In his latest post Gonzalo Ayuso shows how you can automatically inject dependencies into your PHP objects with the help of Pimple, a simple dependency injection container.

I must admit I don’t really know what’s the correct title for this post. Finally I use “Auto injecting dependencies in PHP objects”. I know it isn’t very descriptive. Let me explain it a little bit. This time I want to automate the Hollywood Principle (“Don’t call us, we’ll call you”). [...] We need to use Reflection to create our instance and to call our action. Sometimes I need to work with custom frameworks and legacy PHP applications. I’ve done it in a couple of projects, but now I want to create a library to automate this operation.

He includes a simple example of a "Controller" class that is injected with a "Request" via constructor injection. He refactors this to create the dependency injection container with a "Builder" class) and shows how to fetch the instance of the "Bar" class from it. It's this Builder class he shares on GitHub.