Accelerating Node.js Applications with HTTP/2 Server Push | Hacker News Reader

Accelerating Node.js Applications with HTTP/2 Server Push

blog.cloudflare.com

50 pointsjgrahamc6 comments

Does this tech sense to someone?

For example, while I'm playing one youtube video, they would download the next one.

smh.

No it would be used for cases like sending you the CSS and JS for the page, before the browser has actually started to parse the HTML.

It simply means you can reduce the latency of fetching resources which are referred to within the document.

It wouldn't really make sense to use this for something like YouTube videos - that's more application level rather than the HTTP level.

That sounds nice and all, but most static files have caching done on them, so it seems like this tech may (currently) be a solution in search of a real problem.

The problem is that many people will leave a page if it doesn't load within a few seconds. When someone is hitting your page for the first time (and therefore doesn't have your site's assets cached), it needs to load fast, or you'll lose visitors.

HTTP/2 Server Push is a large micro-optimization that requires a lot of effort (as in, server-side logic, and in some cases, client-side code) to use properly.

The Chromium team, employed by one of the largest backers of HTTP/2 Push, recently did a thorough analysis (excellent read) [1], which recommends the following best practices; paraphrased, commentary mine:

[A] watch and aggressively respond to network utilization

[B] construct a dependency graph of resources (presumably by actually parsing the HTML on server-side, or beforehand out-of-band and store it some other place)

[C] have the client communicate the state of its cache! (there's an RFC already being proposed for this [2], and some software already implements it or something similar [3][4])

[D] have custom, conditional logic for cookies

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[1] https://docs.google.com/document/d/1K0NykTXBbbbTlv60t5MyJvXj... [2] https://tools.ietf.org/html/draft-ietf-httpbis-cache-digest-... [3] https://mariusgundersen.net/module-pusher/ [4] https://h2o.examp1e.net/configure/http2_directives.html#http...

If the browser doesn't want the resource, it can cancel the stream.

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