今天将python中socket模块的基本API学习完后，照着书上的实例编写一个套接字服务器和客户端。采用python3.5版本，在注释中会标明python2和python3的不同之处。
1.代码
(1)服务器端及对应代码解释
1 # ！ /usr/bin/env python
2 # -*- coding: utf-8 -*-
3 # 编写回显服务器
4
5 import socket
6 import sys
7 import argparse
8
9 # 定义常量
10 host = ‘localhost‘
11 data_payload = 2048
12 backlog = 5
13
14
15 def echo_server(port):
16
17 # 创建一个TCP socket
18 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
19
20 # 设置TCP套接字关联选项——重用地址
21 sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
22
23 # 建立套接字端口
24 server_address = (host, port)
25 print("Starting up echo server on %s port %s" % server_address)
26
27 # 将socket绑定到server_address地址
28 sock.bind(server_address)
29
30 # 监听客户端
31 # backlog指定最多允许多少个客户连接到服务器。它的值至少为1。收到连接请求后，这些请求需要排队，如果队列满，就拒绝请求。
32 # 这里设定为5
33 sock.listen(backlog)
34 # 在调用 Listen 之前，必须首先调用 Bind 方法，否则 Listen 将引发 SocketException。
35 while True:
36 print("Waiting to receive message from client")
37
38 # 调用accept方法时，socket会时入“waiting”状态。客户请求连接时，方法建立连接并返回服务器。
39 # accept方法返回一个含有两个元素的 元组(connection,address)。第一个元素connection
40 # 是新的socket对象，服务器必须通过它与客户通信；第二个元素 address是客户的Internet地址。
41 client, address = sock.accept()
42
43 # 指定data最大长度为2048字节
44 data = client.recv(data_payload)
45 if data:
46 print("Data: %s" % data)
47 client.send(data)
48 print("sent %s bytes back to %s" % (data, address))
49 # 关闭连接
50 client.close()
51
52 if __name__ == ‘__main__‘:
53 # 创建一个解析对象,其中描述为"Socket Error Examples"
54 parser = argparse.ArgumentParser(description=‘Socket Server Example‘)
55 # 采用add_argument方法
56 # name or flags —— 必须的参数，该参数接收选项参数或者是位置参数
57 # action：
58 # (1)store —— 默认action模式，储存值到指定变量
59 # (2)store_const —— 储存值在参数的const部分指定，多用于实现非布尔的命令行flag
60 # (3)store_true/store_false —— 布尔开关。可以2个参数对应一个变量
61 # (4)append —— 储存值到列表，储存值在参数的const部分指定
62 # (5)append_const —— 储存值到列表，储存值在参数的const部分指定
63 # (6)version —— 输出版本信息然后退出
64 # type —— 把从命名行输入的结果转成设置的类型，通常用来检查值的范围，以及合法性。默认string
65 # required —— 指定某个选项在命名中出现， 默认False, 若为 True, 表示必须输入该参数
66 # dest —— 把位置或者选项关联到一个特定的名字
67 parser.add_argument(‘--port‘, action="store", dest="port", type=int, required=True)
68 # 调用parse_args()方法进行解析
69 given_args = parser.parse_args()
70 port = given_args.port
71 echo_server(port)
72
73 def bind(self, address): # real signature unknown; restored from __doc__
74 """
75 bind(address)
76
77 Bind the socket to a local address. For IP sockets, the address is a
78 pair (host, port); the host must refer to the local host. For raw packet
79 sockets the address is a tuple (ifname, proto [,pkttype [,hatype]])
80 """
81 pass
82 def listen(self, backlog=None): # real signature unknown; restored from __doc__
83 """
84 listen([backlog])
85
86 Enable a server to accept connections. If backlog is specified, it must be
87 at least 0 (if it is lower, it is set to 0); it specifies the number of
88 unaccepted connections that the system will allow before refusing new
89 connections. If not specified, a default reasonable value is chosen.
90 """
91 pass
服务器端代码
(2)客户端及对应代码解释
1 # ！ /usr/bin/env python
2 # -*- coding: utf-8 -*-
3 # 编写回显客户端
4
5 import socket
6 import sys
7 import argparse
8
9 host = ‘localhost‘
10
11
12 def echo_client(port):
13 # 创建TCP socket连接
14 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
15 # 获取服务器端host和端口号
16 server_address = (host, port)
17 print("Connecting to %s port %s" % server_address)
18 sock.connect(server_address)
19
20 try:
21 # 将message内容发送到服务器端
22 message = "Test message, This will be echoed"
23 print("Sending %s" % message)
24 # python2和python3此处不同
25 # python2—— sock.sendall(message)
26 # sendall()发送完整的TCP数据，成功返回None，失败抛出异常
27 sock.sendall(message.encode())
28
29 # 服务器端将发送的数据回传给客户端并打印
30 amount_received = 0
31 amount_expected = len(message)
32 while amount_received < amount_expected:
33 data = sock.recv(1024)
34 amount_received += len(data)
35 print("Received: %s" % data)
36 # 处理相对应错误
37 except socket.error as e:
38 print("socket error: %s" % str(e))
39 except Exception as e:
40 print("Other exception: %s" % str(e))
41 finally:
42 print("Closing connection to the server")
43 sock.close()
44
45 if __name__ == ‘__main__‘:
46 parser = argparse.ArgumentParser(description=‘Socket Server Example‘)
47 parser.add_argument(‘--port‘, action="store", dest="port", type=int, required=True)
48 given_args = parser.parse_args()
49 port = given_args.port
50 echo_client(port)
客户端代码
(3)运行结果
1 1. 服务器端 2 Abel$ python3 1_13a_echo_server.py --port=9900 3 Starting up echo server on localhost port 9900 4 Waiting to receive message from client 5 6 2.客户端发送数据时，服务器端 7 Data: b‘Test message, This will be echoed‘ 8 sent b‘Test message, This will be echoed‘ bytes back to (‘127.0.0.1‘, 62389) 9 Waiting to receive message from client 10 11 3.客户端 12 Abel$ python3 1_13b_echo_client.py --port=9900 13 Connecting to localhost port 9900 14 Sending Test message, This will be echoed 15 Received: b‘Test message, This will be echoed‘ 16 Closing connection to the server
时间： 2024-12-25 04:18:25