[JDEV] GZipping Jabber Messages

[kadokev at msg.net]

Ben writes:
> I'm not convinced that much would be gained by gzipping a 5K SOAP packet,
> especially when you consider the overhead caused on CPU/memory usage.

Realistically, on 'small' messages you gain a lot more using an XML-aware
compression method to compress the (very predictable) 'envelope' overhead
of the message, and let the body alone.
 
OTOH, If the client is already doing SSL, there are provisions in OpenSSL
to use the gzip-style compression functionality of 'zlib' for compressing the
cleartext before encrypting. I'm not aware of anybody actually using this
feature explicitly at this time.


> I think it would definitely need some sort of hash to verify data integrity.
> Hmm... still seems like it'd be an interesting idea to toy with.

Since my first NNTP server admin days,  I've advocated the compression of
'redundant' header information and the optional 'gzip' compression of message
bodies, where the sender would only compress the message body when the
content length is so excessively large that compression pays off.


If every client is REQUIRED to have the ability to decode compressed 'body'
content then the benefit of this feature is vastly enhanced, as otherwise
you'd need to have functionality in the server to uncompress the body before
passing the message along to non-compression aware clients.

If you can assume that all clients can uncompress, then this puts the CPU
and memory overhead solely on the clients.

Kevin Kadow