec-websocket-extensions'];
    const extensions = {};

    if (
      this.options.perMessageDeflate &&
      secWebSocketExtensions !== undefined
    ) {