Decentralization & real-time with PubSubHubbub

Transcript

1. Decentralization & real-time with PubSubHubbub Bruno Renié soft-shake 2013
2. exoscale
3. FeedHQ.org github.com/feedhq
4. 2009 RSS Readers
5. Any update? Any update? Any update? Nope. Nope. Yup. Blog RSS Reader
6. Polling sucks — everyone
7. Publisher Hub Subscriber
8. De�nitions Topic The unit to which one can subscribe to changes Hub Intermediary Subscriber Entity willing to be noti�ed of changes on a topic Subscription Subscriber - Topic relation Callback URL URL at which a subscriber wishes to receive noti�cations. Noti�cation Payload describing how a topic's contents have changed
9. Publisher Declares his hub Pings the hub about new content <link href="http://example/hub" rel="hub"/> POST http://example/hub hub.url=<feed url> hub.mode=publish
10. Subscriber Notices the publisher has a hub Subscribes to the hub POST http://example/hub hub.topic=<feed url> hub.mode=subscribe hub.callback=<callback url>
11. Hub Receives pings Fetches publisher feeds Receives subscriptions Noti�es all subscribers
12. Subscription Subscriber sees link with rel="hub" <link href="http://example/hub" rel="hub"/> Subscriber makes POST request to hub POST http://example/hub hub.topic=<feed url> hub.mode=subscribe hub.callback=http://subscriber/callback
13. Subscription Hub makes GET request to subscriber callback GET http://subscriber/callback hub.topic=<feed url> hub.mode=subscribe hub.challenge=hello hub.lease_seconds=86400
14. Publication Publisher pings the hub POST http://example/hub hub.url=<feed url> hub.mode=publish
15. Publication Hub fetches the topic & posts the content to callback POST http://subscriber/callback Link: <http://example/hub>; rel="hub", <feed url>; rel="self" Content-Type: application/xml <payload>
16. Demo http://www.flickr.com/photos/usnavy/6628020661/
17. PubSubHubbub HTTP-based pub/sub protocol Open-Source GAE implementation Decentralized
18. Decentralized? Anyone can host a hub In practice: Google hub & superfeedr http://pubsubhubbub.appspot.com/ http://superfeedr.com/
19. Security Making sure noti�cations come from the real hub Hub/Subscriber shared secret Hub signs its requests with HMAC SHA1 digest X-Hub-Signature: sha1=d07d89c67…
20. Real-life publishers wordpress / wordpress.com tumblr �attr blogger youtube GitHub
21. feedhq.org ~25% of feeds have a hub
22. Beyond RSS Initial spec (0.3) targeted Atom/RSS Current (0.4) allows arbitrary content <link href="http://example/hub" rel="hub"/> Link: <http://example/hub>; rel="hub"
23. Publisher Hub Subscriber Subscriber Subscriber Subscriber Subscriber Subscriber
24. Hub Publisher Subscriber Publisher Subscriber Publisher Subscriber
26. Thanks ! @brutasse bruno@renie.fr