Quart-Flask-Patch

Quart-Flask-Patch is a Quart extension that patches Quart to work with Flask extensions.

Quickstart

Quart-Flask-Patch must be imported first in your main module, so that the patching occurs before any other code is initialised. For example, if you want to use Flask-Login,

import quart_flask_patch

from quart import Quart
import flask_login

app = Quart(__name__)
login_manager = flask_login.LoginManager()
login_manager.init_app(app)

Extensions known to work

The following flask extensions are tested and known to work with quart,

• Flask-BCrypt
• Flask-Caching
• Flask-KVSession
• Flask-Limiter See also Quart-Rate-Limiter
• Flask-Login See also Quart-Login or Quart-Auth
• Flask-Mail
• Flask-Mako
• Flask-Seasurf
• Flask-SQLAlchemy See also Quart-DB
• Flask-WTF

Extensions known not to work

The following flask extensions have been tested are known not to work with quart,

• Flask-CORS, as it uses app.make_response which must be awaited. Try Quart-CORS instead.
• Flask-Restful as it subclasses the Quart (app) class with synchronous methods overriding asynchronous methods. Try Quart-OpenApi or Quart-Schema instead.

Caveats

Flask extensions must use the global request proxy variable to access the request, any other access e.g. via ~quart.local.LocalProxy._get_current_object will require asynchronous access. To enable this the request body must be fully received before any part of the request is handled, which is a limitation not present in vanilla flask.

Trying to use Flask alongside Quart in the same runtime will likely not work, and lead to surprising errors.

The flask extension must be limited to creating routes, using the request and rendering templates. Any other more advanced functionality may not work.

Synchronous functions will not run in a separate thread (unlike Quart normally) and hence may block the event loop.

Finally the flask_patching system also relies on patching asyncio, and hence other implementations or event loop policies are unlikely to work.

Contributing

Quart-Flask-Patch is developed on GitHub. If you come across an issue, or have a feature request please open an issue. If you want to contribute a fix or the feature-implementation please do (typo fixes welcome), by proposing a merge request.

Testing

The best way to test Quart-Flask-Patch is with Tox,

$ pip install tox
$ tox

this will check the code style and run the tests.

Help

The Quart-Flask-Patch documentation is the best places to start, after that try searching stack overflow or ask for help on gitter. If you still can't find an answer please open an issue.