Sending an HTTP response to a Webhook

I want to use Hazel/Keyboard Maestro (os something else) to send an HTTP push to a webhook destination (Integromate, which side note, if you haven’t checked out yet and you use Zapier, you’re missing out!!) with the contents of the file that is triggering the Hazel rule. Is this possible??

Separate into two bits:

  1. What is the trigger for Hazel action? A file being created?
  2. The action itself. I’m pretty sure you can run a script with the filename as input.

(I’ve not done much with Hazel recently but thought breaking the problem down would be helpful.)