Flask `RuntimeError：在应用程序上下文之外工作。` 来自中间件

Question

这是中间件类：

class Middleware:
    def __init__(self, app):
        self.app = app


    def __call__(self, environ, start_response):
        request = Request(environ)
        cookies = request.cookies
        path = request.path

        environ['isAuthenticated'] = isAuthenticated(cookies)

        return self.app(environ, start_response)


def isAuthenticated(cookies):
    if (len(cookies)) > 0 :
        if 'jwt' in cookies:
            payload = decodeJWT(cookies['jwt'])
            connection = connect_db()
            
            
            return payload
    else:
        return False

这是ConnectDB.py ：

def connect_db():
    host = current_app.config['HOST']
    db = current_app.config['DB']
    username = current_app.config['USERNAME']
    password = current_app.config['PASSWORD']
    
    connection = psycopg2.connect(host=host, database=db, user=username, password=password, port=5432, cursor_factory=RealDictCursor)
    return connection

我在挑衅middleware这样的：

app = Flask(__name__)
app.config.from_object('SETTINGS')
app.wsgi_app = Middleware(app.wsgi_app)

我收到此错误：

RuntimeError: Working outside of application context.

This typically means that you attempted to use functionality that needed
to interface with the current application object in some way. To solve
this, set up an application context with app.app_context().  See the
documentation for more information.

我知道我需要从应用程序上下文中调用connect_db来访问数据库凭据，但如何从Middleware类内部访问它？

Answer 1

想通了，我必须将actual or完整的app into传递app into中间件， not just the像这样not just the wsgi`：

app = Flask(__name__)
app.config.from_object('SETTINGS')
app.wsgi_app = Middleware(app.wsgi_app, app)

然后Middleware变成这样：

class Middleware:
    def __init__(self, wsgi, app):
        self.wsgi = wsgi
        self.app = app


    def __call__(self, environ, start_response):
        request = Request(environ)
        cookies = request.cookies
        path = request.path

        with self.app.app_context():
            environ['isAuthenticated'] = isAuthenticated(cookies)

        return self.wsgi(environ, start_response)