class IsAuthenticated(object):
    @staticmethod
    def has_permission(permission):
        def real_decorator(function):
            def function_wrapper(self, request, *args, **kwargs):
                try:
                    x_key = request.META['HTTP_X_KEY']
                    x_route = request.META['HTTP_X_ROUTE']
                    x_signature = request.META['HTTP_X_SIGNATURE']

                    x_route = x_route.split(';')
                    x_route.sort()
                    x_route = ';'.join(x_route)
                    x_route = str.encode(x_route)

                    signature = hmac.new(x_route, str.encode(x_key))
                    if x_signature == signature.hexdigest():
                        return function(self, request, *args, **kwargs)
                    raise PermissionDenied()
                except Exception as e:
                    print(str(e))
                    raise PermissionDenied()
                raise PermissionDenied()
            return function_wrapper
        return real_decorator