该如何在鸿蒙arkts中如何实现ftp服务？

// 1. 添加权限声明(module.json5)
"requestPermissions": [
  {
    "name": "ohos.permission.INTERNET",
    "reason": "FTP服务需要网络访问权限"
  },
  {
    "name": "ohos.permission.READ_MEDIA",
    "reason": "读取设备文件"
  },
  {
    "name": "ohos.permission.WRITE_MEDIA",
    "reason": "写入设备文件" 
  }
]

// 2. 创建FTP服务器核心类框架
import socket from '@ohos.net.socket';
import fileIO from '@ohos.fileio';

class FTPServer {
  private controlSocket: socket.TCPSocketServer; // 控制连接
  private dataSocket: socket.TCPSocketServer;    // 数据连接
  private currentDir: string = '/';              // 当前目录
  private isPassiveMode: boolean = false;         // 传输模式标识
  
  // 启动服务器
  async start(port: number = 21) {
    this.controlSocket = socket.constructTCPSocketServerInstance();
    this.controlSocket.listen({ address: '0.0.0.0', port: port, family: 1 }, (err) => {
      if (err) {
        console.error('FTP Server启动失败:', err);
        return;
      }
      console.log(`FTP Server运行在端口 ${port}`);
      this.handleControlConnection();
    });
  }

  // 处理控制连接
  private async handleControlConnection() {
    this.controlSocket.on('connect', (clientSocket) => {
      clientSocket.sendMessage('220 HarmonyOS FTP Service Ready\r\n');
      
      clientSocket.on('message', async (data: ArrayBuffer) => {
        const command = String.fromCharCode(...new Uint8Array(data)).trim();
        await this.processCommand(clientSocket, command);
      });
    });
  }

  // 解析FTP命令
  private async processCommand(socket: socket.TCPSocket, command: string) {
    const [cmd, ...args] = command.split(' ');
    switch(cmd.toUpperCase()) {
      case 'USER':
        socket.sendMessage('331 Password required\r\n');
        break;
      case 'PASS':
        socket.sendMessage('230 User logged in\r\n');
        break;
      case 'PWD':
        socket.sendMessage(`257 "${this.currentDir}"\r\n`);
        break;
      case 'TYPE': // 设置传输类型
        socket.sendMessage('200 Type set to I\r\n');
        break;
      case 'PASV': // 被动模式处理
        this.setupPassiveMode(socket);
        break;
      case 'LIST': // 文件列表
        this.sendFileList(socket);
        break;
      // 其他命令处理...
    }
  }

  // 实现被动模式
  private setupPassiveMode(socket: socket.TCPSocket) {
    const dataPort = 2000 + Math.floor(Math.random() * 1000);
    this.dataSocket = socket.constructTCPSocketServerInstance();
    this.dataSocket.listen({ address: '0.0.0.0', port: dataPort, family: 1 }, () => {
      const ip = '192.168.1.100'; // 需替换为实际IP
      const portBytes = [(dataPort >> 8) & 0xFF, dataPort & 0xFF];
      socket.sendMessage(`227 Entering Passive Mode (${ip.replace(/\./g,',')},${portBytes[0]},${portBytes[1]})\r\n`);
      this.isPassiveMode = true;
    });
  }

  // 发送文件列表
  private async sendFileList(socket: socket.TCPSocket) {
    const dirReader = fileIO.createDir(this.currentDir);
    const entries = dirReader.readNextEntries();
    let list = '';
    entries.forEach(entry => {
      list += `${entry.isDirectory() ? 'd' : '-'}rwxr-xr-x 1 owner group ${entry.length} ${entry.mtime} ${entry.name}\r\n`;
    });
    socket.sendMessage('150 Opening data connection\r\n');
    // 数据通道发送实际内容...
  }
}

import { FtpServer } from 'ftp-srv';

const server = new FtpServer({
    url: 'ftp://0.0.0.0:2121', // 监听地址和端口
    anonymous: true,          // 是否允许匿名访问
});

server.on('login', ({ connection, username, password }, resolve, reject) => {
    if (username === 'admin' && password === 'password') {
        resolve({ root: '/path/to/root' }); // 设置根目录
    } else {
        reject(new Error('Invalid credentials'));
    }
});

server.listen().then(() => {
    console.log('FTP server is running on port 2121');
});

import socket from '@ohos.net.socket';

let tcpServer = socket.constructTCPSocketInstance();

tcpServer.bind({
    address: { address: '0.0.0.0', port: 2121, family: 0 },
    listen: true,
}).then(() => {
    console.log('FTP server is listening on port 2121');
    tcpServer.on('connection', (clientSocket) => {
        console.log('Client connected');
        clientSocket.on('data', (data) => {
            console.log(`Received data: ${data}`);
            // 解析 FTP 命令并处理
        });
    });
}).catch((err) => {
    console.error('Failed to start FTP server:', err);
});

import fileio from '@ohos.fileio';

// 文件读取示例
function readFile(path) {
    const file = fileio.openSync(path, fileio.OpenMode.READ_ONLY);
    const buffer = new ArrayBuffer(1024);
    const bytesRead = fileio.readSync(file.fd, buffer);
    fileio.closeSync(file);
    return buffer.slice(0, bytesRead);
}

// 文件写入示例
function writeFile(path, data) {
    const file = fileio.openSync(path, fileio.OpenMode.CREATE | fileio.OpenMode.WRITE_ONLY);
    fileio.writeSync(file.fd, data);
    fileio.closeSync(file);
}

"requestPermissions": [
    "ohos.permission.INTERNET",
    "ohos.permission.READ_USER_STORAGE",
    "ohos.permission.WRITE_USER_STORAGE"
]