IPC Control

gSlapper supports runtime control via Unix domain sockets, allowing you to control playback from scripts or other applications.

Enabling IPC

Start gSlapper with the -I or --ipc-socket option:

gslapper -I /tmp/gslapper.sock -o "loop" DP-1 video.mp4

Sending Commands

Use nc (netcat) or socat to send commands:

# Using nc
echo "pause" | nc -U /tmp/gslapper.sock

# Using socat
echo "pause" | socat - UNIX-CONNECT:/tmp/gslapper.sock

Available Commands

help

List all available IPC commands.

echo "help" | nc -U /tmp/gslapper.sock

Response: List of all supported commands with brief descriptions.

pause

Pause video playback.

echo "pause" | nc -U /tmp/gslapper.sock

Response: OK

resume

Resume paused playback.

echo "resume" | nc -U /tmp/gslapper.sock

Response: OK

query

Get current state and wallpaper path.

echo "query" | nc -U /tmp/gslapper.sock

Response: STATUS: playing image /path/to/wallpaper.jpg or STATUS: paused video /path/to/video.mp4

change <path>

Switch to a different wallpaper.

echo "change /path/to/new/video.mp4" | nc -U /tmp/gslapper.sock

Response: OK: transition started (if transitions enabled) or OK

stop

Stop gSlapper.

echo "stop" | nc -U /tmp/gslapper.sock

Response: OK (gSlapper exits)

set-transition <type>

Set transition effect type. Options: none, fade.

echo "set-transition fade" | nc -U /tmp/gslapper.sock
echo "set-transition none" | nc -U /tmp/gslapper.sock

Response: OK or ERROR: <message>

Transitions

Transitions only work between static images. Videos always use instant switch regardless of transition settings.

set-transition-duration <seconds>

Set transition duration in seconds (0.0-5.0).

echo "set-transition-duration 2.0" | nc -U /tmp/gslapper.sock

Response: OK or ERROR: <message>

get-transition

Query current transition settings.

echo "get-transition" | nc -U /tmp/gslapper.sock

Response: TRANSITION: <type> <enabled|disabled> <duration>

Example: TRANSITION: fade enabled 1.50

Response Format

• OK - Command succeeded
• OK: <message> - Command succeeded with additional info
• ERROR: <message> - Command failed with error message
• ERROR: File not found: <path> - File access error with detailed reason
• ERROR: Permission denied: <path> - Permission error with system details
• ERROR: Invalid input: <reason> - Input validation failed
• STATUS: <state> <type> <path> - Query response
• TRANSITION: <type> <enabled|disabled> <duration> - Transition query response

Error Messages

Recent improvements provide more detailed error messages:

• File not found: ERROR: File not accessible: /path/to/file.mp4 (No such file or directory)
• Permission denied: ERROR: File not accessible: /path/to/file.mp4 (Permission denied)
• Path too long: ERROR: Path too long (max 4096 characters)
• Invalid characters: ERROR: Invalid input: contains control characters

Example Script

#!/bin/bash
SOCKET="/tmp/gslapper.sock"

case "$1" in
    pause)
        echo "pause" | nc -U "$SOCKET"
        ;;
    resume)
        echo "resume" | nc -U "$SOCKET"
        ;;
    next)
        echo "change /path/to/next/video.mp4" | nc -U "$SOCKET"
        ;;
    status)
        echo "query" | nc -U "$SOCKET"
        ;;
    transition)
        echo "set-transition fade" | nc -U "$SOCKET"
        echo "set-transition-duration 2.0" | nc -U "$SOCKET"
        ;;
    *)
        echo "Usage: $0 {pause|resume|next|status|transition}"
        exit 1
        ;;
esac

Cache Management Commands

These commands require --cache-size to be enabled.

cache-list

List all cached images with dimensions and sizes.

echo "cache-list" | nc -U /tmp/gslapper.sock

Response: List of cached images, one per line:

/path/to/image1.jpg 3840x2160 31.64 MB [*]
/path/to/image2.png 2560x1440 14.06 MB

The [*] marker indicates currently displayed image.

cache-stats

Show cache usage statistics.

echo "cache-stats" | nc -U /tmp/gslapper.sock

Response: 45.70/256.00 MB (2 images) or Cache disabled

unload <target>

Remove images from cache. Target can be: - unused - Remove all images not currently displayed - all - Clear entire cache (including displayed image) - <path> - Remove specific image by path

echo "unload unused" | nc -U /tmp/gslapper.sock
echo "unload all" | nc -U /tmp/gslapper.sock
echo "unload /path/to/image.jpg" | nc -U /tmp/gslapper.sock

Response: OK: Unloaded N image(s) or ERROR: <message>

listactive

Show currently displayed wallpaper(s) and output(s).

echo "listactive" | nc -U /tmp/gslapper.sock

Response: ACTIVE: <output> <type> <path>

Example: ACTIVE: DP-1 image /home/user/wallpaper.jpg