I'm using notification feeds where users get a notification when other users add replies into a forum thread they are part of.
I'd like to know how I can remove activities from all feeds when the reply is deleted?
I can't seem to find any information about that. The examples show how I can remove an activity from one users feed. But I don't necessarily know all the users that might have the activity on their notifications feed.
Or is there a way to get a list of notification feeds that contain activities with a foreign id?
When you delete an activity from a feed, a delete is propagated to every feed that received that activity via follow relationship or to field. In your example, if you delete the activity from the "origin" feed you should be OK. If that's not the case you should probably expand your question with more detail.
Since you mentioned it: deletes by foreign_id allow you to delete all activities from one feed that share the same foreign_id value. For example: say that you have many activities in a feed with foreign_id "post:42" and you want to delete them all in once, you can perform a delete on foreign_id="post:42".
来源：https://stackoverflow.com/questions/34180033/how-to-remove-activity-from-multiple-feeds