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Re: [widgets] Widgets URI scheme

From: Mikael Nilsson <mikael@nilsson.name>
Date: Fri, 23 May 2008 13:29:16 +0200
To: Marcos Caceres <marcosscaceres@gmail.com>
Cc: www-tag@w3.org, "WAF WG (public)" <public-appformats@w3.org>, Jon Ferraiolo <jferrai@us.ibm.com>
Message-Id: <1211542156.6927.7.camel@daneel>

fre 2008-05-23 klockan 15:57 +1000 skrev Marcos Caceres:
> Dear TAG,
> The WAF working group is seeking advice on the creation of a Widget
> URI scheme. The proposal is to introduce a URI scheme that is used
> internally by widgets at runtime. Amongst other things, the primary
> purpose is to stop implementations from having to use file:// or some
> arbitrary URI scheme for addressing resources inside a widget package.
> For the benefit of those who have not read the widget spec [1], a
> widget resource is essentially a Zip file. Authors, obviously, store
> their resources (images, HTML files, etc) inside the Zip file and then
> address those resources using either relative or absolute paths (eg
> "/images/bg.gif", etc).

Couldn't cid: be made to work in this case?

http://tools.ietf.org/html/rfc2392

or, for that matter, what's wrong with using only relative URIs?

/Mikael

> 
> At runtime, a user agent resolves the paths to resources inside the
> widget package using the widget URI scheme.
> 
> This is our strawman proposal:
> 
> widget-URI      = "widget:" "//" UUID "/" zip-rel-path
> zip-rel-path     = [ *localized-folder ] [ *folder ] [ filename ] /
>                    [localized-folder] [ *folder] / [ folder ]
> localized-folder = language-tag delimiter
> folder           = filename delimiter
> delimiter        = U+002F
> filename         = 1*254( *basename [file-extension] )
> basename         = allowed-chars
> file-extension   = "." 1*allowed-chars
> allowed-chars    = cp437 / utf8-range
> utf8-chars       = ascii-range / U+0080 and beyond
> cp437-chars      = ascii-range / x80-FF;
> ascii-chars      = ALPHA / DIGIT / SP / "$" / "%" / "'" / "-" / "_" / "@"
>                     / "~" / "`" / "!" / "(" / ")" / "^" / "#" / "&" / "+"
>                     / "," / "." / "=" / "[" / "]"
> 
> Language-tag is defined in RFC4646 (BCP47). UUID (Universally Unique
> IDentifier) is defined in rfc4122. The intention of using UUIDs (or
> some random number) is to identify the current running instance of a
> widget when multiple instances are running simultaneously. Authors
> would not be able to address other widgets via this scheme (in fact,
> there should be no reason at all for authors to use this scheme).
> 
> Within WAF, concerns have been raised about using UUIDs as the
> identifier and arguments have been made that UUID should be replaced
> by some random number generated internally by a widget engine (ie.
> leave the choice of random number sequence as an implementation
> detail. Eg hashing the name of the widget and time of download).
> However, not all members are comfortable with leaving the generation
> of random number sequence to implementations as it could introduce
> issues.
> 
> It has also been proposed that, instead of using "widget://", we use
> "zip://" to create a more generic addressing mechanism for Zip files
> [2].
> 
> Any thoughts, comments, or guidance would be appreciated.
> 
> Kind regards,
> Marcos
> 
> [1] http://dev.w3.org/2006/waf/widgets/
> [2]
-- 
<mikael@nilsson.name>

Plus ça change, plus c'est la même chose
Received on Friday, 23 May 2008 11:29:52 GMT

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