I have implemented a different Access Control List using Zend Framework. It does not use Zend_Acl – I had a hard time implementing it. Too hard and too confusing 
And there are no real-world examples on how to use it. The documentation in the manual is too simple. Using it is easy – but implementing it is a different story.
This implementation uses a Plugin that will be called when a controller is accessed/loaded. The plugin is executed just before the controller’s action is “executed”. In short, it is in the preDispatch().
Please note that this tutorial is written AS IS. If you find mistakes, then feel free to correct me. Also, it only gives you the first step. I still have to write the user interface for assigning roles, white-list, and so on and so fourth. But if you get the idea, you could do that on your own.
Click here for the tutorial.
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