使用socket编程，用python实现一个FTP服务器和客户端

好的，我可以为您提供一个简单的FTP服务器和客户端的Python代码示例，您可以根据您的需求进行修改和完善。

FTP服务器代码：

import socket
import os

def serve():
    server_socket = socket.socket()
    server_socket.bind(('localhost', 8000))
    server_socket.listen(5)
    print('FTP server started, waiting for connections...')

    while True:
        conn, addr = server_socket.accept()
        print('Connected by ', addr)

        while True:
            data = conn.recv(1024).decode()
            if not data:
                break
            cmd = data.split()[0]
            if cmd == 'LIST':
                files = os.listdir('.')
                conn.sendall('\n'.join(files).encode())
            elif cmd == 'RETR':
                filename = data.split()[1]
                if os.path.isfile(filename):
                    with open(filename, 'rb') as f:
                        content = f.read()
                    conn.sendall(content)
                else:
                    conn.sendall('File not found'.encode())

        conn.close()

if __name__ == '__main__':
    serve()

FTP客户端代码：

import socket

def get_file_list():
    client_socket = socket.socket()
    client_socket.connect(('localhost', 8000))
    client_socket.sendall('LIST'.encode())
    data = client_socket.recv(1024).decode()
    print('File list:')
    print(data)
    client_socket.close()

def download_file(filename):
    client_socket = socket.socket()
    client_socket.connect(('localhost', 8000))
    client_socket.sendall(('RETR ' + filename).encode())
    content = client_socket.recv(1024)
    with open(filename, 'wb') as f:
        while content:
            f.write(content)
            content = client_socket.recv(1024)
    print('Downloaded file:', filename)
    client_socket.close()

if __name__ == '__main__':
    get_file_list()
    download_file('file.txt')

这个简单的FTP服务器和客户端实现了两个命令：LIST 和 RETR。LIST 命令列出当前目录下的所有文件，RETR 命令下载指定的文件。在客户端中，您可以根据您的需求修改和添加其他命令。