黏包

一.subprocess模块

在学习这个模块前，我们先用Python的help()函数查看一下subprocess模块是干嘛的：

即允许你去创建一个新的进程让其执行另外的程序，并与它进行通信，获取标准的输入、标准输出、标准错误以及返回码等。

 subprocess模块中定义了一个Popen类，通过它可以来创建进程，并与其进行复杂的交互。

应用:

import subprocess

res=subprocess.Popen("ipconfig",
                     shell=True,
                     stderr=subprocess.PIPE,
                     stdout=subprocess.PIPE)

print(res.stdout.read().decode("gbk"))

 简单应用

import socket
import subprocess

sever=socket.socket()

sever.bind(('192.168.13.137',8016))

sever.listen(10)

while True:
    print('服务器准备好了')
    conn,addr=sever.accept()

    while True:
        try:
            cmd=conn.recv(1024).decode('utf-8')
            if cmd=='exit':
                break
            res=subprocess.Popen(cmd,
                             shell=True,
                             stderr=subprocess.PIPE,
                             stdout=subprocess.PIPE,
                             )
            out=res.stdout.read()
            err = res.stderr.read()
            if out:
                conn.send(out)

            else:
                conn.send(err)

        except Exception as e:
            break
    conn.close()

import socket
client=socket.socket()
client.connect(('192.168.13.137',8016))
while True:
    cmd=input('请输入命令:')
    if cmd=='exit':
        client.send(cmd.encode('utf-8'))
        break
    client.send(cmd.encode('utf-8'))
    ret=client.recv(1024)
    print(ret.decode('gbk'))

 二.黏包

1..struct模块

import struct
res=struct.pack('i',12535353)  #压包
print(res)
print(len(res))
ret=struct.unpack('i',res)  #解包
print(ret[0])

实例:

import socket
import subprocess

sever=socket.socket()

sever.bind(('192.168.13.137',8016))

sever.listen(10)

while True:
    print('服务器准备好了')
    conn,addr=sever.accept()

    while True:
        try:
            cmd=conn.recv(1024).decode('utf-8')
            if cmd=='exit':
                break
            res=subprocess.Popen(cmd,
                             shell=True,
                             stderr=subprocess.PIPE,
                             stdout=subprocess.PIPE,
                             )
            out=res.stdout.read()
            err = res.stderr.read()
            if out:
                import struct
                header_pack = struct.pack('i', len(out))
                # 发送报头
                conn.send(header_pack)
                # 发送数据
                conn.send(out)

            else:
                # 构建报头数据
                import struct
                header_pack=struct.pack('i',len(err))
                # 发送报头
                conn.send(header_pack)
                # 发送数据
                conn.send(err)

        except Exception as e:
            break
    conn.close()

import socket
import struct
client=socket.socket()
client.connect(('192.168.13.137',8016))
while True:
    cmd=input('请输入命令:')
    if cmd=='exit':
        client.send(cmd.encode('utf-8'))
        break
    client.send(cmd.encode('utf-8'))
    header_pack=client.recv(4)
    data_length=struct.unpack('i',header_pack)

    recv_data_length=0
    total_size=b''
    while recv_data_length<data_length[0]:
        data=client.recv(1024)
        recv_data_length+=len(data)
        total_size+=data
    print(total_size.decode('gbk'))

 2.hashlib模块

import hashlib
md5=hashlib.md5()
md5.update(b'sd')
md5.update(b'ghjk')  #追加上传,不是覆盖
print(md5.hexdigest())

import hashlib
md5=hashlib.sha3_512()  #加密效果更好
md5.update(b'sd')
md5.update(b'ghjk')
print(md5.hexdigest())

import hashlib
md5=hashlib.sha3_256()  #加密效果更好
md5.update(b'sd')
md5.update(b'ghjk')
print(md5.hexdigest())