Flask-admin 无法识别模型视图中的 current_user

我在 Flask-admin 中创建了 ModelView，并希望为用户提供角色选择，以便只有管理员才能创建具有角色经理、管理员或用户的用户。用户不应该选择授予管理员权限或类似的权限。我正在尝试这段代码，但它给了我：

AttributeError：“NoneType”对象没有属性“is_authenticated”

class UserView(ModelView):
    column_exclude_list = ['logs', 'password_hash',]
    form_excluded_columns = ['logs']
    can_edit = True
    if login.current_user or current_user.is_authenticated:
        if login.current_user.role == 'a':
            form_choices = {
            'role': [ ('a', 'Admin'), ('m', 'Manager'), ('u', 'User') ]
            }
        if login.current_user.role == 'm':
            form_choices = {
        'role': [
            ('m', 'Manager'),
            ('u', 'User')
            ]
    }

任何帮助将不胜感激。

评估current_user总是返回一个NoneType除非它在 ​​Flask 应用程序上下文中。执行如下操作：

def get_user_roles():

    _roles = []
    
    if current_user and current_user.is_authenticated:
        if current_user.role == 'a':
            _roles =  [('a', 'Admin'), ('m', 'Manager'), ('u', 'User')]
        elif login.current_user.role == 'm':
            _roles = [('m', 'Manager'), ('u', 'User')]

    return _roles

class UserView(ModelView):

    form_choices = {
        'role' : get_user_roles
    }

单个文件示例。如果您在未登录的情况下运行此命令，您将在角色选择中仅看到“用户”角色：

requirements.txt

Babel==2.11.0
blinker==1.5
click==8.1.3
colorama==0.4.6
dnspython==2.2.1
email-validator==1.3.0
Flask==2.2.2
Flask-Admin==1.6.0
Flask-BabelEx==0.9.4
Flask-Login==0.6.2
Flask-Mail==0.9.1
Flask-Principal==0.4.0
Flask-SQLAlchemy==3.0.2
Flask-WTF==1.0.1
greenlet==2.0.1
idna==3.4
itsdangerous==2.1.2
Jinja2==3.1.2
MarkupSafe==2.1.1
passlib==1.7.4
pytz==2022.6
speaklater==1.3
SQLAlchemy==1.4.44
Werkzeug==2.2.2
WTForms==3.0.1

app.py

import os
from datetime import datetime
from werkzeug.security import generate_password_hash, check_password_hash
import click
from flask import Flask, current_app
from flask_admin import Admin
from flask_admin.contrib.sqla import ModelView
from flask_login import current_user, UserMixin, LoginManager
from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()
login_manager = LoginManager()


class User(db.Model, UserMixin):
    __tablename__ = 'users'

    id = db.Column(db.Integer, primary_key=True)

    first_name = db.Column(db.Unicode(length=255), nullable=False)
    last_name = db.Column(db.Unicode(length=255), nullable=False, index=True)

    # Identification Data: email & password
    email = db.Column(db.Unicode(length=254), nullable=False, unique=True)
    password = db.Column(db.Unicode(length=255), nullable=False)
    active = db.Column(db.Boolean(), default=False)

    role = db.Column(db.Unicode(length=255), nullable=False)


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


basedir = os.path.abspath(os.path.dirname(__file__))

app = Flask(__name__)

app.config['SECRET_KEY'] = '123456790'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'database.db')

db.init_app(app)
login_manager.init_app(app)


@app.cli.command('create-database', short_help='Create sample database')
def create_database():

    """
        Create database
    """

    db.drop_all()
    db.create_all()

    users = [
        {
            'email': '[email protected] /cdn-cgi/l/email-protection',
            'first_name': 'Paul',
            'last_name': 'Cunningham',
            'password': generate_password_hash('pa$$word'),
            'active': True,
            'role': 'a',
        },
        {
            'email': '[email protected] /cdn-cgi/l/email-protection',
            'first_name': 'Jane',
            'last_name': 'Smith',
            'password': generate_password_hash('pa$$word'),
            'active': True,
            'role': 'm'
        },
    ]

    for user in users:
        _user_db = User(**user)
        db.session.add(_user_db)

    db.session.commit()


@app.route('/')
def index():  # put application's code here
    return '<a href="/admin/">Click me to get to Admin!</a>'


admin = Admin(app, template_mode="bootstrap3")


def get_user_roles():

    # default role is a user
    _roles = [('u', 'User')]

    if current_user and current_user.is_authenticated:
        if current_user.has_role('a'):
            print('Current user is an admin')
            _roles = [('a', 'Admin'), ('m', 'Manager'), ('u', 'User')]
        elif current_user.has_role('m'):
            print('Current user is a manager')
            _roles = [('m', 'Manager'), ('u', 'User')]

    print(f"Roles assigned to role choices: {_roles}")
    return _roles


class UserView(ModelView):

    column_list = ('first_name', 'last_name', 'email', 'role')

    form_columns = column_list

    form_choices = {
        'role': get_user_roles
    }


admin.add_view(UserView(User, db.session))


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

运行以下命令来初始化 SQLite 数据库。

flask create-database