gistfile1.php

<?php

interface RequestSpecification
{
    /**
     * @param Request $request
     * @return bool
     */
    public function isSatisfiedBy(Request $request);
}

class QueryParamSpecificationDatum
{
    public $name;

    public $possibleValues = array();

    public $required = true;

    public function getPossibleValues()
    {
        return $this->possibleValues;
    }

    public function getName()
    {
        return $this->name;
    }

    public function isRequired()
    {
        return $this->required;
    }
}

class QueryParamSpecification implements RequestSpecification
{
    /**
     * @var QueryParamSpecificationDatum
     */
    protected $datum;

    public function setDatum(QueryParamSpecificationDatum $datum)
    {
        $this->datum = $datum;
        return $this;
    }
    
    public function onMatchRequestDatum(RequestMatchEvent $event)
    {
        $queryParamDatums = $event->getRequestDatum()->getQueryParamSpecificationDatums();
        
        foreach ($queryParamDatums as $queryParamDatum) {
            $this->setDatum($queryParamDatum);
            
            if (!$this->isSatisfiedBy($event->getRequest())) {
                return false;
            }
        }
       
        return true;
    }

    public function isSatisfiedBy(Request $request)
    {
        if (!$this->datum) {
            throw new \Exception('No datum provided!');
        }

        if (!$this->datum->isRequired()) {
            return true;
        }

        $query = $request->query;
        $datum = $this->datum;

        foreach ($datum->getPossibleValues() as $value) {

            if ($query->has($datum->getName())) {

                if ($value === $query->get($datum->getName())) {
                    return true;
                }
            }
        }

        return false;
    }
}

class RequestDatum
{
    protected $queryParamSpecificationDatums;

    public function __construct()
    {
        $this->queryParamSpecificationDatums = new ArrayCollection();
    }

    public function getQueryParamSpecificationDatums()
    {
        return $this->queryParamSpecificationDatums;
    }
}

class RequestMatchEvent extends Event
{
    protected $request; 
    
    protected $requestDatum;

    protected $matches = true;

    public function __construct(Request $request, RequestDatum $requestDatum)
    {
        $this->request = $request;
        $this->requestDatum = $requestDatum;
    }

    public function setMatches($matches)
    {
        return $this->matches = (bool) $matches;
    }

    public function matches()
    {
        return $this->matches;
    }
    
    public function getRequest()
    {
        return $this->request;
    }
    
    public function getRequestDatum()
    {
        return $this->requestDatum;
    }
}

class RequestMatcher implements RequestSpecification
{
    const MATCHING_REQUEST = 'matching.request';
    /**
     * @var RequestDatum
     */
    protected $datum;

    protected $dispatcher;
    
    protected $request;

    public function __construct(Request $request, EventDispatcherInterface $dispatcher)
    {
        $this->request = $request;
        $this->dispatcher = $dispatcher;
    }

    public function setRequestData(RequestDatum $datum)
    {
        $this->datum = $datum;
    }

    /**
     * @param Request $request
     * @return bool
     */
    public function isSatisfiedBy(Request $request)
    {
        $event = new RequestMatchEvent($this->request, $this->datum);

        $this->dispatcher->dispatch(self::MATCHING_REQUEST, $event);

        return $event->matches();
    }
}