Re: [hybi] Payload only compression extension, again

[John Tamplin <[e-mail]>]

On Mon, Jul 25, 2011 at 2:03 AM, Takeshi Yoshino <[e-mail]>wrote:

> Servers can get some advice about this from application level, but user
> agents don't have any way. May we ask API side to add some interface to
> allow JavaScript to give some hint? Something like
>

It seems unlikely to get this into the JS API anytime soon -- I think the
initial version will have to be entirely without hints from JS.

Longer term, I think you need to allow the JS code more control over
compression to get the best results, as frequently you can do much better
with domain-specific compression algorithms.  For example, chess endgame
databases get 2-3 times better compression with algorithms that know how the
index is structured.


> It's also an option that we introduce COMP bit in wire spec but initially
> have no API exposed for JavaScript to control that.
>

That would also be useful if there were heuristics to choose when to
compress the data.

However, as long as the compression state is maintained across frames, I
don't think it is a real problem to simply compress everything.  Sure, if
someone sends random data it will get bigger, but not by much.  Even on
binary data like Quake update frames, there is substantial redundancy to be
removed via compression, so with real-world data the payload is almost never
going to get bigger by compressing.

-- 
John A. Tamplin
Software Engineer (GWT), Google