TrackerNotifier: Tracker SPARQL Library Reference Manual

TrackerNotifier

TrackerNotifier — Listen to changes in the Tracker database

Functions

TrackerNotifierEventType	tracker_notifier_event_get_event_type ()
gint64	tracker_notifier_event_get_id ()
const gchar *	tracker_notifier_event_get_urn ()
guint	tracker_notifier_signal_subscribe ()
void	tracker_notifier_signal_unsubscribe ()

Properties

TrackerSparqlConnection *

connection

Read / Write / Construct Only

Signals

void

events

Types and Values

	TrackerNotifier
enum	TrackerNotifierEventType
	TrackerNotifierEvent

Object Hierarchy

    GBoxed
    ╰── TrackerNotifierEvent
    GEnum
    ╰── TrackerNotifierEventType
    GObject
    ╰── TrackerNotifier

Includes

#include <libtracker-sparql/tracker-sparql.h>

Description

TrackerNotifier is an object that receives notifications about changes to the Tracker database. A TrackerNotifier is created through tracker_sparql_connection_create_notifier(), after the notifier is created, events can be listened for by connecting to the “events” signal. This object was added in Tracker 1.12.

Known caveats

The TRACKER_NOTIFIER_EVENT_DELETE events will be received after the resource has been deleted. At that time queries on those elements will not bring any metadata. Only the ID/URN obtained through the event remain meaningful.
Notifications of files being moved across indexed folders will appear as TRACKER_NOTIFIER_EVENT_UPDATE events, containing the new location (if requested). The older location is no longer known to Tracker, this may make tracking of elements in specific folders hard using solely the TrackerNotifier/Tracker data available at event notification time.

Functions

tracker_notifier_event_get_event_type ()

TrackerNotifierEventType
tracker_notifier_event_get_event_type (TrackerNotifierEvent *event);

Returns the event type.

Parameters

event

A TrackerNotifierEvent

Returns

The event type

tracker_notifier_event_get_id ()

gint64
tracker_notifier_event_get_id (TrackerNotifierEvent *event);

Returns the tracker:id of the element being notified upon. This is a gint64 which is used as efficient internal identifier for the resource.

Parameters

event

A TrackerNotifierEvent

Returns

the resource ID

tracker_notifier_event_get_urn ()

const gchar *
tracker_notifier_event_get_urn (TrackerNotifierEvent *event);

Returns the Uniform Resource Name of the element. This is Tracker's public identifier for the resource.

This URN is an unique string identifier for the resource being notified upon, typically of the form "urn:uuid:...".

Parameters

event

A TrackerNotifierEvent

Returns

The element URN

tracker_notifier_signal_subscribe ()

guint
tracker_notifier_signal_subscribe (TrackerNotifier *notifier,
                                   GDBusConnection *connection,
                                   const gchar *service,
                                   const gchar *object_path,
                                   const gchar *graph);

Listens to notification events from a remote SPARQL endpoint as a DBus service (see TrackerEndpointDBus). If the object_path argument is NULL, the default "/org/freedesktop/Tracker3/Endpoint" path will be used. If graph is NULL, all graphs will be listened for.

The signal subscription can be removed with tracker_notifier_signal_unsubscribe().

Parameters

notifier	a TrackerNotifier
connection	a GDBusConnection
service	DBus service name to subscribe to events for
object_path	DBus object path to subscribe to events for, or `NULL`.	[nullable]
graph	graph to listen events for, or `NULL`.	[nullable]

Returns

An ID for this subscription

Since: 3.0

tracker_notifier_signal_unsubscribe ()

void
tracker_notifier_signal_unsubscribe (TrackerNotifier *notifier,
                                     guint handler_id);

Undoes a DBus signal subscription, the handler_id argument was previously obtained with a tracker_notifier_signal_subscribe() call.

Parameters

notifier	a TrackerNotifier
handler_id	a handler ID obtained with `tracker_notifier_signal_subscribe()`

Since: 3.0

Types and Values