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Re: DataCache API - editor's draft available

From: Mark Nottingham <mnot@yahoo-inc.com>
Date: Sat, 18 Jul 2009 09:50:14 +1000
Cc: public-webapps WG <public-webapps@w3.org>, Charles McCathieNevile <chaals@opera.com>, Arthur Barstow <art.barstow@nokia.com>
Message-Id: <E2B83CF8-E047-4B5B-A1EB-69627A9A172E@yahoo-inc.com>
To: "Nikunj R. Mehta" <nikunj.mehta@oracle.com>
I think this work is in an interesting space but, unfortunately, it's  
doing it without reference to the existing HTTP caching model,  
resulting in a lot of duplicated work, potential conflicts and  
ambiguities, as well as opportunity cost.

Furthermore, it's specifying an API as the primary method of  
controlling caches. While that's understandable if you look at the  
world as a collection of APIs, it's also quite limiting; it precludes  
reuse of information, unintended uses, and caching by anything except  
the browser.

A much better solution would be to declaratively define what URIs  
delineate an application (e.g., in response headers and/or a separate  
representation), and then allow clients to request an entire  
application to be fetched before they go offline (for example). I'm  
aware that there are other use cases and capabilities here, this is  
just one example.

Doubtless there's still a need for some new APIs here, but I think  
they should be minimal (e.g., about querying the state of the cache,  
in terms of offline/online, etc.), not re-defining the cache itself.

FWIW, I'd be very interested in helping develop protocols and APIs  
along what's outlined above.

Cheers,

P.S. This draft alludes to automatic prefetching without user  
intervention. However, there is a long history of experimentation with  
pre-fetching on the Web, and the general consensus is that it's of  
doubtful utility at best, and dangerous at worst (particularly in  
bandwidth-limited deployments, where bandwidth is charged for, as well  
as when servers are taken down because of storms of prefetch requests).


On 17/07/2009, at 6:10 AM, Nikunj R. Mehta wrote:

> I have published the first draft of the DataCache API, which is  
> based on Oracle's BITSY proposal [1]. Here's a link to the draft:
>
> http://dev.w3.org/2006/webapi/DataCache/
>         This document defines APIs for dynamically and statically  
> serving off-line representations of HTTP resources.
>
> As the Chairs have concluded this to be within the scope of our  
> current charter, I would request feedback from you so we can  
> incorporate it before publication as a working draft.
>
> Nikunj
> http://o-micron.blogspot.com
>
> [1] http://www.oracle.com/technology/tech/feeds/spec/bitsy.html
> [2] http://lists.w3.org/Archives/Public/public-webapps/2009JulSep/0098.html
>

--
Mark Nottingham       mnot@yahoo-inc.com
Received on Friday, 17 July 2009 23:51:31 GMT

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