[uf-discuss] Subscription lists in XOXO

Tantek Ç elik tantek at cs.stanford.edu
Thu Dec 1 11:38:07 PST 2005

On 12/1/05 4:06 AM, "Danny Ayers" <danny.ayers at gmail.com> wrote:

> Big apologies if I missed it, but I was wondering if there was already
> a preferred way of expressing aggregator subscription lists in XHTML.

The only current prior art/attempt at this is Attention.xml, which was
design without the benefit of the microformats process, and although does
reuse XOXO, VoteLinks, and XFN, could use a bit analysis / improvements to
make it a proper microformat (and I'm saying that as one of the


> I found an example for simple link lists, but am not sure about the
> best way of expressing what in OPML would look like:
> <outline text="A Blog"
>           type="rss"
>           htmlUrl="http://example.org/page.html"
>           xmlUrl="http://example.org/feed.xml"/>
> I had a fiddle at [1], my crack at the bit in question looking like this:
> <ul>A Blog
>  <li>
>      <a href="http://example.org/page.html">homepage</a>
>  </li>
>  <li>
>      <a href="http://example.org/feed.rss" type="application/xml">feed</a>
>  </li>
> </ul>

Well, the XOXO spec does discuss what to do with "text", "type" and
"htmlUrl" properties.

Take a closer look.


> Les Orchard's had a fiddle at [2], his version:
> <li class="rss">
>   <a class="xmlUrl" type="application/xml"
> href="http://example.org/feed.rss">XML</a>
>   <a class="htmlUrl" href="http://example.org/page.html" title="A
> Blog">A Blog</a>
> </li>
> I think Les has it much closer to what's needed,

This is closer, except that two <a> siblings are an implied list.

> the use of class
> seems wise.

There is definitely a difference in approach between XOXO, which uses
definition lists for property/value pairs, and the class name approach. I
think we're still figuring out how to best use these two approaches

One approach has been to define a microformat for the specific *item*
(whether it is a subscription, a wish, a song, etc.), and then just use XOXO
to express lists of that item (subscription lists, wish lists, play lists,
etc.).  We want to avoid the incredibly bad habit of many other format
designers to make up a new list element for each different kind of thing
they want to keep a list of.

A few more concrete examples.

We have hCard for contact info.  Do we need a new microformat for a contact
list?  No.  You simply use XOXO+hCard (e.g. <li class="vcard">...</li> )


S5 (the XOXO version) is another good example.
The slides are <li class="slide">...</li>

> But is this a list of URIs? Definitions? I dunno.


> Another
> question would be how to extend this, if for example there was a
> description of the feed available too (check Les' OPML source -
> there's description and a few more attributes in there).

In the general case, the use of definition lists in XOXO lets you extend
this however you want. However...

> When it comes to parsing the stuff, it would be nice to have a common
> convention ;-)

Precisely.  And extensions are typically contrary to common convention
(otherwise they wouldn't call them extensions ;).

I think what we need is perhaps a page on the wiki to discuss specific uses
of XOXO (e.g. subscription lists), along with experiments/thoughts with how
to do so (i.e. the markup sample you gave above).

Perhaps the XOXO brainstorming page would be appropriate for this


I noticed that DavidJanes has already started the analysis of subscription

Please feel free to jump-in and offer alternative examples / markup in the
brainstorming document.



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