flask-http2-push

Bottom line: A Flask extension to add HTTP2 server push to your application.

This is a drop in library for doing HTTP2 server push with a Flask application. It needs a server that supports HTTP2 push, like Google Appengine or Cloudfare. Once added to your Flask application it will generate the necessary headers for server push to work.

Getting started

To install run:

pip install flask-http2-push

Usage

You need to create a push_manifest.json file (can be named anything you want) that contains the files you want to push (Appengine currently has a limit of 10 files). The file format is very easy:

{
    "/path/to/file-to-push.js": {
        "type": "script",
        "weight": 1
    },
    "/path/to/file-to-push.css": {
        "type": "style",
        "weight": 1
    },
    "/path/to/file-to-push.woff2": {
        "type": "font",
        "weight": 1
    },
    "/path/to/file-to-push.html": {
        "type": "document",
        "weight": 1
    },
}

There is a library for automatically generating the file. You can find it here (https://www.npmjs.com/package/http2-push-manifest).

Once you have your manifest file, you can use the library in your flask view functions like so:

import flask
from flask_http2_push import http2push

app = flask.Flask(__name__)

@app.route('/')
@http2push()
def main():
    return 'hello, world!'

This will try to find a file named push_manifest.json at the root of the project. If you would like to name the manifest differently or use another location, you can specify it in the decorator:

@app.route('/')
@http2push('static/my_manifest.json')
def main():
    return 'hello, world!'

Running the tests

pip install -r requirements.txt
nosetests

Aknowledgements

This library is inspired by the Google Appengine HTTP2 push library (https://github.com/GoogleChrome/http2push-gae). The explainer document contained within that repo is a very good read if you want to further explore how HTTP2 push works (https://github.com/GoogleChrome/http2push-gae/blob/master/EXPLAINER.md)

License

MIT license. See LICENSE.txt for full info.