Flask-Firehose

HTTP/2 Server Push for your Flask apps.

Installation

pip install flask-firehose

Usage

Initialization

Direct initialization:

app = Flask(__name__)
Firehose(app)

With application factories:

firehose = Firehose()

def create_app():
    app = Flask(__name__)
    firehose.init_app(app)
    return app

Pushing resources

Let the HTML template writer decide what to push:

{% extends 'base.html' %}
{% block body %}
    <link rel="stylesheet" href="{{ push('/static/css/main.css', as='style', rel='preload') }}">
    This is some document.
{% endblock %}

Let the backend developer decide what to push:

from flask_firehose import push

@app.route('/someroute')
def render_someroute():
    push('/static/css/main.css', **{'as': 'style', 'rel': 'preload'})
    return render_template('some_template')

Tracking pushed resources

Ideally, resources already pushed during a session shouldn’t be pushed again. So, Flask-Firehose includes a simple utility class to track pushed resources using session variable ‘h2-pushed’. Additionally, Flask-Firehose can also work with external code to track pushed resources in case the provided implementation is unsuitable.

class Custom_connector():

    def get_pushed(self):
        """Returns a set of items that have been already pushed to client.

        Returns
        -------
        set
            Set of items that are pushed.

        """
        # your code here

    def set_pushed(self, inset):
        """Update client state after pushing more items at the end of request.

        Parameters
        ----------
        inset : set
            A set of URLs of pushed items.
        """
        # your code here

Using custom connector with Firehose

firehose = Firehose(connector=Custom_connector())
firehose.init_app(app)

Configure NGINX

location = /myapp {
    proxy_pass http://upstream;
    http2_push_preload on;
}

Testing

To initialize a development environment in ./venv:

make devenv

To run unit tests:

make test

To run integration testing with NGINX with docker:

make dockertest

Release files for Flask-Firehose 0.2.3

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Built distribution (wheel)

Table of built distributions (wheels) for Flask-Firehose 0.2.3
File	Interpreter	ABI	Platform	Reset
Flask_Firehose-0.2.3-py3-none-any.whl 4.2 kB Apr 11, 2020	Python 3	none	any	Details

Release files / Flask_Firehose-0.2.3-py3-none-any.whl

Download URL	Flask_Firehose-0.2.3-py3-none-any.whl
Size	4.2 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`78303033ca873753b4fdb4920d0c16a9f396f2d4a905aefebe34bfe19c35cde2`
BLAKE2b-256 checksum How to use checksums	`8006f8f540998ef7bc85b0645732ce2b4eca155d3bbe02a80e8c1386e6731530`
Upload date	Apr 11, 2020
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/1.15.0 pkginfo/1.5.0.1 requests/2.22.0 setuptools/41.2.0 requests-toolbelt/0.9.1 tqdm/4.32.2 CPython/3.7.5`