share link in express js

1app.get('/download', function(req, res, next) {
2  // Get the download sid
3  var downloadSid = req.query.sid;
4
5  // Get the download file path
6  getDownloadFilePath(downloadSid, function(err, path) {
7    if (err) return res.end('Error');
8
9    // Read and send the file here...
10
11    // Finally, delete the download session to invalidate the link
12    deleteDownload(downloadSid, function(err) {
13      // ...
14    });
15  });
16});