-
-
Save K-7/eb8844d9b747b8a483e8822291d644cc to your computer and use it in GitHub Desktop.
Asynchronous requests in Flask with gevent
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| """Asynchronous requests in Flask with gevent""" | |
| from time import time | |
| from flask import Flask, Response | |
| from gevent.pywsgi import WSGIServer | |
| from gevent import monkey | |
| import requests | |
| # need to patch sockets to make requests async | |
| monkey.patch_all() | |
| CHUNK_SIZE = 1024*1024 # bytes | |
| app = Flask(__name__) # pylint: disable=invalid-name | |
| app.debug = True | |
| @app.route('/Seattle.jpg') | |
| def seattle(requests_counter=[0]): # pylint: disable=dangerous-default-value | |
| """Asynchronous non-blocking streaming of relatively large (14.5MB) JPG | |
| of Seattle from wikimedia commons. | |
| """ | |
| requests_counter[0] += 1 | |
| request_num = requests_counter[0] | |
| url = 'http://upload.wikimedia.org/wikipedia/commons/3/39/Seattle_3.jpg' | |
| app.logger.debug('started %d', request_num) | |
| rsp = requests.get(url, stream=True) | |
| def generator(): | |
| "streaming generator logging the end of request processing" | |
| yield '' # to make greenlet switch | |
| for data in rsp.iter_content(CHUNK_SIZE): | |
| yield data | |
| app.logger.debug('finished %d', request_num) | |
| return Response(generator(), mimetype='image/jpeg') | |
| def main(): | |
| "Start gevent WSGI server" | |
| # use gevent WSGI server instead of the Flask | |
| http = WSGIServer(('', 5000), app.wsgi_app) | |
| # TODO gracefully handle shutdown | |
| http.serve_forever() | |
| if __name__ == '__main__': | |
| main() |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment