本文共 9141 字，大约阅读时间需要 30 分钟。

1. socket介绍

1.1 socket套接字

python中提供socket.py标准库，非常底层的接口库

socket是一种通用的网络编程接口，和网络层次没一一对应的关系

1.2 协议族

AF表示Address Family,用于socket()第一个参数

1.3 Socket类型

2. TCP编程

  socket编程，需要两端，一般来说需要一个服务端、一个客户端，服务端称为Server，客户端称为Client。这种编程模式也称为CS编程。

2.1 TCP服务端编程

2.1.1 服务端编程步骤

• 创建socket对象
• 绑定IP地址Address和端口Port。bind()方法，IPv4地址为一个二元组(‘IP地址字符串’，Port)
• 开始监听，将在指定的IP的端口上监听，listen()方法。
• 获取用于传送数据的socket对象。socket.accept() -> (socket object, address info) accept方法阻塞等待客户端建立连接，返回一个新的Socket对象和客户端地址的二元地址是远程客户端的地址，IPv4中它是一个二元组(clientaddr, port)
• 接收数据：recv(bufsize[, flags]) 使用缓冲区接收数据
• 发送数据：send(bytes)发送数据

TCP server端开发：

# TCP server 端开发import socket# import timeserver = socket.socket()  # TCP 连接 IPv4ip = '127.0.0.1'  # 本机回环地址，永远指向本机port = 9999  # 建议使用1000以上; TCP 65536种状态server.bind((ip, port))  # address,此方法只能绑定一次server.listen()  # 真正的显示出端口，监听不是阻塞函数# time.sleep(100)print(server)# print(server.accept())  # 默认阻塞，不懂千万不要修改new_socket, client_info = server.accept()print(new_socket)print('new_socket', client_info)while True:    # new_socket.send(b'server ack')    data = new_socket.recv(1024)  # 缺省情况下是阻塞的    print(data)    new_socket.send('server ack. data={}'.format(data.decode()))new_socket.close()# new2, client2 = server.accept()  # 新的连接，之前的连接已经关闭，并且两次连接可能在不同的进程# print(new2)# print('new2', client2)# data = new2.recv(1024)# print(data)# new2.send('server new2 ack. data={}'.format(data.encode()))# new2.close()server.close()

实战——写一个群聊程序

需求分析 聊天工具是CS程序，C是每一个客户端client，S是服务器端server 服务器应该具有的功能：

1. 启动服务，包括绑定地址和端口，并监听
2. 建立连接，能和多个客户端建立连接
3. 接收不同用户的信息
4. 分发，将接收的 某个用户的信息转发到已连接的所有客户端
5. 停止服务
6. 记录连接的客户端

代码实现

# tcp server 端开发import socketimport threadingimport loggingfrom datetime import datetimeFORMAT = "%(threadName)s %(thread)d %(message)s"logging.basicConfig(format=FORMAT, level=logging.INFO)class ChatServer:    def __init__(self, ip='127.0.0.1', port=9999):        self.sock = socket.socket()        self.address = ip, port        self.event = threading.Event()        self.lock = threading.Lock()        self.clients = {
   }    def start(self):        self.sock.bind(self.address)        self.sock.listen()        threading.Thread(target=self.accept, name='accept').start()    def accept(self):        while not self.event.is_set():            try:                new_sock, client_info = self.sock.accept()  # 阻塞等待连接            except Exception as e:                logging.error(e)            with self.lock:                self.clients[client_info] = new_sock                threading.Thread(target=self.rec, name='rec', args=(new_sock, client_info)).start()    def rec(self, sock, client):        while not self.event.is_set():            try:                data = sock.recv(1024)  # 阻塞等待接收信息，接收信息也可能出现异常            except Exception as e:                logging.error(e)                data = b''            print(data.decode(encoding='cp936'))            if data.strip() == b'quit' or data.strip() == b'':  # 客户端主动断开连接                with self.lock:                    self.clients.pop(client)  # 将断开连接的客户ip和端口从字典中移除，因为下文还要遍历字典                sock.close()  # 此句比较耗时，可以放在锁的外面                break            msg = "{:%Y/%m/%d %H:%M:%S} [{}:{}] - {}".format(datetime.now(), *client, data.decode(encoding='cp936'))            exc = []            exs = []            with self.lock:                for c, s in self.clients.items():  # 遍历的是时候不允许别人pop和add，所以加锁                    try:                        s.send(msg.encode(encoding='cp936'))  # 给所有的new_sock发送的信息。注意此句可能会出现异常，如网络断了                    except Exception as e:                        logging.error(e)                        exc.append(c)                        exs.append(s)                for c in exc:                    self.clients.pop(c)            for s in exs:  # 此句比较耗时，所以放在锁外面                s.close()    def stop(self):        self.event.set()        with self.lock:            values = list(self.clients.values())            self.clients.clear()  # 这是一个好习惯        for s in values:            s.close()        self.sock.close()cs = ChatServer()cs.start()while True:    cmd = input(">>>").strip()    if cmd == 'quit':        cs.stop()        break    logging.info(threading.enumerate())    logging.info(cs.clients)

socket常用方法

makefile

socket.makefile(mode=‘r’, buffering=None, *, encoding=None, error=None, newline=None) 创建一个与该套接字相关联的文件对象，将recv方法看做读方法，将send方法看做写方法。

import sockets = socket.socket()s.bind(('127.0.0.1', 9999))s.listen()s1, info = s.accept()print(s1.getpeername())  # ('127.0.0.1', 55934)print(s1.getsockname())  # ('127.0.0.1', 9999)f = s1.makefile('rw')data = f.read(10)  # 一次读取10个字节print(data)msg = 'server rec {}'.format(data)f.write(msg)f.flush()print(f, s1, sep='\n')f.close()s1.close()s.close()

makefile练习

使用makefile改写群聊类

import datetimeimport threadingimport socketimport loggingFORMAT = "%(asctime)s %(threadName)s %(thread)d %(message)s"logging.basicConfig(level=logging.INFO, format=FORMAT)class ChatServer:    def __init__(self, ip='127.0.0.1', port=9999):        self.sock = socket.socket()        self.address = ip, port        self.event = threading.Event()        self.clients = {
   }        self.lock = threading.Lock()    def start(self):        self.sock.bind(self.address)        self.sock.listen()        threading.Thread(target=self.accept, name='accept').start()    def accept(self):        while not self.event.is_set():            new_sock, client_info = self.sock.accept()            new_file = new_sock.makefile('rw')            with self.lock:                self.clients[client_info] = new_file, new_sock  # 增加了item，所以必须加锁，多线程处理同一个资源                threading.Thread(target=self.rec, name='rec', args=(new_file, client_info)).start()    def rec(self, f, client):        while not self.event.is_set():            line = f.readline()  # 阻塞等一行来，输入数据的时候要加换行符            print(line)            if line.strip() == 'quit' or line.strip() == '':  # line为字符串。不能再写成b''和b'quit'了                with self.lock:                    _, s = self.clients.pop(client)                f.close()                s.close()                break            msg = '{:%Y/%m/%d %H:%M:%S} [{}: {}] {}'.format(datetime.datetime.now(), *client, line)            # 此处的line不用解码了，因为readline读取的是字符串            with self.lock:                for ff, _ in self.clients.values():  # 注意ff不能与上面的f重复                    ff.write(msg)                    ff.flush()    # def rec(self, f, client):    #     while not self.event.is_set():    #         try:    #             line = f.readline()    #         except Exception as e:    #             logging.error(e)    #             line = 'quit'    #         msg = line.strip()    #         if msg == 'quit' or msg == '':    #             with self.lock:    #                 _, sock = self.clients.pop(client)    #                 f.close()    #                 sock.close()    #                 logging.info('{} quits.'.format(client))    #                 break    #         msg = '{:%Y/%m/%d %H:%M:%S} [{}: {}] {}'.format(datetime.datetime.now(), *client, line)    #         logging.info(msg)    #         with self.lock:    #             for ff, _ in self.clients.values():    #                 ff.write()    #                 ff.flush()    def stop(self):        self.event.set()        # keys = []        with self.lock:            for f, s in self.clients.values():                f.close()                s.close()        self.sock.close()def main():    cs = ChatServer()    cs.start()    while True:        cmd = input(">>>").strip()        if cmd == 'quit':            cs.stop()            threading.Event().wait(3)            break        logging.info(threading.enumerate())        logging.info(cs.clients)if __name__ == '__main__':    main()

2.2 客户端编程

2.2.1 客户端编程步骤

• 创建socket对象
• 连接到远端服务端的ip和port，connect()方法
• 传输数据：使用send、recv方法发送、接收数据
• 关闭连接，释放资源

import socketclient = socket.socket()ip_address = ('127.0.0.1', 9999)client.connect(ip_address)  # 直接连接服务器client.send(b'abc\n')data = client.recv(1024)  # 阻塞等待client.close()

import socketimport threadingimport datetimeimport loggingFORMAT = "%(threadName)s %(thread)d %(message)s"logging.basicConfig(format=FORMAT, level=logging.INFO)class ChatClient:    def __init__(self, ip='127.0.0.1', port=9999):        self.client = socket.socket()        self.address = ip, port        self.event = threading.Event()    def start(self):        self.client.connect(self.address)        self.send("I'm ready.")        threading.Thread(target=self.rec, name='rec').start()    def rec(self):        while not self.event.is_set():            try:                data = self.client.recv(1024)  # 此句可能会出现异常，如网络中断            except Exception as e:                logging.error(e)                break                            msg = "{:%Y/%m/%d %H:%M:%S} [{}:{}] {}".format(datetime.datetime.now(), *self.address, data)            logging.info(msg)    def send(self, msg: str):        data = "{}\n".format(msg.strip()).encode()        self.client.send(data)    def stop(self):        self.client.close()        self.event.wait(3)        self.event.set()        logging.info('Client stops')cc = ChatClient()cc.start()while True:    cmd = input(">>>").strip()    if cmd == 'quit':        cc.stop()        break    cc.send(cmd)

转载地址：http://opfvi.baihongyu.com/