# DBUS Interface

This API is currently unstable and is likely to change in the future.

## Introduction

GNOME Screensaver exposes a DBUS API for programs to obtain information about the screensaver state and to interact with the screensaver in limited ways.

The following constants are used to uniquely refer to the GnomeScreensaver object when making DBUS method calls:

DBUS Service: | `org.gnome.ScreenSaver`
DBUS Object Path: | `/org/gnome/ScreenSaver`
DBUS Interface: | `org.gnome.ScreenSaver`

## Methods

These are the DBUS methods.

### `Lock`

Request that the screen be locked. This bypasses all Inhibit requests.

### `Cycle`

Request that the screen saver theme be restarted and, if applicable, switch to the next one in the list.

### `SimulateUserActivity`

Simulate user activity. If the screensaver is activated this will attempt to deactivate and authentication will be requested if necessary. If the screensaver is not activated then the idle timers will be reset.

### `Inhibit`

Request that saving the screen due to system idleness be blocked until UnInhibit is called or the calling process exits.

Direction | Type | Description
--- | --- | ---
in | string | the application name, e.g. "totem"
in | string | the localized reason to inhibit, e.g. "playing movie"
out | unsigned integer | the cookie

A cookie is a random, unique, non-zero UINT32 used to identify the inhibit request.

### `UnInhibit`

Cancel a previous call to Inhibit() identified by the cookie.

Direction | Type | Description
--- | --- | ---
in | unsigned integer | the cookie

### `Throttle`

Request that running themes while the screensaver is active be blocked until UnThrottle is called or the calling process exits.

Direction | Type | Description
--- | --- | ---
in | string | the application name, e.g. "gnome-power-manager"
in | string | the localized reason to inhibit, e.g. "on battery power"
out | unsigned integer | the cookie

A cookie is a random, unique, non-zero UINT32 used to identify the throttle request.

### `UnThrottle`

Cancel a previous call to Throttle() identified by the cookie.

Direction | Type | Description
--- | --- | ---
in | unsigned integer | the cookie

### `SetActive`

Request a change in the state of the screensaver. Set to TRUE to request that the screensaver activate. Active means that the screensaver has blanked the screen and may run a graphical theme. This does not necessary mean that the screen is locked.

Direction | Type | Description
--- | --- | ---
in | boolean | TRUE to request activation, FALSE to request deactivation

### `GetActive`

Returns the value of the current state of activity. See SetActive().

Direction | Type | Description
--- | --- | ---
out | boolean | Activation state

### `GetActiveTime`

Returns the number of seconds that the screensaver has been active. Returns zero if the screensaver is not active.

Direction | Type | Description
--- | --- | ---
out | unsigned integer | Active time in seconds

### `GetSessionIdle`

Returns the value of the current state of session idleness.

Direction | Type | Description
--- | --- | ---
out | boolean | If the session is idle

### `GetSessionIdleTime`

Returns the number of seconds that the session has been idle. Returns zero if the session is not idle.

Direction | Type | Description
--- | --- | ---
out | unsigned integer | Idle time in seconds

## Signals

These are the DBUS signals.

### `ActiveChanged`

See method GetActive().

Direction | Type | Description
--- | --- | ---
out | boolean | Returns the value of the current state of activity.

### `SessionIdleChanged`

See method GetActive().

Direction | Type | Description
--- | --- | ---
out | boolean | Returns the value of the current state of activity.

### `AuthenticationRequestBegin`

Emitted before an authentication request

### `AuthenticationRequestEnd`

Emitted after an authentication request

## Examples

You can get the number of seconds the screensaver has been active by running the following:

    dbus-send --session \
              --dest=org.gnome.ScreenSaver \
              --type=method_call \
              --print-reply \
              --reply-timeout=20000 \
              /org/gnome/ScreenSaver \
              org.gnome.ScreenSaver.GetSessionIdleTime

You can activate the screensaver like so:

    dbus-send --session \
              --dest=org.gnome.ScreenSaver \
              --type=method_call \
              --print-reply \
              --reply-timeout=20000 \
              /org/gnome/ScreenSaver \
              org.gnome.ScreenSaver.SetActive \
              boolean:true

You can monitor screensaver changes:

    dbus-monitor --session \
              "type='signal',interface='org.gnome.ScreenSaver'"

Or watch for a specific screensaver signal:

    dbus-monitor --session \
              "type='signal',interface='org.gnome.ScreenSaver',member='SessionIdleChanged'"