His list of four is:

• Doc Comments
• Flexible Parameters
• Use method Entry contracts
• Be Stateful and Refactor

The "Doc Comments" is pretty obvious, but some of the others need a bit more explaining. Being flexible with your parameters is more about requiring the least from a developer, "entry contracts" being the restrictions to let the developer know what you're expecting and refactoring commonly used functionality into a easy, single point of contact.

You can't pass variables well without adding more commands to mod_rewrite. So here you'll learn to add unlimited parameters to your links with only one simple PHP function.

He starts with a mini-refresher course on the contents of the previous article and moves to the simple rewrite example that makes it possible - a two line statement. Then, it's on to the PHP - again, a simple function that does things simply, grabs all of the parameters from the URL and splits them out into a global parameters array. He even includes a simple example as a tutorial you can try out with the demo.

Bernard Peh, the author, sets up what the Google API is and includes the way to grab your own API key (your pass into the powerful Google backend). The other two requirements for the project are the PEAR SOAP package and an install of at least PHP 4 or higher.

There's a list of input parameters for the functionality, with each described for what it does, and pley of code to help you integrate them into the API call. They give the example of the class grabbing the needed info (via SOAP), parsing out your URL from those results, and a simple form to make checking different URLs all the simpler.