Flask 用户登录，表单提交

from flask import Flask, render_template, jsonify, request, redirect
 
# 指定template文件夹
# app = Flask(__name__,template_folder=)
app = Flask(__name__)
 
 
@app.route('/login', methods=['GET','POST'])
def login():
    # return '登录'   # HttpResponse
    # return render_template('login.html') # render
    # return jsonify({'code':1000,'data':[1,2,3]}) # JsonResponse
    if request.method == 'GET':
        return render_template('login.html')
 
    #print(request.form) 
    user = request.form.get('user')
    pwd = request.form.get('pwd')
 
    if user == 'admin' and pwd == "123":
        #return "登录成功"
        return redirect('/index')
    # return '登录失败'
    error = '用户名或密码错误'
    return render_template('login.html',error=error)
 
@app.route('/index')
def index():
    return '首页'
 
if __name__ == '__main__':
    app.run()

html>
<head>
  <title>页面标题title>
head>
 
<body>
    <h1>登录h1>
 
    <form method="post">
        <input type="text" name="user">
        <input type="text" name="pwd">
        <input type="submit" value="提交">
        <span style="color: red;">{{error}}span>
 
    form>
 
body>