6. Categories

Notifications can optionally have a type indicator. Although neither client or nor server must support this, some may choose to. Those servers implementing categories may use them to intelligently display the notification in a certain way, or group notifications of similar types.

Categories are in class.specific form. class specifies the generic type of notification, and specific specifies the more specific type of notification.

If a specific type of notification does not exist for your notification, but the generic kind does, a notification of type class is acceptable.

Third parties, when defining their own categories, should discuss the possibility of standardizing on the hint with other parties, preferably in a place such as the xdg mailing list at freedesktop.org. If it warrants a standard, it will be added to the table above. If no consensus is reached, the category should be in the form of "x-vendor.class.name."

The following table lists standard notifications as defined by this spec. More will be added in time.

Table 2. Categories

TypeDescription
"device" A generic device-related notification that doesn't fit into any other category.
"device.added"A device, such as a USB device, was added to the system.
"device.error"A device had some kind of error.
"device.removed" A device, such as a USB device, was removed from the system.
"email" A generic e-mail-related notification that doesn't fit into any other category.
"email.arrived"A new e-mail notification.
"email.bounced"A notification stating that an e-mail has bounced.
"im" A generic instant message-related notification that doesn't fit into any other category.
"im.error"An instant message error notification.
"im.received"A received instant message notification.
"network" A generic network notification that doesn't fit into any other category.
"network.connected" A network connection notification, such as successful sign-on to a network service. This should not be confused with device.added for new network devices.
"network.disconnected" A network disconnected notification. This should not be confused with device.removed for disconnected network devices.
"network.error" A network-related or connection-related error.
"presence" A generic presence change notification that doesn't fit into any other category, such as going away or idle.
"presence.offline"An offline presence change notification.
"presence.online"An online presence change notification.
"transfer" A generic file transfer or download notification that doesn't fit into any other category.
"transfer.complete"A file transfer or download complete notification.
"transfer.error"A file transfer or download error.