Is it possible to send html HEAD early (chunked)?
mdounin at mdounin.ru
Mon Jul 14 12:54:10 UTC 2014
On Sun, Jul 13, 2014 at 02:49:18PM +0200, Martin Grotzke wrote:
> Hi all,
> inspired by the bigpipe pattern I'm wondering if it's possible to send the
> An idea would be that the proxied backend uses a chunked encoding and sends
> the html head as first chunk. The body would be sent as a separate chunk as
> soon as all data is collected.
> Not sure if this is relevant: In our particular case we're using ssi in the
> body to assemble the whole page, and some of the includes might take some
> time to be loaded. The html head contains an include as well, but this
> should always be loaded from the cache or should be served really fast by
> the backend.
> What do you think about this? Has anybody tried this already?
By default, nginx just sends what's already available. And for
SSI, it uses chunked encoding. That is, if a html head is
immediately available in your case, it will be just sent to a
There is a caveat though: the above might not happen due to
buffering in various places. Notably, this includes
postpone_output and gzip filter. To ensure buffering will not
happen you should either disable appropriate filters, or use
flushes. Latter is automatically done on each buffer sent when
using "proxy_buffering off" ("fastcgi_buffering off" and so on).
Flush can be also done explicitly via $r->flush() when when using
the embedded perl module.
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