简单的web框架(python)

Posted 2021-12-23 yuyafeng

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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 socket


server = 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\n
        Host: 127.0.0.1:8000\r\n
        Connection: keep-alive\r\n
        Upgrade-Insecure-Requests: 1\r\n
        User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (Khtml, like Gecko) Chrome/74.0.3729.131 Safari/537.36\r\n
        Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3\r\n
        Accept-Encoding: gzip, deflate, br\r\n
        Accept-Language: zh-CN,zh;q=0.9,und;q=0.8,en;q=0.7\r\n
        Cookie: 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 socket

server = 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\n
        Host: 127.0.0.1:8000\r\n
        Connection: keep-alive\r\n
        Upgrade-Insecure-Requests: 1\r\n
        User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36\r\n
        Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3\r\n
        Accept-Encoding: gzip, deflate, br\r\n
        Accept-Language: zh-CN,zh;q=0.9,und;q=0.8,en;q=0.7\r\n
        Cookie: 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 = None
        for url in urls:
            if url[0] == current_path:
                res = url[1]()
                break
            else:
                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 urls

server = 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\n
        Host: 127.0.0.1:8000\r\n
        Connection: keep-alive\r\n
        Upgrade-Insecure-Requests: 1\r\n
        User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36\r\n
        Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3\r\n
        Accept-Encoding: gzip, deflate, br\r\n
        Accept-Language: zh-CN,zh;q=0.9,und;q=0.8,en;q=0.7\r\n
        Cookie: 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 = None
        for url in urls.urls:
            if url[0] == current_path:
                res = url[1]()
                break
            else:
                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 = None
    for url in urls:
        if current_path == url[0]:
            func = url[1]
            break
    if 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 = None
    for url in urls:
        if current_path == url[0]:
            func = url[1]
            break
    if 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 pymysql


def 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(‘@@[email protected]@‘, current_time)  # 字符串的替换
    return res


def 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>
@@[email protected]@
</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>

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