def catalogMapping(domain, retJson=True):
    """ Return message catalog as a mapping.

        @param domain
        domain of the message catalog

        @param retJson
        format return value to json format or not( default True )

        @return
        a dict with the following format:
        {
            'success': True,
            'msg': 'Get message catalog mapping success.',
            'mapping': {
                u'text1': u'translated text1',
                u'text2': u'translated text2',
                ...
            }
        }

        """
