[Nepomuk] Re: Akonadi <-> Nepomuk interaction

[Christian Mollekopf]

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.

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....

> 
> 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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