完成登录功能，用session记住用户名

登录功能完成：

js:设置return

function fnLogin() {
            var oUname = document.getElementById("uname");
            var oError = document.getElementById("error_box");
            var oUpass = document.getElementById("upass");
            var isError=true;
            oError.innerHTML="<br>"

            if(oUname.value.length<6 || oUname.value.length >12){
                oError.innerHTML="用户名6-12位";
                return false;
            }else if ((oUname.value.charCodeAt(0)>=48) && (oUname.value.charCodeAt(0)<=57)){
                oError.innerHTML="第一位只能是字母";
                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="只能是字母或数字";
                    return false;
                }
            }
            if(oUpass.value.length<6 || oUpass.value.length>12){
                oError.innerHTML="密码6-12位";
                return false;
            }
            return true;
            window.alert("登录成功")
        }

html:设置

form
input

onclick="return fnLogin()"

{% extends'base.html' %}
{% block title %}
    登录
{% endblock %}
{% block head %}
    <link href="../static/css/hh.css" rel="stylesheet" type="text/css">
    <script src="../static/js/dl.js"></script>
{% endblock %}
{% block main %}
<body><br><br><br>
  <div><h1>武林|登录</h1></div>

    <div class="box">
        <form action="{{ url_for('login') }}" method="post">
        <div class="input_box">
             姓名：<input type="text" id="uname" name="username" placeholder="敢问阁下大名">
        </div>
        <br>
        <div class="input_box">
             密码：<input type="password" id="upass"  name="password" placeholder="请输入通关密码">
        </div>
        <br>
        <div id="error_box"><br></div>
        <div class="input_box">
            <button onclick="return fnLogin()">登录</button>

        </div>
        <br>
    </div>

</div>
{% endblock %}
</body>
</html>

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

from flask import Flask, render_template,url_for,redirect,request,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(20))
# db.create_all()
''' 
    user=User(username='hehe',password='1234567')
    db.session.add(user)
    db.session.commit()
'''
@app.route('/')
def hh():
    return render_template('hh.html')

@app.route('/login/',methods=['GET','POST'])
def login():
    if request.method == "GET":
        return render_template("dl.html")
    else:
        username = request.form.get("username")
        password = request.form.get("password")
        user = User.query.filter(User.username == username).first()
        if user:
            if user.password == password:
                session['user'] = username

                return redirect(url_for('login'))
            else:
                return '密码错误'
        else:
            return '用户名不存在'


@app.route('/regist/',methods=['GET','POST'])
def regist():
    if request.method=='GET':
        return render_template("zc.html")
    else:
        username = request.form.get("username")
        password = request.form.get("password")
        user = User.query.filter(User.username == username).first()
        if user:
            return ' 用户名已存在'
        else:
            user = User(username=username, password=password)
            db.session.add(user)#数据库，添加操作
            db.session.commit()
            return redirect(url_for('login'))

@app.route('/wenda/')
def wenda():
    return render_template("wenda.html")


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

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

SECRET_KEY = os.urandom(24)