[whatwg] Web Storage: apparent contradiction in spec

[Michael Nordman]

On Wed, Aug 26, 2009 at 5:14 PM, Brady Eidson <beidson at apple.com> wrote:

> I started writing a detailed rebuttal to Linus's reply, but by the time I
> was finished, many others had already delivered more targetted replies.
>
> So I'll cut the rebuttal format and make a few specific points.
>
>  - Many apps act as a "shoebox" for managing specific types of data, and
> users are used to using these apps to manage that data directly.  See
> iTunes, Windows Media Player, iPhoto, and desktop mail clients as examples.
>  This trend is growing, not waning.  Browsers are already a "shoebox" for
> history, bookmarks, and other types of data.
> Claiming that this data is "hidden" from users who are used to handling
> obscure file management scenarios  and therefore we shouldn't fully respect
> it is trying to fit in with the past, not trying to make the future better.
>
>  - No one is suggesting that UAs not have whatever freedom they want in
> deciding *what* or *how much* to store.  We're only suggesting that once the
> UA has committed to storing it, it *not* be allowed to arbitrarily purge it.
>
>  - One use of LocalStorage is as a cache for data that is transient and
> non-critical in nature, or that will live on a server.  But another,
> just-as-valid use of LocalStorage is for persistent, predictable storage in
> the client UA that will never rely on anything in the cloud.
>
>  - And on that note, if developers don't have faith that data in
> LocalStorage is actually persistent and safe, they won't use it.
> I've given talks on this point 4 times in the last year, and I am stating
> this as a fact, based on real-world feedback from actual, real-world web
> developers:  If LocalStorage is defined in the standard to be a purgable
> cache, developers will continue to use what they're already comfortable
> with, which is Flash's LocalStorage.
>
> When a developer is willing to instantiate a plug-in just to reliably store
> simple nuggets of data - like user preferences and settings - because they
> don't trust the browser, then I think we've failed in moving the web
> forward.
>
> I truly hope we can sway the "LocalStorage is a cache crowd."  But if we
> can't, then I would have to suggest something crazy - that we add a third
> Storage object.
>
> (Note that Jens - from Google - has already loosely suggested this)
>
> So we'd have something like:
> -SessionStorage - That fills the "per browsing context" role and whose
> optionally transient nature is already well spec'ed
> -CachedStorage - That fills Google's interpretation of the "LocalStorage"
> role in that it's global, and "will probably be around on the disk in the
> future, maybe"
> -FileStorage - That fills Apple's interpretation of the "LocalStorage" role
> in that it's global, and is as sacred as a file on the disk (or a song in
> your media library, or a photo in your photo library, or a bookmark, or...)
>

In addition to the key/value pair storage apis, i think we'd need to make
this distinction for databases and appcaches too. This distinction may be
better handled in a way not tied to a particular flavor on storage. Or a
similar distinction could be expressible within the database and appcache
interfaces.
window.openPermanentDatabase() / openPurgeableDatabase()
manifest file syntax games:  PURGEABLE or PERMANENT keyword in there
somewhere.


>
> The names are just suggestions at this point.
>
> ~Brady
>
>
>
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