This week I just finished the last remaining items on my todo list for my Google Summer of Code project, (which is available in the form of the RDFIO MediaWiki extension). Those things, which I also mentioned in my last blog post were to:
Regarding the first point, it might not be overly easy to see the usefulness of it at once, so I just created a screencast to show the difference between using it and not:
It demonstrates the problem of choosing sensible wiki titles for general RDF entities in case no good property for naming is available, (such as rdfs:label etc) ... since "entity" URIs often just consist of nonsensible id:s and often no namespace prefixes are defined for them. RDFIO lets you add "pseudo" namespaces (using a simplified splitting pattern, not necessarily consistent with XMLns specs), in order to come around this problem.
Hopefully I'll find time to also demonstrate the second point above, as well as the "filter by ontology" feature for the SPARQL endpoint, with screencasts early next week.
Otherwise, the coming week I'll use for doing some refactoring of the currently quite unmanageable code, as well as add commenting, and hopefully also add the feature to filter RDF export by a [[Export RDF::false]] SMW property (which was the "it time permits" item of my TODO list).
New for this release is a "export by ontology" feature, that - when possible - restricts the URIs used for a wiki page to only those that appears in an ontology that the user points to. To give an idea of this feature see the following screenshot:
On the page "Samuel", I have one fact:
... and on the page "Property:has_blog", there are a number of facts, including:
From the "remaining TODO list" from my last blog post, the following are finished with this release:
The remaining items ones are now:
In a previous blog post I demonstrated with a screen cast the RDFIO extension for Semantic MediaWiki but nothing on installation.
By testing I realized that the install procudure was VERY painful. I have now (with much valuable help from Oleg Simakoff) corrected a number of errors in the instructions and the code, and added to the install instructions commandline snippets for linux/ubuntu. I also created a screencast which goes through the steps from scratch (except Apache/MySQL/PHP setup), in a little more than 5 minutes. Hope this makes things easier for you testers! (And as you might try it out, please report any bugs or issues in the issue tracker!)
Sorry for the low volume level! Didn't realize that while recording ... :/
So, for those of you who might think the Install instructions for the RDFIO Semantic MediaWiki extension I'm working on are a bit daunting but would like a glimpse of what my GSoC project is up to anyway, I created a short (3:20) screencast demonstrating (ARC2 based) RDF Import and SPARQL "Update" functionality for some example data. (Sorry for the lame speaking ... :P ... didn't sleep for a looong time )
The screencast shows how you can import RDF/XML into Semantic MediaWiki and then use the SPARQL endpoint to insert or remove data to/from articles, even using the original format of the RDF that you imported earlier.
(For you who decide to try to install, please have a look at the error fixing happening in this thread.)
One of the things we try to do in my GSoC project is to select suitable wiki titles when importing arbitrary RDF triples into Semantic MediaWiki (The full RDF URI:s are very ugly to use as wiki titles!).
Simply shorting the namespace in the entitiy's URI to it's prefix (as specified in the import data) could be a general fallback (see screenshot) but for many types of data it could be nice to make use of a property that puts some "natural language" label for the entity instead. We came up with this list of properties so far:
Ok, even nicer now ... after allowing to introduce custom namespace prefixes also with '?' and '=' as separators (Don't know if that is valid for QNames though? Anyone knows?) than before (blog post 1, and post 2):
Code (see code repo) is still quite ugly though. Just typed together to get things working. Will look at structuring things more as soon as I have slept a little better :)
I also got to think of these random issues, which is foremost questions to myself, that might not be fully thought-through yet, but jotting them down here for possible feedback (hoping it's readable ^^):
I now managed, (using ARC2 and SMWWriter, in a MediaWiki extension) to populate Semantic MediaWiki pages with triples, from a snippet of RDF/XML (Thanks to Egon Willighagen for the RDF-ized NMRShiftDB data, submitted further below), yay! But ... as you can see, using the full URI:s as wiki names is not a good idea. URI:s as wiki titles is ugly ... and the predicates in this case even got truncated and all treated as the same one, since they had hashes in it, which MediaWiki obviously doesn't allow in titles), so that's the whole background for our talking so much about the "equivalent URI handler" (mentioned here for example), which is thought to be a configurable handler of mappings from URI patterns to (sensible) wiki titles. Also, optimally the same pattern can then be used both on import and export so that the format is kept, allowing to use SMW as a (collaborative) RDF editor! (which is one of the main motivations for my GSoC project).
Well, the hard bits (URI -> Wiki title mapping) remains. Diving in to it now ...
Now I have a working RDF Store connector for Semantic MediaWiki, that uses ARC2:s RDF store, rather than SMW:s built-in store. This will allow to take advantage of functionality in ARC2, such as possibility to set up a SPARQL endpoint etc.
The ARC2 connector implements the same amount of the SMWStore API as the JosekiStore, but I'm not yet sure if more needs to be implemented, for the things we want to do (general RDF import/export). Gotta figure that out.
Feel free to try it out, but be warned that it has been only very briefly much tested at all yet!