Flask-Login: AttributeError: type object 'User' 没有属性 'get'

Question

我在 Flask 登录时遇到问题。 每次我尝试登录时，都会出现此错误：

 AttributeError: type object 'User' has no attribute 'get'

我不知道这是从哪里来的，因为我使用的是 flask 文档中的推荐代码。 这是代码：

from flask import Flask, escape, request, render_template, redirect, url_for
from flask_sqlalchemy import SQLAlchemy
from datetime import datetime
from flask_login import UserMixin, login_manager, login_user, login_required, logout_user, current_user, LoginManager
from flask_wtf import FlaskForm
from flask_wtf.form import FlaskForm
from flask_wtf.recaptcha import validators
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import InputRequired, Length, ValidationError
from flask_bcrypt import Bcrypt



app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///data_task.db'
db = SQLAlchemy(app)
app.config['SECRET_KEY'] = "HEXODECICUL"
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

bcrypt = Bcrypt(app)

login_manager = LoginManager()
login_manager.init_app(app)
login_manager.login_view = "login"


class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), nullable=False, unique=True)
    password = db.Column(db.String(80), nullable=False)

class RegisterForm(FlaskForm):
    username = StringField(validators=[InputRequired(), Length(min=4, max=20)], render_kw={"placeholder": "Username"})
    password = PasswordField(validators=[InputRequired(), Length(min=4, max=20)], render_kw={"placeholder": "Password"})
    submit = SubmitField("Register")

    def validate_username(self, username):
        existing_usernames = User.query.filter_by(username=username.data).first()

        if existing_usernames:
            raise ValidationError("That username alreadu exists. Please choose a different one.")

class LoginForm(FlaskForm):
    username = StringField(validators=[InputRequired(), Length(min=4, max=20)], render_kw={"placeholder": "Username"})
    password = PasswordField(validators=[InputRequired(), Length(min=4, max=20)], render_kw={"placeholder": "Username"})
    submit = SubmitField("Login")



@app.route('/dash', methods=['GET', 'POST'])
@login_required
def dash():
    return render_template("index.html")


@app.route("/login", methods=["GET", "POST"])
def login():
    form = LoginForm()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.username.data).first()
        if user:
            if bcrypt.check_password_hash(user.password, form.password.data):
                login_user(user)
                return redirect(url_for('dash'))
    return render_template("login.html", form = form)


@app.route("/logout")
@login_required
def logout():
    logout_user()
    return redirect(url_for('login'))



@app.route("/register", methods=['GET', 'POST'])
def register():
    form = RegisterForm()
    if form.validate_on_submit():
        hashed_password = bcrypt.generate_password_hash(form.password.data)
        new_user = User(username=form.username.data, password=hashed_password)
        db.session.add(new_user)
        db.session.commit()
        return redirect(url_for('login'))
    return render_template("register.html", form=form)


@app.route('/', methods=["GET", "POST"])
def accueil():
    return "Home"


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

flask中的错误：

    AttributeError
AttributeError: type object 'User' has no attribute 'get'

Traceback (most recent call last)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/app.py", line 2091, in __call__
    def __call__(self, environ: dict, start_response: t.Callable) -> t.Any:
        """The WSGI server calls the Flask application object as the
        WSGI application. This calls :meth:`wsgi_app`, which can be
        wrapped to apply middleware.
        """
        return self.wsgi_app(environ, start_response)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/app.py", line 2076, in wsgi_app
response = self.handle_exception(e)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/app.py", line 2073, in wsgi_app
response = self.full_dispatch_request()
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/app.py", line 1518, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/app.py", line 1516, in full_dispatch_request
rv = self.dispatch_request()Open an interactive python shell in this frame
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/app.py", line 1502, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
File "/Users/christophechouinard/Feuille_encaisse/app.py", line 69, in login
return render_template("login.html", form = form)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/templating.py", line 146, in render_template
ctx.app.update_template_context(context)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask/app.py", line 756, in update_template_context
context.update(func())
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask_login/utils.py", line 379, in _user_context_processor
return dict(current_user=_get_user())
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask_login/utils.py", line 346, in _get_user
current_app.login_manager._load_user()
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/flask_login/login_manager.py", line 318, in _load_user
user = self._user_callback(user_id)
File "/Users/christophechouinard/Feuille_encaisse/app.py", line 52, in load_user
    password = PasswordField(validators=[InputRequired(), Length(min=4, max=20)], render_kw={"placeholder": "Username"})
    submit = SubmitField("Login")
 
@login_manager.user_loader
def load_user(user_id):
    return User.get(user_id)
 
@app.route('/dash', methods=['GET', 'POST'])
@login_required
def dash():
    return render_template("index.html")
AttributeError: type object 'User' has no attribute 'get'
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我知道这个问题已经在这里得到回答： https://stackoverflow.com/questions/ask#:~:text=AttributeError%3A%20type%20object%20%27Message,pack()%20display.update()% 20def%20... 但我试过了，但仍然出现这个错误（而且我不太了解这个问题的答案......）

非常感谢 ！！

Answer 1

检查您的用户加载程序。 在那你调用User.get(user_id) 。 但是，它应该如下所示。

@login_manager.user_loader
def load_user(user_id):
    return User.query.get(user_id)

通过这些行，SQLAlchemy 用于根据用户从数据库中的 id 查询用户。

Answer 2

我尝试了这个解决方案，它允许我进入我的网页并实际登录，但我遇到了另一个错误。

/Users/xinyuyang/PycharmProjects/flask authentication/main.py:22: LegacyAPIWarning: Query.get() 方法在 SQLAlchemy 的 1.x 系列中被认为是遗留的，并成为 2.0 中的遗留构造。 该方法现在可用作 Session.get()（自以下版本弃用：2.0）（SQLAlchemy 2.0 的背景位于： https://sqlalche.me/e/b8d9 ）返回 User.query.get(user_id)

根据文档，它是一个过时的 function，他们推荐了另一种方法来执行此操作，但如果我尝试新方法，则会出现另一个错误。

我不断收到“TypeError: Session.get() missing 1 required positional argument: 'ident'”的错误

然后我阅读了文档，所以我将这部分代码更改为：

@login_manager.user_loader
def load_user(user_id):
    # session = Session(User)
    return Session.get(User,{"id":int(user_id)})
Then I keep getting the error of "TypeError: Session.get() missing 1 required positional argument: 'ident'"

文档说身份参数通常是字典，但我的字典在这里不起作用。

有谁知道如何解决这一问题？ 非常感谢！