Registry Development, Technical Issues, The Registry!

TimeSlices and Versions

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You can now retrieve a snapshot in time of the RDF or XSD serialization of a Concept/Scheme/Vocabulary by appending a ‘TimeSlice’ to the URI. For example: http://metadataregistry.org/uri/NSDLEdLvl/ts/20060422200002.rdf or http://metadataregistry.org/uri/NSDLEdLvl/ts/20060422200002.xsd will always and forever retrieve the SKOS/RDF or XML Schema representation of the NSDL Ed Level Vocabulary as it appeared at 2 seconds after 8PM on April 22, 2006 (2006-04-22 20:00:02). If you follow the above .rdf link you’ll notice that the concept URIs that the TimeSliced Vocabulary references have also had a TimeSlice appended: http://metadataregistry.org/uri/NSDLEdLvl/1001/ts/20060422200002.rdf in order to lock them into that precise point in time on an individual basis as well. We hope the utility of being able to reference a vocabulary at a particular point in time regardless of subsequent changes will be, well, useful.In order to make retrieving TimeSlices for specific events in the history of a vocabulary a bit handier, we added a TimeSlice link to every history event. You can specify a TimeSlice for any point in time regardless of its relationship to a history event, but the link just makes it simpler (it’s over on the right side of each line):

The Registry! :: NSDL Education Level Vocabulary :: History of ChangesUploaded with plasq‘s Skitch!

Named Versions

You’ll maybe also have noticed that there’s a ‘Name’ link nestled to the right of the RDF and XSD links. If you’re a Vocabulary Administrator, then you now have the ability to label a TimeSlice with a distinct version name. That link again is there to make it easy to reference a point in historical time and clicking on it pre-enters that TimeSlice into the Create new version form:

The Registry! :: Creating new versionUploaded with plasq‘s Skitch!There’s no limit to the number of versions you can create, and versions (unlike TimeSlices) can be deleted or edited by any Vocabulary Admin:

The Registry! :: NSDL Education Level Vocabulary :: List VersionsUploaded with plasq‘s Skitch!…although we think that either editing or deleting a version is likely to be a less-than-ideal practice. Still, we allow it — it’s your vocabulary after all.Once a named version has been associated with a TimeSlice, it will appear in the event history list just above the point in time it references:

The Registry! :: NSDL Education Level Vocabulary :: History of ChangesUploaded with plasq‘s Skitch!The RDF and XSD links on the right side of the version line now reference the version name:http://metadataregistry.org/uri/NSDLEdLvl/version/release+1.0.rdfBut this is where it gets a little incorrect… Since the named version URL is just a TimeSlice reference, it does a silent redirect to the referenced TimeSlice. It should probably do a 303 redirect instead. We’ll fix this later, unless it’s a show-stopper for one of our many users.

Technical Issues, The Registry!

Improved user management

We’ve been promising for a while now that we’d make it easier, actually a better word is ‘possible’, for Vocabulary Owners to add ‘Members’ to Owner/Agents and ‘Maintainers’ to Vocabularies. We finally implemented it today! It’s unfortunate that it has taken us so long, since one of the primary goals of the Registry is to support multi-user vocabulary development, but it turned out to require more infrastructure twiddling than we thought it would.

If you’re a vocabulary owner and are logged in, you can add other registered folks as ‘members’ of your Owner/Agent and you can even make them administrators if you want:

The Registry! :: NSDL Registry :: List Members

The Registry! :: Editing NSDL Registry permissions for Diane Hillmann

Uploaded with plasq‘s Skitch!

We hope the process is pretty self-explanatory.

Once you’ve added a user as a member of your Owner/Agent group, you can add them to your vocabularies as Vocabulary Maintainers or Administrators.

The Registry! :: NSDL Registry Agents Vocabulary :: List Maintainers

The Registry! :: Adding maintainer to NSDL Registry Agents Vocabulary
Uploaded with plasq‘s Skitch!

We realize that this is still somewhat limited and of course the documentation is ummm, poor, but we’ll be doing more with user management shortly.

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Just a test

This is just a test of “ScribeFire:

“ScribeFire is an extension for the Mozilla Firefox Web browser that integrates with your browser to let you easily post to your blog: you can drag and drop formatted text from pages you are browsing, take notes, and post to your blog.”

Technical Issues, The Registry!

Registry News

We’ve updated the front page of the Registry to include a Registry-specific news feed from the Registry blog. You can subscribe to it right from (t)here and stay up-to-date with the Registry as we move it forward. Notes like this will be typical and probably pretty frequent over the next few months.

The Registry!

Major update

The registry database was updated last week, in both the sandbox and the registry, to support history tracking. This is in preparation for finally enabling timeslice retrieval and versioning.We also made some significant changes to the site layout and css, so if things still look a little funky, try refreshing your browser — most browsers seem to be caching our css and not detecting the changed files.In the process, we broke search (you may not have even noticed), but it’s fixed now.

Technical Issues, The Registry!

New Host

Since the beginning of the project, we’ve been running our own web server. After a significant number of local service outages on the part of Time Warner this year, particularly in July, we finally decided that had to change.

As of today, we’re running on Dreamhost. Dreamhost isn’t perfect, but they offer a nice package of services, reasonably good support and, with the right promo code, the price was right. So we’re going to give it a try for a while.

Moving from a host where we had complete control of the Apache and MySql servers to a shared host where we don’t has required some minor configuration changes to the blog and the wiki, and some significant changes to trac and subversion, but no changes to the Registry. As a side effect of the wiki tweak, we can have prettier URLs — http://metadataregistry.org/wiki/index.php?title=Main_Page becomes http://metadataregistry.org/wiki/Main_Page. Links will default to the new style, although the older form will still work in order to keep older bookmarks working too.

We updated trac and subversion to the latest stable releases, moved trac from a lighttpd server to Apache and moved subversion from a subversion server to Apache as well. This has changed the user authentication process for both services, hopefully for the better.

The Registry!

Registry update

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We made some major/minor changes to the Registry software last week. If you’ve used it lately you may have noticed the fairly ugly tabs that replaced the links at the top of the browse pages. They still need some work, but it’s generally a lower priority than some other things.

The major change was reworking a significant amount of the Registry code to bring it up to the Symfony 1.0 release. We’d been working with a fairly ancient version of Symfony while waiting for the final and as a result there were significant structural changes required. We also wrote a bunch of automated functional tests so that we can be a bit more confident that future releases will have fewer bugs. You shouldn’t notice any of this when using the Registry, but please let us know if we broke anything.

We cleared up a few small existing bugs, one of which was that the Registry was a little too aggressive in checking to see if a prefLabel was unique, so the check is now local to the Vocabulary instead of the entire Registry. Another was that under some circumstances the URIs generated by the Registry Sandbox had a hard-to-see double slash after the base domain, causing the URIs to fail to resolve properly. In addition to fixing the bug we also fixed all of the bad existing URIs.

More updates are imminent.

RDF

DSPs, DCAPs, and WIKIs, oh my!

The Dublin Core Metadata Initiative is looking for someone to build them a wiki. At least I think that’s what they want.

From the Call for Tender page:
“DCMI Call for Tender 2007-03: Wiki format for application profiles convertible into XML”
From the DCMI home page:
“Call for tender for a machine-processable application profile format”

I don’t think that these two descriptions are describing the same thing at all. Of course, that just reflects my sense that “machine-processable application profile” doesn’t mean “application profile that can be scraped from a wiki page and expressed as XML”.

I’m more inclined to think that a “machine-processable application profile” means a DCAP that can be directly used to validate data that has been created with the intention of conforming to a specified DCAP (or is it DSP? — I wish that they wouldn’t suddenly change the terminology just to fit the model).

Increasingly, I’m viewing “machine-processable application profile” as meaning machine-processable-DCAP-derived data-entry forms (XFORMS) used to generate DCAP-conformant XML data that can be validated using a machine-processable-DCAP-derived RELAX NG schema, W3C XML Schema, or Schematron ruleset. RDF triples would then have to be derived from the validated XML.

The intermediate XML validation is necessary because a sensibly efficient way to validate RDF against a DCAP currently doesn’t exist. Although Alistair‘s notion of rules-based RDF validation based on SPARQL query assertions looks like it might work in a Schematron-like way. This would then imply the ability to derive SPARQL queries from a machine-processable DCAP.

While the idea of a wiki-based DCAP editor is conceptually interesting, it would seem to me that a tender to produce exemplars of the above based on the current DCAP XML expression would be far more useful in actually providing useful test cases for determining the validity and utility of that expression.

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Uncategorized

Potluck

Danny Ayers points to a screencast by David Huynh of MIT demonstrating a new data viewing tool.It’s indeed awesome — one of those things where about halfway through I said “holy mackerel!” or words to that effect. It’s definitely must-see TV.

David Huynh of MIT, responsible for wonders such as Timeline and Exhibit has made a short screencast demoing his latest marvel, Potluck. It’s currently a research prototype though appears very close to being web-ready. When you’ve seen the screencast I think you’ll agree with me – it’s awesome .

Potluck.

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