new_contents: from mojo.events import addObserver
  from mojo.roboFont import CurrentFont
  from mojo.tools import registerFileExtension
  
  from glyphConstructionController import GlyphBuilderController
  
  
  fileExtension = "glyphConstruction"
  registerFileExtension(fileExtension)
  
  
  class GlyphConstructionFileOpener(object):
  
      def __init__(self):
          addObserver(self, "applicationOpenFile", "applicationOpenFile")
  
      def applicationOpenFile(self, notification):
          path = notification["path"]
          ext = notification["ext"]
          fileHandler = notification["fileHandler"]
          if ext == ".%s" % fileExtension:
              controller = GlyphBuilderController(CurrentFont())
              controller.setFile(path)
              fileHandler["opened"] = True
  
  
  GlyphConstructionFileOpener()
  
subject: add file handler