网络编程

一、md5验证

import hashlib
m=hashlib.md5()
m.update(b"test")
print (m.hexdigest())
结果：098f6bcd4621d373cade4e832627b4f6

二、客户端代码
　　

#客户端
import socket
client=socket.socket() #生成socket连接对象
client.connect(("localhost",6969))
while True:
    msg=input(">>>:")
    if not msg:
        continue
    if msg.startswith("get"):
        client.send(msg.encode("utf-8")) #发送命令到服务端 ；
        cmd_res_size=client.recv(1024) #接收文件的大小；
        print ("文件大小为：",cmd_res_size)
        client.send(b"ready to recv file..")
        cmd_size=0
        cmd_data=b''
        filename=msg.split()[1]
        f=open(filename+".new","wb")
        while cmd_size!=int(cmd_res_size.decode()):
            data=client.recv(1024)
            cmd_size+=len(data)
            f.write(data)
        else:
            print ("cmd received done !",cmd_size)
            print (cmd_data.decode())
        f.close()
client.close()

三、服务端
　　

#服务端
import socket,os
so_server=socket.socket()
so_server.bind(("localhost",6969))
so_server.listen()
print ("等电话!")
while True: #实现多个链路连接；
    conn,addr=so_server.accept()
    print ("new connect",addr)
    while True:
        print ("等待新指令!")
        data = conn.recv(1024)
        if not data:
            print("客户端已经断开")
            break
        cmd,filename=data.decode().split()
        if os.path.isfile(filename):
            f=open(filename,"rb")
            file_size=str(os.stat(filename).st_size)
            print (file_size.encode())
            conn.send(file_size.encode())
            conn.recv(1024) #wait for ack;
            for line in f:
                conn.send(line)
            f.close()
so_server.close()

    8.文件md5较验.