Development/Tutorials/Metadata/Nepomuk/StorageService: Difference between revisions
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1. Use [http://api.kde.org/kdesupport-api/kdesupport-apidocs/soprano/html/classSoprano_1_1Client_1_1DBusClient.html Soprano::Client::DBusClient] to create a connection to the Nepomuk Server: | 1. Use [http://api.kde.org/kdesupport-api/kdesupport-apidocs/soprano/html/classSoprano_1_1Client_1_1DBusClient.html Soprano::Client::DBusClient] to create a connection to the Nepomuk Server: | ||
< | <syntaxhighlight lang="cpp-qt"> | ||
Soprano::Client::DBusClient* client = new Soprano::Client::DBusClient( "org.kde.NepomukStorage" ); | Soprano::Client::DBusClient* client = new Soprano::Client::DBusClient( "org.kde.NepomukStorage" ); | ||
Soprano::Model* model = client->createModel( "main" ); | Soprano::Model* model = client->createModel( "main" ); | ||
</ | </syntaxhighlight> | ||
The Nepomuk Server registers as DBus service ''org.kde.NepomukStorage'' and the name of the main data repository is ''main''. | The Nepomuk Server registers as DBus service ''org.kde.NepomukStorage'' and the name of the main data repository is ''main''. | ||
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2. Use the Nepomuk library, i.e. [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1ResourceManager.html ResourceManager] to access the main model: | 2. Use the Nepomuk library, i.e. [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1ResourceManager.html ResourceManager] to access the main model: | ||
< | <syntaxhighlight lang="cpp-qt"> | ||
Soprano::Model* model = Nepomuk::ResourceManager::instance()->mainModel(); | Soprano::Model* model = Nepomuk::ResourceManager::instance()->mainModel(); | ||
</ | </syntaxhighlight> | ||
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. | 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. | ||
When implementing a Nepomuk service use [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1Service.html Service] to access the main repository: | When implementing a Nepomuk service use [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1Service.html Service] to access the main repository: | ||
< | <syntaxhighlight lang="cpp-qt"> | ||
class MyService : public Nepomuk::Service { | class MyService : public Nepomuk::Service { | ||
public: | public: | ||
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} | } | ||
}; | }; | ||
</ | </syntaxhighlight> | ||
So all in all the easy way is also the recommended one: use ''libnepomuk'' and the [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1ResourceManager.html ResourceManager] or [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1Service.html Service] to access the data. | So all in all the easy way is also the recommended one: use ''libnepomuk'' and the [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1ResourceManager.html ResourceManager] or [http://api.kde.org/4.x-api/kdelibs-apidocs/nepomuk/html/classNepomuk_1_1Service.html Service] to access the data. | ||
Latest revision as of 20:53, 29 June 2011
| Tutorial Series | Nepomuk |
| Previous | |
| What's Next | OntologyLoader |
| Further Reading | Nepomuk Services, Nepomuk Server |
Nepomuk Storage Service
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. When implementing a Nepomuk service use Service to access the main repository:
class MyService : public Nepomuk::Service {
public:
MyService( QObject* parent ) : Service( parent ) {
Soprano::Model* model = mainModel();
}
};So all in all the easy way is also the recommended one: use libnepomuk and the ResourceManager or Service to access the data.