Watchdog is an app for monitoring file changes in directories.
It is built with OMC engine:
https://github.com/abra-code/OMC/
It utilizes "watchdog" python module:
https://pypi.org/project/watchdog/
The window is an ActionUI JSON document, Watchdog.app/Contents/Resources/Base.lproj/Watchdog.json,
and every command handler is a Python script under Watchdog.app/Contents/Resources/Scripts/.
The commands themselves are declared in Watchdog.app/Contents/Resources/Command.json.
Requires OMC 5.3 or newer.
The eye button opens a second ActionUI document, Base.lproj/Preview.json, holding
one QuickLook element. That element comes from the ActionUIQuickLook add-on,
which Abracode.framework links and registers at launch, so the preview is a
window of this app rather than a qlmanage process. A chain request carries no
payload, so the selected path travels from the event window to the preview
window's init handler on a named pasteboard, keyed by the event window's uuid -
which the engine hands the new window's subcommands as $OMC_PARENT_DIALOG_GUID.
The applet ships no nib of its own. Info.plist names no NSMainNibFile, so the
engine installs the standard macOS menu bar programmatically. There is no
MainMenu.json either: Watchdog adds nothing to that bar and needs no overrides.
(Abracode.framework still carries nibs for the engine's own input dialogs.)
watchdog.export.events reads the event table over the OMC 5.3 ActionUI remote
bridge (import omc), which is the only way a handler can ask the window what it
currently holds. Every other handler reads the values the engine exports when it
dispatches the command.
appletbuilder test Watchdog.app
Tests/ sits next to the bundle and runs the real handlers against a simulated
OMC environment. See omctest_guide.md in the OMC documentation.
Watchdog began as a shell-driven applet with an Interface Builder nib window and a nib menu bar, and was used as a worked example of moving such an applet to Python. The original step-by-step walkthrough and the parallel shell scripts are kept, unmaintained, under Archive/.