Exceptions should respect the requested content type

[neos-bot]

Jira issue originally created by user @bwaidelich:

The Flow ExceptionHandler s currently only adjust their rendering based on request type (Web/CLI) and context (DebugExceptionHandler/ProductionExceptionHandler).

They should, in addition, be able to react upon the requested format, e.g. by evaluating the Accept HTTP header of the current request.

Jira-URL: https://jira.neos.io/browse/FLOW-202

[neos-bot]

Comment created by @bwaidelich:

Note: We "hotfixed" this for Neos 1.1.* with NEOS-108 but we need a general solution in Flow (see comments on NEOS-108 for previous discussions)

[neos-bot]

Comment created by sorenmalling:

[~bwaidelich] So, I did some looking into this yesterday.

I focused on the ExceptionHandler classes. My idea is to add a configuration similar to matchingStatusCodes and matchingExceptionClassNames for the mediatype

What puzzles me, is that I have no connection to the Request object, so I can't see what media type is accepted.

In that way, a configuration like to following could be an example

TYPO3:
  Flow:
    error:
      exceptionHandler:
        renderingGroups:
          'someFancyGroupName':
            matchingExceptionClassNames: ['TYPO3\Flow\Persistence\Doctrine\Exception\DatabaseException']
            matchingMediaType: 'application/xml'
            options:

[neos-bot]

Comment created by sorenmalling:

So, the actual question is:

How do I get the accepted mediatype for the request, when Request is not available?

Can I somehow inject it or just initialize it?

[neos-bot]

Comment created by @bwaidelich:

[~sorenmalling] I had a similar idea and I like it, although it should be matchingMediaTypes (plural) IMO. Getting hold of the Request is indeed a problem we need to solve.. We can get it via

/****
 * @Flow\Inject
 * @var \TYPO3\Flow\Core\Bootstrap
 ****/
protected $bootstrap;

// ...

$httpRequest = $this->bootstrap->getActiveRequestHandler()->getHttpRequest();

..That's not the best solution in terms of clean coding, but it should work for our case

[neos-bot]

Comment created by @bwaidelich:

..but, true, a problem remains, because we don't know what the negotiated format is, because that's set by AbstractController::initializeController() in the ActionRequest..

[neos-bot]

Comment created by pumatertion:

I am still pretty unsure about the response format. Except cli response the format should be detected by request header data instead of extension .whatever? Example: Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8