Comet/Hows Jaws Coming Along?

Gordon Guthrie <>
Tue May 16 10:44:55 CEST 2006


Folks

I have stumbled across a long discussion which is very germane to the 
(upcoming) release of Jaws and actually has a mention of Yaws!

http://alex.dojotoolkit.org/?p=545

Essentially you:
* build a javascript client
* keep a single HTTP connection alive from the brwoser to the client
* push updates up the connection

This allows a smoother multi-user experience without implementing a clock-
tick/check for update on the client side.

Unsurprisingly there are doubts as to whether this will scale under traditional 
technologies like Apache. The people implementing it seem to be focussing on 
building their own (unthreaded) server-side components.

As the article points out it is a reprise of traditionaly middleware/thick 
client architectures.

I would surmise that the javascript client will either need to become insanely 
baroque to write decent clients or you will hold a 'shadow' html page on the 
server and chop it into chunks which you can slide down the pipe for a 
javascript cut'n'paste Dom walker to pop in and out.

On a related matter, in the run up to Jaws, I have been playing with Ajax and 
Erlang myself. I have written a 'naive' spreadsheet application that creates a 
table and then populates each cell with an HTTP request.

For grids of up to 300 cells Mozilla, Firefox and Konqueror all respond fairly 
zipply - with Konqueror by far and away the best. Konqueror manages up to about 
2,500 concurrent requests (although at a crawl) whereas Mozilla/Firefox have 
long given up the ghost.

I foolishly went the whole hog with a 100 by 100 grid and was picking bits of 
broken javascript out of my hair for a week (had to pull the battery out to 
drop the operating system!).

When I get the time I will switch the yaws instance to a networked one and do a 
(still shoddy) pseudo-benchmark. However I think we can rest assured that 
current browsers don't handle concurrency that well!

Gordon


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