web 框架本质  -  Web应用本质上就是一个socket服务端，而用户的浏览器就是一个socket客户端。

 HTTP协议

HTTP协议介绍HTTP协议对收发消息的格式要求每个HTTP请求和响应都遵循相同的格式，一个HTTP包含Header和Body两部分，其中Body是可选的。HTTP响应的Header中有一个 Content-Type表明响应的内容格式。它的值如text/html; charset=utf-8。text/html则表示是网页，charset=utf-8则表示编码为utf-8。

socket 服务端 基础版-------------------------import socketsk = socket.socket()sk.bind(('127.0.0.1',8002))sk.listen()while True:    conn,addr = sk.accept()    data = conn.recv(8096)    print(data)    conn.send(b'HTTP/1.1 200 ok\r\nk1: v1\r\n\r\n')    conn.send(b'
ok!
')    conn.close() ---------------------------------- 根据不同路径返回不同内容

while True:     conn,addr = sk.accept()     data = conn.recv(8096)     data = data.decode()     url = data.split()[1]     conn.send(b'HTTP/1.1 200 ok\r\nk1: v1\r\n\r\n')     if url == '/sx':         conn.send(b'11')     elif url == '/bj':         conn.send(b'22')     else:         conn.send(b'not found!')     conn.close() ----------------------------------- --def 函数版---

import socket sk = socket.socket() sk.bind(('127.0.0.1',8002)) sk.listen() def sx(url):     ret = 'nihao   -  {}'.format(url)     return ret.encode() def bj(url):     ret = 'huairen   -  {}'.format(url)     return ret.encode() while True:     conn,addr = sk.accept()     data = conn.recv(8096)     data = data.decode()     url = data.split()[1]     conn.send(b'HTTP/1.1 200 ok\r\nk1: v1\r\n\r\n')     if url == '/sx':         ret = sx(url)     elif url == '/bj':         ret = bj(url)     else:         ret = b'not found'     conn.send(ret)     conn.close() ----------------------------------- 进阶列表版

import socket sk = socket.socket() sk.bind(('127.0.0.1',8002)) sk.listen() def sx(url):     ret = 'nihao   -  {}'.format(url)     return ret.encode() def bj(url):     ret = 'huairen   -  {}'.format(url)     return ret.encode() # 定义一个地址和函数的对应关系的列表 list1 = [('/sx',sx),('/bj',bj)] while True:     conn,addr = sk.accept()     data = conn.recv(8096) # 接收数据     data = data.decode()     url = data.split()[1]  # 获取url     conn.send(b'HTTP/1.1 200 ok\r\nk1: v1\r\n\r\n')     func = None     for i in list1:         if url == i[0]:             func = i[1]             break     if func:         ret = func(url)     else:         ret = b'not found'      conn.send(ret)     conn.close() ----返回html网页------------------

def index(url):     with open('index.html', 'rb') as f:         ret = f.read()         return ret list1 = [('/sx',sx),('/index',index)] --------返回一个动态页面------------

def timer(url):     now = time.strftime('%Y-%m-%d %H:%M:%S',time.localtime())     with open('time.html','r',encoding='utf-8') as f:         data = f.read()         data = data.replace('@@time@@',now)         return data.encode('utf-8') list1 = [('/sx',sx),('/index',index),('/timer',timer)]

"""根据URL中不同的路径返回不同的内容--函数进阶版返回HTML页面让网页动态起来wsgiref模块版"""--------------------------------------------------from wsgiref.simple_server import make_serverdef index(url):    with open('index.html','r',encoding='utf-8') as f:        s = f.read()        return bytes(s,encoding='utf-8')def timer(url):    import time    with open('time.html','r',encoding='utf-8') as f:        s = f.read()        s = s.replace('@@time@@',time.strftime("%Y-%m-%d %H:%M:%S"))    return bytes(s,encoding='utf-8')list1 = [('/index/',index),('/time/',timer)]def run_server(environ,start_response):    #设置http 响应的状态码和头信息    start_response('200 OK',[('Content-Type', 'text/html;charset=utf8'),])    url = environ['PATH_INFO'] #取到用户输入的url    func = None    for i in list1:        if i[0] == url:            func = i[1]            break    if func:        response = func(url)    else:        response = b'404 not found!'    return [response,]if __name__ == '__main__':    httpd = make_server('127.0.0.1',8888,run_server)    print('我在8888等你呦...')    httpd.serve_forever()

------------引用第三方 jinja2---------- from wsgiref.simple_server import make_serverfrom jinja2 import Templatedef index(url):    #读取html文件    with open('index2.html','r',encoding='utf-8') as f:        data = f.read()        temp = Template(data)  #生成模板文件        ret = temp.render({
   'name':'alex','hobby_list': ['抽烟', '喝酒', '烫头']})#把数据填充到模板中        return bytes(ret,encoding='utf-8')def home(url):    with open('home.html','r',encoding='utf-8') as f:        s = f.read()        return bytes(s,encoding='utf-8')list1 = [('/index/',index),('/home/',home)]def run_server(environ,start_response):    #设置http 响应的状态码和头信息    start_response('200 OK',[('Content-Type', 'text/html;charset=utf8'),])    url = environ['PATH_INFO'] #取到用户输入的url    func = None    for i in list1:        if i[0] == url:            func = i[1]            break    if func:        response = func(url)    else:        response = b'404 not found!'    return [response,]if __name__ == '__main__':    httpd = make_server('127.0.0.1',8888,run_server)    print('我在8888等你呦...')    httpd.serve_forever()