Django框架导读

一、课程导读

1、web应用
运行在浏览器上的应用

2、c/s b/s 架构
client/server:客户端服务器架构,C++
brower/server:浏览器服务器架构,Java、Python
底层均是基于socket

3、Python Web框架
a.socket b.页面路由 c.模板渲染
Django a用的wsgiref b自己写的 c自己写的 功能全面
Flask a用的第三方 b自己写的 c自己写的 小而轻
Tornado a自己写的 b自己写的 c自己写的 支持高并发

二、原生socket服务

  • 目录结构
part1
	-- index.html
	-- server.py
  • 基础socket服务
import socket
# 利用socket建立服务器对象
server = socket.socket()
# 设置ip和端口
server.bind(('127.0.0.1', 8001))
# 设置监听
server.listen(5)
print('服务器设置成功')
print('浏览器访问:http://127.0.0.1:8001')
while True:
    # 阻塞等待客户端数据
    client, address = server.accept()
    # 接收数据
    data = client.recv(1024)
    print('接收到数据: ', data)
    # 返回数据
    client.send(b'Normal Socket Web')
    # 关闭连接(必须关闭每一次连接)
    client.close()  

# 浏览器错误:发送的响应无效,原因:响应不满足http协议
   
'''
# 请求发来的数据
b'GET / HTTP/1.1\r\n
Host: 127.0.0.1:8001\r\n
Connection: keep-alive\r\n
Upgrade-Insecure-Requests: 1\r\n
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36\r\n
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8\r\n
Accept-Encoding: gzip, deflate, br\r\n
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8\r\n
Cookie: csrftoken=szfYLDVuqvRhlveNpNE2rp1GYOcI5x7mRNfvkRWTMRNRwWxXMZWOhL1MqknYJ7jg; sessionid=3pphvmw2icub0bea7nn02u6wev17k4uw\r\n
\r\n'
'''

三、http协议

  • 什么是http协议
# HTTP(HyperText Transport Protocol)是超文本传输协议
# 基于TCP/IP协议基础上的应用层协议,底层实现仍为socket
# 基于请求-响应模式:通信一定是从客户端开始,服务器端接收到客户端一定会做出对应响应
# 无状态:协议不对任何一次通信状态和任何数据做保存
# 无连接:一次连接只完成一次请求-响应,请求-响应完毕后会立即断开连接

网络七层

  • http工作原理(事务)
# 一次http操作称之为一个事务,工作过程可分为四步
# 1.客户端与服务端建立连接
# 2.客户端发生一个http协议指定格式的请求
# 3.服务器端接收请求后,响应一个http协议指定格式的响应
# 4.客户端将服务器的响应显示展现给用户
  • 请求报文
# 请求行  请求头  请求体
'''
POST / HTTP/1.1\r\n
Host: 127.0.0.1:8001\r\n
Connection: keep-alive\r\n
Upgrade-Insecure-Requests: 1\r\n
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36\r\n
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8\r\n
Accept-Encoding: gzip, deflate, br\r\n
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8\r\n
\r\n
usr=abc&pwd=123
'''
  • 响应报文
# 响应行  响应头  响应体
'''
HTTP/1.1 200 OK\r\n
Content-type:text/html\r\n
\r\n
Login Success
'''
  • 修改返回数据,完善响应体
# 字符串
client.send(b'HTTP/1.1 200 OK\r\n')
client.send(b'\r\n')
client.send(b'Normal Socket Web')
# html代码,请求头要设置支持html代码
client.send(b'HTTP/1.1 200 OK\r\n')
client.send(b'Content-type:text/html\r\n')
client.send(b'\r\n')
client.send(b'<h1>Normal Socket Web</h1>')
# html文件(同级目录建立一个index.html页面)
client.send(b'HTTP/1.1 200 OK\r\n')
client.send(b'Content-type:text/html\r\n')
client.send(b'\r\n')
# 利用文件方式读取页面
with open('index.html', 'rb') as f:
    dt = f.read()
client.send(dt)
  • 修改接收数据,模拟后台路由
# 分析接收到的数据
data = client.recv(1024)
# 保证接收到的数据作为字符串进行以下处理
data = str(data, encoding='utf-8')
# 拆分出地址位
route = data.split('\r\n')[0].split(' ')[1]
# 匹配地址,做出不同的响应
if route == '/index':
    with open('index.html', 'rb') as f:
    	dt = f.read()
elif route == '/login':  # 新建login页面
    with open('login.html', 'rb') as f:
    	dt = f.read()
else:
    dt = b'404'
client.send(dt)
# 1打头:消息通知
# 2打头:请求成功
# 3打头:重定向
# 4打头:客户端错误
# 5打头:服务器端错误

四、框架演变

  • 目录结构
part2
	-- favicon.ico
	-- index.html
	-- manage.py
  • manage.py
import socket
import pymysql
# 响应头
RESP_HEADER = b'HTTP/1.1 200 OK\r\nContent-type:text/html\r\n\r\n'

# 请求处理
def index():
    # 以字节方式读取文件
    with open('index.html', 'rb') as f:
        dt = f.read()
    return dt
def ico():
    with open(favicon.jpeg, 'rb') as f:
        dt = f.read()
    return dt
def user():
    # 数据库操作
    conn = pymysql.connect(host='127.0.0.1', port=3306, db='django', user='root', password='root')
    cur = conn.cursor(pymysql.cursors.DictCursor)
    cur.execute('select * from user')
    users = cur.fetchall()
    print(users)
    users = '''%d:%s
    %d:%s''' % (users[0]['id'], users[0]['name'], users[1]['id'], users[1]['name'])
    return users.encode('utf-8')

# 设置路由
urls = {
    # 请求路径与请求处理函数一一对应
    '/index': index,
    favicon.jpeg: ico,
    '/user': user
}

# 设置socket
def serve(host, port):
    server = socket.socket()
    server.bind((host, port))
    print('start:http://' + host + ':' + str(port))
    server.listen(5)
    while True:
        sock, addr = server.accept()
        data = sock.recv(1024)
        data = str(data, encoding='utf-8')
        print(data)
        route = data.split('\r\n')[0].split(' ')[1]

        resp = b'404'
        if route in urls:
            resp = urls[route]()

        sock.send(RESP_HEADER)
        sock.send(resp)
        sock.close()

# 启服务
if __name__ == '__main__':
    serve('127.0.0.1', 8002)

五、项目演变

  • 目录结构
03_proj
	-- template
		-- index.html
		-- user.html
	favicon.ico
	start.py
	urls.py
	views.py
  • index.html
<h1>{{ name }}</h1>
  • user.html
<table border="1">
    <tr>
        <th>id</th>
        <th>name</th>
        <th>password</th>
    </tr>
    {% for user in users%}
    <tr>
        <td>{{user.id}}</td>
        <td>{{user.name}}</td>
        <td>{{user.password}}</td>
    </tr>
    {% endfor %}
</table>
  • start.py
from wsgiref.simple_server import make_server
from urls import urls


def app(env, response):
    print(env)
    # 设置响应头
    response("200 OK", [('Content-type', 'text/html')])
    route = env['PATH_INFO']
    print(route)
    data = urls['error']()
    if route in urls:
        data = urls[route]()
    # 返回二进制响应体
    return [data]


if __name__ == '__main__':
    server = make_server('127.0.0.1', 8003, app)
    print('start:http://127.0.0.1:8003')
    server.serve_forever()
  • urls.py
from views import *
urls = {
    '/index': index,
    '/favicon.ico': ico,
    '/user': user,
    'error': error
}

  • views.py
import pymysql
# 利用jinja2来渲染模板,将后台数据传给前台
from jinja2 import Template

def index():
    with open('templates/index.html', 'r') as f:
        dt = f.read()
    tem = Template(dt)
    resp = tem.render(name='主页')
    return resp.encode('utf-8')

def ico():
    with open('favicon.ico', 'rb') as f:
        dt = f.read()
    return dt

def user():
    # 数据库操作
    conn = pymysql.connect(host='127.0.0.1', port=3306, db='django', user='root', password='root')
    cur = conn.cursor(pymysql.cursors.DictCursor)
    cur.execute('select * from user')
    users = cur.fetchall()
    print(users)

    with open('templates/user.html', 'r') as f:
        dt = f.read()
    tem = Template(dt)
    resp = tem.render(users=users)

    return resp.encode('utf-8')

def error():
    return b'404'