CakePHP: Where to put 'Services' logic

Question

I come from a Java/Grails background and cannot seem to find a definite answer online as to where the service logic for a CakePHP application should be stored. By "Services", I am talking about classes that are usually instantiated through dependency injection to conduct business logic on domain objects. They should be able to query any domain object and make changes in response to a controller action.

Currently, CakePHP's "Component" class seems to be the closest match to this behavior. I can load a component into any controller and execute its methods as needed. However, I have read in several places that components should never access the database and that doing so will result in some steep performance hits.

I have also looked into CakePHP's "Behavior" class and it doesn't seem to fit the ticket at all. It seems well-equipped to organize domain objects into a data structure setting, but that's not the kind of logic that a service would execute. Also, to import any model definition into a Behavior, I would have to edit the model definition itself to allow access, which is very awkward.

So I ask this question: Where should service logic be stored? Certainly not the controller, as it should only contain the minimal logic to process a request and send a response.

Answer 1

Components are the service layer in CakePHP. They are constructed by a dependency injection container (Components Collection) and get passed the controller, request and response that is to be handled.

There are no restrictions in what Components can do other than maintaining separation between layers. It is fine to use database connections, or use models, directly from a component and modify the request.

Components are actually very light-weighted if you only make them act for specific cases. Inspecting the action name, is a common way of limiting the reach of a component. You can also inject setting so it can know when is OK to execute custom service logic.