: Use a server-side programming language (like Python, Node.js) to create an endpoint that accepts the URL, downloads the file (possibly in chunks to handle large files), and then returns the file to the user.

If your interest is less about software algorithms and more about the physical hardware file management (how the downloadfile.php actually retrieves bits from a NAND chip), a better paper would be:

app.get('/download', async (req, res) => const url = req.query.url; // URL to download from try const response = await axios( method: 'get', url: url, responseType: 'stream' );