As discussed on the RevitPythonShell forum, previous examples of using
ExternalEvent don’t work anymore with Revit 2017.
Turns out, the fix was really easy: You just need to implement the
IExternalEventHandler.GetName method. I have placed a comment explaining this very briefly on the page that introduces embedding a webserver in Autodesk Revit with the RevitPythonShell. The source for the updated
RpsHttpServer is, of course, on GitHub: rpshttpserver.py
Thanks to Callum for finding the bug and @PMoureu for providing the solution :)