Question

我是node的新手，正在尝试编写发送原始十六进制数据的最小tcp客户端。如果我应该使用缓冲区，那怎么办？如果我可以将十六进制作为字符串发送，那怎么办？非常感谢指导！

这是当前的无效代码：

var hexVal = `504f5354202f6c696e653320485454502f312e310d0a557365722d4167656e743a206e6f64652d6170700d0a4163636570743a202a2f2a0d0a686f73743a203139322e3136382e31342e39343a333030300d0a636f6e74656e742d747970653a206170706c69636174696f6e2f6a736f6e0d0a636f6e74656e742d6c656e6774683a2031390d0a436f6e6e656374696f6e3a20636c6f73650d0a0d0a227b757365726e616d653a202776616c277d22` // my raw hex, unwantendly sent as string


var net = require('net');

var HOST = '192.168.14.94';
var PORT = 3000;

var client = new net.Socket();
client.connect(PORT, HOST, function() {
    console.log('CONNECTED TO: ' + HOST + ':' + PORT);
    client.write(hexVal);
});

client.on('data', function(data) { // 'data' is an event handler for the client socket, what the server sent
    console.log('DATA: ' + data);
    client.destroy(); // Close the client socket completely

});

// Add a 'close' event handler for the client socket
client.on('close', function() {
    console.log('Connection closed');
});

服务器：

nc -lvp 3000

Answer 1

给定一个十六进制字符串作为原始字节发送，有一种更方便的方法来执行您想要的操作。

当前，您使用的是Uint8Array，每个字节需要被编码为0x41或类似的字符。

但是，给定十六进制字符串，您可以像这样准备原始的十六进制缓冲区：

const hexString = "41424344";
const rawHex = Buffer.from(hexString, 'hex');

然后您可以将缓冲区写入套接字：

let client = new net.Socket();
client.connect(PORT, IP, () => {
    console.log("Connected");
    client.write(rawHex); //This will send the byte buffer over TCP
})

希望这会有所帮助

Answer 2

您需要先设置服务器!!!

然后只有客户端才能连接到它...

package com.example.music_player;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.Toast;

import java.util.ArrayList;

public class Youtube_Source extends AppCompatActivity {

    WebView youtube;
    Button play;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_youtube__source);
        youtube=findViewById(R.id.youtube);
        youtube.loadUrl("https://www.youtube.com");
        youtube.setWebViewClient(new WebViewClient());

        WebSettings settings=youtube.getSettings();
        settings.setJavaScriptEnabled(true);

        Intent intent=getIntent();
//getting the list of songs from the internal memory from MainActivity
        final ArrayList <String> songs=intent.getStringArrayListExtra("songs");

        //Toast.makeText(this,String.valueOf(songs.size()),Toast.LENGTH_SHORT).show();

        play=findViewById(R.id.button7);
        play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent i=new Intent(Youtube_Source.this,MusicPlayer.class);
                i.putExtra("url",youtube.getUrl());
                i.putExtra("position",String.valueOf(4));
                i.putStringArrayListExtra("songs",songs);
                String url=youtube.getUrl();
                //Toast.makeText(Youtube_Source.this,url,Toast.LENGTH_SHORT).show();
                startService(i);

            }
        });

    }

    @Override
    public void onBackPressed() {
        if (youtube.canGoBack()) {

            youtube.goBack();

        }

        else {

            super.onBackPressed();

        }
    }

}

您甚至还可以将服务器和客户端的代码拆分为两个单独的文件...

然后先启动服务器，然后启动客户端

Answer 3

这解决了它：

var bytesToSend = [0x50, 0x4f, ...],
    hexVal = new Uint8Array(bytesToSend);

NodeJS如何使用原始Hex发送TCP数据包

3 个答案: