ParameterAccessor

composer.json

{
    "require": {
        "symfony/property-access": "2.3.x@dev"
    }
}

ParameterAccessor.php

<?php

use Symfony\Component\PropertyAccess\PropertyAccessorInterface;

class ParameterAccessor
{
    private $parameters;

    /**
     * @var PropertyAccessorInterface
     */
    private $accessor;

    public function __construct(PropertyAccessorInterface $accessor)
    {
        $this->accessor = $accessor;
    }

    public function get($path)
    {
        if (is_array($this->parameters)) {
            if ('[' !== substr($path, 0, 1)) {
                if (false === strpos($path, '.')) {
                    $path = '['.$path.']';
                } else {
                    $path = '['.str_replace('.', '][', $path).']';
                }
            }
        }

        // use the accessor
        return $this->accessor->getValue($this->parameters, $path);
    }

    public function setData($parameters)
    {
        $this->parameters = $parameters;
    }
}

ParameterAccessorTest.php

<?php

use Symfony\Component\PropertyAccess\PropertyAccess;

require "ParameterAccessor.php";

class ParameterAccessorTest extends \PHPUnit_Framework_TestCase
{
    protected $accessor;

    public function setUp()
    {
        $this->accessor = new ParameterAccessor($this->getPropertyAccessor());
    }

    /**
     * @dataProvider getArraysData
     */
    public function testArrays(array $array, $path, $expected)
    {
        $a = $this->accessor;
        $a->setData($array);
        
        $this->assertEquals($expected, $a->get($path));
    }

    public function getArraysData()
    {
        return array(
            // 1 level
            array(array('foo' => 'bar'), 'foo', 'bar'),

            // 2 levels
            array(array('foo' => array('bar' => 'cat')), 'foo.bar', 'cat'),

            // 3 levels
            array(array('foo' => array('bar' => array('cat' => 'dolor'))), 'foo.bar.cat', 'dolor'),

            // normal way
            array(array('foo' => 'bar'), '[foo]', 'bar'),
        );
    }

    /**
     * @dataProvider getObjectsData
     */
    public function testObjects($object, $path, $expected)
    {
        $a = $this->accessor;
        $a->setData($object);
        
        $this->assertEquals($expected, $a->get($path));
    }

    public function getObjectsData()
    {
        return array(
            // 1 level
            array((object) array('foo' => 'bar'), 'foo', 'bar'),

            // 2 levels
            array((object) array('foo' => (object) array('bar' => 'cat')), 'foo.bar', 'cat'),

            // 3 levels
            array((object) array('foo' => (object) array('bar' => (object) array('cat' => 'dolor'))), 'foo.bar.cat', 'dolor'),
        );
    }

    protected function getPropertyAccessor()
    {
        return PropertyAccess::getPropertyAccessor();
    }
}