use of the url resource location as cached id

        e.g.: ``<domain>/foo/bar/a.html => <base>/domain/foo/bar/a.html``

        - map the url to local file

        :param url:
        :type url:
        :return:
        :rtype:

def map_url_to_cache_id(self, url):
        """use of the url resource location as cached id

        e.g.: ``<domain>/foo/bar/a.html => <base>/domain/foo/bar/a.html``

        - map the url to local file

        :param url:
        :type url:
        :return:
        :rtype:
        """
        base, _ = self.get_domain_home_from_url(url)

        if base == '':
            # invalid url
            _sub_page = ''
        elif base == url or base + '/' == url:
            # homepage
            _sub_page = 'homepage'
        else:
            # sub page
            _sub_page = url.replace(base, '').split('/')
            _sub_page = '/'.join([x for x in _sub_page if x])

        if _sub_page:
            full_name = os.path.join(self.cache['site_raw'], _sub_page)
            return full_name
        else:
            return _sub_page