The SitePoint PHP blog has a new post that wants to help you API-ify your legacy application with ToroPHP, a router that's "designed for minimalists" to make routing and handling RESTful requests easier.
For the Google Summer of Code 2014, I was selected for a project to create a REST API for ATutor. ATutor has hundreds of thousands of lines of code, yet is written in core PHP. Introducing a PHP router class for the API was necessary, but we needed something unintrusive.
The result was the ToroPHP library. He introduces the library with some background about why it was created and some of the goals it was trying to achieve. Next he shows you how to create a simple "Hello World" endpoint that just defines the endpoint and echoes back the string. He shows how to separate out the logic from the route handling via the "urls.php" definition file. He also shows the handling of URL prefixes and mentions user authentication, making a "backbone" for the API and reuse of classes for similar objects.