controller.utils.slide_file_watcher

File:

EuljiroWorship/controller/utils/slide_file_watcher.py

Author:

Benjamin Jaedon Choi - https://github.com/saintbenjamin

Affiliated Church:

The Eulji-ro Presbyterian Church [대한예수교장로회(통합) 을지로교회]

Address:

The Eulji-ro Presbyterian Church, 24-10, Eulji-ro 20-gil, Jung-gu, Seoul 04549, South Korea

Telephone:

+82-2-2266-3070

E-mail:

euljirochurch [at] G.M.A.I.L. (replace [at] with @ and G.M.A.I.L as you understood.)

License:

MIT License with Attribution Requirement (see LICENSE file for details); Copyright (c) 2025 The Eulji-ro Presbyterian Church.

Slide file watcher for the slide controller.

This module continuously monitors the slide output JSON file used by the slide controller. It detects file modification events via polling and emits Qt signals when:

• Slide content is updated (non-empty JSON)

• Slide content is cleared (empty JSON), typically indicating the end of emergency caption mode

The watcher is designed to run inside a QThread and communicate with the controller.slide_controller.SlideController via Qt signals only.

class controller.utils.slide_file_watcher.SlideFileWatcher(*args, **kwargs)

Bases: QObject

Watches a slide JSON file and emits signals on content changes.

This watcher polls the target slide file at a fixed interval and detects changes using the file’s modified timestamp.

Signals:

slide_changed(list, int):

Emitted when the slide file is updated with non-empty content. The second argument represents the initial slide index.

slide_cleared():

Emitted when the slide file becomes empty, typically signaling the end of emergency caption mode.

slide_changed

alias of list

__init__(slide_file, poll_interval=1)

Initialize the slide file watcher.

Parameters:

• slide_file (str) – Path to the JSON slide file to monitor.

• poll_interval (int, optional) – Polling interval in seconds. Defaults to 1.

Returns:

None

stop()

Stop the file watching loop.

This method signals the watcher to exit its polling loop gracefully.

Returns:

None

run()

Start monitoring the slide file for changes.

This method runs an infinite polling loop while the watcher is active. When a file modification is detected:

• Emits slide_changed if the file contains slide data

• Emits slide_cleared if the file is empty

This method is intended to be executed inside a QThread.

Returns:

None