soprano

Writing Soprano Plugins

Soprano has five kinds of plugins: Soprano::Backend, Soprano::Parser, Soprano::Serializer, Soprano::Query::Parser, and Soprano::Query::Serializer.

Creating a new plugin for Soprano is pretty easy. Imagine, for example, we want to write a new Backend plugin. We simply create a class that inherits from QObject and the Soprano::Backend interface and use the Q_INTERFACES macro to tell Qt's meta-object system about the new plugin. We then export the plugin via the Q_EXPORT_PLUGIN2 macro in the source file.

An example would look as follows:

 class MyBackend : public QObject, public Soprano::Backend
 {
    Q_OBJECT
    Q_INTERFACES(Soprano::Backend)

 public:
    StorageModel* createModel( const QStringList& options = QStringList() ) const;
    bool deleteModelData( const BackendSettings& settings ) const;
    BackendFeatures supportedFeatures() const;
 };

In the implementation file export the plugin so it can be picked up by the plugin loading framework:

 Q_EXPORT_PLUGIN2(soprano_mybackend, MyBackend)

The plugin then needs to be linked as a library and installed into the lib/soprano target folder.

Finally we need to create a desktop file describing the plugin. The minimal desktop file looks as follows (for details see Soprano Plugin Desktop Files):

 [Desktop Entry]
 Encoding=UTF-8
 X-Soprano-Library=libsoprano_mybackend
 X-Soprano-Version=2.1
 Type=Service
 ServiceTypes=Soprano/Backend
 Name=MyBackend
 Comment=My very cool and fast Soprano backend

The desktop file should be installed into share/soprano/plugins so the Soprano::PluginManager will find it.

All plugin interfaces inherit from Soprano::Error::ErrorCache for error handling and subclasses should use Soprano::Error::ErrorCache::clearError() and Soprano::Error::ErrorCache::setError() to report the status.

soprano

Writing Soprano Plugins

soprano

API Reference