http2-push-manifest

http2-push-manifest

A utility script for doing http2 push and/or preload.

Generates a list of local static resources used in your web app by outputting a json file. This file can be read by your web server to more easily construct the appropriate Link: <URL>; rel=preload headers(s) for http2 push/preload.

Install

npm install --save-dev http2-push-manifest

Run tests

npm test

What's a push manifest?

A manifest is not required by the HTTP2 protocol but is useful for telling your server what resources to push with your main page.*

http2-push-manifest is a Node script for generating a JSON file listing all of the static resources used on a page. It tries to discover the resources in an .html file you specify. This file can be read by your web server to more easily construct the appropriate Link: <URL>; rel=preload headers(s) used in HTTP2 push.

By default, the script generates push_manifest.json in the top level directory of your app with a mapping of <URL>: <PUSH_PRIORITY>. Feel free to add/remove URLs from this list as necessary for your app or change the priority level.

Example of generated push_manifest.json with discovered resources:

{
  "/css/app.css": 1,
  "/js/app.js": 1,
  "/bower_components/webcomponentsjs/webcomponents-lite.js": 1,
  "/bower_components/iron-selector/iron-selection.html": 1,
  ...
  "/elements.html": 1,
  "/elements.vulcanize.html": 1
}

Note: right now the SPDY <PUSH_PRIORITY> is included, but it will be deprecated in the future as the new HTTP2 standard does not include this field.

Examples

Example - list all the static resources of app/index.html (including sub-HTML Imports):

http2-push-manifest app index.html

Example - list all the resources in static/elements/elements.html:

http2-push-manifest static/elements elements.html

Example - using a custom manifest filename:

http2-push-manifest path/to/site index.html -m push.json
http2-push-manifest path/to/site index.html --manifest push.json

Usage on App Engine

If you're using App Engine for your server, check out http2push-gae. It leverages this manifest file format and automagically reads push_mainfest.json, setting the Link: rel="preload" header for you.

Simply decorate your request handler like so:

class Handler(http2.PushHandler):

  @http2push.push('push_manifest.json')
  def get(self):
    # Resources in push_manifest.json will be server-pushed with this handler.