docling-studio/backend/app.py
2025-06-03 15:19:05 +02:00

844 lines
No EOL
30 KiB
Python

#!/usr/bin/env python3
"""
Flask application for DocTags web interface
"""
from flask import Flask, request, send_file, jsonify
import subprocess
import os
import sys
import time
import threading
import logging
from pathlib import Path
import uuid
# Add parent directory to path
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from backend.utils import (ensure_results_folder, count_pdf_pages,
run_command_with_timeout, format_duration)
from backend.config import (HOST, PORT, MAX_CONTENT_LENGTH, ALLOWED_EXTENSIONS,
PREVIEW_DPI, PROCESSING_TIMEOUT, CLEANUP_INTERVAL,
CLEANUP_AGE_HOURS)
from backend.multipart_handler import default_handler
# Configure logging
logging.basicConfig(level=logging.INFO,
format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
logger = logging.getLogger(__name__)
# Initialize Flask app
frontend_path = Path(__file__).parent.parent / 'frontend'
app = Flask(__name__,
static_folder=frontend_path / 'static',
static_url_path='/static')
app.config['MAX_CONTENT_LENGTH'] = MAX_CONTENT_LENGTH
# Task results storage
task_results = {}
# Import batch processor if available
try:
from backend.batch_treatment.batch_processor import (
start_batch_processing, get_batch_processor, cleanup_old_batches
)
batch_processing_available = True
except ImportError:
logger.warning("Batch processing not available")
batch_processing_available = False
# Ensure required directories exist
ensure_results_folder()
# Routes
@app.route('/')
def index():
return send_file(frontend_path / 'index.html')
@app.route('/batch')
def batch_interface():
return send_file(frontend_path / 'batch.html')
@app.route('/static/<path:filename>')
def serve_static(filename):
return send_file(frontend_path / 'static' / filename)
@app.route('/pdf-files')
def pdf_files():
try:
pdf_files = [f for f in os.listdir('.') if f.endswith('.pdf')]
logger.info(f"Found {len(pdf_files)} PDF files")
return jsonify(pdf_files)
except Exception as e:
logger.error(f"Error listing PDF files: {e}")
return jsonify({"error": str(e)}), 500
@app.route('/pdf-info/<path:pdf_file>')
def pdf_info(pdf_file):
"""Get information about a PDF file"""
try:
if not os.path.exists(pdf_file):
return jsonify({'error': f'PDF file not found: {pdf_file}'}), 404
page_count = count_pdf_pages(pdf_file)
return jsonify({
'pageCount': page_count,
'filename': os.path.basename(pdf_file),
'size': os.path.getsize(pdf_file)
})
except Exception as e:
logger.error(f"Error getting PDF info: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/pdf-preview/<pdf_file>/<int:page_num>')
def pdf_preview(pdf_file, page_num):
"""Generate and serve a preview image of a PDF page"""
try:
import pdf2image
from PIL import Image
import io
if not os.path.exists(pdf_file):
return jsonify({'error': f'PDF file not found: {pdf_file}'}), 404
logger.info(f"Generating preview for {pdf_file} page {page_num}")
# Convert PDF page to image
pdf_images = pdf2image.convert_from_path(
pdf_file, dpi=PREVIEW_DPI,
first_page=page_num, last_page=page_num
)
if not pdf_images:
return jsonify({'error': f'Could not extract page {page_num}'}), 400
pil_image = pdf_images[0]
# Resize if too large
max_width = 1200
if pil_image.width > max_width:
ratio = max_width / pil_image.width
new_height = int(pil_image.height * ratio)
pil_image = pil_image.resize((max_width, new_height), Image.LANCZOS)
# Convert to bytes
img_io = io.BytesIO()
pil_image.save(img_io, 'PNG', optimize=True)
img_io.seek(0)
return send_file(img_io, mimetype='image/png')
except Exception as e:
logger.error(f"Error generating PDF preview: {e}")
return jsonify({'error': str(e)}), 500
def run_command(task_id, command):
"""Run a command in a background thread and store result"""
logger.info(f"Running command: {command}")
try:
# Run the command with pipe input to automatically answer "n" to prompts
process = subprocess.Popen(
command,
shell=True,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
text=True,
universal_newlines=True
)
# Send "n" to the process to bypass prompts
stdout, stderr = process.communicate(input="n\n")
# Log output for debugging
logger.info(f"Command stdout: {stdout[:500]}...")
if stderr:
logger.error(f"Command stderr: {stderr}")
# Update task result
if process.returncode == 0:
task_results[task_id] = {
'success': True,
'output': stdout,
'done': True
}
logger.info(f"Command completed successfully: {task_id}")
else:
error_message = stderr or f"Command failed with return code {process.returncode}"
task_results[task_id] = {
'success': False,
'error': error_message,
'done': True
}
logger.error(f"Command failed: {task_id} - {error_message}")
except Exception as e:
import traceback
logger.error(f"Unexpected error: {task_id} - {str(e)}")
logger.error(traceback.format_exc())
task_results[task_id] = {
'success': False,
'error': f"Exception: {str(e)}",
'done': True
}
@app.route('/run-analyzer', methods=['POST'])
def run_analyzer():
try:
pdf_file = request.form.get('pdf_file')
page_num = request.form.get('page_num', 1)
if not pdf_file:
return jsonify({'success': False, 'error': 'PDF file not specified'}), 400
if not os.path.exists(pdf_file):
return jsonify({'success': False, 'error': f'PDF file not found: {pdf_file}'}), 404
command = f"python backend/page_treatment/analyzer.py --image {pdf_file} --page {page_num} --start-page {page_num} --end-page {page_num}"
# Generate task ID
task_id = f"analyzer_{int(time.time())}"
# Initialize task result
task_results[task_id] = {
'success': None,
'output': "Running analyzer...",
'done': False
}
# Start background thread
thread = threading.Thread(target=run_command, args=(task_id, command))
thread.daemon = True
thread.start()
return jsonify({
'success': True,
'task_id': task_id,
'message': f"Analyzer started. Processing {pdf_file} page {page_num}..."
})
except Exception as e:
logger.error(f"Error starting analyzer: {e}")
return jsonify({'success': False, 'error': str(e)}), 500
@app.route('/run-visualizer', methods=['POST'])
def run_visualizer():
try:
pdf_file = request.form.get('pdf_file')
page_num = request.form.get('page_num', 1)
adjust = request.form.get('adjust') == 'true'
if not pdf_file:
return jsonify({'success': False, 'error': 'PDF file not specified'}), 400
command = f"python backend/page_treatment/visualizer.py --doctags results/output.doctags.txt --pdf {pdf_file} --page {page_num}"
if adjust:
command += " --adjust"
# Generate task ID with page number
task_id = f"visualizer_{int(time.time())}_{page_num}"
# Initialize task result
task_results[task_id] = {
'success': None,
'output': "Running visualizer...",
'done': False
}
# Start background thread
thread = threading.Thread(target=run_command, args=(task_id, command))
thread.daemon = True
thread.start()
return jsonify({
'success': True,
'task_id': task_id,
'message': f"Visualizer started. Processing {pdf_file} page {page_num}..."
})
except Exception as e:
logger.error(f"Error starting visualizer: {e}")
return jsonify({'success': False, 'error': str(e)}), 500
@app.route('/run-extractor', methods=['POST'])
def run_extractor():
try:
pdf_file = request.form.get('pdf_file')
page_num = request.form.get('page_num', 1)
adjust = request.form.get('adjust') == 'true'
if not pdf_file:
return jsonify({'success': False, 'error': 'PDF file not specified'}), 400
command = f"python backend/page_treatment/picture_extractor.py --doctags results/output.doctags.txt --pdf {pdf_file} --page {page_num}"
if adjust:
command += " --adjust"
# Generate task ID with page number
task_id = f"extractor_{int(time.time())}_{page_num}"
# Initialize task result
task_results[task_id] = {
'success': None,
'output': "Running picture extractor...",
'done': False
}
# Start background thread
thread = threading.Thread(target=run_command, args=(task_id, command))
thread.daemon = True
thread.start()
return jsonify({
'success': True,
'task_id': task_id,
'message': f"Picture extractor started. Processing {pdf_file} page {page_num}..."
})
except Exception as e:
logger.error(f"Error starting extractor: {e}")
return jsonify({'success': False, 'error': str(e)}), 500
def run_processing_task(task_type, form_data):
"""Generic function to run processing tasks"""
try:
pdf_file = form_data.get('pdf_file')
page_num = form_data.get('page_num', '1')
if not pdf_file:
return jsonify({'success': False, 'error': 'PDF file not specified'}), 400
if not os.path.exists(pdf_file):
return jsonify({'success': False, 'error': f'PDF file not found: {pdf_file}'}), 404
# Build command based on task type
command = build_command(task_type, pdf_file, page_num, form_data)
# Generate task ID with page number
task_id = f"{task_type}_{int(time.time() * 1000)}_{page_num}"
# Initialize task result
with task_lock:
task_results[task_id] = {
'success': None,
'output': f"Running {task_type}...",
'done': False
}
logger.info(f"Created task {task_id} for {task_type} on page {page_num}")
# Start background thread
thread = threading.Thread(target=run_background_task, args=(task_id, command))
thread.daemon = True
thread.start()
return jsonify({
'success': True,
'task_id': task_id,
'message': f"{task_type.capitalize()} started for {pdf_file} page {page_num}"
})
except Exception as e:
logger.error(f"Error starting {task_type}: {e}")
import traceback
traceback.print_exc()
return jsonify({'success': False, 'error': str(e)}), 500
def build_command(task_type, pdf_file, page_num, form_data):
"""Build command for different task types"""
adjust = form_data.get('adjust') == 'true'
if task_type == 'analyzer':
return (f"python backend/page_treatment/analyzer.py --image {pdf_file} "
f"--page {page_num} --start-page {page_num} --end-page {page_num}")
elif task_type == 'visualizer':
cmd = (f"python backend/page_treatment/visualizer.py "
f"--doctags results/output.doctags.txt --pdf {pdf_file} --page {page_num}")
if adjust:
cmd += " --adjust"
return cmd
elif task_type == 'extractor':
cmd = (f"python backend/page_treatment/picture_extractor.py "
f"--doctags results/output.doctags.txt --pdf {pdf_file} --page {page_num}")
if adjust:
cmd += " --adjust"
return cmd
else:
raise ValueError(f"Unknown task type: {task_type}")
@app.route('/task-status/<task_id>')
def task_status(task_id):
if task_id not in task_results:
logger.warning(f"Task {task_id} not found in task_results")
return jsonify({'success': False, 'error': 'Task not found'}), 404
result = task_results[task_id].copy()
# Log the complete result for debugging
logger.info(f"Task {task_id} result: {result}")
# If task is completed successfully, add file paths
if result.get('done') and result.get('success'):
if task_id.startswith('analyzer_'):
doctags_path = Path("results") / "output.doctags.txt"
if doctags_path.exists():
result['doctags_file'] = "results/output.doctags.txt"
logger.info(f"Added doctags_file to result")
else:
logger.warning(f"DocTags file not found: {doctags_path}")
elif task_id.startswith('visualizer_'):
# Extract page number from the end of task_id if it exists
page_num = task_id.split('_')[-1] if len(task_id.split('_')) > 2 else "1"
viz_filename = f"visualization_page_{page_num}.png"
result['image_file'] = f"results/{viz_filename}"
logger.info(f"Found visualization at: {result['image_file']}")
return jsonify(result)
@app.route('/results/<path:filename>')
def serve_results(filename):
"""Serve files from results directory"""
try:
results_dir = ensure_results_folder()
file_path = results_dir / filename
if file_path.exists() and file_path.is_file():
return send_file(file_path)
else:
logger.error(f"File not found: {file_path}")
return jsonify({'error': f"File not found: {filename}"}), 404
except Exception as e:
logger.error(f"Error serving file {filename}: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/check-environment')
def check_environment():
"""Check system environment and configuration"""
try:
import subprocess
# Check for required scripts
required_scripts = ['analyzer.py', 'visualizer.py', 'picture_extractor.py']
backend_dir = Path('backend/page_treatment')
missing_scripts = [s for s in required_scripts if not (backend_dir / s).exists()]
# Get Python version
result = subprocess.run(['python', '--version'], capture_output=True, text=True)
python_version = result.stdout.strip() if result.returncode == 0 else "Unknown"
# Check results directory
results_dir = ensure_results_folder()
return jsonify({
'cwd': os.getcwd(),
'files': os.listdir('.')[:50], # Limit to 50 files
'missing_scripts': missing_scripts,
'pdf_files': [f for f in os.listdir('.') if f.endswith('.pdf')],
'results_dir_exists': results_dir.exists(),
'results_dir_writable': os.access(results_dir, os.W_OK),
'python_version': python_version,
'batch_processing_available': batch_processing_available
})
except Exception as e:
logger.error(f"Error checking environment: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/run-manual-command', methods=['POST'])
def run_manual_command():
"""Run a manual command for debugging"""
try:
command = request.form.get('command')
if not command:
return jsonify({'success': False, 'error': 'No command specified'}), 400
logger.info(f"Running manual command: {command}")
# Update paths in command if needed
if 'backend/page_treatment/' not in command:
for script in ['analyzer.py', 'visualizer.py', 'picture_extractor.py']:
command = command.replace(script, f'backend/page_treatment/{script}')
success, stdout, stderr = run_command_with_timeout(command, 60)
return jsonify({
'success': success,
'output': stdout,
'error': stderr
})
except Exception as e:
logger.error(f"Error running manual command: {e}")
return jsonify({'success': False, 'error': str(e)}), 500
# Batch processing endpoints
if batch_processing_available:
@app.route('/run-batch-processor', methods=['POST'])
def run_batch_processor():
"""Start batch processing job"""
try:
pdf_file = request.form.get('pdf_file')
start_page = int(request.form.get('start_page', 1))
end_page = int(request.form.get('end_page', 1))
if not pdf_file or not os.path.exists(pdf_file):
return jsonify({'success': False, 'error': 'Invalid PDF file'}), 400
# Check if there's already an active batch for this PDF
from backend.batch_treatment.batch_processor import batch_processors, batch_lock
with batch_lock:
for batch_id, processor in batch_processors.items():
if (processor.pdf_file == pdf_file and
not processor.state['completed'] and
not processor.state['cancelled']):
return jsonify({
'success': False,
'error': 'A batch process is already running for this PDF',
'existing_batch_id': batch_id
}), 409
options = {
'adjust': request.form.get('adjust') == 'true',
'parallel': request.form.get('parallel') == 'true',
'generate_report': request.form.get('generate_report') == 'true'
}
batch_id = str(uuid.uuid4())[:8]
if start_batch_processing(batch_id, pdf_file, start_page, end_page, options):
return jsonify({
'success': True,
'batch_id': batch_id,
'message': f'Started processing {end_page - start_page + 1} pages'
})
else:
return jsonify({'success': False, 'error': 'Failed to start'}), 500
except Exception as e:
logger.error(f"Error starting batch: {e}")
return jsonify({'success': False, 'error': str(e)}), 500
@app.route('/batch-status/<batch_id>')
def batch_status(batch_id):
"""Get batch processing status"""
processor = get_batch_processor(batch_id)
if not processor:
return jsonify({'error': 'Batch not found'}), 404
state = processor.get_state()
state['logs'] = state['logs'][-20:] # Last 20 logs only
return jsonify(state)
# Add these routes to your app.py file after the other batch processing endpoints
@app.route('/batch-report/<batch_id>')
def batch_report(batch_id):
"""Serve the batch processing report HTML"""
try:
processor = get_batch_processor(batch_id)
if not processor:
# Try to find existing report even if processor is gone
report_path = ensure_results_folder() / f"batch_{batch_id}" / "report.html"
if report_path.exists():
return send_file(report_path)
else:
return jsonify({'error': 'Batch report not found'}), 404
# Check if report exists
report_path = processor.results_dir / "report.html"
if not report_path.exists():
# Generate report if it doesn't exist
processor.generate_report()
return send_file(report_path)
except Exception as e:
logger.error(f"Error serving batch report: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/batch-report-image/<batch_id>/<image_name>')
def batch_report_image(batch_id, image_name):
"""Serve images from batch report directory"""
try:
image_path = ensure_results_folder() / f"batch_{batch_id}" / image_name
if not image_path.exists():
return jsonify({'error': 'Image not found'}), 404
return send_file(image_path)
except Exception as e:
logger.error(f"Error serving batch image: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/pause-batch/<batch_id>', methods=['POST'])
def pause_batch(batch_id):
"""Pause a batch processing job"""
try:
processor = get_batch_processor(batch_id)
if not processor:
return jsonify({'error': 'Batch not found'}), 404
processor.pause()
return jsonify({'success': True})
except Exception as e:
logger.error(f"Error pausing batch: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/resume-batch/<batch_id>', methods=['POST'])
def resume_batch(batch_id):
"""Resume a batch processing job"""
try:
processor = get_batch_processor(batch_id)
if not processor:
return jsonify({'error': 'Batch not found'}), 404
processor.resume()
return jsonify({'success': True})
except Exception as e:
logger.error(f"Error resuming batch: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/cancel-batch/<batch_id>', methods=['POST'])
def cancel_batch(batch_id):
"""Cancel a batch processing job"""
try:
processor = get_batch_processor(batch_id)
if not processor:
return jsonify({'error': 'Batch not found'}), 404
processor.cancel()
return jsonify({'success': True})
except Exception as e:
logger.error(f"Error cancelling batch: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/download-batch-results/<batch_id>')
def download_batch_results(batch_id):
"""Download batch results as ZIP"""
try:
processor = get_batch_processor(batch_id)
if not processor:
# Try to find existing results
batch_dir = ensure_results_folder() / f"batch_{batch_id}"
if not batch_dir.exists():
return jsonify({'error': 'Batch results not found'}), 404
# Create a temporary processor just for zipping
class TempProcessor:
def __init__(self, batch_id):
self.batch_id = batch_id
self.results_dir = batch_dir
def create_zip_archive(self):
import zipfile
zip_path = self.results_dir / f"batch_results_{self.batch_id}.zip"
with zipfile.ZipFile(zip_path, 'w', zipfile.ZIP_DEFLATED) as zipf:
for file_path in self.results_dir.rglob('*'):
if file_path.is_file() and file_path != zip_path:
arcname = file_path.relative_to(self.results_dir)
zipf.write(file_path, arcname)
return zip_path
processor = TempProcessor(batch_id)
# Create ZIP archive
zip_path = processor.create_zip_archive()
if not zip_path or not zip_path.exists():
return jsonify({'error': 'Failed to create ZIP archive'}), 500
return send_file(
zip_path,
as_attachment=True,
download_name=f"doctags_batch_{batch_id}.zip"
)
except Exception as e:
logger.error(f"Error downloading batch results: {e}")
return jsonify({'error': str(e)}), 500
@app.route('/retry-page', methods=['POST'])
def retry_page():
"""Retry processing a failed page"""
try:
pdf_file = request.form.get('pdf_file')
page_num = int(request.form.get('page_num'))
adjust = request.form.get('adjust') == 'true'
if not pdf_file or not os.path.exists(pdf_file):
return jsonify({'success': False, 'error': 'Invalid PDF file'}), 400
# Run the three processing steps
results = {'success': True, 'errors': []}
# Step 1: Analyzer
command = (f"python backend/page_treatment/analyzer.py --image {pdf_file} "
f"--page {page_num} --start-page {page_num} --end-page {page_num}")
success, stdout, stderr = run_command_with_timeout(command, 60)
if not success:
results['errors'].append(f"Analyzer: {stderr}")
results['success'] = False
# Step 2: Visualizer (only if analyzer succeeded)
if results['success']:
command = (f"python backend/page_treatment/visualizer.py "
f"--doctags results/output.doctags.txt --pdf {pdf_file} --page {page_num}")
if adjust:
command += " --adjust"
success, stdout, stderr = run_command_with_timeout(command, 60)
if not success:
results['errors'].append(f"Visualizer: {stderr}")
results['success'] = False
# Step 3: Extractor (only if previous steps succeeded)
if results['success']:
command = (f"python backend/page_treatment/picture_extractor.py "
f"--doctags results/output.doctags.txt --pdf {pdf_file} --page {page_num}")
if adjust:
command += " --adjust"
success, stdout, stderr = run_command_with_timeout(command, 60)
if not success:
results['errors'].append(f"Extractor: {stderr}")
# Don't fail completely if just extractor fails
if results['success']:
return jsonify({'success': True})
else:
return jsonify({
'success': False,
'error': '; '.join(results['errors'])
})
except Exception as e:
logger.error(f"Error retrying page: {e}")
return jsonify({'success': False, 'error': str(e)}), 500
@app.route('/open-results-folder', methods=['POST'])
def open_results_folder():
"""Open the results folder in the system file explorer"""
try:
import platform
import subprocess
results_dir = ensure_results_folder()
if platform.system() == 'Windows':
os.startfile(str(results_dir))
elif platform.system() == 'Darwin': # macOS
subprocess.Popen(['open', str(results_dir)])
else: # Linux and others
subprocess.Popen(['xdg-open', str(results_dir)])
return jsonify({'success': True})
except Exception as e:
logger.error(f"Error opening results folder: {e}")
return jsonify({
'success': False,
'error': 'Could not open folder automatically. ' +
f'Please navigate to: {ensure_results_folder()}'
})
# API endpoints for file upload
@app.route('/api/upload/doctags', methods=['POST'])
def api_upload_doctags():
"""Simple API endpoint for getting DocTags from uploaded PDF"""
uploaded_file_path = None
try:
if 'file' not in request.files:
return jsonify({'success': False, 'error': 'No file provided'}), 400
file = request.files['file']
success, result = default_handler.save_uploaded_file(file, permanent=True)
if not success:
return jsonify({'success': False, 'error': result.get('error')}), 400
uploaded_file_path = result['filepath']
page_num = request.form.get('page_num', '1')
# Run analyzer
command = (f"python backend/page_treatment/analyzer.py --image {uploaded_file_path} "
f"--page {page_num} --start-page {page_num} --end-page {page_num}")
success, stdout, stderr = run_command_with_timeout(command, 60, "n\n")
if not success:
return jsonify({'success': False, 'error': 'Analysis failed', 'details': stderr}), 500
# Read doctags
doctags_path = ensure_results_folder() / "output.doctags.txt"
if not doctags_path.exists():
return jsonify({'success': False, 'error': 'DocTags not generated'}), 500
with open(doctags_path, 'r', encoding='utf-8') as f:
doctags_content = f.read()
return jsonify({
'success': True,
'filename': result['filename'],
'page': int(page_num),
'doctags': doctags_content
})
except Exception as e:
logger.error(f"Error in api_upload_doctags: {e}")
return jsonify({'success': False, 'error': str(e)}), 500
finally:
# Cleanup uploaded file
if uploaded_file_path and os.path.exists(uploaded_file_path):
try:
os.remove(uploaded_file_path)
logger.info(f"Cleaned up: {uploaded_file_path}")
except Exception as e:
logger.error(f"Cleanup error: {e}")
# Cleanup task
def cleanup_old_files():
"""Periodic cleanup of old files"""
while True:
time.sleep(CLEANUP_INTERVAL)
try:
# Cleanup uploaded files
removed = default_handler.cleanup_old_files(CLEANUP_AGE_HOURS, 'both')
if removed > 0:
logger.info(f"Cleaned up {removed} old files")
# Cleanup old tasks
with task_lock:
cutoff_time = time.time() - (CLEANUP_AGE_HOURS * 3600)
old_tasks = [tid for tid, result in task_results.items()
if result.get('done') and tid.split('_')[1] < str(int(cutoff_time * 1000))]
for tid in old_tasks:
del task_results[tid]
if old_tasks:
logger.info(f"Cleaned up {len(old_tasks)} old tasks")
# Cleanup batch processors if available
if batch_processing_available:
cleanup_old_batches(CLEANUP_AGE_HOURS)
except Exception as e:
logger.error(f"Cleanup error: {e}")
# Start cleanup thread
cleanup_thread = threading.Thread(target=cleanup_old_files)
cleanup_thread.daemon = True
cleanup_thread.start()
if __name__ == '__main__':
logger.info(f"Starting DocTags server on {HOST}:{PORT}")
app.run(debug=True, host=HOST, port=PORT)