On Fri, Feb 09, 2018 at 10:23:46AM +0300, Ruslan Ermilov wrote: > On Thu, Feb 08, 2018 at 08:04:57PM +0000, Alessandro Ghedini wrote: > > On Thu, Feb 08, 2018 at 10:18:54PM +0300, Maxim Dounin wrote: > > > Hello! > > > > > > On Thu, Feb 08, 2018 at 05:07:49PM +0000, Alessandro Ghedini wrote: > > > > > > > On Thu, Feb 08, 2018 at 05:04:58PM +0000, Alessandro Ghedini wrote: > > > > > # HG changeset patch > > > > > # User Alessandro Ghedini <alessan...@cloudflare.com> > > > > > # Date 1518109032 0 > > > > > # Thu Feb 08 16:57:12 2018 +0000 > > > > > # Branch push-copy-headers > > > > > # Node ID 4f7f42e6d13add2ab0c7a9654472bb74085181d1 > > > > > # Parent a49af443656f2b65ca5de9d8cad5594f44e18ff7 > > > > > HTTP/2: copy additional headers in the pushed requests. > > > > > > > > > > To ensure pushed requests are processed consistently with the original > > > > > client request, some headers need to be copied from the original > > > > > request > > > > > into the pushed one. > > > > > > > > > > The headers currently copied are User-Agent, Accept, Accept-Language > > > > > and > > > > > Accept-Encoding. > > > > > > > > So, I'm not quite sure if this is the correct way to go about doing > > > > this, but > > > > I think the issue is real and worth fixing, so I'd be happy to > > > > implement this > > > > differently if you have alternative ideas. > > > > > > Could you please elaborate more on "the issue is real"? > > > > Right, sorry. Essentially the problem is that origins may generate a > > different > > responses dependning on these headers, and a pushed request may be processed > > inconsistently from the original request if these headers are different > > (say, > > stupid example, if the client requests a specific language, the main request > > may get a response in one language, and the pushed one in another). > > > > Additionally things like compression wouldn't work for pushed requests, > > which > > is not optimal. > > > > There are of course other headers that could influence the origin's > > response, > > but this somewhat minimal list of standard headers seemed like a good start. > > > > FWIW, other server push implementations like Apache's mod_http2, h2o (used > > in production by Fastly) and Cloudflare's closed-source implementation, all > > behave like this, and have done so for years, without any apparent issue. > > Akamai copies User-Agent and Accept-Encoding, but sets "Accept: */*", > and doesn't copy/set Accept-Language, on pushes requests: > https://http2.akamai.com > > Pushing "Accept: */* looks redundant, as > https://tools.ietf.org/html/rfc7231#section-5.3.2 > says that "A request without any Accept header field implies that the > user agent will accept any media type in response.". > > h2o seems to blindly copy the headers you mentioned, including Accept > from the original request, which is obviously wrong: > > : [ 1.239] recv (stream_id=13) :method: GET > : [ 1.239] recv (stream_id=13) :scheme: https > : [ 1.239] recv (stream_id=13) :authority: h2o.examp1e.net > : [ 1.239] recv (stream_id=13) :path: /search/jquery-1.9.1.min.js > : [ 1.239] recv (stream_id=13) accept: text/html > : [ 1.239] recv (stream_id=13) accept-encoding: [...] > : [ 1.239] recv (stream_id=13) user-agent: [...] > : [ 1.239] recv (stream_id=13) accept-language: [...] > : [ 1.239] recv PUSH_PROMISE frame <length=207, flags=0x04, stream_id=13> > : ; END_HEADERS > : (padlen=0, promised_stream_id=2) > > https://http2.golang.org/serverpush only sets the minimally required > fields, as we currently do. > > Can't test IIS, but its API allows setting additional headers to push: > https://docs.microsoft.com/en-us/iis/get-started/whats-new-in-iis-10/http2-on-iis#what-about-push > https://msdn.microsoft.com/en-us/library/system.web.httpresponse.pushpromise(v=vs.110).aspx > > Can't tell for Cloudflare as I can't find a working site on it that > uses HTTP/2 with push enabled, maybe due to this: > https://community.cloudflare.com/t/is-http-2-server-push-disabled/5577
Server push is enabled by default for all Cloudflare sites that also have HTTP/2 enabled. You can test with e.g. https://sigsegv.ninja : User-Agent, Accept-Encoding and Accept-Language are copied, but not Accept. Cheers _______________________________________________ nginx-devel mailing list nginx-devel@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx-devel
