博客整理day27

python day27

目录

• python day27
  • subprocess模块
  • 粘包
  • 上传大文件
  • UDP
  • QQ聊天室(基于UDP)
  • socketServer

subprocess模块

subprocess:

​ 可以通过代码,去执行系统的终端命令,并返回终端执行命令后的结果

import subprocess

cmd = input('cmd:')
obj = subprocess.Popen(
	cmd,
    #Shell=True
    shell = True
    #返回正确结果参数
    stdout = subprocess.PIPE
    #返回错误结果参数error
    stderr = subprocess.PIPE
)
result = obj.stdout.read()+obj.stderr.read()
print(reault.decode('gbk'))

粘包

粘包问题:

​ 服务端第一次发送的数据,与客户端无法精确一次性接收完毕,下一次发送的数据与上一次数据粘在一起了

​ 1.无法预知对方需要接收的数据大小

​ 2.多次连续发送数据量小,并且时间间隔短的数据会一次性打包发送

TCP协议特性:

​ tcp是一个流式协议,会将多次连续发送数据量小,并且时间间隔短的数据一次性打包发送

解决粘包问题:

struct模块

必须先定义报头,发送报头,再发送真实数据

当既想发送文件,又想发送文件的描述信息

​ 客户端发送字典给服务端

​ send_dic = {

​ file_name : 文件名

​ file_size : 文件的真实长度

​ }

​ #通过json模块序列化成bytes数据

​ json_data = json.dumps(send_dic)

​ bytes_data = json_data.encode('utf8')

​ #先获取字典的报头

​ headers = struct.pack('i',len(bytes_data))

​ #服务端接收到字典,并接收文件的真实数据

import socket
import struct
import subprocess

server = socket.socket()

server.bind(('192.168.13.161',8888))
server.listen(5)
while True:
    conn,addr = server.accept()
    while True:
        try:
            cmd = conn.recv(1024).decode('utf8')
            if cmd == 'q':
                break
            if len(cmd)==0:
                continue
            print(cmd)
            obj = subprocess.Popen(
                cmd,
                shell=True,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE
            )
            result = obj.stdout.read()+obj.stderr.read()
            headers = struct.pack('i',len(result))
            conn.send(result)
        except Exception as e:
            print(e)
            break
    conn.close()

上传大文件

客户端往服务端上传大文件:

#Client
import socket
import json
import struct

client = socket.socket()

client.connect(('192.168.13.202', 9526))
with open(r'E:	he truth that you leave.mp3','rb') as f:
    music_bytes = f.read()
send_dic = {
    'file_name':'the truth that you leave.mp3',
    'file_size':len(music_bytes)
}
json_data = json.dumps(send_dic)
bytes_data = json_data.encode('utf8')
headers = struct.pack('i',len(bytes_data))
client.send(headers)
client.send(bytes_data)

init_data = 0
with open(r'E:	he truth that you leave.mp3','rb') as f:
    while init_data<len(music_bytes):
        send_data = f.read(1024)
        print(send_data)
        client.send(send_data)
        init_data += len(send_data)

client.close()

#Server
import socket
import struct
import json

server = socket.socket()
server.bind(('192.168.13.202', 9526))
server.listen(5)
while True:
    conn, addr = server.accept()
    try:
        headers = conn.recv(4)

        data_len = struct.unpack('i', headers)[0]

        bytes_data = conn.recv(data_len)
        back_dic = json.loads(bytes_data.decode('utf8'))

        file_name = back_dic.get('file_name')
        file_size = back_dic.get('file_size')
        init_data = 0

        with open(file_name, 'wb') as f:
            while init_data < file_size:
                data = conn.recv(1024)
                f.write(data)
                init_data += len(data)

            print(f'{file_name}接收完毕!')
    except Exception as e:
        print(e)
        break
conn.close()

UDP

udp是一种传输协议

​ 1.不需要建立双向管道

​ 2.不会粘包

​ 3.客户端给服务端发送数据,不需要等待服务端返回成功

​ 4.数据容易丢失,数据不安全

TCP : 就好比打电话

UDP : 就好比发短信

QQ聊天室(基于UDP)

#Server
import socket

server = socket.socket()

server.bind(('192.168.13.202', 9526))

while True:
    msg,addr = server.recvfrom(1024)
    print(addr)
    print(msg.decode('utf-8'))
    send_msg = input('server-->client:').encode('utf8')

    server.sendto(send_msg,addr)

#Client
import socket

client = socket.socket()
server_port = (('192.168.13.202', 9526))

while True:
    send_msg = input('client -- > server:').encode('utf8')
    msg = client.recv(1024)

    print(msg.decode('utf-8'))

socketServer

​ python内置模块,可以简化socket套接字服务端的代码

• 简化TCP与UDP服务端代码
• 必须要创建一个类

import socketserver

# 定义类
# TCP: 必须继承BaseRequestHandler类
class MyTcpServer(socketserver.BaseRequestHandler):
    # 必须重写父类的handle
    def handle(self):

        # 1.接收消息
        print(data)
        # 2.给客户端发送消息
        send_msg = input('服务端: ').encode('utf-8')
        self.request.send(send_msg)

if __name__ == '__main__':
    socketserver.TCPServer.allow_reuse_address = True
    server = socketserver.TCPServer(
        ('192.168.13.202', 9526), MyTcpServer
    )

    # 永久执行服务
    server.serve_forever()