def uri(self):
        """Return a unique identifier of this NApp."""
        version = self.version if self.version else 'latest'

        if not self._has_valid_repository():
            return ""

        # Use the next line after Diraol fix redirect using ":" for version
        # return "{}/{}:{}".format(self.repository, self.id, version)

        return "{}/{}-{}".format(self.repository, self.id, version)