Python学习笔记Day08

目录

• 1.网络协议：http,smtp,dns,ftp,ssh, snmp, icmp, dhcp
• 2.socket:将send,receive封装，协议直接调用即可
• 3.ip与port
• 4.粘包：连续send两次，缓冲区会导致两次数据粘在一起发送（可以插入一次recv）
• 5.socket模拟
  • socket服务端
  • socket客户端
• 6.ftp模拟
  • ftp服务端
  • ftp客户端
• 7.socketserver:对socket的封装，简化

https://www.cnblogs.com/alex3714/articles/5227251.html

1.网络协议：http,smtp,dns,ftp,ssh, snmp, icmp, dhcp

本质上只做send，receive两件事

2.socket:将send,receive封装，协议直接调用即可

3.ip与port

4.粘包：连续send两次，缓冲区会导致两次数据粘在一起发送（可以插入一次recv）

5.socket模拟

socket服务端

import socket
import os


server = socket.socket()  # 1创建服务器socket
server.bind(('0.0.0.0', 9999))  # 2绑定端口
server.listen()  # 3监听
print('开始等电话')
conn, addr = server.accept()  # 4收到请求，创建新连接实例
print(conn, addr)
print('收到电话')
while True:
    data = conn.recv(1024)  # 5接收数据，大小1024bites
    if not data:
        print('客户端已断开')
        break
    conn.send(data.upper())
    print('返回其大写')

server.close()

socket客户端

import socket


client = socket.socket()    #1声明socket类型，同时生成socket连接对象
client.connect(('localhost',9999))  #2连接端口

while True:
    msg = input('>>:').strip()
    if len(msg) == 0:continue
    client.send(msg.encode())   #3发送信息
    serverResponse = client.recv(1024)  #4接收信息
    print('server response:',serverResponse.decode())

6.ftp模拟

ftp服务端

import socket
import hashlib
import os

server = socket.socket()  # 创建服务器
server.bind(('0.0.0.0', 9999))  # 绑定端口
server.listen()  # 监听
while True:  # 多用户
    conn, addr = server.accept()  # 收到请求，创建新连接
    print('new coon:', addr)
    while True:  # 循环接收指令
        print('等待新指令')
        data = conn.recv(1024)  # 接收数据，大小1024bites
        if not data:
            print('客户端已断开')
            break
        cmd, filename = data.decode().split()
        print(filename)
        if os.path.isfile(filename):  # 确认文件存在
            with open(filename, 'rb') as f:
                # m = hashlib.md5()
                m = hashlib.md5(f.read())
                f.seek(0)
                fileSize = os.stat(filename).st_size
                conn.send(str(fileSize).encode())  # 返回文件总大小
                conn.recv(1024)  # 等待确认
                print('正在发送文件')
                sentSize = 0
                for line in f:
                    # m.update(line)
                    conn.send(line)
                    sentSize += len(line)
                print('已发送', sentSize)
            conn.send(m.hexdigest().encode())
            print('文件发送完毕')

ftp客户端

import socket
import hashlib

client = socket.socket()
client.connect(('localhost', 9999))
while True:
    cmd = input('>>:').strip()
    if len(cmd) == 0: continue
    if cmd.startswith('get'):
        client.send(cmd.encode())
        serverResponse = client.recv(1024)
        print('fileSize:', serverResponse)
        client.send(b'ready to recv file')
        fileSize = int(serverResponse.decode())
        filename = cmd.split()[1]
        suffix = filename.rsplit('.', 1)[1]
        newFilename = '%s_new.%s' % (filename.rstrip('.%s' % suffix), suffix)
        with open(newFilename, 'wb') as f:
            recvSize = 0
            m = hashlib.md5()
            while recvSize < fileSize:
                if fileSize - recvSize > 1024:  # 不止一次
                    size = 1024
                else:
                    size = fileSize - recvSize
                data = client.recv(size)
                recvSize += len(data)
                m.update(data)
                f.write(data)
            else:
                newMd5 = m.hexdigest()
                print('文件接收完毕：', recvSize)
                print('new md5:',newMd5)
        originMd5 = client.recv(1024).decode()
        print('origin md5:',originMd5)
        if newMd5 == originMd5:
            print('文件成功接收')
        else:
            print('文件传输错误')

client.close()

7.socketserver:对socket的封装，简化

import socketserver

class MyTCPHandler(socketserver.BaseRequestHandler):
    def handle(self):
        while True:
            try:
                self.data = self.request.recv(1024).strip()
                print(self.data)
            except ConnectionResetError as e:
                print('error:', e)
                break

if __name__ == "__main__":
    HOST, PORT = "localhost", 9999
    # Create the server, binding to localhost on port 9999
    server = socketserver.ThreadingTCPServer((HOST, PORT), MyTCPHandler)
    server.serve_forever()