@gen.coroutine
    def has_doc(self, doc_id):
        url = '{0}/{1}'.format(self.db_name, url_escape(doc_id))
        r = yield self._http_head(url)
        raise gen.Return(r['code'] == 200)
Check if document with the given `doc_id` exists.
dataset/ETHPy150Open nephics/tornado-couchdb/couch/couch.py/AsyncCouch.has_doc