OpenShift has a OPENSHIFT_NODEJS_PORT process.env variable which works well with HTTP.
However, I could not find any information about HTTPS. Is there another process.env variable for it? Or should I use OPENSHIFT_NODEJS_PORT for HTTPS too?
https is terminated at the node level proxy that is in front of your gear, so the ssl never actually reaches your gear directly. You should just write your application as if it is using http and it will be fine. if you need to determine whether or not it was accessed via https, look for the x-forwarded-for http header.