Stage

A special type of play.api.mvc.Handler which allows custom logic to be inserted during handling. A Stage accepts a RequestHeader then returns a new RequestHeader along with the next Handler to use during request handling. The next handler could be a terminal Handler like an EssentialAction, but it could also be another Stage. This means it's possible to chains of Stages that should each be executed in turn. To automatically execute all Stages you can call play.api.mvc.Handler.applyStages.