[XML-SIG] XBEL metadata question

Chad Loder cloder@acm.org
Thu, 23 Mar 2000 14:06:32 -0500 (EST)


Yeah, I'm not advocating a DTD change. I should be able to get by with
the existing metadata structure.

What do you think about setting the owner URI to the href of the page itself?
Wouldn't that kinda make sense?

On Thu, 23 Mar 2000, Fred L. Drake, Jr. wrote:

>   Regarding the question about where to put page-embedded metadata, I
> think a recommendation for a specific application name can be made in
> the XBEL documentation.  The recommendation should probably include a
> way to state the last date the data was modified and that, if
> modified, all old data should be removed (even if an updated value
> isn't available; say a metadata field is removed from the document).
>   Another possibility is a DTD change that gives specific structure:
> <docmeta> (or whatever) could allow (meta | link)+, where <meta> and
> <link> are defined as for HTML 4.0/XHTML ?.?.  The biggest problem I'd 
> have with this is that software would have to be updated to deal with
> it, and I don't currently have time to update & re-release Grail
> (which I'd consider a requirement, at for myself).
>   Is anyone actually using Grail with XBEL, or is everyone doing
> things independently of the browser?

I am not using Grail or even Python for that matter. I wrote all this stuff
in Java. I feel like a heretic, but I don't have the energy to learn
another language just now. :)

>  > 	If 301 moved, add note about old URL and change href (and check
>  > 	new href)
>   I thought about adding this kind of update into Grail when
> encountering a permanent move of a page in Grail, if the original was
> bookmarked, but never got around to it.

Yeah, it's not so hard. Just gotta look at the Location header. I
suppose the difficulty is at a higher level, keeping track of when
the user clicks on a bookmark and feeding the HTTP information back
up the call stack so that the bookmark can be updated. :)

>  > 	Else if succesful, get title and description from page. If
>  > 	bookmark title was missing, set title. If bookmark description
>  > 	was missing, set description. Also set lastVisited date.
>   Do you really want to set lastVisited?  Setting lastModified is
> useful since it tells the user it changed since the last time they
> visited it, but if lastVisited gets modified as well, they can't
> tell.  I see lastVisited as a user-centered bit of data.  See the XBEL 
> documentation:

Ah, good point. I will do it that way.

>  > I could also use the HTTP header Last-Modified to set the lastModified
>  > date. It's just a matter of writing some code to convert HTTP (GMT)
>  > style datetimes into ISO8601 datetimes.
>   There's code to parse the HTTP Last-Modified the Grail source:
> http://grail.python.org/

I will take a look, but I don't want to use any of your code until I
am sure I can open source my stuff.

>  > What would be nice is a folder metadata called dmozCategory which maps
>  > each folder onto its closest Open Directory category (www.dmoz.org). This
>  > would allow separate collections to be merged together automatically.
>   This would be cool!

I can release all this stuff, but I don't know if I'll be able to release
all the source code because I'm using some Java HTTP classes I developed
for a product at my real job. :) But it's a small amount of stuff I
would need to rewrite, and then I could GPL the source.

An example of the DMOZ categories is listed (in RDF format) at

How about something like this:

<folder id="1234">
	<title>Artificial Intelligence</title>


It should be easy to create a dmoz.org URL out of the metadata,
so that automatic conversion tools can create a "See Also" link
directly to the category on the dmoz website.

What do you think?


| Chad Loder - Somerville, MA, USA                 |
| EMail:     cloder@acm.org                        |
| Home Page: http://www.ccs.neu.edu/home/cloder    |