python socket user interaction + MD5 encryption

Original link: https://www.jianshu.com/

The use of socket file transfer command from the client to the server and then returned to the content byte size

socketserver use (important)

note:

## client.recv (1024) is particularly important instruction sentence

- each received the maximum 1024 is generally less than 1024,

- byte size must be determined for each transmission to ensure that the content and accumulating until the received content is not less than a given server

- otherwise continued transmission

client codes

'''
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'''
import socket
client=socket.socket()
client.connect(('localhost',999))
while True:
    cmd=input(">>:").strip()
    if len(cmd)==0:
        continue
    client.send(cmd.encode("utf-8"))
    cmd_res_size=client.recv(1024)  #接收命令长度
    print("命令长度为",cmd_res_size.decode())
    receive_size=0
    while receive_size!=int(cmd_res_size.decode()):
        cmd_res=client.recv(1024)       #每次收到最大1024 一般都小于1024，不能用for判断
        receive_size+=len(cmd_res.decode())
        print(cmd_res.decode())

    print("done 打印长度为",receive_size)
client.close()

server Code

'''
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'''
import socket,os
server=socket.socket()
server.bind(('localhost',999))

server.listen()

while True:
    conn,addr=server.accept()
    print("new conn",addr)
    while True:
        data=conn.recv(1024)
        if not data:
            print("用户已断开")
            break
        print("执行指令:",data)
        cmd_res=os.popen(data.decode()).read()
        if len(cmd_res) == 0:
            cmd_res = "your input is wrong!"

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

server.close()

supplement:

1. Only a String only encode transcoder, so other int / double type must first turn into a String

2.send function only byte byte-transfer, the ASCII code for the character string may be added directly in front of b transcoding operation Example: b'ssadads'

However, if you want Chinese characters to ASCII must encode transcoding (this has explained in detail in day4 school in python)

3. The digital values ​​are the same on both sides even if len len measured with different byte string and still different

To the comparison value, to decode the decoded string or byte compared before transcoding

---

socket upgraded version socketserver focus

'''
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'''
import socketserver       　　　　　　　　　　　　　　　　　　　  #对socket进行封装
class MyTCP(socketserver.BaseRequestHandler):  　　　　　　　 #定义处理类，继承于BaseRequestHandler
    def handle(self):       　　　　　　　　　　　　　　　　　　　#与所有客户端的交互都在handle里完成 重写此函数
        while True:
           try:
                self.data=self.request.recv(1024).strip()   #接收信息
                print(self.client_address[0],"write")       #显示用户ip
                print(self.data)                            #打印传输数据
                if not self.data:
                    self.request.send(self.data.upper())    #返回大写
           except ConnectionRefusedError as e:              #抓住异常并打印
               print("err",e)
               break
HOST,PORT="localhost",999                                   #初始化
#server=socketserver.TCPServer((HOST,PORT),MyTCP)           #单线程 实例化一个server对象
server=socketserver.ThreadingTCPServer((HOST,PORT),MyTCP)   #多线程 实例化一个server对象
server.serve_forever()                                      #处理请求 永远执行
server.close()

As a server can support multiple threads request a wide range of client

=======================================

supplement:

MD5 encrypted form to transfer files

import socket,hashlib
client=socket.socket()                  #实例化socket对象
client.connect(("localhost",999))       #连接
while True:
    cmd=input(">>:".strip())            #用户输入指令 去空格
    if len(cmd)==0:continue             #输入为空重新输入
    if cmd.startswith("get"):           #指令以get开头
        client.send(cmd.encode())       #发送命令
        server_response=client.recv(1024)   #接收server端回复
        print("文件大小",server_response.decode())  #打印server端的信息（文件大小）
        client.send(b"ready......")         #回复server端
        size=int(server_response.decode())  #文件大小
        receive_size=0                      #接收信息size累加
        filename=cmd.split()[1]             #文件名
        f=open("lala","wb")                 #打开文件
        m=hashlib.md5()                     #实例化MD5加密
        while receive_size<size:            #由于client传输的信息每次传输最大为1024 但实际不到
            if(size-receive_size>1024):     #因此每次都得累加传输的信息数量与总理做对比
                a=1024
            else:
                a=size-receive_size
                print(a,size,receive_size)
            data=client.recv(a)             #接收client传输的信息
            receive_size+=len(data)         #累加
            m.update(data)                  #MD5累加数据用update函数
            f.write(data)
        print("file rece done")
        new_file_md5=m.hexdigest()          #16进制数据字符串

        f.close()
        server_file_md5=client.recv(1024)
        print("server file",server_file_md5)
        print("client file",new_file_md5)

client.close()

Direct docking above socketserver