Currently, Discourse RSS feed items have GUIDs like “topic-$topicnumber”.
I have several Discourse subscriptions in my RSS reader and there are number of misbehaviors because of this:
- When you mark a topic from one instance as read, a topic with same guid from other instances also marked as read.
- When you read one instance feed, you can see topics from other instances.
So, obvious solution could be to concatenate current guid with instance’s domain or some persistent UUID.
GUID is stands for “Globally Unique IDentifier” so obviously it must be uniq across all instances.