写一个远程控制代码，要求，多并发，实现功能，打开文件，关闭文件，上传文件，下载文件，远程监控，

以下是一个简单的远程控制代码，实现了打开、关闭、上传、下载文件，以及远程监控的功能。代码使用 Python 3 编写，使用了 socket 和 threading 库。请注意，此代码仅供学习和参考，不应用于非法用途。

服务端代码：

import socket
import threading
import os

HOST = '0.0.0.0'
PORT = 8888

def handle_client(conn, addr):
    print(f'Connected by {addr}')
    while True:
        data = conn.recv(1024).decode('utf-8')
        if not data:
            break
        cmd, *args = data.split()
        if cmd == 'open':
            try:
                os.startfile(args[0])
                conn.send('Opened\n'.encode('utf-8'))
            except:
                conn.send('Failed\n'.encode('utf-8'))
        elif cmd == 'close':
            try:
                os.system(f'taskkill /f /im {args[0]}')
                conn.send('Closed\n'.encode('utf-8'))
            except:
                conn.send('Failed\n'.encode('utf-8'))
        elif cmd == 'upload':
            try:
                with open(args[1], 'wb') as f:
                    f.write(conn.recv(1024))
                conn.send('Uploaded\n'.encode('utf-8'))
            except:
                conn.send('Failed\n'.encode('utf-8'))
        elif cmd == 'download':
            try:
                with open(args[0], 'rb') as f:
                    conn.sendall(f.read())
                conn.send('Downloaded\n'.encode('utf-8'))
            except:
                conn.send('Failed\n'.encode('utf-8'))
        elif cmd == 'monitor':
            try:
                while True:
                    data = conn.recv(1024)
                    if not data:
                        break
                    print(f'{addr}: {data.decode("utf-8")}')
            except:
                pass

    conn.close()
    print(f'Connection closed by {addr}')

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.bind((HOST, PORT))
    s.listen()

    print(f'Server started at {HOST}:{PORT}')

    while True:
        conn, addr = s.accept()
        t = threading.Thread(target=handle_client, args=(conn, addr))
        t.start()

客户端代码：

import socket

HOST = '127.0.0.1'
PORT = 8888

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))

    while True:
        cmd = input('> ').strip()
        if not cmd:
            continue
        if cmd == 'exit':
            break
        s.send(cmd.encode('utf-8'))
        data = s.recv(1024).decode('utf-8')
        print(data)
        if cmd.startswith('download') and data == 'Downloaded\n':
            with open(cmd.split()[1], 'wb') as f:
                while True:
                    data = s.recv(1024)
                    if not data:
                        break
                    f.write(data)