小编Raj*_*ngh的帖子

我正在尝试创建登录功能。但它只适用于那些。前 - 当我提供错误的用户名和密码时，在取消该消息并提供正确的用户名和密码后，我得到了正确的错误消息“无法登录”，然后我得到“pymysql.err.Error：已经关闭”，下面是示例代码.

import pymysql

# Connect to the database
connection = pymysql.connect(host='localhost',
                             user='root',
                             password='',
                             db='python_code',
                             charset='utf8mb4',
                             cursorclass=pymysql.cursors.DictCursor)
class LoginModel:
    def check_user(self, data):

        try:
            with connection.cursor() as cursor:
                # Read a single record
                sql = "SELECT `username` FROM `users` WHERE `username`=%s"
                cursor.execute(sql, (data.username))
                user = cursor.fetchone()
                print(user)

            if user:
                if (user, data.password):
                    return user
                else:
                    return False
            else:
                return False

        finally:
            connection.close()