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Value of Server-Sent Events

From: Maciej Stachowiak <mjs@apple.com>
Date: Fri, 23 Oct 2009 15:21:19 -0700
Cc: Arthur Barstow <art.barstow@nokia.com>, public-webapps <public-webapps@w3.org>
Message-id: <FBCE7C53-79C2-4535-977A-3DAE434F6BE1@apple.com>
To: Jonas Sicking <jonas@sicking.cc>

On Oct 23, 2009, at 1:44 PM, Jonas Sicking wrote:

>
> I also continue to miss actual developer demand for server sent
> events. Seems like it doesn't add a lot of sugar over simply using
> XMLHttpRequest and progress events. But again, I'm fine with
> publishing a new WD.

Besides syntactic sugar, here are some advantages over using XHR and  
progress events (or readystatechange events, which some client-side JS  
libraries use today):

- Does not force the full event stream to be stored in memory until  
the connection is closed (XHR's responseText effectively forces this).  
This is the biggest one. A long event stream shouldn't take  
progressively more memory.

- Does not force you to reparse the event stream each time new data  
comes in (XHR + progress events doesn't have an easy way to get just  
the new data chunk).

- Dealing with message boundaries instead of packet boundaries (or  
arbitrary batching-within-the-network-layer boundaries) is way more  
convenient and likely more efficient to a degree that I think goes  
beyond mere syntactic sugar.

Regards,
Maciej
Received on Friday, 23 October 2009 22:21:55 GMT

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