Development/Tutorials/Metadata/Nepomuk/NepomukServer

Nepomuk Server

Tutorial Series	Nepomuk
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What's Next	Advanced Queries
Further Reading	Introduction to RDF and Ontologies, Handling Resources with Nepomuk, Nepomuk Services

The Nepomuk Server

The Nepomuk Server is a daemon which hosts all Nepomuk service including the main Nepomuk data repository. In normal operation it is started through KDE's autostart feature when logging into KDE. Starting it manually is as simple as typing "nepomukserver". This will start the daemon and all services.

The main repository is an RDF database using Soprano including a Soprano full text index. The interface of the repository is exported via DBus (The DBus interface is defined by Soprano). When using the Soprano DBus interface from within a KDE application there is no need to bother with QDBus. Soprano provides the Soprano::Client::DBusModel class which wraps all DBus communication into a nice Soprano::Model interface.

There are two ways to access this wrapper model:

1. Use Soprano::Client::DBusClient to create a connection to the Nepomuk Server:

Soprano::Client::DBusClient* client = new Soprano::Client::DBusClient( "org.kde.NepomukStorage" ); Soprano::Model* model = client->createModel( "main" );

The Nepomuk Server registers as DBus service org.kde.NepomukStorage and the name of the main data repository is main.

2. Use the Nepomuk library, i.e. ResourceManager to access the main model:

Soprano::Model* model = Nepomuk::ResourceManager::instance()->mainModel();

The advantage of the first version is that there is no need to link to libnepomuk. On the other hand the main model as provided by libnepomuk connects via a local socket if available which is faster. Also, it provides an automatic re-connect feature.

So all in all the easy way is also the recommended one: use libnepomuk and the ResourceManager to access the data.