I'm trying to write a resource class like the twisted.web.script.PythonScript class. As an example, I've got this in a file named TestResource.py: from twisted.web.resource import Resource class TestScript(resource.Resource): isLeaf = 1 def __init__(self, filename, registry): self.filename = filename self.registry = registry def render(self, request): request.setHeader("x-powered-by","Twisted/%s" % copyright.version) request.write("We've arrived in TestScript.render") request.finish() return server.NOT_DONE_YET However, when I go to create a .tap file using the command: mktap web --path=webroot --processor=".cht=TestResource.TestScript" --port=8880 I get the error: NameError: name 'resource' is not defined Now I've seen that almost all (if not all) the examples of deriving from Resource have a line like "resource = MyResource()", the PythonScript class is conspicuous in that it doesn't have such a line, and in fact is in the middle of a file with other Resource classes where trying to assign some class instance to a variable named "resource" would be ambiguous. And in fact I've grepped the source of the twisted.web directory structure and can't find anyplace a PythonScript is explicitly instantiated. But I know it works, as I've created a .epy file which does what I'd expect in a basic web.tap application. So my question is, how can I create a class like the PythonScript class, which doesn't explicitly declare a "resource" variable, can get associated with a file extension via the "mktap --processor" command, and then behaves intuitively at runtime? Many thanks, Donnie P.S. Somewhere in the docs there should be a comment that if you use the --processor flag for mktap on windows, you need to surround the "ext=processor" part of the parameters with double-quotes (see above). If you don't do that, mktap will complain about the options not having the right number of values to unpack. That took a while to figure out.