Socket网路编程

1.简单实例

import socket

client = socket.socket()  #声明Socket类型，同时生成socket连接对象
client.connect(('localhost',6969))
client.send(b'hello,world!')
data = client.recv(1024)
print("recv:",data)
client.close()

import socket

server = socket.socket()
server.bind(('localhost',6969)) # 绑定
server.listen() # 监听
print("等待电话")
#conn就是客户端连过来而在服务器端为其生成一个连接实例
conn,addr = server.accept()  #等待
print(conn,addr)
print("电话来了")
data = conn.recv(1024)
print("recv:",data)
conn.send(data.upper())
server.close()

 2.通过socket 实现简单的ssh  。客户端连接上服务器后，服务器执行命令，并返回结果给客户端

import socket
import os

server = socket.socket()
server.bind(('localhost',9969))
server.listen()

while True:
    conn,addr = server.accept()
    print("new conn:",addr)
    while True:
        data = conn.recv(1024)
        if not data:
            print("客户端已经断开")
            break
        print("执行指令")
        cmd_res = os.popen(data.decode("utf-8")).read()
        if len(cmd_res) == 0:
            cmd_res = "cmd has no output!"
        #conn.send(cmd_res.encode("utf-8"))  # send这里发送数据，客户端接受的数据buf不够，把剩下的放在缓冲区，下一次调用send，假设这里的只有900多数据，但是这里只会先把缓冲区的发出去，
                                            # 剩下的放在缓冲区，等待下次发送。所以会出现返回结果混乱的问题。缓存区可提高 io 效率
        
server.close()

import socket

client = socket.socket()
client.connect(('localhost',9969))

while True:
    cmd = input(">>:").strip()
    if len(cmd) == 0:continue
    client.send(cmd.encode('utf-8'))
    cmd_res = client.recv(1024)
    print(cmd_res.decode())

client.close()

 3.完整版简单ssh，解决数据混乱（即缓冲区可能一次不能发完的事件）

import socket
client = socket.socket()
client.connect(('localhost',6969))
while True:
    cmd = input(">>:").strip()
    if len(cmd) == 0:continue
    client.send(cmd.encode("utf-8"))
    cmd_res_size =client.recv(2048)
    print("接受命令执行结果的长度,",cmd_res_size)
    received_size = 0
    received_data = b''
    while received_size < int(cmd_res_size):
        data = client.recv(2048)
        received_size += len(data)
        print(received_size)
        received_data += data
    else:
        print("cmd res receive done....",received_size)
        print(received_data.decode())

client.close()

# 接受命令执行结果的长度, b'1141'
# 1141
# cmd res receive done.... 1141
# 
# Windows IP 配置

import socket
import os
server = socket.socket()
server.bind(('localhost',6969))
server.listen()

while True:
    conn,addr = server.accept()
    print("等待conn:",addr)
    while True:
        data = conn.recv(2048)
        print("收到")
        if not data:
            print("客户端已经断开")
            break
        print("执行指令",data.decode())
        cmd_res = os.popen(data.decode()).read()
        if len(cmd_res) == 0:
            cmd_res = "cmd has no out put"
        conn.send(str(len(cmd_res.encode("utf-8"))).encode("utf-8"))   #可能存在中文，因为中文占三个字节，所以这里先把结果encode，在len，str，encode
        conn.send(cmd_res.encode("utf-8"))

server.close()