简单的web框架(python)

1、web框架介绍

Web框架（Web framework）是一种开发框架，用来支持动态网站、网络应用和网络服务的开发。这大多数的web框架提供了一套开发和部署网站的方式，也为web行为提供了一套通用的方法。web框架已经实现了很多功能，开发人员使用框架提供的方法并且完成自己的业务逻辑，就能快速开发web应用了。浏览器和服务器的是基于HTTP协议进行通信的。也可以说web框架就是在以上十几行代码基础张扩展出来的，有很多简单方便使用的方法，大大提高了开发的效率。

 

2、实现简单的web框架

基于socket写一个web应用

第一版本   

　　通过HTTP协议传送过来的信息返回页面

import socketserver = socket.socket()
server.bind(('127.0.0.1',8000))
server.listen(5)while True:conn,addr = server.accept()while True:data = conn.recv(1024)'''***data***b'GET /index/ HTTP/1.1\r\nHost: 127.0.0.1:8000\r\nConnection: keep-alive\r\nUpgrade-Insecure-Requests: 1\r\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3\r\nAccept-Encoding: gzip, deflate, br\r\nAccept-Language: zh-CN,zh;q=0.9,und;q=0.8,en;q=0.7\r\nCookie: csrftoken=kzAhOkqkoPdnQuOxI7AQTa8aOmT7g6ebPiwrI0jpQ8m04NmYLkzkFvDtD8febu41; Hm_lvt_080836300300be57b7f34f4b3e97d911=1559726342,1559732417\r\n\r\n''''conn.send(b'HTTP/1.1 200 OK\r\n\r\n')'''页面显示Hello必须遵守http协议返回一个响应头'''current_path = data.decode('utf-8').split('\r\n')[0].split(' ')[1]'''/index/'''if current_path == '/index/':with open('index.html', 'rb') as f:conn.send(f.read())else:conn.send(b'404')conn.close()

第二版本

　　根据HTTP传送过来的信息返回相应的页面，通过列表保存信息模拟django中的urls，通过函数返回数据模拟django中views

import socketserver = socket.socket()
server.bind(('127.0.0.1', 8000))
server.listen(5)def index():return 'index'def login():return 'login'def error():return '404'urls = [('/index/', index),
    ('/login/', login)
]while True:conn, addr = server.accept()while True:data = conn.recv(1024)'''***data***b'GET /index/ HTTP/1.1\r\nHost: 127.0.0.1:8000\r\nConnection: keep-alive\r\nUpgrade-Insecure-Requests: 1\r\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3\r\nAccept-Encoding: gzip, deflate, br\r\nAccept-Language: zh-CN,zh;q=0.9,und;q=0.8,en;q=0.7\r\nCookie: csrftoken=kzAhOkqkoPdnQuOxI7AQTa8aOmT7g6ebPiwrI0jpQ8m04NmYLkzkFvDtD8febu41; Hm_lvt_080836300300be57b7f34f4b3e97d911=1559726342,1559732417\r\n\r\n''''conn.send(b'HTTP/1.1 200 OK\r\n\r\n')'''页面显示Hello必须遵守http协议返回一个响应头'''current_path = data.decode('utf-8').split('\r\n')[0].split(' ')[1]'''/index/'''
　　　　 res = Nonefor url in urls:if url[0] == current_path:res = url[1]()breakelse:res = error()conn.send(res.encode('utf-8'))

第三版

　　将其拆分成start.py   urls.py   views.py

import socket
import urlsserver = socket.socket()
server.bind(('127.0.0.1', 8000))
server.listen(5)def error():return '404'while True:conn, addr = server.accept()while True:data = conn.recv(1024)'''***data***b'GET /index/ HTTP/1.1\r\nHost: 127.0.0.1:8000\r\nConnection: keep-alive\r\nUpgrade-Insecure-Requests: 1\r\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3\r\nAccept-Encoding: gzip, deflate, br\r\nAccept-Language: zh-CN,zh;q=0.9,und;q=0.8,en;q=0.7\r\nCookie: csrftoken=kzAhOkqkoPdnQuOxI7AQTa8aOmT7g6ebPiwrI0jpQ8m04NmYLkzkFvDtD8febu41; Hm_lvt_080836300300be57b7f34f4b3e97d911=1559726342,1559732417\r\n\r\n''''conn.send(b'HTTP/1.1 200 OK\r\n\r\n')'''页面显示Hello必须遵守http协议返回一个响应头'''current_path = data.decode('utf-8').split('\r\n')[0].split(' ')[1]'''/index/'''res = Nonefor url in urls.urls:if url[0] == current_path:res = url[1]()breakelse:res = error()conn.send(res.encode('utf-8'))

import views
urls = [('/index/', views.index),('/login/', views.login)
]

def index():return 'index'def login():return 'login'

高级版

　　使用wsgiref.simple_server的make_server配置web应用

from wsgiref.simple_server import make_server
from urls import *def run(env, response):''':param env: 请求相关的信息，一个处理好的字符串:param response:  响应相关信息:return:'''response('200 OK', [('username', 'jason'), ('password', '123')])  # 固定写法 后面列表里面一个个元祖会以响应头kv键值对的形式返回给客户端current_path = env.get('PATH_INFO')func = Nonefor url in urls:if current_path == url[0]:func = url[1]breakif func:res = func(env)else:res = error(env)return [res.encode('utf-8')]if __name__ == '__main__':server = make_server('127.0.0.1', 8080, run)server.serve_forever()

def index(env):return 'index'def login(env):return 'login'def error(env):return '404'

from views import *
urls = [('/index/', index),('/login/', login)
]

终极版

　　使用jinja2对模板进行替换，对数据库进行连接

from wsgiref.simple_server import make_server
from urls import *def run(env, response):''':param env: 请求相关的信息，一个处理好的字符串:param response:  响应相关信息:return:'''response('200 OK', [('username', 'jason'), ('password', '123')])  # 固定写法 后面列表里面一个个元祖会以响应头kv键值对的形式返回给客户端current_path = env.get('PATH_INFO')func = Nonefor url in urls:if current_path == url[0]:func = url[1]breakif func:res = func(env)else:res = error(env)return [res.encode('utf-8')]if __name__ == '__main__':server = make_server('127.0.0.1', 8080, run)server.serve_forever()

import time
from jinja2 import Template
import pymysqldef index(env):return 'index'def login(env):return 'login'def get_time(env):# 先获取当前时间current_time = time.strftime('%Y-%m-%d %X')# 打开html文件读取内容返回给客户端with open(r'templates/get_time.html', 'r', encoding='utf-8') as f:data = f.read()# 因为是以r模式打开的文件，所有获取到的内容就是一堆字符串res = data.replace('@@time@@', current_time)  # 字符串的替换return resdef get_user(env):with open(r'templates/get_user.html', 'r', encoding='utf-8') as f:data = f.read()tmp = Template(data)# 将字典传递给前端页面 前端通过变量名user_dic就可以获取到该字典return tmp.render(user_dic={'name': "jason", 'password': '123'})def get_db(env):# 连接数据库 获取数据 渲染到前端页面conn = pymysql.connect(host='127.0.0.1',port=3306,user='root',password='123',database='blog',charset='utf8',autocommit=True)cursor = conn.cursor(pymysql.cursors.DictCursor)cursor.execute('select * from userinfo')user_dict = cursor.fetchall()  # [{},{},{},{}]with open(r'templates/get_db.html', 'r', encoding='utf-8') as f:data = f.read()tmp = Template(data)return tmp.render(user_dict=user_dict)def error(env):return '404 error'

from views import *urls = [('/index',index),('/login',login),('/get_time',get_time),('/get_user',get_user),('/get_db',get_db),
]

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
@@time@@
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<p>{{ user_dic }}</p>
<p>{{ user_dic.name }}</p>
<p>{{ user_dic['password'] }}</p>
<p>{{ user_dic.get('name') }}</p>
</body>
</html>