Gzip compression and Transfer-Encoding

[Igor Sysoev]

On Mon, Oct 22, 2007 at 05:53:22PM +1000, Dave Cheney wrote:

> 	We use the following settings for gzip compression
> 
>    gzip  on;
>    gzip_min_length  1100;
>    gzip_comp_level  5;
>    gzip_buffers     4 16k;
>    gzip_types       text/html text/plain text/xml text/css  
> application/x-javascript application/atom+xml;
> 
> 	Which leads to good compression but regardless of the size of the  
> document always requires chunked encoding to send the resulting data.  
> For larger documents this doesn't matter, but for smaller documents I  
> would like to provide a Content-Length header and avoid chunked  
> encoding.

What problem with chunked encoding ?

> 	Is their a buffer setting that specifies the size of the initial  
> buffer to be compressed, the idea being that if the whole response  
> body fits in that one buffer, it can be compressed in one go, and the  
> resulting content length discovered.

The problem is that gzip is filter: the header sent to client before
compression even starts. However, it is possible to postpone header
processing to know the compressed size.


-- 
Igor Sysoev
http://sysoev.ru/en/