flask-image-uploader

A small Flask application demonstrating HTML Server-Sent Events (EventSource). Visitors upload an image and it is pushed, in real time, to every other connected visitor. Only the most recent images are retained on disk.

Inspired by: https://github.com/jkbr/chat

Requirements

flask-image-uploader supports Python 3.10 through 3.14.

Running the development server

Run the app directly with uv:

uv run flask-image-uploader

Then open http://127.0.0.1:5000 and upload an image. Uploaded images appear in every connected browser as they arrive.

Running with gunicorn

The streaming endpoint relies on cooperative greenlets, so serve it with a gevent worker:

uv run gunicorn --worker-class gevent --timeout 300 flask_image_uploader:app