python web 框架的本质

Posted 2020-09-21

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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。

python标准库提供的独立WSGI服务器称为wsgiref。

 1 from wsgiref.simple_server import make_server
 2  
 3  
 4 def RunServer(environ, start_response):
 5     start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
 6     return [bytes(‘<h1>Hello, web!</h1>‘, encoding=‘utf-8‘), ]
 7  
 8  
 9 if __name__ == ‘__main__‘:
10     httpd = make_server(‘‘, 8000, RunServer)
11     print("Serving HTTP on port 8000...")
12     httpd.serve_forever()

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详解environ参数的由来

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简单的从用户输入中获取url,并处理请求

 1 #!usr/bin/env python
 2 #-*- coding:utf-8 -*-
 3 
 4 # wsgiref遵循了WSGI规范,内部帮我们实现了socket,
 5 from wsgiref.simple_server import make_server
 6 
 7 def new():
 8     f=open("reg.html","r")
 9     data=f.read()
10     f.close()
11     return data
12 def index():
13     return "index"
14 URLS={
15     "/new":new,
16     "/index":index,
17 }
18 def RunServer(environ, start_response):
19     start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
20     url=environ[‘PATH_INFO‘]
21     if url=="/index":
22         ret=index()
23     elif:url=="/new"
24         ret=new()
25     else:
26         ret="404"
27     return ret
28 if __name__ == ‘__main__‘:
29     httpd = make_server(‘‘, 8000, RunServer)
30     httpd.serve_forever()

View Code

这样写业务逻辑非常的不好,一旦url很多,就非常的麻烦,改进如下:

 1 #!usr/bin/env python
 2 #-*- coding:utf-8 -*-
 3 
 4 # wsgiref遵循了WSGI规范,内部帮我们实现了socket,
 5 from wsgiref.simple_server import make_server
 6 
 7 def new():
 8     f=open("reg.html","r")
 9     data=f.read()
10     f.close()
11     return data
12 def index():
13     return "index"
14 URLS={
15     "/new":new,
16     "/index":index,
17 }
18 def RunServer(environ, start_response):
19     start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
20     url=environ[‘PATH_INFO‘]
21     if url in URLS.keys():
22         func_name=URLS[url]
23         ret=func_name()
24     else:
25         ret="404"
26     return ret
27 if __name__ == ‘__main__‘:
28     httpd = make_server(‘‘, 8000, RunServer)
29     httpd.serve_forever()