Socket_SSH-3（粘包）

粘包：两次数据粘到一起了。在Windows中基本看不出来效果。

服务器端的配置：

import socket,os,time

server=socket.socket()

server.bind(('localhost',9999))

server.listen()

while True:

    conn,addr=server.accept()

    print("new connection is :",addr)

    while True:

        data=conn.recv(1024)

        if not data:

            print("客户端已经断开")

            break

        cmd_res=os.popen(data.decode('utf-8')).read()

        if len(cmd_res)==0:

            cmd_res="命令无效，没有返回值"

        conn.send(str(len(cmd_res.encode())).encode('utf-8'))

        #整数不能直接encode，需要先转成字符串，再encode.发大小给客户端

        #time.sleep(0.5) #防止粘包

        client_ack=conn.recv(1024) #wait client to confirm

        print("ack from client:",client_ack)

        conn.send(cmd_res.encode('utf-8'))

server.close()

客户端的配置：

import socket

client=socket.socket()

client.connect(('localhost',9999))

while True:

    cmd=input(">>:").strip()

    if len(cmd)==0:

        break

    client.send(cmd.encode('utf-8'))

    cmd_res_size=client.recv(1024) #接收命令结果的长度。

    print("命令结果大小：",cmd_res_size)

    client.send('准备好接收了，你可以发了'.encode("utf-8"))

    received_size=0

    received_data=b""

    while received_size<int(cmd_res_size.decode("utf-8")):

        data=client.recv(1024)

        received_size=received_size+len(data) #每次收到的有效数字，有可能小于1024

        received_data=received_data+data

    else:

        print("cmd res received done...",received_size)

        print(received_data.decode('utf-8'))

client.close()