orgfreedesktopNotifications

org.freedesktop.Notifications is a D-Bus interface defined by freedesktop.org for desktop notifications. It provides a standardized way for applications to deliver notifications to a user through a notification server or daemon. The interface is a key component of the Desktop Notifications Specification and is implemented by many Linux desktop environments and toolkits, enabling cross-desktop compatibility.

The core API comprises several methods. Notify sends a notification with parameters including app_name, replaces_id, app_icon, summary, body, actions, hints, and expire_timeout, and returns a notification id. GetCapabilities returns a list of server-supported features. CloseNotification can be used to close a notification by id. GetServerInformation returns the server’s name, vendor, version, and the specification version it implements. The arguments include data types such as strings, unsigned integers, arrays, and dictionaries, with expire_timeout expressed in milliseconds and a value of -1 indicating no timeout.

Two signals are defined to notify clients of user interactions and lifecycle events. NotificationClosed is emitted when a notification is closed, either by timeout, user action, or programmatic closing, with a reason code. ActionInvoked is emitted when a user activates a specified action on a notification, providing the notification id and the action key.

In practice, clients construct notifications using a combination of summary and body text, optional actions, and hints that describe presentation details or behavior. Hints may influence urgency, category, or icon, while actions provide interactive responses. Implementations include libnotify and various desktop environments, with applications such as notify-send acting as simple clients. The interface supports replacement of existing notifications via replaces_id and is designed to maintain interoperability across different systems implementing the standard.