WebSub Subscription

WebSub Subscription Nodes are special Nodes in your Tenant. They implement the Hub's side of an active subscription to a single topic.

The differ from other Nodes in the following ways:

• You cannot directly create WebSub Subscription Nodes. They are created by the WebSub Hub Node when a new subscription is activated.
• You cannot see WebSub Subscription Nodes in your Tenant's network. They are only accessible through inspecting the owning WebSub Hub Node. This is because there could be thousands of these Nodes in your Tenant, and showing them in your Tenant's directed graph woudl be overwhelming.
• You cannot update WebSub Subscription Nodes, although you can start/stop them and delete them (which cancels the subscription by issuing a denial).

Each WebSub Subscription Node tracks the subscription's:

• callback URL: This is the URL that content will be posted to using webhooks. It should be unique as per the WebSub specification, but this is not enforced.
• topic URL: This is the topic that was subscribed to.
• subscriber: The identity of the subscriber, as determined by the BaseUser instance's identity property that you return from your Api Authenticator Function.

The topic URL combined with the callback URL will always identify a unique subscription.