Python实现SocketServer(一)

说明

TCP 服务器是web后端开发必须学习的一环，此文章记录了我个人在学习python web开发过程中开发SocketServer的流程

Socket通信流程

网上找的图

逐步实现SocketServer

实现单次Soket Server与Client逻辑

依照以上述逻辑，使用python 标准库socket 模块实现单次接收/发送的Server/Client.

注：开始未将代码写成类是应为个人觉得OOP主要用来复用代码、解耦、抽象化复杂对象，对于第一步来说，使用类反而会让整个TCPServer创建流程不够直观。因此我会在后面需要的步骤将其重构为类

socket构造参数

参数	值	含义
family	默认为AF_INET	协议簇,指定socket使用的协议，默认使用IPv4协议簇
type	默认值未SOCKET_STREAM	指定套接字类型，默认为流式套接字
proto	默认值为0	指定套接字使用协议簇中的哪个协议，默认为TCP协议
fileno	默认值为None	指定socket打开的文件描述符

socket常用方法

方法	参数	含义
bind()	address	绑定socket到特点的ip和port上，形式为(‘127.0.0.1’, 80)
listen()		开始监听请求
accept()		接收请求，在未收到请求时阻塞
send()	bytes、flags(可选)	发送二进制数据，flags是一系列标志，可以控制发送的行为
rcev()	buffersize, flags(可选)	指定接收缓冲区的大小，flags可控制接收行为

其他的方法不列举了，以后用到在写.

Code

Client Code

#!/usr/bin/env python3
# encoding: utf-8

from socket import socket, AF_INET, SOCK_STREAM

def client(server_addr, msg):
"""
This function is a simple client to connect to TCPserver.

Args:
server_addr: String of Server IP address.
msg: The message that you want to send to server.It't type can
be str or bytes
"""
with socket(AF_INET, SOCK_STREAM) as sock  # TCP/IPv4 Socket
sock.connect(server_addr)
if not isinstance(msg, bytes):
msg = bytes(msg, 'utf-8')
sock.send(msg)
data = sock.recv(4096)
print(data.decode('utf-8'))

if __name__ == '__main__':
client(('127.0.0.1', 8080), "I'm client.")

ServerCode

#!/usr/bin/env python3
# encoding: utf-8
from socket import socket as Socket, AF_INET, SOCK_STREAM
from sys import exit, stderr
import logging

logging.basicConfig(
level=logging.INFO,
stream=stderr,
format="[%(levelname)s] %(asctime)s %(message)s"
)
log = logging.getLogger('SocketServer')

def check_addr(address):
"""
Check server address format
Not complete. TODO
"""
# check address
if len(address) < 2:
exit("You miss ip address or port.")
ip_addr, port = address

# Check port format
if isinstance(port, str):
try:
port = int(port)
except ValueError:
exit("Error Port Number: %s" % port)
return (ip_addr, port)

def recv_msg(socket):
"""Receive message from client"""
data = socket.recv(4096)
if isinstance(data, bytes):
data = data.decode('utf-8')
log.info("The receive data from client is: %s", data)

def send_msg(socket, msg):
"""Send message to client"""
socket.send(bytes(msg, 'uft-8'))
log.info("Send '%s' to client", msg)

def server(address=None, *, ip_addr=None, port=None):
"""
This is a simple TcpServer.It can receive data once from client.

Args:
ip_addr: String of ip address which server bind.
port: The port number which server bind. Type can be int or str.
address: Tuple like ('127.0.0.1', 80). Contain ip_addr and port. If
you use ip_addr or port with address param, it will override these.
"""
if not address:
address = (ip_addr, port)
address = check_addr(address)

with Socket(AF_INET, SOCKET_STREAM) as socket:
socket.bind(address)
s, _ = socket.accept()
recv_msg(s)
send_msg(s, 'Hello')

log.info("The Tcp Server close.")

if __name__ == "__main__":
server(('127.0.0.1', 8080))

接下来的计划

下面这些问题将在下一篇文章中解决

- 实现服务端接收多个client访问

- 当server处理程序消耗时间长时提高server处理效率