Is the goal to display a “an administrator has entered” or a “Administrator Overseer has entered” message? I haven’t tried these suggestions myself but having just written a ARI app that handed over to a conference bridge here are some ideas:
If your goal is the former it might be possible to poll for the data. Per It is possible to get active calls by ARI? - #8 by jcolp you can use the API variable getters to read function values. I haven’t tested this personally but you might be able to get the output of CONFBRIDGE_INFO()(1) using GET /asterisk/variable(2) to get the count of administrators in the conference. You’d have to poll it at whatever frequency is appropriate for your app. This may or may not be an acceptable solution depending on the detail needed, frequency of updates, and acceptable server load for your situation.
Another option would be to send all the inbound admins through a Stasis() app in the dialplan before joining the conference. That would give your ARI consumer the full details of the channel, which you could then immediately hand back to the dialplan with the channel/{channelId}/continue(3) endpoint. If you need to maintain the admin’s channel event stream after continuing the call back to the dialplan manually subscribing your app to the channel with the /applications/{applicationName}/subscription(4) endpoint might help.
(1) CONFBRIDGE_INFO - Asterisk Documentation
(2) Asterisk - Asterisk Documentation
(3) Channels - Asterisk Documentation
(4) Applications - Asterisk Documentation