http2 - HTTP/2 Push JSON Payload

Question

The most use cases for http/2 server push is to pre-emptively push assets files (such as javascript and css files) to browser. I am wondering can http/2 server push be used to send dynamic payload such as JSON documents to client application? From the http2-spec, it doesn't mention anything about this. Can anyone elaborate more on this? Why or why not?

Answer 1

HTTP/2 is not intended as a replacement of websockets in that you make a request (e.g. a web page) and may get several resources back (e.g. The web page, the CSS needed to display the webpage, JavaScript needed to run that webpage... etc.).

HTTP/2 is therefore not truly bidirectional in that it still responds to an initial request.

So if you're intending to send the JSON request in response to the initial request then that's fine - it's just another resource in much the same as CSS and javascript.

However if you're intending to keep the channel open to continually send further JSON payloads to keep your page up to date then that's not what HTTP/2 is intended for. That's what websockets are for.

This question has some further details on HTTP/2 versus websockets: Does HTTP/2 make websockets obsolete?