Decentralization & real-time with PubSubHubbub

Transcript

1. Decentralization &
   real-time with
   PubSubHubbub
   Bruno Renié soft-shake 2013
   

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2. exoscale
   

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3. FeedHQ.org
   github.com/feedhq
   

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4. 2009
   RSS Readers
   

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5. Any update?
   Any update?
   Any update?
   Nope.
   Nope.
   Yup.
   Blog
   RSS Reader
   

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6. Polling sucks
   — everyone
   

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7. Publisher
   Hub
   Subscriber
   

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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
   

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9. Publisher
   Declares his hub
   Pings the hub about new content
   
   POST http://example/hub
   hub.url=
   hub.mode=publish
   

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10. Subscriber
    Notices the publisher has a hub
    Subscribes to the hub
    POST http://example/hub
    hub.topic=
    hub.mode=subscribe
    hub.callback=
    

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11. Hub
    Receives pings
    Fetches publisher feeds
    Receives subscriptions
    Noti�es all subscribers
    

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12. Subscription
    Subscriber sees link with rel="hub"
    
    Subscriber makes POST request to hub
    POST http://example/hub
    hub.topic=
    hub.mode=subscribe
    hub.callback=http://subscriber/callback
    

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13. Subscription
    Hub makes GET request to subscriber callback
    GET http://subscriber/callback
    hub.topic=
    hub.mode=subscribe
    hub.challenge=hello
    hub.lease_seconds=86400
    

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14. Publication
    Publisher pings the hub
    POST http://example/hub
    hub.url=
    hub.mode=publish
    

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15. Publication
    Hub fetches the topic & posts the content to callback
    POST http://subscriber/callback
    Link: ; rel="hub",
    ; rel="self"
    Content-Type: application/xml
    
    

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16. Demo
    http://www.flickr.com/photos/usnavy/6628020661/
    

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17. PubSubHubbub
    HTTP-based pub/sub protocol
    Open-Source GAE implementation
    Decentralized
    

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18. Decentralized?
    Anyone can host a hub
    In practice: Google hub & superfeedr
    http://pubsubhubbub.appspot.com/
    http://superfeedr.com/
    

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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…
    

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20. Real-life publishers
    wordpress / wordpress.com
    tumblr
    �attr
    blogger
    youtube
    GitHub
    

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21. feedhq.org
    ~25% of feeds have a hub
    

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22. Beyond RSS
    Initial spec (0.3) targeted Atom/RSS
    Current (0.4) allows arbitrary content
    
    Link: ; rel="hub"
    

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23. Publisher
    Hub
    Subscriber
    Subscriber
    Subscriber
    Subscriber
    Subscriber
    Subscriber
    

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24. Hub
    Publisher
    Subscriber
    Publisher
    Subscriber
    Publisher
    Subscriber
    

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26. Thanks !
    @brutasse
    bruno@renie.fr
    

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