So im dont have to use any device handler, I just interact with the blue iris serve via HTML tags. I use the smartapp here https://github.com/aderusha/SmartThings/blob/master/Send-Trigger-to-Blue-Iris.groovy
And that sends a trigger to blue iris based on smart things events.
For the opposite direction I use HTTP Motion Endpoint from KristopherKubicki which will allow me to trigger smartthings from blue iris. The writeup for that is in this thread: https://community.smartthings.com/t/blue-iris-motion-detection-to-activate-smart-app/25169