# ！ /usr/bin/env python

 # -*- coding: utf-8 -*-

 # 编写回显服务器

 import socket

 import sys

 import argparse

 # 定义常量

 host = 'localhost'

 data_payload = 2048

 backlog = 5

 def echo_server(port):

     # 创建一个TCP socket

     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

     # 设置TCP套接字关联选项——重用地址

     sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

     # 建立套接字端口

     server_address = (host, port)

     print("Starting up echo server on %s port %s" % server_address)

     # 将socket绑定到server_address地址

     sock.bind(server_address)

     # 监听客户端

     # 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。

     # 这里设定为5

     sock.listen(backlog)

     # 在调用 Listen 之前，必须首先调用 Bind 方法，否则 Listen 将引发 SocketException。

     while True:

         print("Waiting to receive message from client")

         # 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。

         # accept方法返回一个含有两个元素的 元组(connection,address)。第一个元素connection

         # 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。

         client, address = sock.accept()

         # 指定data最大长度为2048字节

         data = client.recv(data_payload)

         if data:

             print("Data: %s" % data)

             client.send(data)

             print("sent %s bytes back to %s" % (data, address))

         # 关闭连接

         client.close()

 if __name__ == '__main__':

     # 创建一个解析对象,其中描述为"Socket Error Examples"

     parser = argparse.ArgumentParser(description='Socket Server Example')

     # 采用add_argument方法

     # name or flags —— 必须的参数，该参数接收选项参数或者是位置参数

     # action：

         # (1)store —— 默认action模式，储存值到指定变量

         # (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

         # (3)store_true/store_false —— 布尔开关。可以2个参数对应一个变量

         # (4)append —— 储存值到列表，储存值在参数的const部分指定

         # (5)append_const —— 储存值到列表，储存值在参数的const部分指定

         # (6)version —— 输出版本信息然后退出

     # 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  

     # 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

     # dest —— 把位置或者选项关联到一个特定的名字

     parser.add_argument('--port', action="store", dest="port", type=int, required=True)

     # 调用parse_args()方法进行解析

     given_args = parser.parse_args()

     port = given_args.port

     echo_server(port)

 def bind(self, address):  # real signature unknown; restored from __doc__

     """

     bind(address)

     Bind the socket to a local address.  For IP sockets, the address is a

     pair (host, port); the host must refer to the local host. For raw packet

     sockets the address is a tuple (ifname, proto [,pkttype [,hatype]])

     """

     pass

 def listen(self, backlog=None):  # real signature unknown; restored from __doc__

     """

     listen([backlog])

     Enable a server to accept connections.  If backlog is specified, it must be

     at least 0 (if it is lower, it is set to 0); it specifies the number of

     unaccepted connections that the system will allow before refusing new

     connections. If not specified, a default reasonable value is chosen.

     """

     pass

 # ！ /usr/bin/env python

 # -*- coding: utf-8 -*-

 # 编写回显客户端

 import socket

 import sys

 import argparse

 host = 'localhost'

 def echo_client(port):

     # 创建TCP socket连接

     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

     # 获取服务器端host和端口号

     server_address = (host, port)

     print("Connecting to %s port %s" % server_address)

     sock.connect(server_address)

     try:

         # 将message内容发送到服务器端

         message = "Test message, This will be echoed"

         print("Sending %s" % message)

         # python2和python3此处不同

         # python2—— sock.sendall(message)

         # sendall()发送完整的TCP数据，成功返回None，失败抛出异常

         sock.sendall(message.encode())

         # 服务器端将发送的数据回传给客户端并打印

         amount_received = 0

         amount_expected = len(message)

         while amount_received < amount_expected:

             data = sock.recv(1024)

             amount_received += len(data)

             print("Received: %s" % data)

     # 处理相对应错误

     except socket.error as e:

         print("socket error: %s" % str(e))

     except Exception as e:

         print("Other exception: %s" % str(e))

     finally:

         print("Closing connection to the server")

         sock.close()

 if __name__ == '__main__':

     parser = argparse.ArgumentParser(description='Socket Server Example')

     parser.add_argument('--port', action="store", dest="port", type=int, required=True)

     given_args = parser.parse_args()

     port = given_args.port

     echo_client(port)