Flask：'str' 对象没有属性 'is_active'

Question

我使用 PostgreSQL 作为我的数据库。 这是我第一天使用flask，但在多次尝试创建一个有效的登录系统后，我开始遇到很多错误，但现在只剩下一个了。 我真的不知道原因，我尝试研究，但我仍然不明白我在哪里犯了错误。 我很容易用 - user_management check_login函数检查用户是否存在

class user_management:

    def __init__(self):
        pass


    def check_login(self, username, password):
        try:

            self.username = username
            self.password = password

            # psycopg2 stuff
            self.connection = psycopg2.connect(host='127.0.0.1', port=5432, password='ssss412', database='postgres', user='postgres')
            self.cursor = self.connection.cursor()
            self.query = f"select * from users where username=('{self.username}') and password=('{self.password}')"
            self.cursor.execute(self.query)
            self.connection.commit()
            self.result = self.cursor.fetchone()

        except KeyError:
            pass

        except Exception as error:
            print('error', error)

        finally:
            self.result = self.result or None

            if self.result:
                return True
            elif not self.result:
                return False
            else:
                return False


User = user_management()

@login_manager.user_loader
def load_user(user_id):
    print('idddd', user_id)
    return 2

class LoginForm(FlaskForm):
    username = StringField('username', validators=[InputRequired(), Length(min=4, max=15)])
    password = PasswordField('password', validators=[InputRequired(), Length(min=8, max=80)])
    remember = BooleanField('remember me')

class RegisterForm(FlaskForm):
    email = StringField('email', validators=[InputRequired(), Email(message='Invalid email address'), Length(max=50)])
    username = StringField('username', validators=[InputRequired(), Length(min=4, max=15)])
    password = PasswordField('password', validators=[InputRequired(), Length(min=8, max=80)])

@app.route('/') # Home
def index():
    return render_template('index.html')

@app.route('/login', methods=['GET', 'POST'])
def login():
    form = LoginForm()
    if form.validate_on_submit():
        print(form.username.data, form.password.data)
        login_check = User.check_login(form.username.data, form.password.data)
        if login_check is True: # Logged in
            verification_check = User.check_verification(form.username.data, form.password.data)
            if verification_check is False:
                logout_user()
                return render_template('verification.html')
            elif verification_check is True:
                print('Verified')
                login_user(form.username.data, remember=form.remember.data)
                return redirect(url_for('dashboard'))
            elif verification_check == 'noacc':
                return render_template('index.html')
            elif verification_check == 'error':
                return render_template('index.html')
            return redirect(url_for('dashboard'))

        elif login_check is False: # Wrong cred
            return render_template('index.html')

    return render_template('login.html',form=form)

编辑：发布整个错误...

Traceback (most recent call last):
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 2463, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 2449, in wsgi_app
    response = self.handle_exception(e)
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 1866, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\_compat.py", line 39, in reraise
    raise value
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 1951, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 1820, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\_compat.py", line 39, in reraise
    raise value
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask\app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "C:\Users\interkodas\Desktop\login -ex\app.py", line 170, in login
    login_user(form.username.data, remember=form.remember.data)
  File "C:\Users\interkodas\AppData\Local\Programs\Python\Python38-32\Lib\site-packages\flask_login\utils.py", line 158, in login_user
    if not force and not user.is_active:
AttributeError: 'str' object has no attribute 'is_active'

Answer 1

Flask-Login login_user(user, remember, duration, force, fresh)方法将用户对象作为第一个参数，而不是代表用户的字符串。

获取用户对象的一种常见方法如下（其中User是应用程序中的用户模型，派生自db.Model ）：

user = User.query.get(form.username.data)

一些额外的帮助可以在这里找到。