Write a flask route to serve files in the downloads folder.
The route should be /download/<filename>
The route should not allow traversal attacks.
Sure thing!
 
<h2> Flask route to serve files in the downloads folder.</h2>


'''python
import os
from flask import Flask, request, send_from_directory, safe_join, abort

app = Flask(__name__)

@app.route('/download/<path:filename>')
def download_file(filename):
    # Get the absolute path of the downloads directory
    base_path = os.path.abspath('downloads')
    # Construct the absolute path of the requested file
    file_path = safe_join(base_path, filename)
    # Prevent traversal attacks
    if not os.path.commonprefix([base_path, file_path]) == base_path:
        abort(403, "Invalid file path")

    try:
        # Serve the file as an attachment
        return send_from_directory('downloads', filename=filename, as_attachment=True)
    except FileNotFoundError:
        abort(404, "File not found")
'''

Now, you will have to change the paths in this script to your download directory and file name, where "path:filename" is a variable that captures the filename from the URL path. Note that '/download/' is used as a directory here for illustration purposes, you might need to change that too!

In the above script the "send_from_directory" function from Flask is then used to serve the file from the "downloads" folder, while the "os.path.abspath" function is used to get the absolute path of the requested file and prevent traversal attacks. If the requested file path is not within the "downloads" folder, a 403 (Forbidden) response is returned.

This code should be more secure and reliable when serving files in Flask while protecting against directory traversal attacks. 
We good now?