public async startProxy()

in src/commands/remoteDebugJava/DebugProxy.ts [32:123]
78 lines of code
6 McCabe index (conditional complexity)

    public async startProxy(context: IActionContext): Promise<void> {
        if (!this._server) {
            this.emit('error', new Error('Proxy server is not started.'));
        } else {
            // wake up the Function App before connecting to it.
            await this.keepAlive(context);

            this._server.on('connection', (socket: Socket) => {
                if (this._wsclient) {
                    ext.outputChannel.appendLog(`[Proxy Server] The server is already connected. Rejected connection to "${socket.remoteAddress}:${socket.remotePort}"`);
                    this.emit('error', new Error(`[Proxy Server]  The server is already connected. Rejected connection to "${socket.remoteAddress}:${socket.remotePort}"`));
                    socket.destroy();
                } else {
                    ext.outputChannel.appendLog(`[Proxy Server] client connected ${socket.remoteAddress}:${socket.remotePort}`);
                    socket.pause();

                    this._wsclient = new websocket.client();

                    this._wsclient.on('connect', (connection: websocket.connection) => {
                        ext.outputChannel.appendLog('[WebSocket] client connected');
                        this._wsconnection = connection;

                        connection.on('close', () => {
                            ext.outputChannel.appendLog('[WebSocket] client closed');
                            this.dispose();
                            socket.destroy();
                            this.emit('end');
                        });

                        connection.on('error', (err: Error) => {
                            ext.outputChannel.appendLog(`[WebSocket] ${err}`);
                            this.dispose();
                            socket.destroy();
                            this.emit('error', err);
                        });

                        connection.on('message', (data: websocket.Message) => {
                            if ('binaryData' in data && data.binaryData) {
                                socket.write(data.binaryData);
                            }
                        });
                        socket.resume();
                    });

                    this._wsclient.on('connectFailed', (err: Error) => {
                        ext.outputChannel.appendLog(`[WebSocket] ${err}`);
                        this.dispose();
                        socket.destroy();
                        this.emit('error', err);
                    });

                    this._wsclient.connect(
                        `wss://${this._site.kuduHostName}/DebugSiteExtension/JavaDebugSiteExtension.ashx`,
                        undefined,
                        undefined,
                        { 'Cache-Control': 'no-cache', Pragma: 'no-cache' },
                        { auth: `${this._publishCredential.publishingUserName}:${this._publishCredential.publishingPassword}` }
                    );

                    socket.on('data', (data: Buffer) => {
                        if (this._wsconnection) {
                            this._wsconnection.send(data);
                        }
                    });

                    socket.on('end', () => {
                        ext.outputChannel.appendLog(`[Proxy Server] client disconnected ${socket.remoteAddress}:${socket.remotePort}`);
                        this.dispose();
                        this.emit('end');
                    });

                    socket.on('error', (err: Error) => {
                        ext.outputChannel.appendLog(`[Proxy Server] ${err}`);
                        this.dispose();
                        socket.destroy();
                        this.emit('error', err);
                    });
                }
            });

            this._server.on('listening', () => {
                ext.outputChannel.appendLog('[Proxy Server] start listening');
                this.emit('start');
            });

            this._server.listen({
                host: 'localhost',
                port: this._port,
                backlog: 1
            });
        }
    }