Hello again, I'd like to politely bump this message to see if anyone would mind taking a look at this patch, either here or on GitHub.
Eric Norris Etsy On Mon, Oct 9, 2023 at 2:50 PM Eric Norris <enor...@etsy.com> wrote: > > Hello all, > > I've submitted a pull request on GitHub here: > https://github.com/apache/httpd/pull/387, per the instructions I found > at https://httpd.apache.org/contribute. I figured it may also be > useful to share the patch here, but please feel free to redirect me as > this is my first time contributing. > > Thanks! > > Eric Norris > Etsy > > > At Etsy, we use mod_php and were investigating what we thought was > surprising behavior - that code executed during PHP's shutdown phase > prevented the request from terminating, even if we didn't expect to send > any additional output to the client. > > We determined that this was not surprising given mod_php's > implementation, but after we developed a proof-of-concept patch that > sent an EOS bucket and a flush bucket via a "userland" PHP function, we > were surprised that it didn't work when compression was enabled for the > request. > > I was able to reproduce this behavior with a simple Apache module built > on top of mod_example_hooks: > > https://gist.github.com/ericnorris/37c7dac401b50d270867e82a47bdd294 > > It seems that this is because mod_deflate receives the EOS bucket and > then calls `deflateEnd` but remains in the filter chain. This means that > it receives the next flush bucket and attempts to call > `flush_libz_buffer`, which of course fails, causing it to print an > AH01385 error to the Apache error log, and perhaps most importantly, to > "eat" the flush bucket and not pass it down the bucket brigade. > > We found that this patch allows us to successfully send an EOS bucket > *and* promptly flush the connection so that the client knows the request > is finished. > --- > modules/filters/mod_deflate.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/modules/filters/mod_deflate.c b/modules/filters/mod_deflate.c > index b7a68d2d43..ad753dc618 100644 > --- a/modules/filters/mod_deflate.c > +++ b/modules/filters/mod_deflate.c > @@ -941,6 +941,10 @@ static apr_status_t deflate_out_filter(ap_filter_t *f, > } > > deflateEnd(&ctx->stream); > + > + /* We've ended the libz stream, so remove ourselves. */ > + ap_remove_output_filter(f); > + > /* No need for cleanup any longer */ > apr_pool_cleanup_kill(r->pool, ctx, deflate_ctx_cleanup); > > -- > 2.40.1
