What's the most efficient method of continually deleting files older than X hours on Windows?

Question

I have a directory that continually fills up with "artefact" files. Many different programs dump their temporary files in this directory and it's unlikely that these programs will become self-cleaning any time soon.

Meanwhile, I would like to write a program that continually deletes files in this directory as they become stale, which I'll define as "older than 30 minutes".

A typical approach would be to have a timed mechanism that lists the files in the directory, filters on the old stuff, and deletes the old stuff. However, this approach is not very performant in my case because this directory could conceivably contain 10s or hundreds of thousands of files that do not yet qualify as stale. Consequently, this approach would continually be looping over the same thousands of files to find the old ones.

What I'd really like to do is implement some kind of directory listener that was notified of any new files added to the directory. This listener would then add those files to a queue to be deleted down the road. However, there doesn't appear to be a way to implement such a solution in the languages I program in (JVM languages like Java and Scala).

So: I'm looking for the most efficient way to keep a directory "as clean as it can be" on Windows, preferably with a JVM language. Also, though I've never programmed with Powershell, I'd consider it if it offered this kind of functionality. Finally, if there are 3rd party tools out there to do such things, I'd like to hear about them.

Thanks.

Answer 1

Why can't you issue a directory system command sorted by oldest first: c:>dir /OD

Take the results and delete all files older than your threshold or sleep if no files are old enough.

Combine that with a Timer or Executor set to a granularity 1 second - 1 minute which guarantees that the files don't keep piling up faster than you can delete them.

Answer 2

If you don't want to write C++, you can use Python. Install pywin32 and you can then use the win32 API as such:

import win32api, win32con
change_handle = win32api.FindFirstChangeNotification(
    path_to_watch,
    0,
    win32con.FILE_NOTIFY_CHANGE_FILE_NAME
)

Full explanation of what to do with that handle by Tim Golden here: http://timgolden.me.uk/python/win32_how_do_i/watch_directory_for_changes.html.