WebPy middleware authorization

class AuthApp(SimpleHTTPRequestHandler):
    def __init__(self, environ, start_response):
        self.headers = []
        self.environ = environ
        self.start_response = start_response

    def send_response(self, status, msg=""):
        self.status = str(status) + " " + msg

    def send_header(self, name, value):
        self.headers.append((name, value))

    def end_headers(self):
        pass

    def log_message(*a): pass

    def __iter__(self):
        environ = self.environ
        self.send_header('WWW-Authenticate','Basic realm="App authorization"')
        self.send_response(401, "Unauthorized")
        self.start_response(self.status, self.headers)
        yield "Unauthorized"

    AUTH = settings.AUTH

    class AuthMiddleware:
        """WSGI Middleware for authentication."""
        def __init__(self, app):
            self.app = app
        def __call__(self, environ, start_response):
            #allowed = [("test", "test")]
            allowed = AUTH
            auth = environ.get('HTTP_AUTHORIZATION')
            authreq = False
            if auth is None:
                authreq = True
            else:
                auth = re.sub('^Basic ','',auth)
                username,password = base64.decodestring(auth).split(':')
                if (username,password) in allowed:
                    return self.app(environ, start_response)
                else:
                    authreq = True
            if authreq:
                return AuthApp(environ, start_response)

app = web.application(urls, locals())
app.add_processor(load_sqla)

application = app.wsgifunc(AuthMiddleware) # for WSGI

if __name__ == "__main__":
    pass
    app.run(AuthMiddleware) # for direct execution