[whatwg] Revised Plan for Server-sent DOM events

Kornel Lesinski kornel at osiolki.net
Mon Jan 7 17:16:46 PST 2008

On Mon, 07 Jan 2008 10:30:29 -0000, Anne van Kesteren <annevk at opera.com>  

>> - Continued problems of the 2 connection limit on HTTP server  
>> scalability
> Is there any realistic solution to this other than to use separate  
> domains and have cross-domain working?

Sharing of event-source connection between many pages/windows would help  

Currently each <event-source> on every page gets its own connection. This  
makes use of it as standard element of page's design (e.g. live stock  
ticker in a sidebar on financial portal) impractical - for every page in  
every window browser would open separate connection, easily reaching the  

This could be improved, if connection to event source was handled outside  
of page's context, in a global pool of stream connections. Browser would  
never use more than one connection to the same source and would use one  
connection to trigger events on all pages that subscribe to the given  
source. As a bonus, browser could also keep connection open while user  
navigates between pages instead of closing and re-opening stream  
connections each time.

The downside is that applications couldn't rely on seeing every event in  
the source, so they couldn't rely on incremental updates. To remedy this,  
an additional feature, like checkpoints in the stream and replaying of  
past events would be neccessary.

regards, Kornel Lesiński

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