How to specify FieldSets in requests to Odnoklassniki API?

Question

Classmates

Hello, I have difficulty using api. I use the form on the site apiok.ru to send a request to api. The first request to the group.getInfo method, I fill in everything as it should be: session, keys. I want to get group info with a certain id. Field fields I fill in this way: uid, members_count, name. (data taken from FieldSets tooltip). All remarkably fulfills, the data is returned.
Now I'm trying to access mediatopic.getByIds. I fill in the secret fields, enter topic_ids, write author_ref in the fields field (taken from the same tip on FieldSets). It returns error_code=100, invalid parameter fields value: [author_ref]
What could be wrong?

Answer 1

If the request does not return the same entity, but different entities may be returned (for example, a media topic may include the properties of the user who sent it, the application that posted it, and so on) - you must specify prefixes before the property, for example, not id, but app.id , not * but app.*.