https://github.com/miguelgrinberg/aioflask

Flask running on asyncio!
https://github.com/miguelgrinberg/aioflask

async-await asyncio flask greenlet

Last synced: about 11 hours ago
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Flask running on asyncio!

• Host: GitHub
• URL: https://github.com/miguelgrinberg/aioflask
• Owner: miguelgrinberg
• License: mit
• Created: 2020-07-16T17:58:43.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2023-06-20T11:57:35.000Z (over 1 year ago)
• Last Synced: 2024-05-02T04:52:49.143Z (8 months ago)
• Topics: async-await, asyncio, flask, greenlet
• Language: Python
• Homepage:
• Size: 97.7 KB
• Stars: 200
• Watchers: 17
• Forks: 16
• Open Issues: 14
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGES.md
  • License: LICENSE

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README

        
# aioflask

![Build status](https://github.com/miguelgrinberg/aioflask/workflows/build/badge.svg) [![codecov](https://codecov.io/gh/miguelgrinberg/aioflask/branch/main/graph/badge.svg?token=CDMKF3L0ID)](https://codecov.io/gh/miguelgrinberg/aioflask)

Flask 2.x running on asyncio!

Is there a purpose for this, now that Flask 2.0 is out with support for async

views? Yes! Flask's own support for async handlers is very limited, as the

application still runs inside a WSGI web server, which severely limits

scalability. With aioflask you get a true ASGI application, running in a 100%

async environment.

WARNING: This is an experiment at this point. Not at all production ready!

## Quick start

To use async view functions and other handlers, use the `aioflask` package

instead of `flask`.

The `aioflask.Flask` class is a subclass of `flask.Flask` that changes a few

minor things to help the application run properly under the asyncio loop. In

particular, it overrides the following aspects of the application instance:

- The `route`, `before_request`, `before_first_request`, `after_request`, 

  `teardown_request`, `teardown_appcontext`, `errorhandler` and `cli.command`

  decorators accept coroutines as well as regular functions. The handlers all

  run inside an asyncio loop, so when using regular functions, care must be

  taken to not block.

- The WSGI callable entry point is replaced with an ASGI equivalent.

- The `run()` method uses uvicorn as web server.

There are also changes outside of the `Flask` class:

- The `flask aiorun` command starts an ASGI application using the uvicorn web

  server.

- The `render_template()` and `render_template_string()` functions are

  asynchronous and must be awaited.

- The context managers for the Flask application and request contexts are

  async.

- The test client and test CLI runner use coroutines.

## Example

```python

import asyncio

from aioflask import Flask, render_template

app = Flask(__name__)

@app.route('/')

async def index():

    await asyncio.sleep(1)

    return await render_template('index.html')

```