[Nepomuk] Re: newbie questions about KDE Nepomuk

[Sebastian Trüg]

Hi Darren,

On 01/06/2011 09:45 AM, Darren Cruse wrote:
>>> In my mind I was imagining Nepomuk/Strigi indexing and feeding RDF into
>>> Virtuoso using the Soprano C++ api on one side, and me hitting
>>> Virtuoso's SPARQL endpoint (or manipulating triples in Virtuoso using
>>> their java api) from the other side.
>>
>> This is not the way it is intended. While you have access to the full
>> SPARQL API through C++ and DBus at the moment the idea is that Nepomuk
>> filters all data modifications in order to perform additional checks and
>> add additional data.
>> Currently most of this is in the C++ APIs while it should be in the service.
> 
> Truly I knew nothing about the Semantic Desktop idea till just
> recently, though I'd used stuff like Google Desktop on my Windows
> machine, or Spotlight on my Mac, and then even my exposure to RDF only
> came a few months ago when I started working on this system others had
> initially started.
> 
> And I was surprised when I recognized that what you've done in Nepomuk
> follows the same pattern as what we were doing, with the indexer and
> the RDF store, etc.
> 
> And having used stuff like Google Desktop, which Nepomuk reminded me
> of, I did not at first think about serving our web app using it.
> 
> But considering the work you've done with the faceted browsing in
> Dolphin, your documentation (even your blog entries are more than what
> we have!), the user base you have on KDE that should drive the system
> to greater performance and stability much quicker than our little
> system...  the thought of using Nepomuk the way I described to serve
> our web search interface seems to have a lot of advantages.
> 
> I say this all to ask what I really want to ask:  Do you feel what I
> described is an appropriate use of Nepomuk?  Or does it seem like it's
> fighting what Nepomuk is meant for - that it's not really a use you
> would encourage?
> 
> (I know some of these writings about Nepomuk and the Semantic Desktop
> are referring to "meta data sharing" in a "peer to peer" fashion -
> that seems like it might have addressed the need for remote access to
> the RDF metadata in a different way than our web search interface -
> but I get the impression those features are sometime down the road
> yet?)
> 
>> Well, this could be achieved by creating a simple bridge between the
>> Nepomuk API and a web service.
> 
> I didn't follow at first but then I realized you're saying e.g. a
> "SPARQL endpoint" is really just a RESTful url for sending SPARQL
> queries so I could connect that up myself invoking the C++ query apis
> (or maybe exec'ing out to that "sopranocmd" command?)

yes, exactly.

> And you're saying this would be preferable to me trying to hit
> Virtuoso's endpoint directly?  For the reasons you said about Nepomuk
> doing some things that I should not be "going around" by hitting
> Virtuoso directly?

definitely.

> (is the version of Virtuoso used with Nepomuk really a feature reduced
> version of Virtuoso that doesn't include it's SPARQL endpoint
> functionality?  it hadn't occurred to me to even ask that...)

not feature-reduced but the endpoint is deactivated. The point is that
all data modification should go through Nepomuk. In the future even
through a dedicated non-SPARQL API allowing us to do even more
optimizations and change notifications. The latter is still a major problem.

>>> Do you also have a link handy with instructions on getting/building
>>> the playground version of Mandriva? :)
>>
>> Actually for what you are trying to do there is no need to do that at
>> this point.
> 
> Since I had this Ubuntu setup already, at the moment I've just
> installed kde-desktop on it as a step toward upgrading that to KDE 4.6
> (where I noticed release candidate 2 was put out today).
> 
> Should that alone get me to where I could at least play with e.g. the
> Dolpin faceted search stuff and show some of my teammates?

yes.

> (I'm still a little unclear on what's unique to Mandriva versus what's
> in this KDE 4.6 release that I would put on Kubuntu).

Mandriva ships a few unstable things and some extensions. As far as KDE
4.6 goes it is not clear yet what that will be.

Cheers,
Sebastian