Python Network Programming 2018-01-26 update

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SSH Service side

# 1.接收一个连接实例# 2.接收数据# 3.判断数据是否为空# 4.执行命令# 5.判断命令执行结果# 6.发送命令结果长度# 7.发送命令执行结果import socket,osserver=socket.socket()server.bind(("localhost",22))  #绑定要监听的端口server.listen()  #开始监听while True:    conn,addr=server.accept()  #接收一个客户端实例conn，addr为其地址    print("new conn:",addr)    while True:        data=conn.recv(1024)        if not data:            print("客户端断开")            break        print("执行命令：",data.decode())        cmd_res=os.popen(data.decode()).read()        if len(cmd_res)==0:            cmd_res="wrong"        conn.send(str(len(cmd_res.encode())).encode())        client_ack=conn.recv(1024)  #等待客户端响应，防止粘包        conn.send(cmd_res.encode())        print("等待新指令")server.close()

SSH Client

import socketclient=socket.socket()client.connect(("localhost",22))while True:    cmd=input(">>:").strip()    if len(cmd)==0:continue    client.send(cmd.encode())    cmd_res_size=client.recv(1024) #接收命令结果的长度    client.send("准备好了".encode())    recv_size=0    while recv_size<int(cmd_res_size.decode()):        cmd_res=client.recv(1024)        recv_size+=len(cmd_res)        print(cmd_res.decode())    print("命令结果大小：",cmd_res_size.decode())    print("已接受结果大小:",recv_size)client.close()

FTP Service side

# 1.检测文件是否存在# 2.发送文件大小给客户端# 3.打开文件,开始边读边发数据# 4.发送md5import socket,os,hashlibserver=socket.socket()server.bind(("0.0.0.0",2121))server.listen()while True:    conn,addr=server.accept()    print("new conn:",addr)    while True:        data=conn.recv(1024)        if not data:            print("client lost")            break        cmd,filename=data.decode().split()        if os.path.isfile(filename):            with open(filename,"rb") as f:                file_size=os.stat(filename).st_size                print(file_size)                conn.send(str(file_size).encode())                conn.recv(1024)                m=hashlib.md5()                for line in f:                    m.update(line)                    conn.send(line)                print("file md5:",m.hexdigest())                conn.recv(1024)                conn.send((m.hexdigest()).encode())        print("send done")server.close()

FTP client

import socketclient=socket.socket()client.connect(("0.0.0.0",2121))while True:    cmd=input(">>:").strip()    if len(cmd)==0:continue    if cmd.startswith("get"):        client.send(cmd.encode())        file_size=client.recv(1024)        client.send(b"ready to recv data")        recv_size=0        filename=cmd.split()[1]        with open(filename+".new","wb") as f:            while recv_size<int(file_size.decode()):                data=client.recv(1024)                recv_size+=len(data)                f.write(data)        client.send(b"over")        print(recv_size)        print(file_size.decode())        file_md5=client.recv(1024)        print("file md5:",file_md5.decode())        print("recv done")client.close()

Python Network Programming 2018-01-26 update