A platform I'm working on will need to periodically update engagement data (reaction count, comment count, share count) for a number of public page posts across facebook matching specific criteria. Access to those posts would be gained either via Page Public Content Access or, I reckon, can be also had via webhooks (I gather the Page Public Content Access permission -or, "feature" is still required, though).
Now, with Graph API requests, a public post would be queried in increasing time intervals during a period of time (say, a week) after which you can assume the post will be buried deep down enough that new interactions are numerically irrelevant - so there would be a certain number of Graph API request to that post's specific endpoint.
The possibility to have updates with webhooks (to which I'm new) for this looks interesting, but I have a few questions that seem not to be addressed in detail in the Facebook webhooks docs:
are Public Page Posts actually "visible" from webhooks? (ie: one can create a webhook subscription to a specific post in the graph?)
if the above use case is actually feasible, would facebook post to my endpoint for each and every single modification (e.g. "post like" or "new comment") to a post object or would/could these updates be somewhat aggregated (maybe: every X updates or every 10 minutes, whichever is the shortest)?
would webhooks notifications for a specific post last forever OR is there some kind of expiration (perhaps, that might be configured on subscription) built in?
