I am trying to use Subscription API to get the call duration of the current ongoing call. But I didn't found much about this API in API Explorer. Can anyone please explain me this API in details and how to get call details using ongoing calls "sessionId"?
At the same time it is impossible to get call direction directly from push notification. We are adding this option in one of the future releases.
However, this subscription has an expiration time but using the official RingCentral SDK’s enables developers to automatically renew the subscription(s) on a timely basis.
When using this approach for your application(s) to receive events on your RingCentral account, no polling is involved.
Subscription API: https://developer.ringcentral.com/api-docs/latest/index.html#!#Notifications.html
View the (official and community developed) RingCentral SDKs: https://developers.ringcentral.com/library/sdks.html
We also have a Tutorial in node.js which you could take a look at under the 'Tutorials' section on our developer portal: