web框架本质

来个简单的socket服务端

#!/usr/bin/env python

import socket

def handle_request(client):
    buf = client.recv(1024)
    client.send("HTTP/1.1 200 OK\r\n\r\n".encode())
    client.send('<h1>Hollo,Boy</h1>'.encode())
    
    
def main():
    sock = socket.socket()
    sock.bind(('localhost',80))
    sock.listen(5)
    
    while True:
        connection, address = sock.accept()
        handle_request(connection)
        connection.close()
        
    
if __name__ == "__main__":
    main()

上述通过socket来实现了其本质，而对于真实开发中的python web程序来说，一般会分为两部分：服务器程序和应用程序。服务器程序负责对socket服务器进行封装，并在请求到来时，对请求的各种数据进行整理。应用程序则负责具体的逻辑处理。

python标准库提供的独立WSGI服务器称为wsgiref

WSGI（Web Server Gateway Interface）是一种规范，它定义了使用python编写的web app与web server之间接口格式，实现web app与web server间的解耦。

from wsgiref.simple_server import make_server
 
 
def RunServer(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    return [bytes('<h1>Hello, web!</h1>', encoding='utf-8'), ]
 
 
if __name__ == '__main__':
    httpd = make_server('', 8000, RunServer)
    print("Serving HTTP on port 8000...")
    httpd.serve_forever()

自定义web框架

通过python标准库提供的wsgiref模块开发一个自己的Web框架

#!/usr/bin/env python
#coding:utf-8
from wsgiref.simple_server import make_server
 
def index():
    return ['index',]
 
def login():
    return ['login',]
 
def routers():
     
    urlpatterns = (
        ('/index/',index),
        ('/login/',login),
    )
     
    return urlpatterns
 
def RunServer(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    url = environ['PATH_INFO']
    urlpatterns = routers()
    func = None
    for item in urlpatterns:
        if item[0] == url:
            func = item[1]
            break
    if func:
        return func()
    else:
        return [b'404 not found',]
     
if __name__ == '__main__':
    httpd = make_server('', 8000, RunServer)
    print("Serving HTTP on port 8000...")
    httpd.serve_forever()