完成登录功能，用session记住用户名

登录功能完成：

1. js:设置return
2. html:设置
   1. form
   2. input

   3. onclick="return fnLogin()"

3. 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：

1. 从`flask`中导入`session`
2. 设置`SECRET_KEY`
3. 操作字典一样操作`session`：增加用户名`session['username']=`username

   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)
       nickname = db.Column(db.String(50))
   
   #db.create_all()
   
   @app.route('/')
   def shouye():
       return render_template('base.html') #跳转首页\
   
   
   @app.route('/denglu/',methods=['GET','POST'])
   def gg():
       if request.method == 'GET':
           return render_template('denglu.html') #跳转登录
       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('shouye'))
               else:
                   return u'password error'
           else:
               return u'username is not existed'
   
   @app.route('/zhuche/', methods=['GET','POST'])
   def login ():
       if request.method =='GET':
           return render_template('zhuche.html')#跳转注册
       else:
           usern = request.form.get('username')
           passw = request.form.get('password')
           nickn = request.form.get('nickname')
           user = User.query.filter(User.username == usern).first()
           if user:
               return u'username existed'
           else:
               user1 = User(username = usern,password = passw,nickname = nickn)
               db.session.add(user1)#数据库操作
               db.session.commit()
               return redirect(url_for('gg'))
   @app.route('/tupian/')
   def hh():
       return render_template('tupian.html') #跳转图片库
   @app.route('/fabu/')
   def fabu():
       return render_template('fabu.html') # 跳转发布
   if __name__ == '__main__':
       app.run(debug=True)

    

{% extends 'base.html' %}

{% block denglutitle %}登陆{% endblock %}

{% block dengluhead %}
    <link href="../static/css/denglu.css" rel="stylesheet" type="text/css">
    <script src="../static/js/denglu.js"></script>


{% endblock %}

{% block denglubody %}
    <div class="box">
        <h2>Login</h2>
        <form action="{{ url_for('gg') }}" method="post">
        <div class="input_box">
            <input type="text" id="uname" placeholder="Your Name" name="username">
        </div>
        <div class="input_box">
            <input type="password" id="upass" placeholder="password" name="password">
        </div>
        <div id="error_box"><br></div>
        <div class="input_box">
            <button onclick="fnLogin()">Enter</button>
        </div>
</form>
    </div>
{% endblock %}

 

import os

SQLALCHEMY_DATABASE_URI = 'mysql+pymysql://root:@127.0.0.1:3306/mis_15?charset=utf8'
SQLALCHEMY_TRACK_MODIFICATIONS = False

SECRET_KEY = os.urandom(24)

 

function fnLogin() {
    var oUname = document.getElementById("uname");
    var oUpass = document.getElementById("upass");
    var oError = document.getElementById("error_box");

    oError.innerHTML = "<br>"
    // uname
    if (oUname.value.length > 20 || oUname.value.length < 6) {
        oError.innerHTML = "your Name：6-20";
        return false;
    } else if ((oUname.value.charCodeAt(0) >= 48) && (oUname.value.charCodeAt(0) <= 57)) {
        oError.innerHTML = "first number";
        return false;
    } else for (var i = 0; i < oUname.value.length; i++) {
        if ((oUname.value.charCodeAt(i) < 48) || (oUname.value.charCodeAt(i) > 57) && (oUname.value.charCodeAt(i) < 97) || (oUname.value.charCodeAt(i) > 122)) {
            oError.innerHTML = "letters or numbers";
            return false;
        }
    }

// upass
    if (oUpass.value.length > 20 || oUpass.value.length < 6) {
    oError.innerHTML = "password：6-20位";
    return false;
    }
    window.alert("Login successful！")
}