The Middleware Container

While the skeleton creates a general PSR-11 container in which to map all of your dependencies, this can pose problems when you are attempting to pull middleware and request handlers; you could potentially, accidentally, pull something of an entire type entirely, which may not work in either context!

To prevent this from happening, we provide Zend\Expressive\MiddlewareContainer. It decorates your application container, and adds the following behavior:

• has() will return true if a service does not exist in the container, but is a class that exists.
• get():
  • will instantiate a class directly if the service does not exist, but is a class that exists.
  • decorate PSR-15 RequestHandlerInterface implementations using Zend\Stratigiliity\RequestHandlerMiddleware.
  • raise an exception of the instance to return is no a PSR-15 MiddlewareInterface implementation.

Internally, this class is used by the MiddlewareFactory and the Zend\Expressive\Middleware\LazyLoadingMiddleware class; you should never need to interact with it directly, unless the above features are of interest to you.