Add improved example demonstrating watched folder functionality

Closes #466

misc/watcher.py

@@ -0,0 +1,70 @@
+# Copyright (C) 2019 Ian Alexander: https://github.com/ianalexander
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import time
+from datetime import datetime
+from pathlib import Path
+
+from watchdog.events import PatternMatchingEventHandler
+from watchdog.observers import Observer
+
+import ocrmypdf
+
+INPUT_DIRECTORY = os.getenv('OCR_INPUT_DIRECTORY', '/input')
+OUTPUT_DIRECTORY = os.getenv('OCR_OUTPUT_DIRECTORY', '/output')
+OUTPUT_DIRECTORY_YEAR_MONTH = bool(os.getenv('OCR_OUTPUT_DIRECTORY_YEAR_MONTH', False))
+PATTERNS = ['*.pdf']
+
+
+def execute_ocrmypdf(file_path):
+    filename = Path(file_path).name
+    if OUTPUT_DIRECTORY_YEAR_MONTH:
+        today = datetime.today()
+        output_directory_year_month = Path(
+            f'{OUTPUT_DIRECTORY}/{today.year}/{today.month}'
+        )
+        if not output_directory_year_month.exists():
+            output_directory_year_month.mkdir(parents=True, exist_ok=True)
+        output_path = Path(output_directory_year_month) / filename
+    else:
+        output_path = Path(OUTPUT_DIRECTORY) / filename
+    print(f'New file: {file_path}.\nAttempting to OCRmyPDF to: {output_path}')
+    ocrmypdf.ocr(file_path, output_path)
+
+
+class HandleObserverEvent(PatternMatchingEventHandler):
+    def on_any_event(self, event):
+        if event.event_type in ['created', 'modified']:
+            execute_ocrmypdf(event.src_path)
+
+
+if __name__ == "__main__":
+    print(
+        f"Starting OCRmyPDF watcher with config:\n"
+        f"Input Directory: {INPUT_DIRECTORY}\n"
+        f"Output Directory: {OUTPUT_DIRECTORY}\n"
+        f"Output Directory Year & Month: {OUTPUT_DIRECTORY_YEAR_MONTH}"
+    )
+    handler = HandleObserverEvent(patterns=PATTERNS)
+    observer = Observer()
+    observer.schedule(handler, INPUT_DIRECTORY, recursive=True)
+    observer.start()
+    try:
+        while True:
+            time.sleep(1)
+    except KeyboardInterrupt:
+        observer.stop()
+    observer.join()