code: function(req, res) {
          var activeSessions = [],
              sessionId;
  
          // Create array of format '[{ "id" : SESSION_ID, "capabilities" : SESSION_CAPABILITIES_OBJECT }]'
          for (sessionId in _sessions) {
              activeSessions.push({
                  "id" : sessionId,
                  "capabilities" : _sessions[sessionId].getCapabilities()
              });
          }
  
          res.success(null, activeSessions);
      }
docs: private: