HTTP/2 Server Push: Difference between revisions

Revision as of 21:27, 20 November 2023

Revision as of 20:10, 11 December 2023

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{{Short description |WebOutdated web optimization protocol}}

{{use dmy dates|date=April 2022|cs1-dates=y}}

{{Multiple issues|

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== History ==

On May 14, 2015, HTTP/2 was standardized by {{IETF RFC|7540}}, ratified as a Proposed Standard. The document includes section 8.2 entitled "Server Push" which introduced the concept to the protocol as an optional extension. [[Google Chrome]] 40 became the first browser supporting the final standardized HTTP/2 version, including the optional Server Push.<ref>{{Cite web |last= |first= |date=2015-02-10 |title=Google announces SPDY's coming demise as HTTP/2 approaches |url=https://arstechnica.com/information-technology/2015/02/google-announces-spdys-coming-demise-as-http2-approaches/ |access-date=2023-07-30 |website=Ars Technica |language=en-us}}</ref>

In February 2018, [[Nginx]] 1.13.9 was released with optional support for HTTP/2 Server Push.<ref name=":1" />

In November 2020, [[Google]] announced their intent to remove Server Push from Google Chrome implementation of HTTP/2 and [[QUIC|gQUIC]] (which later evolved into HTTP/3).<ref>{{Cite web |last=Lassey |first=Brad |date=2020-11-12 |title=Intent to Remove: HTTP/2 and gQUIC server push |url=https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/vOWBKZGoAQAJ |access-date=2023-11-20 |website=Blink mailing list}}</ref>

In October 2022, Google announced their intent to remove Server Push from Google Chrome citing the poor performance of the extension in practice, lack of use and better alternatives. Chrome 106 became the first release disabling Server Push by default.<ref name=":2">{{Cite web |date=2022-08-18 |title=Removing HTTP/2 Server Push from Chrome |url=https://developer.chrome.com/blog/removing-push/ |access-date=2023-07-30 |website=Chrome Developers |language=en}}</ref>

== Protocol ==

Unlike [[HTTP|HTTP/1.1]], HTTP/2 can multiplex multiple streams on one TCP connection. Server Push allows the server to open new streams by sending PUSH_PROMISE frames, in order to send the client resources it expects will be needed. A PUSH_PROMISE frame is similar to a GET request, but sent by the server. A client may choose to reject the push by sending an RST_STREAM frame, for example if it already has the resource cached; if it does not, it will store the pushed data in a cache associated with the connection which will be consulted before a request is sent down that connection. Clients can also request that servers not send server pushes using a SETTINGS frame. The specification itself does not specify how servers choose what to push: a webserver might send pushes to clients only on their first visit, to avoid redundantly sending cached resources.<ref>{{Cite web |date=2022-03-17 |title=HTTP/1.1 vs HTTP/2: What's the Difference? |url=https://www.digitalocean.com/community/tutorials/http-1-1-vs-http-2-what-s-the-difference |access-date=2023-11-20 |website=DigitalOcean |language=en}}</ref><ref>{{Cite web |date=2018-02-20 |title=Introducing HTTP/2 Server Push with NGINX 1.13.9 |url=https://www.nginx.com/blog/nginx-1-13-9-http2-server-push/ |access-date=2023-11-20 |website=Nginx |language=en}}</ref><ref>{{Cite web |date=2016-04-28 |title=Announcing Support for HTTP/2 Server Push |url=https://blog.cloudflare.com/announcing-support-for-http-2-server-push-2/ |access-date=2023-11-20}}</ref>

== Implementations ==

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|[[Google Chrome]]

|Client

|40 (May 2015)

|?

|106 (September 2022)<ref name=":0" /><ref name=":2" /><ref>{{Cite web |date=2022-10-31 |title=Remove HTTP/2 push |url=https://chromestatus.com/feature/6302414934114304 |access-date=2023-07-12 |website=chromestatus.com}}</ref>

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