一 Web框架本质
1. 自己开发Web框架 - socket - http协议 - HTML知识 - 数据库(pymysql,SQLAlchemy) HTTP: 无状态、短连接 TCP: 不断开 WEB应用(网站): Http协议: 发送: POST /index HTTP/1.1 Host: 127.0.0.1:8080 Connection: keep-alive Cache-Control: max-age=0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.89 Safari/537.36 HTTPS: 1 Accept-Encoding: gzip, deflate, sdch Accept-Language: zh-CN,zh;q=0.8 Cookie: csrftoken=hNmu2JOtntGMN0hSRSPmMQk2newEb3o8zb6pXW5Cc3m54IaA5VlTkUvqWsFezpni p=123 响应: 200 OK Cache-Control:public, max-age=15 Connection:keep-alive Content-Encoding:gzip Content-Type:text/html; charset=utf-8 Date:Wed, 14 Jun 2017 01:21:17 GMT Expires:Wed, 14 Jun 2017 01:21:33 GMT Last-Modified:Wed, 14 Jun 2017 01:21:03 GMT Transfer-Encoding:chunked Vary:Accept-Encoding X-Frame-Options:SAMEORIGIN X-UA-Compatible:IE=10 用户在页面看到的内容“字符串”(看到页面效果,由于浏览器解析) 浏览器(socket客户端) 2. www.cnblogs.com(42.121.252.58,80) sk.socket() sk.connect((42.121.252.58,80)) sk.send(‘我想要xx‘) 5. 接收 6. 连接断开 博客园(socket服务端) 1. 监听ip和端口(42.121.252.58,80) while True: 用户 = 等待用户连接 3. 收到‘我想要xx‘ 4. 响应:“好” 用户断开 import socket sock = socket.socket() sock.bind((‘127.0.0.1‘,8080)) sock.listen(5) while True: conn,addr = sock.accept() # hang住 # 有人来连接了 # 获取用户发送的数据 data = conn.recv(8096) conn.send(b"HTTP/1.1 200 OK\r\n\r\n") conn.send(b‘123123‘) conn.close() 1. Http,无状态,短连接 2. 浏览器(socket客户端) 网站(socket服务端) 3. 自己写网站 a. socket服务端 b. 根据URL不同返回不同的内容 路由系统: URL -> 函数 c. 字符串返回给用户 模板引擎渲染: HTML充当模板(特殊字符) 自己创造任意数据 字符串 4. Web框架: 框架种类: - a,b,c --> Tornado - [第三方a],b,c --> wsgiref -> Django - [第三方a],b,[第三方c] --> flask, 分类: - Django框架(Web。。。。。。) - 其他
web 框架本质
众所周知,对于所有的Web应用,本质上其实就是一个socket服务端,用户的浏览器其实就是一个socket客户端。
import socket def handle_request(client): buf = client.recv(1024) client.send("HTTP/1.1 200 OK\r\n\r\n") client.send("Hello, Seven") def main(): sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.bind((‘localhost‘,8000)) 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。
为了方便应用程序的开发,就出现了众多的Web框架,例如:Django、Flask、web.py 等。
不同的框架有不同的开发方式,但是无论如何,开发出的应用程序都要和服务器程序配合,才能为用户提供服务。这样,服务器程序就需要为不同的框架提供不同的支持。
这样混乱的局面无论对于服务器还是框架,都是不好的。对服务器来说,需要支持各种不同框架,对框架来说,只有支持它的服务器才能被开发出的应用使用。这时候,标准化就变得尤为重要。
我们可以设立一个标准,只要服务器程序支持这个标准,框架也支持这个标准,那么他们就可以配合使用。
一旦标准确定,双方各自实现。这样,服务器可以支持更多支持标准的框架,框架也可以使用更多支持标准的服务器。
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。
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()
二 自定义Web框架
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()
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:
index.html
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title></title> </head> <body> <h1>Index</h1> </body> </html>
login.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?
- 1)自定义一套特殊的语法,进行替换
- 2)使用开源工具jinja2,遵循其指定语法
index.html
<!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
三 自己开发web框架
实现静态网站
import socket def f1(request): """ 处理用户请求,并返回相应的内容 :param request: 用户请求的所有信息 :return: """ f = open(‘index.fsw‘,‘rb‘) data = f.read() f.close() return data def f2(request): f = open(‘aricle.tpl‘,‘r‘,encoding=‘utf-8‘) data = f.read() f.close() import time ctime = time.time() data = data.replace(‘@@[email protected]@‘,str(ctime)) return bytes(data,encoding=‘utf-8‘) def f3(request): import pymysql # 创建连接 conn = pymysql.connect(host=‘127.0.0.1‘, port=3306, user=‘root‘, passwd=‘‘, db=‘db666‘) cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) cursor.execute("select id,username,password from userinfo") user_list = cursor.fetchall() cursor.close() conn.close() content_list = [] for row in user_list: tp = "<tr><td>%s</td><td>%s</td><td>%s</td></tr>" %(row[‘id‘],row[‘username‘],row[‘password‘]) content_list.append(tp) content = "".join(content_list) f = open(‘userlist.html‘,‘r‘,encoding=‘utf-8‘) template = f.read() f.close() # 模板渲染(模板+数据) data = template.replace(‘@@[email protected]@‘,content) return bytes(data,encoding=‘utf-8‘) def f4(request): import pymysql # 创建连接 conn = pymysql.connect(host=‘127.0.0.1‘, port=3306, user=‘root‘, passwd=‘‘, db=‘db666‘) cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) cursor.execute("select id,username,password from userinfo") user_list = cursor.fetchall() cursor.close() conn.close() f = open(‘hostlist.html‘,‘r‘,encoding=‘utf-8‘) data = f.read() f.close() # 基于第三方工具实现的模板渲染 from jinja2 import Template template = Template(data) data = template.render(xxxxx=user_list,user=‘sdfsdfsdf‘) return data.encode(‘utf-8‘) routers = [ (‘/xxx‘, f1), (‘/ooo‘, f2), (‘/userlist.htm‘, f3), (‘/host.html‘, f4), ] def run(): sock = socket.socket() sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) sock.bind((‘127.0.0.1‘,8080)) sock.listen(5) while True: conn,addr = sock.accept() # hang住 # 有人来连接了 # 获取用户发送的数据 data = conn.recv(8096) data = str(data,encoding=‘utf-8‘) headers,bodys = data.split(‘\r\n\r\n‘) temp_list = headers.split(‘\r\n‘) method,url,protocal = temp_list[0].split(‘ ‘) conn.send(b"HTTP/1.1 200 OK\r\n\r\n") func_name = None for item in routers: if item[0] == url: func_name = item[1] break if func_name: response = func_name(data) else: response = b"404" conn.send(response) conn.close() if __name__ == ‘__main__‘: run()
s1.py
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <h1>用户登录</h1> <form> <p><input type="text" placeholder="用户名" /></p> <p><input type="password" placeholder="密码" /></p> </form> </body> </html> index.fsw
index.fsw
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <table border="1"> <thead> <tr> <th>ID</th> <th>用户名</th> <th>邮箱</th> </tr> </thead> <tbody> <tr> <th>1</th> <th>root</th> <th>[email protected]</th> </tr> </tbody> </table> </body> </html> aricle.tpl
aricle.tpl
实现动态网站
import socket def f1(request): """ 处理用户请求,并返回相应的内容 :param request: 用户请求的所有信息 :return: """ f = open(‘index.fsw‘,‘rb‘) data = f.read() f.close() return data def f2(request): f = open(‘aricle.tpl‘,‘r‘,encoding=‘utf-8‘) data = f.read() f.close() import time ctime = time.time() data = data.replace(‘@@[email protected]@‘,str(ctime)) return bytes(data,encoding=‘utf-8‘) def f3(request): import pymysql # 创建连接 conn = pymysql.connect(host=‘127.0.0.1‘, port=3306, user=‘root‘, passwd=‘‘, db=‘db666‘) cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) cursor.execute("select id,username,password from userinfo") user_list = cursor.fetchall() cursor.close() conn.close() content_list = [] for row in user_list: tp = "<tr><td>%s</td><td>%s</td><td>%s</td></tr>" %(row[‘id‘],row[‘username‘],row[‘password‘]) content_list.append(tp) content = "".join(content_list) f = open(‘userlist.html‘,‘r‘,encoding=‘utf-8‘) template = f.read() f.close() # 模板渲染(模板+数据) data = template.replace(‘@@[email protected]@‘,content) return bytes(data,encoding=‘utf-8‘) def f4(request): import pymysql # 创建连接 conn = pymysql.connect(host=‘127.0.0.1‘, port=3306, user=‘root‘, passwd=‘‘, db=‘db666‘) cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) cursor.execute("select id,username,password from userinfo") user_list = cursor.fetchall() cursor.close() conn.close() f = open(‘hostlist.html‘,‘r‘,encoding=‘utf-8‘) data = f.read() f.close() # 基于第三方工具实现的模板渲染 from jinja2 import Template template = Template(data) data = template.render(xxxxx=user_list,user=‘sdfsdfsdf‘) return data.encode(‘utf-8‘) routers = [ (‘/xxx‘, f1), (‘/ooo‘, f2), (‘/userlist.htm‘, f3), (‘/host.html‘, f4), ] def run(): sock = socket.socket() sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) sock.bind((‘127.0.0.1‘,8080)) sock.listen(5) while True: conn,addr = sock.accept() # hang住 # 有人来连接了 # 获取用户发送的数据 data = conn.recv(8096) data = str(data,encoding=‘utf-8‘) headers,bodys = data.split(‘\r\n\r\n‘) temp_list = headers.split(‘\r\n‘) method,url,protocal = temp_list[0].split(‘ ‘) conn.send(b"HTTP/1.1 200 OK\r\n\r\n") func_name = None for item in routers: if item[0] == url: func_name = item[1] break if func_name: response = func_name(data) else: response = b"404" conn.send(response) conn.close() if __name__ == ‘__main__‘: run() s1.py
s1.py
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <h1>用户登录</h1> <form> <p><input type="text" placeholder="用户名" /></p> <p><input type="password" placeholder="密码" /></p> </form> </body> </html> index.fsw
index.fsw
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <table border="1"> <thead> <tr> <th>ID</th> <th>用户名</th> <th>邮箱</th> </tr> </thead> <tbody> <tr> <th>1</th> <th>@@[email protected]@</th> <th>[email protected]</th> </tr> </tbody> </table> </body> </html> aricle.tpl
aricle.tpl
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <table border="1"> <thead> <tr> <th>ID</th> <th>用户名</th> <th>邮箱</th> </tr> </thead> <tbody> {% for row in xxxxx %} <tr> <td>{{row.id}}</td> <td>{{row.username}}</td> <td>{{row.password}}</td> </tr> {% endfor %} </tbody> </table> {{user}} </body> </html> userlist.html
userlist.htmlWeb
原文地址:https://www.cnblogs.com/bigtreei/p/8366349.html