[Nepomuk] Re: Akonadi <-> Nepomuk interaction

Christian Mollekopf chrigi_1 at fastmail.fm
Tue Feb 22 15:28:56 CET 2011 

It just occured to me, that if I add a Thing of the type pimo:document, that 
actually gives already enought information that this Thing is for annotations 
of the document (content) and not the todo/note itself.

So for annotating one would have to pick the correct thing first, or create an 
appropriate one.

The only problem I see, is it possible to assign multiple Nepomuk::Things to a 
Nepomuk::Resource, or should there normally only be one?

At least Resource::pimoThing() does not seem to support it.

Cheers,

Chris

On Tuesday 22 February 2011 14:53:12 Christian Mollekopf wrote:
> Just one thing which I forgot.
> 
> The point is that I need to annotate the content (text) of the Todo/Note
> not the Todo/Note itself.
> 
> I annotate the content with pimo:Topics and random items like files, other
> akonadi items, etc.
> If I would simple set the Thing which I annotated with those items as the
> Thing of the Todo/Note directly, another application could add annotation
> to the Thing i.e. a location for a Todo.
> Now that annotation is really only valid for the Todo not the content in
> general. So if that item is converted to a Note, the location annotation
> should not be kept, while all the associated files, etc and pimo:Topics are
> still valid as they are actually annotations of the content (text).
> 
> That was also why I used the separate resource (for annotating the content
> of the todo/note).
> 
> Cheers,
> 
> Chris
> 
> On Tuesday 22 February 2011 14:31:10 Sebastian Trüg wrote:
> > Hi Chris,
> > 
> > On 02/22/2011 02:23 PM, Christian Mollekopf wrote:
> > > On Tuesday 22 February 2011 11:41:27 Sebastian Trüg wrote:
> > >> Hi Chris,
> > >> 
> > >> I always figured that there would be only two resources:
> > >> 1. The main indexed resource created by the feeder
> > >> 2. The pimo:Thing that contains all the annotations and relations.
> > >> 
> > >> IMHO there is no need for a third resource which is maintained by your
> > >> app. The only problem I see here is the update by the feeder since
> > >> that should maintain the relation to the pimo:Thing.
> > >> But I think that could be handled by the feeder. It simply needs to
> > >> handle updates differently than a simple delete+add. Instead it should
> > >> make sure the resource URI is reused and the relation to the
> > >> pimo:Thing is kept.
> > > 
> > > The problem with using the Resource created by the feeder is that it is
> > > not clear if my app or the feeder is first to create it, so I would
> > > have to make sure that also if I create the Resource first, the feeder
> > > reuses it. But I guess that should be possible.
> > 
> > AFAIK Akonadi uses a dedicated property to identify their resources. You
> > could reuse that.
> > I suppose it would be best to put that into shared code somehow. That
> > way it can be assured that the resources are reused.
> > 
> > > Further I also have to see when to delete the Thing, as sometimes I
> > > wan't to reuse it (when converting the item).
> > > 
> > > What I don't really get: for one specific note there should only be one
> > > Thing, right? So If I create the Thing and assign it to the Resource
> > > created by the Feeder, will the feeeder delete the Thing, when he
> > > deletes the Resource or will I have to do that?
> > > 
> > > The ownership of Resources/Things is not yet really clear to me....
> > 
> > The feeder does not delete the things. This is something that is not
> > defined yet. It could of course be very easy to add thing deletion to
> > the feeder.
> 
> In this case
> 
> > Cheers,
> > Sebastian
> > 
> > >> Once that works you might only have to update the pimo:Thing type. I
> > >> am not sure if this should also be done in the feeder or if your app
> > >> should do that.
> > >> 
> > >> Cheers,
> > >> Sebastian
> > >> 
> > >> On 02/19/2011 02:33 PM, Christian Mollekopf wrote:
> > >>> Hi,
> > >>> 
> > >>> As I don't feel that there is a real solution how to handle notes and
> > >>> kcal items in akonadi and nepomuk.  I'm going to explain here how I
> > >>> plan to implement the interaction between aknoadi::items and
> > >>> nepomuk::resources in my application.
> > >>> 
> > >>> I know there is some work going on in Baske/Semnotes/Kjots and the
> > >>> issue has been discussed before focusing on notes. But as I couldn't
> > >>> find a real conclusion on the ml, and since I have some more
> > >>> requirements/usecases, I think it is time to continue this discussion
> > >>> =)
> > >>> 
> > >>> Usecase:
> > >>> My application manages Incidences (todos/events) and Notes using the
> > >>> KCal and Akonotes resource in akonadi. (I do believe that storing
> > >>> those in akonadi is the right way, and storing them in nepomuk is not
> > >>> a valid option for various reasons).
> > >>> 
> > >>> I organize all items using PIMO::Topics (instead of collections
> > >>> inside akonadi). Further I plan to add functionality to associate
> > >>> random data (files, websites, mails, ...) with the topics and/or a
> > >>> certain Akonadi::Item using Nepomuk.
> > >>> 
> > >>> One functionality which showed some further requirements, is
> > >>> converting i.e. a note to an incidence. This made me realize that
> > >>> I'm normally actually tagging the Content of the note/event/todo and
> > >>> not i.e. todo itself.
> > >>> 
> > >>> 
> > >>> All of this lead me to the following conclusion how to handle those
> > >>> items in Nepomuk:
> > >>> 
> > >>> For each Akonadi::Item I create a Nepomuk::Resource (Content
> > >>> Resource) of the type NFO:HtmlDocument (since it is only the
> > >>> content, not the task itself) with an identifier consisting of an
> > >>> application-specific prefix + akonadi::item url (to avoid conflicts
> > >>> with the items generated in the nepomukfeeder agents). For all
> > >>> annotations I use the pimoThing (Content Thing), on which I set the
> > >>> type PIMO:Document. (See the attached diagram for reference)
> > >>> 
> > >>> So if I convert the item i.e. from note to todo, which means deleting
> > >>> the old Akonadi::Item and creating a new one, I simply set the new
> > >>> Nepomuk::Resource (created with the new akonadi::item url) as a
> > >>> groundingOccurence of the existing Pimo:Document. This way all
> > >>> annotations remain untouched.
> > >>> 
> > >>> The obvious downside of this is, that other applications do not
> > >>> profit from annotations made in my application, and I am not yet
> > >>> sure how to overcome this. Maybe I can annotate the
> > >>> Nepomuk::Resource which has been created by the feederagent with the
> > >>> Pimo:Document of the same item, and therefore implicitly share the
> > >>> annotations?
> > >>> 
> > >>> Also I am not storing any real content in those Resources, I use the
> > >>> Content Resource and the Content Thing only to annotate the content
> > >>> of the item. For fulltext search or similar things I expect to use
> > >>> the items created by the FeederAgent (meaning I will have to create
> > >>> a feederagent for notes as well).
> > >>> 
> > >>> 
> > >>> Anyhow, this solution doesn't seem ideal, so I'd be interested how
> > >>> you guys intend to solve the issues. Especially what Resources you
> > >>> create and how you tell them apart from the ones created by the
> > >>> Feederagents.
> > >>> 
> > >>> Also are you using Nepomuk purely internal, or do you actually create
> > >>> content which could be reused by other applications?
> > >>> 
> > >>> Cheers,
> > >>> 
> > >>> Chris
> > >>> 
> > >>> PS: Some background info on my app in case youre interested
> > >>> http://gitorious.org/notetaker/pages/Home
> 
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