An example response registry for WebCore 2, eliminating the need for the hard-coded response handlers in web.core.application and the weirdness of the templating middleware.

response-registry.py

import types

class IFile(object):
    pass

class ResponseRegistry(object):
    def __init__(self):
        self.registry = list()
    
    def register(self, *kinds):
        def inner(fn):
            self.registry.append((kinds, fn))
            return fn
        
        return inner
    
    def __call__(self, response):
        for k, v in self.registry:
            if isinstance(response, k):
                result = v(response)
                if result is not None:
                    return result

def main():
    registry = ResponseRegistry()

    # @registry.register(Response)
    # def webob_response(response, environ, start_response):
    #     return response

    @registry.register(tuple)
    def templated_response(args):
        return "template response"

    @registry.register(list, types.GeneratorType)
    def generator_response(generator):
        return "generator response"
        # web.core.response.app_iter = generator
        # return web.core.response(environ, start_response)

    @registry.register(unicode)
    def unicode_response(body):
        return "unicode response"
        # web.core.response.unicode_body = body
        # return web.core.response(environ, start_response)

    @registry.register(str)
    def string_response(body):
        return "string response"
        # web.core.response.body = body
        # return web.core.response(environ, start_response)

    @registry.register(type(None))
    def none_response(body):
        return "empty response"
        # return web.core.response(environ, start_response)
    
    @registry.register(file, IFile)
    def file_response(fh):
        return "file or filelike response"
    
    print registry(None)
    print registry("foo")
    print registry(open('/dev/null'))
    print registry(u"bar")


if __name__ == '__main__':
    main()