code: function retrieveByURI(uri, callback) {
    var query = {
      query: {
        term: {
          uri : uri
        }
      }
    };
    getEs().search({ _index : GLOBAL.config.ESEARCH._index, _type : 'contentItem'}, query, function(err, res) {
      if (!err && res && res.hits.total) {
        if (res.hits.total > 1) {
          // That would be weird.
          throw new Error('more than one result for', uri);
        }
        res = res.hits.hits[0];
      }
      callback(err, res);
    });
  }
docs: Retrieves a complete contentItem by URI.