Thursday, June 06, 2013


publishers Push updates to a Hub and updates are Pulled by Subscribers from the hub.

PuSH (PubSubHubbub) is a good way to solve the publishers and hubs problems (offloading work and polling lots of sites respectively). The idea with PushHubPullSub is to simplify subscribers by having them poll the hub.

See Does polling scale better than push?

Update: Moved the Does polling scale better than push section to a blog post of it's own.

This was inspired by my notes on Push vs Pull on the IndieWebCamp wiki.

1 comment:

Vishnu S Iyengar said...

I guess the obvious thing that occurs to me is if that you want to push updates and your updates are too frequent, you could just throttle them out and send them once a minute. So your push can be curtailed :).

other related concerns I can think of though
1) pushing requires you to also build a pull for "lost updates". However this pull could afford to be highly throttled and much less efficient.
2) pushing will require all subscribers to be reachable.
3) pushing requires each publisher to maintain data about each subscriber, even those who have stopped caring.
4) to satisfy pull, you have to maintain enough state to satisfy each pull request. ... this could be divided into an efficient pull that has a low throttle rate and serves data upto a minute (or 5 minutes) old and an inefficient pull that has a lot more throttling but can satisfy really old requests.