如何将数据从 Node 发送到另一台服务器

Question

我正在尝试找出一种将 Node 用作客户端的方法，该客户端会将数据发送到侦听 Android 应用程序的服务器。 android 应用程序最初将使用其公共 IP 地址和它将侦听的端口（套接字）向 Node 服务器发送一个 post 请求。一旦有任何新的东西，Node 服务器就会通过注册的套接字将 JSON 数据包发送到该特定应用程序。

这在 Node 中是否可行，如果不是，我如何在 Javascript 中实现它，或者实现它的最佳方法是什么？

这是 Android 应用服务器

public class AndroidAppLocalServer {
    Activity activity;
    ServerSocket serverSocket;
    String message = "";
    static final int socketServerPORT = 8080;

    public AndroidAppLocalServer(Activity activity) {
        this.activity = activity;
        Thread socketServerThread = new Thread(new SocketServerThread());
        socketServerThread.start();
    }

    public int getPort() {
        return socketServerPORT;
    }

    public void onDestroy() {
        if (serverSocket != null) {
            try {
                serverSocket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    private class SocketServerThread extends Thread {

        int count = 0;

        @Override
        public void run() {
            try {
                // create ServerSocket using specified port
                serverSocket = new ServerSocket(socketServerPORT);

                while (true) {
                    // block the call until connection is created and return
                    // Socket object
                    Socket socket = serverSocket.accept();
                    count++;
                    message += "#" + count + " from "
                            + socket.getInetAddress() + ":"
                            + socket.getPort() + "\n";

                    activity.runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Log.v("MyApp", message);
                        }
                    });

                    SocketServerReplyThread socketServerReplyThread = new SocketServerReplyThread(socket, count);
                    socketServerReplyThread.run();

                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    private class SocketServerReplyThread extends Thread {

        private Socket hostThreadSocket;
        int cnt;

        SocketServerReplyThread(Socket socket, int c) {
            hostThreadSocket = socket;
            cnt = c;
        }

        @Override
        public void run() {
            OutputStream outputStream;
            String msgReply = "Hello from AndroidAppLocalServer, you are #" + cnt;

            try {
                outputStream = hostThreadSocket.getOutputStream();
                PrintStream printStream = new PrintStream(outputStream);
                printStream.print(msgReply);
                printStream.close();

                message += "replayed: " + msgReply + "\n";

                activity.runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        Log.v("MyApp", message);
                    }
                });

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                message += "Something wrong! " + e.toString() + "\n";
            }

            activity.runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    Log.v("MyApp", message);
                }
            });
        }

    }

    public String getIpAddress() {
        String ip = "";
        try {
            Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface.getNetworkInterfaces();
            while (enumNetworkInterfaces.hasMoreElements()) {
                NetworkInterface networkInterface = enumNetworkInterfaces.nextElement();
                Enumeration<InetAddress> enumInetAddress = networkInterface.getInetAddresses();
                while (enumInetAddress.hasMoreElements()) {
                    InetAddress inetAddress = enumInetAddress.nextElement();

                    if (inetAddress.isSiteLocalAddress()) {
                        ip += "AndroidAppLocalServer running at : " + inetAddress.getHostAddress();
                    }
                }
            }

        } catch (SocketException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            ip += "Something Wrong! " + e.toString() + "\n";
        }
        return ip;
    }
}

Answer 1

是的，您可以在 Node.js 中执行此操作，假设应用程序运行在实际上可公开访问的手机上。由于您在 Android 应用程序中使用的是普通 TCP 套接字，因此您可以先使用netcat 或telnet 等工具手动连接套接字来验证（例如，netcat <PUBLIC-IP> 8080）。

如果这可行，您可以使用 net.Socket 类在 Node.js 中执行相同的操作。

const net = require('net');
const client = new net.Socket();
client.connect(8080, '<PUBLIC-IP>', () => {
    // callback, when connection successfull
    client.write('Data sent to the App');
});
client.on('data', (data) => {
    // callback, when app replies with data
});
client.on('close', (data) => {
    // callback, when socket is closed
});

但是，根据您实际尝试实现的目标，您可能需要了解 Android 应用程序通常如何实现推送通知。