So I made some progress. I can now move the viewport camera around. The axis are all messed up, so I'll need to do some math, but both translation and rotation are getting correct values from the device.
My issue now is that after moving with the spacenav, if you use the mouse/keyboard to move it snaps back to the previous position (before you moved with the spacenav). I guess the editor has it's own copy of the transform it uses, so I may have to hook into that rather than modifying the camera directly. Hopefully that is possible with a plugin and won't need source access.
I also had to rewrite the function to find the camera. That code works for a game, but not in the editor. In the editor you have to find the Viewports and then get the Camera from that. Here is the new function.
func find_camera(node, list) :
if node is Viewport:
var camera = node.get_camera()
for child in node.get_children():
And you can call it like this:
var editor = get_editor_interface()
var viewport = editor.get_editor_viewport()
var results = find_camera(viewport, )
var camera = results
The number 1 is needed because I have 1 user camera in my scene (results, the first editor camera is results). If I had more, that would be a different number. It would also be a higher number if you used the split view for multiple view angles in the editor. I'll have to figure out a way to determine where you are looking rather than hard-coding the index.