On-construct ADR content type negotiation

MyAction.php

<?php

class MyAction
{
    protected $request;
    protected $responder;
    
    public function __construct(Aura\Web\Request $request, ResponderInterface $responder) {
        // you'd inject other stuff here normally, but let's assume that this is extended elsewhere
        $this->request = $request;
        $this->responder = $responder;
        // throws InvalidArgumentException if not acceptable; handle it in the front controller
        // we could also inject a responder chain or the like, to decide which responder to use
        $this->responder->setAccept($request->accept);
    }
    
    public function __invoke() {
        // marshal parameters, call domain logic, etc.
        $data = ['id' => 123, 'name' => 'Something Useful'];
        
        // returns a responder, which then gets invoked by the dispatcher to in turn get a response, to render
        return $this->responder->setData($data);
    }
}

MyResponder.php

<?php

class MyResponder implements ResponderInterface
{
    protected $response;
    protected $accept;
    protected $data;
    
    protected static $acceptableContentTypes = ['application/json', 'text/csv'];
    
    public function __construct(Aura\Web\Response $res) {
        $this->response = $res;
    }
    
    public function setAccept(Aura\Web\Request\Accept $accept) {
        $this->accept = $accept;
        if (!$accept->media->negotiate(static::$acceptableContentTypes)) {
            throw new \InvalidArgumentException(implode(',', static::$acceptableContentTypes), 406);
        }
        return $this;
    }
    
    public function setData($data) {
        $this->data = $data;
        return $this;
    }
    
    public function __invoke() {
        // build response as needed; CSVs will get built differently than JSON
        return $this->response;
    }
}