import socket

sock=socket.socket() # TCP协议

IP_PORT=("127.0.0.1",8899)

sock.bind(IP_PORT)

sock.listen(5)

while 1:

    conn,addr=sock.accept()

    while 1:

        try:

            data=conn.recv(1024).decode("utf8")

            user,pwd=data.strip().split("|")  #strip 是为了去掉接受到文件中的空格

                         #split是以|为分割线，分隔输入进来的字符串分割后形成列表

            # 文件操作

            flag=False

            with open("account","r") as f:

                for line in f:

                    username,password=line.strip().split(":")

                    if username==user and password==pwd:

                        flag=True

                        break

            if flag:

                conn.send(b"success")

            else:

                conn.send(b"fail")

        except Exception as e:

            break                                                    

服务端

import subprocess

res=subprocess.Popen("dir",

                     shell=True,

                     stderr=subprocess.PIPE,

                     stdout=subprocess.PIPE)

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

subprocess

import struct

res=struct.pack("i","52526") #i 是一个整形模式

print(res) #b'Q\xe4\x06\x00' 是一个看不懂四个字节

print(len(res))

obj=struct.unpack("i",res)

print（obj） #（52526，）

print(obj[0]) #取元组的第一项

#功能，把一组数据转化为一个4位数字是东西
# 构造报头数据

hashlib 的经典用法:做数据移植性校验，就是本地上用一次，对面用一次，利用不可逆性，发生修改的话队形的hashlib将会不一样
import hashlib

md5=hashlib.md5()

md5.update(b"hello")

md5.update(b"yuan")

print(md5.hexdigest())

print(len(md5.hexdigest()))

# # helloyuan:   d843cc930aa76f7799bba1780f578439      两次加密的效果是一样的

# #              d843cc930aa76f7799bba1780f578439

#############################################

md5=hashlib.md5()

with open("ssh_client.py","rb") as f:

    for line in f:   #文件较大的话，一次打开太占内存

        md5.update(line) #此方法和md5.update(f.read())的结果是一样的 和上面的效果是一样

print(md5.hexdigest()) # f.read()

 # by luffycity.com

 import socket

 import subprocess

 server = socket.socket()

 server.bind(('127.0.0.1',8008))

 server.listen(5)

 while True:

     print("server is working.....")

     conn,addr = server.accept()

     # 字节类型

     while True:

         # 针对window系统

         try:

             cmd = conn.recv(1024).decode("utf8") # 阻塞

             if cmd == b'exit':

                 break

             res=subprocess.Popen(cmd,

                              shell=True,

                              stderr=subprocess.PIPE,

                              stdout=subprocess.PIPE,

                              )

             # print("stdout",res.stdout.read())

             # print("stderr",res.stderr.read().decode("gbk"))

             out=res.stdout.read()

             err=res.stderr.read()

             print("out响应长度",len(out))

             print("err响应长度",len(err))

             if err:

                  import struct

                  header_pack = struct.pack("i", len(err))

                  conn.send(header_pack)

                  conn.send(err)

             else:

                  #构建报头

                  import struct

                  header_pack=struct.pack("i",len(out))

                  print("header_pack",header_pack)

                  # # 发送报头

                  conn.send(str(len(out)).encode("utf8"))

                  # 发送数据

                  conn.send(out)

         except Exception as e:

             break

     conn.close()

 import socket

 import struct

 sk = socket.socket()

 sk.connect(('127.0.0.1',8008))

 while 1:

     cmd = input("请输入命令：")

     sk.send(cmd.encode('utf-8')) # 字节

     if cmd=="":

         continue

     if cmd == 'exit':

         break

     # header_pack=sk.recv(4)

     # data_length=struct.unpack("i",header_pack)[0]

     # print("data_length",data_length)

     '''

     b'xxx/xxx/xxx/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb'

     '''

     data_length=int(sk.recv(1024).decode("utf8"))

     print("data_length",data_length)

     recv_data_length=0

     recv_data=b""

     while recv_data_length<data_length:

         data=sk.recv(1024)

         recv_data_length+=len(data)

         recv_data+=data

     print(recv_data.decode("gbk"))

 sk.close()