Serve.py

# Serve React App
# This route serves 'index.html' for the root path and any other path not caught by an API route.
# It also serves static files like JS, CSS, images from the React build directory.

from flask import Flask, send_from_directory
import os
app = Flask(__name__)

REACT_BUILD_DIR = "ui/dist"

@app.route('/', defaults={'path': ''})
@app.route('/<path:path>')
def serve_react_app(path):
    if path != "" and os.path.exists(os.path.join(REACT_BUILD_DIR, path)):
        # If the path points to an existing file in the React build directory (e.g., static assets)
        print(f"{REACT_BUILD_DIR}/{path}")
        return send_from_directory(REACT_BUILD_DIR, path)
    elif os.path.exists(os.path.join(REACT_BUILD_DIR, 'index.html')):
        # Otherwise, serve the 'index.html'. This is crucial for client-side routing in React.
        return send_from_directory(REACT_BUILD_DIR, 'index.html')
    else:
        # If 'index.html' is not found, return an error.
        return "React build not found. Have you run `npm run build` in your React app directory (e.g., 'frontend')?", 404

# It's good practice to put app.run() inside a conditional
# to ensure it only runs when the script is executed directly.
if __name__ == '__main__':
    app.run(debug=True) # Added debug=True for development convenience