Google.org created Alert Hub to aggregate all data feeds with emergency information in one location. By pushing alerts and other kinds of emergency information here, publishers can make it easy for developers around the world to ingest and distribute relevant data to users.
Alert Hub implements PubSubHubbub, a simple, open, server-to-server publish and subscribe protocol. Publishers send their alert feeds to Alert Hub, and it will push the updates in that feed to subscribers.
This hub is supported and run by Google.org's Crisis Response team as a free service.
You start with an Atom or RSS feed of alerts. Don't have Atom or RSS? We're open to other formats. Ask us.
Every time you issue a new alert, tell the hub. Code is available in PHP, Java, C#, Python, Perl, Ruby, and more. Don't want to write code? Ask us. We can periodically poll your feed for new alerts.
You'll also want to include a link in your feed to tell your users that they can subscribe to Alert Hub and get updates pushed to them instead of polling your feed. This reduces traffic to your servers and pushes alerts to your subscribers faster.
Atom:
<?xml version="1.0"?> <feed xmlns:atom="http://www.w3.org/2005/Atom"> <link rel="hub" href="//alert-hub.appspot.com"/> ... </feed>
RSS:
<?xml version="1.0"?> <rss xmlns:atom="http://www.w3.org/2005/Atom"> <channel> <atom:link rel="hub" href="//alert-hub.appspot.com"/> ... </channel> </rss>
You can view stats on your feed using the publish page.
How to subscribe
You subscribe to Alert Hub by providing 2 URLs:
http://alertpublisher.info
had a feed of alerts at http://alertpublisher.info/atom
. A subscriber at http://example.com
wants to subcribe to this feed. He writes some code that uses the PubSubHubbub protocol and exposes it at http://example.com/pshb
. Then he subscribes by passing
http://alertpublisher.com/atom
http://example.com/pshb
http://alertpublisher.info/alertfeed
to that same callback URL.
If you don't want to start from scratch, a number of frameworks and content management systems already support the PubSubHubbub protocol. See the full list. Client code is also available in PHP, Java, C#, Python, Ruby, and more. See the specification for full details.
You can use the subscribe page to view stats and debug your subscription.
FAQ