ReadDataService methods

All Read messages are processed synchronously in the ReadDataService service.

While almost all Create, Update and Delete messages are processed asynchronously through AddMessage method of the DataService service, this is not convenient for Read messages, which are used to read data from itslearning in real-time.

The available methods are:

Internal note:

There is a flag `isReadMessage` in `messageType` table in `ContentImport` database, which indicated that messages of selected type are processed as "Read" messages.It's not possible to change this setting from UI. The only way to change it is to update database manually.