traversal.py

from wsgiref.simple_server import make_server

from webob.dec import wsgify

class Traverser(object):
    def __init__(self, root):
        self.root = root

    @wsgify
    def __call__(self, request):
        node = self.root
        while request.path_info_peek():
            name = request.path_info_pop()
            child = getattr(node, name, None)
            if child is None:
                break
            node = child
        return request.send(node)

@wsgify
def node2(request):
    return "OK. I'm node2"

@wsgify
def node3(request):
    return "OK. I'm node3"

class Root(object):
    a = staticmethod(node2)

    def __init__(self):
        self.b = node3

    @wsgify
    def __call__(self, request):
        return "OK. I'm node1"

node1 = Root()

node3.a = node1
node3.b = node2


if __name__ == '__main__':
    httpd = make_server('', 8080, Traverser(node1))
    httpd.serve_forever()

traversal_test.py

from unittest import TestCase, SkipTest, main

from webtest import TestApp


class TestTraversal(TestCase):
    def _get_application(self):
        from traversal import Traverser, node1
        return TestApp(Traverser(node1))

    def test_root(self):
        app = self._get_application()
        res = app.get('/')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node1")

    def test_child(self):
        app = self._get_application()
        res = app.get('/a')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node2")

    def test_child_with_trailing_slash(self):
        app = self._get_application()
        res = app.get('/a/')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node2")

    def test_unknown_child(self):
        app = self._get_application()
        res = app.get('/c')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node1")

    def test_unknown_child_with_trailing_slash(self):
        app = self._get_application()
        res = app.get('/c/')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node1")

    def test_grandchild(self):
        app = self._get_application()
        res = app.get('/b/a')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node1")

    def test_grandchild_with_trailing_slash(self):
        app = self._get_application()
        res = app.get('/b/a/')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node1")

    def test_intermediate_node(self):
        app = self._get_application()
        res = app.get('/b')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node3")

    def test_intermediate_node_with_trailing_slash(self):
        app = self._get_application()
        res = app.get('/b/')
        self.assertEqual(res.status_code, 200)
        self.assertEqual(res.body, "OK. I'm node3")


if __name__ == '__main__':
    main()