Update app.py

app.py

@@ -2,6 +2,7 @@ import base64
 import io
 import os
 import zipfile
+import logging
 from threading import Thread
 
 import dash
@@ -10,6 +11,10 @@ from dash import dcc, html, Input, Output, State, callback, MATCH, ALL
 from dash.exceptions import PreventUpdate
 from PyPDF2 import PdfReader, PdfWriter
 
+# Set up logging
+logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
+logger = logging.getLogger(__name__)
+
 app = dash.Dash(__name__, external_stylesheets=[dbc.themes.BOOTSTRAP])
 
 # Global variables
@@ -50,6 +55,7 @@ app.layout = dbc.Container([
     dbc.Progress(id='progress-bar', className="my-3"),
     dbc.Button("Download ZIP", id='download-button', color="success", className="mt-3", disabled=True),
     dcc.Download(id="download-zip"),
+    html.Div(id='log-output', style={'whiteSpace': 'pre-line'}),  # Add this line for log output
 ], fluid=True)
 
 @callback(
@@ -60,6 +66,7 @@ app.layout = dbc.Container([
 )
 def update_output(contents, filename):
     if contents is not None:
+        logger.info(f"PDF file uploaded: {filename}")
         return f"Selected file: {filename}", False
     return "No file selected", True
 
@@ -75,6 +82,7 @@ def manage_ranges(add_clicks, remove_clicks, existing_ranges):
     triggered_id = ctx.triggered[0]['prop_id'].split('.')[0]
 
     if triggered_id == 'add-range':
+        logger.info("Adding new range input")
         new_index = len(existing_ranges)
         new_range = dbc.Row([
             dbc.Col(dbc.Input(id={'type': 'range-input', 'index': new_index}, type='text', placeholder='Enter page range (e.g., 1-3)'), width=10),
@@ -83,6 +91,7 @@ def manage_ranges(add_clicks, remove_clicks, existing_ranges):
         existing_ranges.append(new_range)
     elif 'remove-range' in triggered_id:
         remove_index = json.loads(triggered_id)['index']
+        logger.info(f"Removing range input at index {remove_index}")
         existing_ranges = [range for range in existing_ranges if json.loads(range['props']['children'][1]['props']['children']['props']['id'])['index'] != remove_index]
 
     return existing_ranges
@@ -90,15 +99,18 @@ def manage_ranges(add_clicks, remove_clicks, existing_ranges):
 def process_pdf(contents, filename, ranges):
     global generated_file, progress
     progress = 0
+    logger.info(f"Starting PDF processing for file: {filename}")
     
     try:
         content_type, content_string = contents.split(',')
         decoded = base64.b64decode(content_string)
         pdf = PdfReader(io.BytesIO(decoded))
+        logger.info(f"PDF loaded successfully. Total pages: {len(pdf.pages)}")
         
         writers = []
         for range_str in ranges:
             start, end = map(int, range_str.split('-'))
+            logger.info(f"Processing range: {start}-{end}")
             writer = PdfWriter()
             for i in range(start - 1, min(end, len(pdf.pages))):
                 writer.add_page(pdf.pages[i])
@@ -108,6 +120,7 @@ def process_pdf(contents, filename, ranges):
         with zipfile.ZipFile(zip_buffer, 'w', zipfile.ZIP_DEFLATED) as zf:
             for i, writer in enumerate(writers):
                 progress = (i + 1) / len(writers) * 100
+                logger.info(f"Creating split PDF {i+1}/{len(writers)}")
                 pdf_buffer = io.BytesIO()
                 writer.write(pdf_buffer)
                 pdf_buffer.seek(0)
@@ -116,13 +129,15 @@ def process_pdf(contents, filename, ranges):
         zip_buffer.seek(0)
         generated_file = zip_buffer.getvalue()
         progress = 100
+        logger.info("PDF processing completed successfully")
     except Exception as e:
-        print(f"Error processing PDF: {str(e)}")
+        logger.error(f"Error processing PDF: {str(e)}", exc_info=True)
         progress = -1
 
 @callback(
     Output('progress-bar', 'value'),
     Output('download-button', 'disabled'),
+    Output('log-output', 'children'),
     Input('split-button', 'n_clicks'),
     State('upload-pdf', 'contents'),
     State('upload-pdf', 'filename'),
@@ -131,28 +146,35 @@ def process_pdf(contents, filename, ranges):
 )
 def split_pdf(n_clicks, contents, filename, ranges):
     if not contents or not ranges:
+        logger.warning("Split PDF clicked but no content or ranges provided")
         raise PreventUpdate
     
+    logger.info("Split PDF button clicked")
     ranges = [r for r in ranges if r]  # Filter out empty ranges
+    logger.info(f"Processing {len(ranges)} ranges")
+    
     thread = Thread(target=process_pdf, args=(contents, filename, ranges))
     thread.start()
     
-    return 0, True
+    return 0, True, "PDF splitting process started. Check console for detailed logs."
 
 @callback(
     Output('progress-bar', 'value', allow_duplicate=True),
     Output('download-button', 'disabled', allow_duplicate=True),
+    Output('log-output', 'children', allow_duplicate=True),
     Input('progress-bar', 'value'),
     prevent_initial_call=True
 )
 def update_progress(value):
     global progress
     if progress == 100:
-        return 100, False
+        logger.info("PDF splitting completed")
+        return 100, False, "PDF splitting completed. Click 'Download ZIP' to get your files."
     elif progress == -1:
-        return 0, True
+        logger.error("PDF splitting failed")
+        return 0, True, "Error occurred during PDF splitting. Check console for details."
     else:
-        return progress, True
+        return progress, True, f"Processing... {progress:.0f}% complete"
 
 @callback(
     Output("download-zip", "data"),
@@ -162,10 +184,12 @@ def update_progress(value):
 def download_zip(n_clicks):
     global generated_file
     if generated_file is not None:
+        logger.info("Initiating ZIP file download")
         return dcc.send_bytes(generated_file, "split_pdfs.zip")
+    logger.warning("Download attempted but no file generated")
     raise PreventUpdate
 
 if __name__ == '__main__':
-    print("Starting the Dash application...")
+    logger.info("Starting the Dash application...")
     app.run(debug=True, host='0.0.0.0', port=7860)
-    print("Dash application has finished running.")
+    logger.info("Dash application has finished running.")