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Comment by v3ss0n | Hacker News Reader

HTTP/2 Push was really useful when we wanted to avoid Websocket , Ajax Polling , Long Polling.

The problem with not adopting is due to Websocket getting more popular and Devs stop caring about HTTP2 altogether. But there are many cases Websocket is overkill , even text chat application dosen't need websocket.

Similar functionality can already be achieved by using SSE/Eventsource although HTTP/2 Push was more powerful.

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Are you talking about Server-sent Events (https://developer.mozilla.org/en-US/docs/Web/API/Server-sent...)? Which can be implemented under HTTP/1 too.

HTTP/2 Server Push is another thing. It allows server to send additional related resources to a client without the client explicitly requesting.

Not wrong, but for context: websocket http/1.1 only. It cannot use http/2 at all.

I think it's more of a problem on the implementation side.

IETF RFC 8441 (https://www.rfc-editor.org/rfc/rfc8441.html) described a way to bootstrap WebSocket under HTTP/2.

That said, I don't know whether or not people are actually doing it in the wild.

As far as web frameworks go, WebSockets over HTTP/2 are supported in for example ASP.NET by default (https://learn.microsoft.com/en-us/aspnet/core/fundamentals/w...). There is however still a surprising amount of languages/libraries/frameworks/servers where the support is missing (e.g. go https://github.com/golang/go/issues/49918).

On the client side, both Chrome (https://chromestatus.com/feature/6251293127475200) and Firefox will use it when available, but I have encountered some issues with cross-origin support (https://issues.chromium.org/issues/363015174)

GP here. This was completely new to me despite working with it day to day. Thanks for sharing. This gives me some hope about having websockets be more in line with the rest of the stack.

In what practical sense are websockets overkill? As far as I know, the resource usage isn't really all that different. It also isn't as if websockets are that difficult to use these days.

I am also skeptical of the "doesn't need websocket" statement. It is technically true that you can use other technologies. But, WebSockets provide bidirectional communication, while Ajax Polling and Long Polling are used for periodic updates. HTTP/2 Push is more suited for pushing resources or data from the server to the client. As far as my understanding goes the use case there is specifically aimed at pushing resources the server "knows" the client will need as well without the client requesting them. I am sure that with some creative code you can also use this to implement a chat of sorts but that is a bit besides the point.

Is there any reason to use websockets over webtransport now?

Absolutely: https://developer.mozilla.org/en-US/docs/Web/API/WebTranspor...

Probably the most major one is if you want cross-browser support, AFAIK, WebTransport still isn't available in Safari.

Perhaps i misunderstand, but i feel like http2 push was trying to achieve something very different than websicket/ajax poling/long polling/sse. They dont seem comparable to me at all.

That's an interesting point, would you mind elaborating on how you think the goals of HTTP2 Push differed?

Even is if is a misunderstanding it would still be useful to consider.

I don't know how to ask this without being quite direct. But why would you ask someone that when the differences are quite obvious? Certainly between web sockets (bidirectional, client initiated) and HTTP2 push (server initiated, one directional).

Are you asking because you basically want to know more about the technologies? In that case why not frame it like that?

HTTP2 is to hide connection latency by preloading.

The other things are for bidirectional communication with a server.

I would consider them very much apples and oranges. Its not just that they are designed for different purposes; i don't think it is possible to even use server push for the purpose websockets is used for in the browser.

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