Python 利用三个简易模块熟悉前后端交互流程
准备工作
在学习Django之前，先动手撸一个简单的WEB框架来熟悉一下前后端交互的整体流程
本次用到的模块：
1.
wsgiref，这是一个Python自带的模块，用于构建路由与视图2.
pymysql，第三方模块，用于数据库与视图层进行数据交互3.
jinja2，第三方模块，用于对前端页面进行模板渲染
请使用pip install modulename进行安装
如果安装jinja2失败，请使用easy_install Jinja2命令进行安装
数据交互
其实前面已经有大量的地方讨论浏览器与后端服务器如何进行交互，也用socket进行实现过简单的交互，但是我们需要在前者基础上做一个优化，即用户在地址栏输入什么路径，就返回请求的路径名字。
当这个需求完成后，我们就可以根据不同的请求路径，返回出不同的HTML文档信息，但是使用原生的socket这个过程会十分的繁琐，所以用一次就放弃吧。
from socket import *
def run():
server = socket(AF_INET, SOCK_STREAM) # 传输层基于TCP协议
server.bind(("127.0.0.1", 8080))
server.listen(5)
while 1:
conn, addr = server.accept()
try: # 防止Windows平台下Client端异常关闭导致双向链接崩塌Server端异常的情况发生
data = conn.recv(1024)
if not data: # bug修复：针对类UNIX环境
continue
request_path = data.decode("utf-8").split(" ")[1] # 拿到请求的路径
conn.sendall(bytes("HTTP/1.1 201 OK \r\n\r\n", "utf8")) # 返回响应头
conn.sendall(bytes("<h1>{0}</h1>".format(request_path), "utf8")) # 返回响应体
except Exception:
continue
conn.close()
if __name__ == '__main__':
run()
wsgiref
以下是利用wsgiref实现上面的功能，简单了许多，并且代码变得更加明了。
此外新增加了访问路径不存在时给出404错误提示。
from wsgiref.simple_server import make_server
def index(request):
return "You visited index"
def login(request):
return "You visited login"
def error(request):
return "404 Resource request error"
urls = [
("/index", index),
("/login", login),
]
def run(request, response):
"""
request:① 请求相关的所有数据
response：② 响应相关的数据
return：③ 返回给浏览器的数据
"""
response("200 OK",[]) # 响应首行，响应头
func = None
request_path = request.get("PATH_INFO") # 拿到路径
for url in urls:
if request_path == url[0]:
func = url[1]
break # 匹配到后结束for循环
if func:
res = func(request)
else:
res = error(request)
return [res.encode("utf-8")]
if __name__ == '__main__':
server = make_server("localhost", 8080, run)
# ③ 实时监听127.0.0.1:8080地址，只要有链接请求，都交给run函数处理
server.serve_forever() # ④ 开启服务
代码解耦
我们对上述代码进行解耦，将不同功能的代码放在不同的文件夹下。
-- webproject
-- view # 视图相关代码
-- view.py
-- urls # 路由相关代码
-- urls.py
-- run.py # 启动相关代码
# view.py
def index(request):
return "You visited index"
def login(request):
return "You visited login"
def error(request):
return "404 Resource request error"
# urls.py
from view.view import *
urls = [
("/index", index),
("/login", login),
]
# run.py
from wsgiref.simple_server import make_server
from urls.urls import *
def run(request, response):
"""
request:① 请求相关的所有数据
response：② 响应相关的数据
return：③ 返回给浏览器的数据
"""
response("200 OK",[]) # 响应首行，响应头
func = None
request_path = request.get("PATH_INFO") # 拿到路径
for url in urls:
if request_path == url[0]:
func = url[1]
break # 匹配到后结束for循环
if func:
res = func(request)
else:
res = error(request)
return [res.encode("utf-8")]
if __name__ == '__main__':
server = make_server("localhost", 8080, run)
# ③ 实时监听127.0.0.1:8080地址，只要有链接请求，都交给run函数处理
server.serve_forever() # ④ 开启服务返回页面
继续上面的流程，已经将代码进行解耦了，此时我们新建一个template文件夹用于专门存放返回的网页。
并在该文件夹下新建index.html以及login.html
-- webproject
-- view # 视图相关代码
-- view.py
-- urls # 路由相关代码
-- urls.py
-- template # 前端页面
-- index.html
-- login.html
-- run.py # 启动相关代码
<!DOCTYPE html>
<html lang="en"> <head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src='https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.js'></script>
<link rel='stylesheet' href='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css'
integrity='sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u' crossorigin='anonymous'>
<script src='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js'
integrity='sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa'
crossorigin='anonymous'></script>
<title>Document</title>
<style> .carousel .item {
height: 400px;
background-color: #777;
} .carousel-inner>.item>img {
position: absolute;
top: 0;
left: 0;
min-width: 100%;
height: 100%;
}
</style>
</head> <body> <nav class="navbar navbar-inverse">
<div class="container-fluid">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse"
data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">INDEX</a>
</div> <!-- Collect the nav links, forms, and other content for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<form class="navbar-form navbar-left">
<div class="form-group">
<input type="text" class="form-control" placeholder="Search">
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
<ul class="nav navbar-nav navbar-right">
<li><a href="HTTP://127.0.0.1:8080/login">LOGIN</a></li>
<li><a href="#">REGISTER</a></li>
</ul>
</div><!-- /.navbar-collapse -->
</div><!-- /.container-fluid -->
</nav> <div class="container-fluid"> <div class="row">
<div class="col-xs-12 col-sm-12 col-md-12 col-lg-12 input-lg-5g bg-primar ">
<div class="page-header">
<h1>Example page header <small>Subtext for header</small></h1>
</div>
</div> <div class="col-xs-3 col-sm-3 col-md-3 col-lg-3">
<div class="list-group">
<a href="#" class="list-group-item active">
Cras justo odio
</a>
<a href="#" class="list-group-item">Dapibus ac facilisis in</a>
<a href="#" class="list-group-item">Morbi leo risus</a>
<a href="#" class="list-group-item">Porta ac consectetur ac</a>
<a href="#" class="list-group-item">Vestibulum at eros</a>
</div>
</div> <div class="col-xs-9 col-sm-9 col-md-9 col-lg-9">
<div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
<!-- Indicators -->
<ol class="carousel-indicators">
<li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
<li data-target="#carousel-example-generic" data-slide-to="1"></li>
</ol> <!-- Wrapper for slides -->
<div class="carousel-inner">
<div class="item active">
<img src="https://tse4-mm.cn.bing.net/th/id/OIP._PbxAuEi3ce9S1DtQ3KilwHaEK?w=306&h=180&c=7&o=5&dpr=1.25&pid=1.7"
alt="...">
</div>
<div class="item">
<img src="https://tse2-mm.cn.bing.net/th/id/OIP.Det5e8us-qsNAGEhnL6u0AHaF7?w=238&h=190&c=7&o=5&dpr=1.25&pid=1.7"
alt="...">
</div>
</div> <!-- Controls -->
<a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
<span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
<span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
</div> </div> </div> </body> </html>
index.html
<!DOCTYPE html>
<html lang="en"> <head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src='https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.js'></script>
<link rel='stylesheet' href='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css'
integrity='sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u' crossorigin='anonymous'>
<script src='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js'
integrity='sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa'
crossorigin='anonymous'></script> <style>
body {
display: flex;
justify-content: center;
align-self: center;
height: 100vh;
background-color: rebeccapurple; } form.form1 {
display: flex;
flex-flow: column;
justify-content: center;
align-self: center;
border: 1px solid #ddd;
padding: 10px;
width: 30%;
background-color: white;
border-radius: 15px;
}
</style> </head> <body> <form class="form1" action="#">
<div class="form-group">
<label for="exampleInputEmail1">username</label>
<input type="email" class="form-control" id="exampleInputEmail1" placeholder="please enter user name">
</div>
<div class="form-group">
<label for="exampleInputPassword1">Password</label>
<input type="password" class="form-control" id="exampleInputPassword1"
placeholder="please enter user password">
</div> <button type="submit" class="btn btn-default" disabled>Submit</button>
</form> </body> </html>
login.html
除此之外，还要将视图中index函数与login函数的返回结果改一下
# view.py def index(request):
with open(file="template/index.html",mode="r",encoding="utf-8") as f:
res = f.read()
return res def login(request):
with open(file="template/login.html",mode="r",encoding="utf-8") as f:
res = f.read()
return res def error(request):
return "404 Resource request error"
view.py
那么目前，我们的框架已经初具雏形了，能够根据请求路径的不同返回不同的HTML文档。
pymsql
继续接着做逻辑，点击login后输入用户名和密码提交完应该对数据库进行验证，判断该用户是否存在。
那么现在我们就需要用到pymysql模块了，还是新建一个文件夹叫db，然后创建db文件进行操作。
import pymysql class DbServer(object):
def __init__(self):
self.conn = pymysql.connect(
host="localhost",
database="db1",
charset="utf8mb4",
user="root",
cursorclass=pymysql.cursors.DictCursor, # 记录结果，字典显示
autocommit=True, # 自动提交
) self.cursor = self.conn.cursor() def select(self, sql, val=None):
res = self.cursor.execute(sql, val)
return res, self.cursor.fetchone() # 返回查找行数，查找结果 def insert(self, sql, val=None):
pass def drop(self, sql, val=None):
pass def deletle(self, sql, val=None):
pass def __del__(self):
# 关闭程序前关闭链接与游标
self.cursor.close()
self.conn.close() if __name__ != '__main__': # 不能当作独立文件进行运行
dbserver = DbServer()
db.py
记得在数据库中先插入数据
create table user(
id INT PRIMARY KEY AUTO_INCREMENT,
name CHAR(12) NOT NULL,
password CHAR(12) NOT NULL,
INDEX(name) -- 添加索引
); INSERT INTO user(name,password) VALUES
("Yunya","");
MySQL命令
别忘了在view.py中进行导入，与此同时，还要写一个验证功能。
from db.db import dbserver
import jinja2 def index(request):
with open(file="template/index.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login(request):
with open(file="template/login.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login_verif(request):
# GET 请求 QUERY_STRING
request_msg = request.get("QUERY_STRING", None).split("&")
user_dict = {} for msg in request_msg:
key, value = msg.split("=")
user_dict[key] = value
from db.db import dbserver def index(request):
with open(file="template/index.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login(request):
with open(file="template/login.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login_verif(request):
# GET 请求 QUERY_STRING
request_msg = request.get("QUERY_STRING", None).split("&")
user_dict = {} for msg in request_msg:
key, value = msg.split("=")
user_dict[key] = value sql = "select * from user where name=%s and password = %s"
val = (user_dict.get("username"), user_dict.get("password"))
result = dbserver.select(sql, val)
if result[0]:
return "Welcome" + result[1].get("name")
else:
return "Login failed, no such user" def error(request):
return "404 Resource request error"
view.py
还要在urls.py文件中增加验证的路由解析。
from view.view import * urls = [
("/index", index),
("/login", login),
("/login_verif", login_verif),
]
urls.py
最后一步修改前端login.html中的form提交路径
<form class="form1" action="http://127.0.0.1:8080/login_verif">
<div class="form-group">
<label for="username">username</label>
<input type="text" id="username" name="username" class="form-control" placeholder="please enter user name">
</div>
<div class="form-group">
<label for="password">Password</label>
<input type="password" id="password" name="password" class="form-control"
placeholder="please enter user password">
</div> <button type="submit" class="btn btn-default">Submit</button>
</form>
login.html
jinja2
在验证完成后，我们应该根据用户名与密码是否正确来返回不同的内容。
这个时候可以使用jinja2的模板语言了。
首先在Template文件夹下新建一个verification.html做验证
然后修改一下view中的login_verif代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body> <div class="container"> <div class="row">
<div class="col-xs-6 col-sm-6 col-md-6 col-lg-6 col-xs-offset-3 col-sm-offset-3 col-md-offset-3 col-lg-offset-3 ">
<div class="page-header">
{% if login_msg.status %}
<h1>欢迎回家{{login_msg.username}}</h1>
{% else %}
<h1>无此用户！请检查用户名或密码是否输入正确</h1>
{% endif %}
</div>
</div>
</div> </div> </body>
</html>
verification.html
def login_verif(request):
# GET 请求 QUERY_STRING
request_msg = request.get("QUERY_STRING", None).split("&")
user_dict = {} for msg in request_msg:
key, value = msg.split("=")
user_dict[key] = value sql = "select * from user where name=%s and password = %s"
val = (user_dict.get("username"), user_dict.get("password"))
result = dbserver.select(sql, val) with open("./template/verification.html","r",encoding="utf-8") as f:
data = f.read() tmp = jinja2.Template(data) # 做成模板 if result[0]:
msg = {"username":result[1].get("name"),"status":1} else:
msg = {"username":None,"status":0} res = tmp.render(login_msg=msg) # 模板中添加变量
return res
view.py def login_verif
成果演示
代码总和
db - db.py
import pymysql class DbServer(object):
def __init__(self):
self.conn = pymysql.connect(
host="localhost",
database="db1",
charset="utf8mb4",
user="root",
cursorclass=pymysql.cursors.DictCursor, # 记录结果，字典显示
autocommit=True, # 自动提交
) self.cursor = self.conn.cursor() def select(self, sql, val=None):
res = self.cursor.execute(sql, val)
return res, self.cursor.fetchone() # 返回查找行数，查找结果 def insert(self, sql, val=None):
pass def drop(self, sql, val=None):
pass def deletle(self, sql, val=None):
pass def __del__(self):
# 关闭程序前关闭链接与游标
self.cursor.close()
self.conn.close() if __name__ != '__main__':
dbserver = DbServer()
template - index.html
<!DOCTYPE html>
<html lang="en"> <head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src='https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.js'></script>
<link rel='stylesheet' href='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css'
integrity='sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u' crossorigin='anonymous'>
<script src='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js'
integrity='sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa'
crossorigin='anonymous'></script>
<title>Document</title>
<style> .carousel .item {
height: 400px;
background-color: #777;
} .carousel-inner>.item>img {
position: absolute;
top: 0;
left: 0;
min-width: 100%;
height: 100%;
}
</style>
</head> <body> <nav class="navbar navbar-inverse">
<div class="container-fluid">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse"
data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">INDEX</a>
</div> <!-- Collect the nav links, forms, and other content for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<form class="navbar-form navbar-left">
<div class="form-group">
<input type="text" class="form-control" placeholder="Search">
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
<ul class="nav navbar-nav navbar-right">
<li><a href="HTTP://127.0.0.1:8080/login">LOGIN</a></li>
<li><a href="#">REGISTER</a></li>
</ul>
</div><!-- /.navbar-collapse -->
</div><!-- /.container-fluid -->
</nav> <div class="container-fluid"> <div class="row">
<div class="col-xs-12 col-sm-12 col-md-12 col-lg-12 input-lg-5g bg-primar ">
<div class="page-header">
<h1>Example page header <small>Subtext for header</small></h1>
</div>
</div> <div class="col-xs-3 col-sm-3 col-md-3 col-lg-3">
<div class="list-group">
<a href="#" class="list-group-item active">
Cras justo odio
</a>
<a href="#" class="list-group-item">Dapibus ac facilisis in</a>
<a href="#" class="list-group-item">Morbi leo risus</a>
<a href="#" class="list-group-item">Porta ac consectetur ac</a>
<a href="#" class="list-group-item">Vestibulum at eros</a>
</div>
</div> <div class="col-xs-9 col-sm-9 col-md-9 col-lg-9">
<div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
<!-- Indicators -->
<ol class="carousel-indicators">
<li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
<li data-target="#carousel-example-generic" data-slide-to="1"></li>
</ol> <!-- Wrapper for slides -->
<div class="carousel-inner">
<div class="item active">
<img src="https://tse4-mm.cn.bing.net/th/id/OIP._PbxAuEi3ce9S1DtQ3KilwHaEK?w=306&h=180&c=7&o=5&dpr=1.25&pid=1.7"
alt="...">
</div>
<div class="item">
<img src="https://tse2-mm.cn.bing.net/th/id/OIP.Det5e8us-qsNAGEhnL6u0AHaF7?w=238&h=190&c=7&o=5&dpr=1.25&pid=1.7"
alt="...">
</div>
</div> <!-- Controls -->
<a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
<span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
<span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
</div> </div> </div> </body> </html>
template - login.html
<!DOCTYPE html>
<html lang="en"> <head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src='https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.js'></script>
<link rel='stylesheet' href='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css'
integrity='sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u' crossorigin='anonymous'>
<script src='https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js'
integrity='sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa'
crossorigin='anonymous'></script> <style>
body {
display: flex;
justify-content: center;
align-self: center;
height: 100vh;
background-color: rebeccapurple; } form.form1 {
display: flex;
flex-flow: column;
justify-content: center;
align-self: center;
border: 1px solid #ddd;
padding: 10px;
width: 30%;
background-color: white;
border-radius: 15px;
}
</style> </head> <body> <form class="form1" action="http://127.0.0.1:8080/login_verif">
<div class="form-group">
<label for="username">username</label>
<input type="text" id="username" name="username" class="form-control" placeholder="please enter user name">
</div>
<div class="form-group">
<label for="password">Password</label>
<input type="password" id="password" name="password" class="form-control"
placeholder="please enter user password">
</div> <button type="submit" class="btn btn-default">Submit</button>
</form> </body> </html>
template - verifcation.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body> <div class="container"> <div class="row">
<div class="col-xs-6 col-sm-6 col-md-6 col-lg-6 col-xs-offset-3 col-sm-offset-3 col-md-offset-3 col-lg-offset-3 ">
<div class="page-header">
{% if login_msg.status %}
<h1>欢迎回家{{login_msg.username}}</h1>
{% else %}
<h1>无此用户！请检查用户名或密码是否输入正确</h1>
{% endif %}
</div>
</div>
</div> </div> </body>
</html>
urls - urls.py
from view.view import * urls = [
("/index", index),
("/login", login),
("/login_verif", login_verif),
]
view - view.py
from db.db import dbserver
import jinja2 def index(request):
with open(file="template/index.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login(request):
with open(file="template/login.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login_verif(request):
# GET 请求 QUERY_STRING
request_msg = request.get("QUERY_STRING", None).split("&")
user_dict = {} for msg in request_msg:
key, value = msg.split("=")
user_dict[key] = value
from db.db import dbserver def index(request):
with open(file="template/index.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login(request):
with open(file="template/login.html", mode="r", encoding="utf-8") as f:
res = f.read()
return res def login_verif(request):
# GET 请求 QUERY_STRING
request_msg = request.get("QUERY_STRING", None).split("&")
user_dict = {} for msg in request_msg:
key, value = msg.split("=")
user_dict[key] = value sql = "select * from user where name=%s and password = %s"
val = (user_dict.get("username"), user_dict.get("password"))
result = dbserver.select(sql, val) with open("./template/verification.html","r",encoding="utf-8") as f:
data = f.read() tmp = jinja2.Template(data) if result[0]:
msg = {"username":result[1].get("name"),"status":1} else:
msg = {"username":None,"status":0} res = tmp.render(login_msg=msg) # 返回登录信息
return res def error(request):
return "404 Resource request error"
run.py
from wsgiref.simple_server import make_server
from urls.urls import * def run(request, response): """
request:① 请求相关的所有数据
response：② 响应相关的数据
return：③ 返回给浏览器的数据
""" response("200 OK",[]) # 响应首行，响应头
func = None
request_path = request.get("PATH_INFO") # 拿到路径 for url in urls:
if request_path == url[0]:
func = url[1]
break # 匹配到后结束for循环 if func:
res = func(request)
else:
res = error(request) return [res.encode("utf-8")] if __name__ == '__main__':
server = make_server("localhost", 8080, run)
# ③ 实时监听127.0.0.1:8080地址，只要有链接请求，都交给run函数处理
server.serve_forever() # ④ 开启服务
最后结论
其实通过这三个基础模块，相信你已经了解了其基本的流程，但是用这三个模块来做成一个建议的Web框架还是存在大量的不足。
1.
HTML文件代码冗余过度2.提交全部为
GET方式，这使得密码等传输极度不安全3.原生
SQL语句操纵数据库，开发效率偏低4.路由的
URL解析太过死板，不能灵活解析
这些不足点在Django框架中都会有非常好的解决方案，因此Django框架是学习PythonWeb的首选。
总之前后端交互的大体流程就是这样，前端给请求路径，后端根据路径查询数据库中数据并进行处理后返回HTML文档再由模板语言进行解析（前后端不分离），最终呈现出一个完整的动态页面。
当然还有很多知识点没有涉及到，如cookie，ajax，权限管理等等，这些都会在之后慢慢做介绍。
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