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首先我们明白了其本质就是socket，如果从socket开始开发应用程序那么效率就太低了，正确的做法是底层的socket处理代码由专门的服务器软件实现，而对于真实开发中的python web程序来说也是一般会分为两个部分：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。
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。
import socket
def handle_request(client):
#接收客户端信息并进行处理
buf = client.recv(1024)
client.send("HTTP/1.1 200 OK\r\n\r\n".encode())
client.send("Hello, Seven".encode())
def main():
# 实例socket对象
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# 绑定端口
sock.bind((‘localhost‘,8888))
# 设置监听客户端数量
sock.listen(5)
while True:
# 获取客户端socket对象和端口
connection, address = sock.accept()
handle_request(connection)
connection.close()
if __name__ == ‘__main__‘:
main()
python标准库提供的独立WSGI服务器称为wsgiref
from wsgiref.simple_server import make_server
def RunServer(environ, start_response):
start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
return [‘<h1>Hello, web!</h1>‘.encode(‘utf-8‘)] #py3
# return ‘<h1>Hello, web!</h1>‘ py2
if __name__ == ‘__main__‘:
httpd = make_server(‘‘, 8888, RunServer)
print("Serving HTTP on port 8888...")
httpd.serve_forever()
通过python标准库提供的wsgiref模块开发一个自己的web框架
from wsgiref.simple_server import make_server
def index():
return [‘index‘.encode("utf-8")]
def login():
return [‘login‘.encode("utf-8")]
def routers():
# 路由函数
urlpatterns = (
(‘/index/‘,index),
(‘/login/‘,login),
)
return urlpatterns
def RunServer(environ, start_response):
# 响应头
start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
# 获取客户端url信息
url = environ[‘PATH_INFO‘]
# 执行路由函数，获取路由元组
urlpatterns = routers()
func = None
for item in urlpatterns:
# 判断当前url，对应获取函数名
if item[0] == url:
func = item[1]
break
if func:
return func()
else:
return [‘404 not found‘.encode("utf-8")]
if __name__ == ‘__main__‘:
httpd = make_server(‘‘, 8888, RunServer)
print("Serving HTTP on port 8888...")
httpd.serve_forever()
在上一步骤中，返回到浏览器给客户看的只是一个简单的字符串，而在真实的生活场景里，我们看到更多的是一个复杂的HTML规则字符串，所以我们一般将要返回给客户的HTML写在指定文件中，然后返回
from wsgiref.simple_server import make_server
def index():
# return ‘index‘
f = open(‘views/index.html‘)
data = [f.read().encode()]
return data
def login():
# return ‘login‘
f = open(‘views/login.html‘)
data = [f.read().encode()]
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‘.encode()]
if __name__ == ‘__main__‘:
httpd = make_server(‘‘, 8888, run_server)
print("Serving HTTP on port 8888...")
httpd.serve_forever()
可能说，你对这还不满意，因为只是一个静态页面，根本就没有动态效果，好，那怎么给客户返回动态内容？？
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <h1>{{name}}</h1> {% for item in user_list %} <li>{{item}}</li> {% endfor %} </body> </html>
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(‘views\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(‘views/login.html‘)
data = [f.read().encode("utf-8")]
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‘.encode("utf-8")]
if __name__ == ‘__main__‘:
httpd = make_server(‘‘, 8888, run_server)
print("Serving HTTP on port 8888...")
httpd.serve_forever()
一个web框架应该包括路由系统和模板引擎等基本的东西，让我们看看一个高仿真自定义web框架：
from wsgiref.simple_server import make_server
import time
def new():
f = open(‘s1.html‘, ‘r‘)
data = f.read()
f.close()
# 模拟模板引擎处理数据,将html里文件的item替换成其他数据
# 这里仅仅是用字符串的替换来最简单的说明下原理
new_data = data.replace("{{item}}", str(time.time()))
return new_data
def index():
f = open(‘index.html‘, ‘r‘)
data = f.read()
f.close()
return data
def home():
return ‘home‘
URLS = { # 定义一个字典，简单模拟路由系统
"/new": new, # 一个url对应一个函数处理
"/index": index,
"/home": home,
}
def application(environ, start_response):
start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
url = environ[‘PATH_INFO‘]
if url in URLS.keys(): # 不同的url执行不同的函数
func_name = URLS[url]
ret = func_name()
else:
ret = "404"
return [ret.encode(‘utf-8‘)] # 最后将结果返回
httpd = make_server(‘‘, 8000, application)
httpd.serve_forever()
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原文地址：http://www.cnblogs.com/xinsiwei18/p/5815797.html
