Detecting if a flowfile is a packed file

[James McMahon <js...@gmail.com>]

Hello. Does anyone have an approach they would recommend for reliably
detecting if a flowfile is a packed file that needs to be routed through
UnpackContent?

I have a RouteOnAttribute within which I check for filenames that end in
tar or zip, but that seems unsophisticated and overly reliant on the file
name. I OR that with a check of mime.type too, but that result is sometimes
determined by file name too.

Any other "best practices" to do this?