In this new post to his blog Jim Plush looks at a design pattern that could help you and your application become less reliant on external content sources and increase your user satisfaction for it.

No one has a 100% SLA. This means that more than ever you need to code defensively to prevent external resources from tarnishing the user experience of your site. This is where the Circuit Breaker Stability Pattern comes into play (From the book "Release It").

The concept behind the breaker is easy - too many failures from the resource and the script to grab the content is "broken" and no request is made until the connection check signals the "all clear". He includes a class and a walk through to show how it might work in a connection to a script on a test server. The CircuitBreaker class has enough smarts to be able to tell if the given resource can be fetched from (the circuit is closed) or not.