完成登录功能，用session记住用户名

Posted 2020-10-15 杜丽晖

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登录功能完成：

js:设置return
html:设置
1. form
2. input
3. ```
onclick="return fnLogin()"
```
py:
1. @app.route设置methods
2. GET
3. POST
  1. 读取表单数据
  2. 查询数据库
    1. 用户名密码对：
      1. 记住用户名
      2. 跳转到首页
    2. 用户名密码不对：
      1. 提示相应错误。

session：

从`flask`中导入`session`
设置`SECRET_KEY`
操作字典一样操作`session`：增加用户名`session[‘username‘]=`username

import os

SQLALCHEMY_DATABASE_URI = ‘mysql+pymysql://root:@127.0.0.1:3306/niub1?charset=utf8‘
SQLALCHEMY_TRACK_MODIFICATIONS = False

SECRET_KEY = os.urandom(24)

from flask import Flask,render_template,request,redirect,url_for,session
from flask_sqlalchemy import SQLAlchemy
import config

app = Flask(__name__)
app.config.from_object(config)
db=SQLAlchemy(app)

class User(db.Model):
    __tablename__=‘user‘
    id=db.Column(db.Integer,primary_key=True,autoincrement=True)
    username = db.Column(db.String(20), nullable=False)
    password = db.Column(db.String(20), nullable=False)


# db.create_all()

#db.create_all()

# #增加
# user = User(username=‘l123123‘,password = ‘666666‘)
# db.session.add(user)
# db.session.commit()
#
# #查询
# user =User.query.filter(User.username ==‘a321321‘).first()
# print(user.username,user.password)
#
# #修改
# user =User.query.filter(User.username ==‘l123123‘).first()
# user.password=‘66666666‘
# print(user.username,user.password)
# db.session.commit()
#
# #删除
# user =User.query.filter(User.username ==‘l123123‘).first()
# print(user.username,user.password)
# db.session.delete(user)
# db.session.commit()

@app.route(‘/‘)
def base():
    return render_template(‘base.html‘)

@app.route(‘/base2‘)
def base2():
    return render_template(‘base2.html‘)

@app.route(‘/login/‘,methods=[‘GET‘,‘POST‘])
def login():
    if request.method ==‘GET‘:
        return  render_template(‘login.html‘)
    else:
        usern = request.form.get(‘username‘)
        passw = request.form.get(‘password‘)
        user = User.query.filter(User.username == usern).first()
        if user:
            if user.password == passw:
                session[‘user‘]=usern
                return redirect(url_for("base2"))
            else:
                return u‘用户密码错误！‘
        else:
            return u‘用户不存在！‘



@app.route(‘/res/‘,methods=[‘GET‘,‘POST‘])
def res():
    if request.method ==‘GET‘:
        return  render_template(‘res.html‘)
    else:
        usern = request.form.get(‘name‘)
        passw = request.form.get(‘password‘)
        user = User.query.filter(User.username==usern).first()
        if user:
            return ‘username existed‘
        else:
            user= User(username=usern,password=passw)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for(‘login‘))


if __name__ == ‘__main__‘:
    app.run(debug=True)

{% extends ‘base.html‘ %}
{% block title %}LOGIN{% endblock %}
{% block head %}
    <link rel="stylesheet" type="text/css" href="../static/css/login.css">
    <script src="../static/js/login.js"></script>
{% endblock %}

{% block main %}

<body class="bg">

<div class="box" >
    <form action="{{url_for(‘login‘)}}" method="post">
    <div class="lg1" ><h2>?  欢迎登录  ?</h2></div>
    <div class="box2" >
        姓名：<input id="name" type="text" placeholder="请输入用户名" name="username"><br>
        密码：<input id="password" type="password" placeholder="请输入密码" name="password"><br>
    </div>

        <div id="error_box"><br></div>
      <form class="lg2" >
         <button type="submit" onclick="myLogin()">登录</button>
         <button type="submit" onclick=window.alert("是否取消登录！")>取消</button>
          <br>
          <div class="design">
          <div class="lg3" ></div>
                <p>Design by Doublewhere</p>
         </div>
      </form></form>>
    </div>
</div>

</body>
{% endblock %}

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