Socket传输简单的信息以及粘包问题的解决

　　一、简单的socket程序——传输简短文字：

# -*- coding: utf-8  -*-

# -*- Author: WangHW -*-

import socket

whw_client = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

whw_client.connect(('127.0.0.1',9001))

while 1:

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

    if not cmd:

        continue

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

    recv_data = whw_client.recv(1024)

    data = recv_data.decode('utf-8')

    print('server data:',data)

client

# -*- coding: utf-8  -*-

# -*- Author: WangHW -*-

import socket

whw_server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

whw_server.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)

whw_server.bind(('127.0.0.1',9001))

whw_server.listen(5)

print('listening......')

conn,addr = whw_server.accept()

#通信循环

while 1:

    try:

        recv_data = conn.recv(1024)

        data = recv_data.decode('utf-8')

        print('client data:',data)

        conn.send(data.swapcase().encode('utf-8'))

    except ConnectionResetError:

        break

conn.close()

server

　　演示如下：

二、模拟SSH命令——解决粘包问题版：

　　关于粘包问题的解决方案：

　　在服务器端，由于解析出来的命令结果非常多，所以我们在发送结果之前需要先给客户端发送一个“报文”，这个报文保存着具体的命令结果的信息——其中关键的信息就是结果的长度，客户端只有知道这个结果的长度后，才能制定相应的接收规则：

# -*- coding: utf-8  -*-

# -*- Author: WangHW -*-

import socket

import json

import struct

whw_client = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

whw_client.connect(('127.0.0.1',9000))

while 1:

    try:

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

        if not cmd:

            continue

        #发命令

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

        #1.收报头长度

        obj = whw_client.recv(10)

        #注意structunpack出来的[0]值为长度信息

        header_size = struct.unpack('i',obj)[0]

        #2.收报头——根据报头长度来收

        header_bytes = whw_client.recv(header_size)

        #3.从报头中解析出'total_size'

        header_json = header_bytes.decode('utf-8')

        header_dic = json.loads(header_json)

        total_size = header_dic['total_size']

        #根据total_size开始接收真实的数据

        recv_size = 0

        recv_data = b''

        while recv_size < total_size:

            res = whw_client.recv(1024)

            recv_data += res

            recv_size += len(res)

        print('命令结果:\n',recv_data.decode('gbk'))

    except Exception as e:

        whw_client.close()

client

# -*- coding: utf-8  -*-

# -*- Author: WangHW -*-

import socket

import subprocess

import json

import struct

whw_server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

whw_server.bind(('127.0.0.1',9000))

whw_server.listen(5)

print('Listening......')

conn,addr = whw_server.accept()

while 1:

    try:

        #收命令

        cmd_recv = conn.recv(1024).decode('utf-8')

        #解析命令

        obj = subprocess.Popen(cmd_recv,shell=True,stdout=subprocess.PIPE,stderr=subprocess.PIPE)

        stdout = obj.stdout.read()

        stderr = obj.stderr.read()

        #将命令返回给客户端

        #1.制作固定报头——注意报头里面要包含数据的总长度！

        header_dic = {'filename':'whw','total_size':len(stdout)+len(stderr)}

        header_json = json.dumps(header_dic)

        header_bytes = header_json.encode('utf-8')

        #2.发送报头长度——struct:把数字打成固定长度

        conn.send(struct.pack('i',len(header_bytes)))

        #3.发送报头

        conn.send(header_bytes)

        #4.发送真实数据

        conn.send(stdout)

        conn.send(stderr)

    except ConnectionResetError:

        break

conn.close()

server

　　演示如下：