python socket

模拟ssh

server:

import socket
import os

server=socket.socket(socket.AF_INET, socket.SOCK_STREAM)  #定义socket,使用tcp协议
server.bind(('127.0.0.1',5000))  #绑定5000端口
server.listen(5)
n=1
while True:#循环接收客户端连接请求
    ip,addr=server.accept()#接受客户端连接请求
    while True:#循环接受客户端信息
        data=ip.recv(1024)  #buffer1024,最大为8196
        if data:#如果data不为空
            print(n)
            n+=1
            msg=os.popen(data.decode('gb2312')).read()  #执行客户端查询命令
            if not msg:#如果命令错误
                msg='sorry,no output!!!'
            msg=msg.encode('gb2312')#查询结果encode为bytes
            l=str(len(msg)).encode('gb2312')#将结果的长度变成byte返回给客户端
            ip.send(l)
                ip.recv(1024) #防止粘包
            ip.send(msg)
        else:
            break

server.close()

client:

import socket
import time
cli=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
cli.connect(('127.0.0.1',5000))#连接5000端口
while True:#循环发送和接受
    msg=input('>:')#输入命令
    cli.send(msg.encode('gb2312'))#发送命令
    print('send is ok')
    data=cli.recv(1024)#接受结果的长度
    n=int(int(data.decode())/1024)+1 #判断结果需要几次接受完毕,例如n=int(2244/1024)+1
    cli.send(b'ok') #防止粘包
     r=b''
    for i in range(n):#循环接受打印
        r+=cli.recv(1024)
    print(r.decode('gb2312'))

模仿ftp 

server:

import socket
import os
import hashlib
server=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
server.bind(('127.0.0.1',9999))
server.listen(6)
cli,addr=server.accept()
n=0

# D:\firefox下载\mysql-connector-java.jar
while True:
    n+=1
    print(n)
    file=cli.recv(1024)#文件路径
    d=file.decode('utf-8')
    j=os.path.isfile(file) #判断文件是不是存在
    if j:#文件存在
        s=os.path.getsize(file)
        cli.send(str(s).encode('utf-8'))
        cli.recv(1024)
        m=hashlib.md5()
        with open(file,'rb') as f:
            for line in f:
                m.update(line)
                cli.send(line)
        cli.recv(1024)
        md=m.hexdigest()
        cli.send(md.encode('utf-8'))
    else:
        break

client:

import socket,os
import hashlib
cli = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
cli.connect(('127.0.0.1', 9999))
while True:
    file = input('>')
    base=os.path.splitext(file)[0]+'_cp'+os.path.splitext(file)[1]
    print(base)
    if file:
        cli.send(file.encode('utf-8'))
        size=cli.recv(1024)
        size=int(size.decode('utf-8'))
        print(size)
        cli.send(b'ok,ready to receive')
        recv_size=0
        m=hashlib.md5()
        with open(base,'wb') as f:
            while recv_size<size:
                last=size-recv_size
                if last>1024:
                     d=cli.recv(1024)
                else:
                     d=cli.recv(last)
                m.update(d)
                recv_size+=len(d)
                f.write(d)
        cli.send(b'copy completely')
        md_server=cli.recv(1024)
        md_client=m.hexdigest()
        if md_client==md_server.decode('utf-8'):
             print('copy really completely')
    else:
        continue