Upcoming SPDY support details

Valentin V. Bartenev ne at vbart.ru
Thu May 17 13:17:56 UTC 2012

On Thursday 17 May 2012 16:06:21 Alek Storm wrote:
> On Thu, May 17, 2012 at 6:23 AM, Valentin V. Bartenev <ne at vbart.ru> wrote:
> > First implementation of SPDY support will work only on frontend side. So,
> > nginx
> > will be able to talk with backends by HTTP, FastCGI, uwsgi, or SCGI
> > protocols.
> Got it. Looking forward to backend SPDY support, so crucial advantages like
> multiplexing are preserved. Will nginx at least add headers like
> "X-Priority" to the forwarded request?

Surely, I added the $spdy_request_priority configuration variable and it is 
suitable for such tasks.

> > that
> > the next step is to add pushing by special response header from backend
> > (like
> > "X-Accel-Redirect" but with the list of URIs to push).
> That'll work, but am I correct in assuming that the response containing
> "X-Accel-Redirect" is different from the response to the original request?

In the most simplest implementation they will be the same.

> If they are the same, then nginx will not be notified of the URIs to push
> until the server is ready to send the headers for the response to the
> original request. This would be more restrictive than SPDY's semantics,
> which allow pushing resources before the SYN_REPLY frame for the original
> request is even sent.

Yes, you're right. And this question is still undecided and requires further 
investigation. I think that we also need some sort of configuration directives 
for server pushing.

 wbr, Valentin V. Bartenev

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