python socket简单实现SSH服务器端

#server

import socket,os
server = socket.socket()
server.bind(('localhost',9999))

server.listen()

while True:
    conn,addr=server.accept()
    while True:
        data = conn.recv(1024)
        if not data:
            print("客户端已经断开")
            break
        print("执行指令",data)
        cmd_res = os.popen(data.decode()).read()#接受字符串，执行结果是字符串
        print("before send",len(cmd_res))
        if len(cmd_res) == 0:
            cmd_res = "cmd has no output..."
        conn.send( str (len(cmd_res.encode())).encode("utf-8"))#先发大小给客户端
        conn.send(cmd_res.encode("utf-8"))
        print("semd done")

server.close()

#client

import socket

client = socket.socket()
client.connect(("localhost",9999))

while True:
    cmd = input(">>:").strip()
    if len(cmd) ==0 :continue
    client.send(cmd.encode('UTF-8'))
    cmd_res_size = client.recv(1024)#接受命令的长度
    print("命令结果大小：",cmd_res_size)
    received_size= 0
    received_data=b''
    while received_size< int(cmd_res_size.decode()):
        data = client.recv(1024)
        received_size +=len(data)#每次收到的有可能小于1024，所以必须用len判断
        received_data +=data

    else:
        print("cmd res receive done...",received_size)
        print(received_data.decode())


client.close()