W3C home > Mailing lists > Public > public-html@w3.org > December 2008

Re: link relationship registration

From: Phil Archer <phil@philarcher.org>
Date: Wed, 10 Dec 2008 11:50:09 +0000
Message-ID: <493FACF1.7080401@philarcher.org>
To: Anne van Kesteren <annevk@opera.com>
CC: Mark Nottingham <mnot@mnot.net>, "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>, Atom Syntax <atom-syntax@imc.org>, www-tag@w3.org, HTML WG <public-html@w3.org>



Anne van Kesteren wrote:
> 
> On Wed, 10 Dec 2008 11:59:33 +0100, Mark Nottingham <mnot@mnot.net> wrote:
>> On 10/12/2008, at 9:52 PM, Anne van Kesteren wrote:
>>> In HTML5 the tokens are not URIs and are not really URI-references 
>>> either because they have to be case-insensitively matched (the HTML5 
>>> specification is currently wrong on this). 
>>> (http://www.iana.org/assignments/relation/stylesheet and stylesheet 
>>> are therefore not equal either.)
>>
>> The registered tokens are effectively tokens, and can be considered 
>> case-insensitive (see the notes on use in HTML4).
> 
> If you have
> 
>   http://example.com/foo
>   http://example.com/FOO
> 
> they would be the same in HTML, but would not be for the Link HTTP 
> header... (It's also not really clear to me why relationship values are 
> have to be resolved and why we not just use the same rules as we do for 
> namespaces.)

Case sensitivity is an issue. Hmmm... can 04 say that tokens given as 
rel types SHOULD be lower case and that UAs SHOULD treat such tokens as 
case insensitive? Would that put too much of a strain on saying that 
tokens are treated as relative URIs? (I know that paths are case sensitive).

> 
> Also, I definitely do not want to start having to implement support for 
> http://www.iana.org/assignments/relation/stylesheet besides just 
> stylesheet. (Not for the Link HTTP header or for the HTML elements.) 
> That's just additional complexity for no gain and will only lead to bugs 
> and differences among browsers.

There shouldn't be any need for UAs to resolve tokens given as values 
for @rel as absolute URIs and no one's suggesting that UAs should 
actually make an HTTP request of any kind to iana.org every time there's 
a link to a stylesheet. It's the person minting the new relationship 
type that needs to check. What it means is that if you create a link 
(HTML or HTTP) and use a @rel type 'foo' that gives a 404 from 
http://www.iana.org/assignments/relation/foo then you really shouldn't 
expect UAs to do anything sensible with it.

Whether a UA chooses to actually implement support for a registered @rel 
type remains very much up to the UA developer of course.

> 
> 
>>> In HTML5 people can simply provisionally register a new token by 
>>> putting it on a wiki page. The token does not have to be a URI. 
>>> (Though it could be a string that is also a URI.)
>>
>> See the discussion with Phil.
> 
> That's sort of the reason why I started replying...

Always a pleasure to stir things up a little!

> 
> 
>>> In HTML5 there is no rev "link-param" because (non-academic) studies 
>>> have shown that people do not really know how to use it.
>>
>> See current discussion about deprecating it.
> 
> What does deprecating mean here for the various parties (e.g. 
> implementors and authors)?
> 
> 
>>> In HTML5 media, hreflang, and sizes (just for <link>) also influence 
>>> the relationship. Your draft does not have these "link-param"s.
>>
>> Other extensions are allowed; again, see the appendix about use in HTML.
> 
> It says they are believed to be defunct... media is pretty damn 
> important for style sheets at least.
> 
> 

-- 
Phil Archer
w. http://philarcher.org/
Received on Wednesday, 10 December 2008 11:50:49 GMT

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