Probably the best you can do is have a CRON job that runs every few minutes that checks for the existence of a new file. If you do this, I'd suggest that you have the job

1. Spot the existence of the new file.
2. Wait for a bit, then see if the file's size has changed.
3. Only parse and format the data when the file size has stabilized.

Otherwise, you're in danger of parsing the file before it's fully uploaded.

stephen