flask用session记录状态

<form action="/login" method="POST">
    <input type="text" name="username">
    <input type="password" name="password">
    <input type="submit" value="提交">
</form>

# -*- coding:utf-8 -*-



from flask import Flask,session,redirect,url_for,request,render_template
app = Flask(__name__)
app.secret_key='123'    #配置secret_key,否则不能实现session对话
@app.route('/')
def index():
    if session.get('username') == 'wanghao' and session.get('password') == '123':
        return "你已经登陆"
    msg="没有登陆"
    return render_template('from_login.html')

@app.route("/login",methods=["POST","GET"])
def login():
    if request.method=='POST':
        session['username']=request.form['username']
        session['password']=request.form['password']
        return redirect(url_for('index'))
    return '123'

if __name__ == '__main__':
    app.debug=True
    app.run(port=7998)