[whatwg] PaceEntryMediatype

Thomas Broyer t.broyer at gmail.com
Fri Dec 1 15:41:01 PST 2006

2006/12/1, Mark Baker:
> Urgh, sorry for my tardiness; I'm falling behind on my reading.
> On 11/30/06, Thomas Broyer wrote:
> > I'd prefer basing autodiscovery on the media types and not at all on
> > the relationships.
> All a media type tells you (non-authoritatively too) is the spec you
> need to interpret the document at the other end of the link.  That has
> very little to do with the reasons that you might want to follow the
> link, subscribe to it, etc..  Which is why you need a mechanism
> independent from the media type.  Like link types.

See the mail I just sent in response to Ian.

> Consider hAtom.  If you went by media types alone, you'd be confronted with;
> <link type="text/html" href="hatom.html" />
> Not particularly useful for subscription (or anything else for that
> matter) is it?

How does hatom.html relates to the current page? Is it an alternate?
is it a "container" (rel="up", rel="index")? why would I subscribe to
such a thing if I don't know what it is about?
(also, note that rel="" is required for <link> elements).

> This would be better;
> <link rel="feed" type="text/html" href="hatom.html" />

It still doesn't tell me what it has to do with the page I'm looking at.

I do agree there is a "problem" in these cases, and that's why I
originally proposed keeping a rel="feed", but with a clear definition
as a relationship (opposed to a "kind of resource I'm linking to").

> Autodiscovery should ideally be based primarily on link types, and
> only secondarily - as an optimization - on media types.  Even this
> should work;
> <link rel="feed" href="hatom.html" />

As long as hatom.html is a feed where the current page is (or has
been) linked to as an "item".
If you are already looking at hatom.html, your hAtom-aware browser
should already provide you with a "subscribe to this page"
If you can't describe the relationship between the current page and
hatom.html, there is little chance that this is a resource of interest
and that the person reading the page will subscribe to it (at least
without "visiting" it).

With rel="feed" as a real relationship (à la rel="index"),
autodiscovery can be (as it should have already been) based on media
types (am I able to subscribe to such a thing?) *or* rel="feed", with
an equal "priority".
If it appears than my proposed rel="feed" really is identical to
rel="index", then a new mean should be found (e.g. a new attribute
<link rel="index" href="hatom.html" type="text/html" subscribable>)

Saying "this is something you can subscribe to (it's a feed)" is not
talking about relationships. On the contrary, saying "this is an
'index' and it incidentally is something you can subscribe to (it's a
feed; either by using the 'type' attribute an hypothetical
'subscribable' attribute)" is.

Thomas Broyer

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