自定义Web框架
一、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 '404 not found'
if __name__ == '__main__':
httpd = make_server('', 8000, RunServer)
print "Serving HTTP on port 8000..."
httpd.serve_forever()
2、模板引擎
在上一步骤中，对于所有的login、index均返回给用户浏览器一个简单的字符串，在现实的Web请求中一般会返回一个复杂的符合HTML规则的字符串，所以我们一般将要返回给用户的HTML写在指定文件中，然后再返回。如：
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<h1>Index</h1>
</body>
</html>
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<form>
<input type="text" />
<input type="text" />
<input type="submit" />
</form>
</body>
</html>
#!/usr/bin/env python
# -*- coding:utf-8 -*-
from wsgiref.simple_server import make_server
def index():
# return 'index'
f = open('index.html')
data = f.read()
return data
def login():
# return 'login'
f = open('login.html')
data = f.read()
return data
def routers():
urlpatterns = (
('/index/', index),
('/login/', login),
)
return urlpatterns
def run_server(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 '404 not found'
if __name__ == '__main__':
httpd = make_server('', 8000, run_server)
print "Serving HTTP on port 8000..."
httpd.serve_forever()
对于上述代码，虽然可以返回给用户HTML的内容以现实复杂的页面，但是还是存在问题：如何给用户返回动态内容？
- 自定义一套特殊的语法，进行替换
- 使用开源工具jinja2，遵循其指定语法
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<h1>{{name}}</h1>
<ul>
{% for item in user_list %}
<li>{{item}}</li>
{% endfor %}
</ul>
</body>
</html>
#!/usr/bin/env python
# -*- coding:utf-8 -*-
from wsgiref.simple_server import make_server
from jinja2 import Template
def index():
# return 'index'
# template = Template('Hello {{ name }}!')
# result = template.render(name='John Doe')
f = open('index.html')
result = f.read()
template = Template(result)
data = template.render(name='John Doe', user_list=['alex', 'eric'])
return data.encode('utf-8')
def login():
# return 'login'
f = open('login.html')
data = f.read()
return data
def routers():
urlpatterns = (
('/index/', index),
('/login/', login),
)
return urlpatterns
def run_server(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 '404 not found'
if __name__ == '__main__':
httpd = make_server('', 8000, run_server)
print "Serving HTTP on port 8000..."
httpd.serve_forever()
遵循jinja2的语法规则，其内部会对指定的语法进行相应的替换，从而达到动态的返回内容，
对于模板引擎的本质，参考另外一篇博客：白话tornado源码之褪去模板外衣的前戏
