The document discusses PubSubHubbub (PuSH), a publish-subscribe protocol that allows web resources to push updates to subscribers. It describes how PuSH solves problems with traditional polling approaches by using hubs to distribute notifications from publishers to subscribers. Key points covered include how publishers notify hubs of updates, how hubs verify subscriber requests and forward updates, and examples of PuSH support in WordPress, Feedburner, Blogger, Drupal and other systems.
3. Are we there yet?
http://www.flickr.com/photos/geraldbrazell/4562022876/
Tuesday, August 24, 2010
4. Are we there yet?
Are we there yet?
Are we there yet?
Are we there yet?
Are we there yet?
rss.xml
Publisher Subscriber
Yes. Here you are.
Are we there yet?
Tuesday, August 24, 2010
5. Ask developmentseed.org every
30 minutes
for a new blog post, you’ll download
11 MB
for about
9K
blog posts a week.
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6. Do that for
100 similar blogs
and you’ll download
1G of data a week
just for polling.
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7. What’s worse:
Polling many feeds will back up.
http://www.flickr.com/photos/geraldbrazell/4562022876/
Tuesday, August 24, 2010
8. Publish and Subscribe
http://www.flickr.com/photos/geraldbrazell/4562022876/
Tuesday, August 24, 2010
9. Notification
Publisher Subscriber
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10. PubSubHubbub
is a
Publish and Subscribe standard
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20. 1. Subscriber POSTs subscription request to the Hub. The
request contains the endpoint URL where the Hub should
POST new updates.
I want to subscribe to
feed X, send updates
to this URL:
Publisher Hub Subscriber
From http://code.google.com/p/pubsubhubbub/
Tuesday, August 24, 2010
21. 2. Hub POSTs to the endpoint URL to verify the request was
authentic; Subscriber responds with confirmation to the Hub.
Hey there! Did
you really send this
request?
Publisher Hub Subscriber
Yup, that was really
me, not a DoS
attacker.
From http://code.google.com/p/pubsubhubbub/
Tuesday, August 24, 2010
22. 3. Publisher notifies Hub about updates by POSTing feed URLs
to the Hub; Hub pulls the feed again to find new entries.
I have new content
for feed X for you!
Publisher Hub Subscriber
Give me your latest
Here you go. content for feed X,
please.
From http://code.google.com/p/pubsubhubbub/
Tuesday, August 24, 2010
23. 4. When Hub receives new update to feed X, it POSTs the
update to the Subscriber’s endpoint URL.
New update to
feed X - here you go:
Publisher Hub Subscriber
From http://code.google.com/p/pubsubhubbub/
Tuesday, August 24, 2010
24. 5. If feed X has multiple subscribers, the Hub sends updates to
all of them. This reduces load on the Publisher.
New update to
feed X - here you go:
Subscriber
Publisher Hub Subscriber
Subscriber
Subscriber
Subscriber
Tuesday, August 24, 2010
Subscriber
From http://code.google.com/p/pubsubhubbub/