Flask应用程序不会启动“ ImportError：无法从'werkzeug'导入名称'cached_property''

我已经在Flask应用程序上工作了几个星期。我今天完成了它，然后去部署了它……现在它不会启动。

我没有添加或删除任何代码，因此假设部署过程中发生了某些变化？

无论如何，这是终端中显示的完整错误：

Traceback (most recent call last):
  File "C:\Users\Kev\Documents\Projects\Docket\manage.py", line 5, in <module>
    from app import create_app, db
  File "C:\Users\Kev\Documents\Projects\Docket\app\__init__.py", line 21, in <module>
    from app.api import api, blueprint, limiter
  File "C:\Users\Kev\Documents\Projects\Docket\app\api\__init__.py", line 2, in <module>
    from flask_restplus import Api
  File "C:\Users\Kev\.virtualenvs\Docket-LasDxOWU\lib\site-packages\flask_restplus\__init_
_.py", line 4, in <module>
    from . import fields, reqparse, apidoc, inputs, cors
  File "C:\Users\Kev\.virtualenvs\Docket-LasDxOWU\lib\site-packages\flask_restplus\fields.
py", line 17, in <module>
    from werkzeug import cached_property
ImportError: cannot import name 'cached_property' from 'werkzeug' (C:\Users\Kev\.virtualen
vs\Docket-LasDxOWU\lib\site-packages\werkzeug\__init__.py)

这也是上述三个文件中的代码。

manage.py：

from apscheduler.schedulers.background import BackgroundScheduler
from flask_script import Manager
from flask_migrate import Migrate, MigrateCommand

from app import create_app, db

app = create_app()
app.app_context().push()

manager = Manager(app)

migrate = Migrate(app, db)

manager.add_command('db', MigrateCommand)

from app.routes import *
from app.models import *

def clear_data():
    with app.app_context():
        db.session.query(User).delete()
        db.session.query(Todo).delete()
        db.session.commit()
        print("Deleted table rows!")

@manager.command
def run():
    scheduler = BackgroundScheduler()
    scheduler.add_job(clear_data, trigger='interval', minutes=15)
    scheduler.start()
    app.run(debug=True)

if __name__ == '__main__':
    clear_data()
    manager.run()

app/__init__.py：

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager

from config import Config

db = SQLAlchemy()

login = LoginManager()

def create_app():
    app = Flask(__name__)
    app.config.from_object(Config)
    db.init_app(app)

    login.init_app(app)
    login.login_view = 'login'

    from app.api import api, blueprint, limiter
    from app.api.endpoints import users, todos, register
    from app.api.endpoints.todos import TodosNS
    from app.api.endpoints.users import UserNS
    from app.api.endpoints.register import RegisterNS

    api.init_app(app)

    app.register_blueprint(blueprint)

    limiter.init_app(app)

    api.add_namespace(TodosNS)
    api.add_namespace(UserNS)
    api.add_namespace(RegisterNS)

    return app

api/__init__.py：

from logging import StreamHandler
from flask_restplus import Api
from flask import Blueprint
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address

blueprint = Blueprint('api', __name__, url_prefix='/api')

limiter = Limiter(key_func=get_remote_address)
limiter.logger.addHandler(StreamHandler())

api = Api(blueprint, doc='/documentation', version='1.0', title='Docket API',
          description='API for Docket. Create users and todo items through a REST API.\n'
                      'First of all, begin by registering a new user via the registration form in the web interface.\n'
                      'Or via a `POST` request to the `/Register/` end point', decorators=[limiter.limit("50/day", error_message="API request limit has been reached (50 per day)")])

我试过重新安装flask＆flask_restplus但没有运气。

尝试：

from werkzeug.utils import cached_property

https://werkzeug.palletsprojects.com/en/1.0.x/utils/

降级到Werkzeug == 0.16.1可以解决此问题

参见https://github.com/noirbizarre/flask-restplus/issues/777#issuecomment-583235327