[PATCH] HTTP/2: expose function to push single resource to modules

[Alessandro Ghedini]

On Thu, Feb 08, 2018 at 10:00:27PM +0300, Maxim Dounin wrote:
> Hello!
> 
> On Thu, Feb 08, 2018 at 04:52:59PM +0000, Alessandro Ghedini wrote:
> 
> > # HG changeset patch
> > # User Alessandro Ghedini <alessandro at ghedini.me>
> > # Date 1518108716 0
> > #      Thu Feb 08 16:51:56 2018 +0000
> > # Branch expose-push
> > # Node ID 1bb98b06d5536dfc80a407aabd8d06f9309f8df6
> > # Parent  a49af443656f2b65ca5de9d8cad5594f44e18ff7
> > HTTP/2: expose function to push single resource to modules.
> > 
> > This makes it possible for 3rd party modules to implement alternative
> > methods for deciding which resources to push to clients on a per-request
> > basis (e.g. by parsing HTML from the response body, by using a custom
> > Link header parser, ...).
> > 
> > No functional changes.
> 
> Not sure this is a good idea.
> 
> You may consider exposing a variable to be used in http2_push 
> instead.

Right, the problem is that as far as I can tell http2_push only supports a
single resource, even when a variable is used, so it wouldn't be possible to
push multiple resources without specifying multiple http2_push directives,
each with its own variable, and even then you'd only have a fixed number of
resources that can be pushed, which wouldn't work well when the number of
resources changes depending on each request/response.

So in the end exposing the internal functions to modules seemed better than
just trying to make http2_push support multiple resources per directive,
which would add complexity to NGINX itself rather than the external modules
(though I can do that if you think it would be a better solution).

Cheers