Create Mezzio\ApplicationPipeline implementation for better static code analysis

[boesing]

Feature Request

Q	A
New Feature	yes
RFC	yes
BC Break	no

Summary

In this package, Mezzio\ApplicationPipeline is a service identifier to retrieve the assembled middleware pipeline for a mezzio project which does not actually represents a class.

This pipeline is consumed by these classes in a mezzio project:

• mezzio/src/Application.php

  Line 33 in 24bfca0

  MiddlewarePipeInterface $pipeline,

• https://github.com/laminas/laminas-httphandlerrunner/blob/4d337cde83e6b901a4443b0ab5c3b97cbaa46413/src/RequestHandlerRunner.php#L60

That pipeline gets assembled in:

mezzio/src/Container/ApplicationPipelineFactory.php

Line 15 in 24bfca0

return new MiddlewarePipe();

And registered in:

mezzio/src/ConfigProvider.php

Line 54 in 24bfca0

ApplicationPipeline::class => Container\ApplicationPipelineFactory::class,

---

Retrieving this pipeline via a PSR-11 is quite annoying due to the fact that neither an IDE is able to auto-complete the typed service name nor a static-analysis tool is able to understand what is happening.

My suggestion would be to create a class called ApplicationPipeline which implements MiddlewarePipeInterface (which implements both RequestHandlerInterface and MiddlewareInterface) and thus allow factories to retrieve that pipeline via:

1. Mezzio\ApplicationPipeline class-string
2. (optional) Psr\Http\Server\RequestHandlerInterface class-string (alias to Mezzio\ApplicationPipeline)

This would allow us to properly fetch the application pipeline from within the ApplicationFactory and the RequestHandlerRunnerFactory:

mezzio/src/Container/ApplicationFactory.php

Line 33 in 24bfca0

$container->get(ApplicationPipeline::class),

mezzio/src/Container/RequestHandlerRunnerFactory.php

Line 35 in 24bfca0

$container->get(ApplicationPipeline::class),

[boesing]

Created a PoC in #107