I think I've mentioned this in a few posts, but I thought I'd stick it here just in case anyone ever needs a more flexible IR blasting solution to use with NextPVR. It uses a USB IR transciever from IquanaWorks (URL on the wiki pages below). It's worked well for me and allows me to send more than just channel numbers to my cable box and checks to see if the recording is actually working. If it isn't, it trys to turn the cable box on again (mine has a habit of getting in the off state even though I turned off the sleep after idle function). Additionally, it is capable of controlling up to 4 difference cable/satellite boxes (at least in theory). And lastly, as of 2.0.0 there is an option to run this in client/server mode. So if you really need a blaster that can be trigger from a Docker container or Mac OSX, this will work as long as you have another device (either Linux or Windows) to act as the blaster server. In my case I used a Raspberry Pi I had laying around.
Documentation and download information is available at: https://github.com/pkscout/iguana-blaster/wiki
Documentation and download information is available at: https://github.com/pkscout/iguana-blaster/wiki