ProductController.php

<?php

namespace SpeckCatalog\Controller;

use Zend\Mvc\Controller\AbstractActionController;
use Zend\View\Model\ViewModel;

class ProductController extends AbstractActionController
{
    protected $services = array(
        'product'       => 'speckcatalog_product_service',
        'product_uom'   => 'speckcatalog_product_uom_service',
        'builder'       => 'speckcatalog_builder_product_service',
        'configure_buy' => 'speckcatalog_configure_buy_service',
        'cart'          => 'catalog_cart_service',
        'renderer'      => 'zendviewrendererphprenderer',
        'option'        => 'speckcatalog_option_service',
        'product_image' => 'speckcatalog_product_image_service',
    );

    public function getService($name)
    {
        if (!array_key_exists($name, $this->services)) {
            throw new \Exception('invalid service name');
        }
        if (is_string($this->services[$name])) {
            $this->services[$name] = $this->getServiceLocator()->get($this->services[$name]);
        }
        return $this->services[$name];
    }

    public function indexAction()
    {
        $cartItemId     = $this->params('cartItemId');
        $cartService    = $this->getService('cart');
        $product        = $this->getService('product')
            ->setEnabledOnly(true)
            ->getFullProduct($this->params('id'));
        if (!$product) {
            throw new \Exception('no product for that id');
        }

        $this->layout()->crumbs = $this->getService('product')->getCrumbs($product);

        $vars = array(
            'product'     => $product,
            'editingCart' => ($cartItemId ? true : false),
            'cartItem'    => ($cartItemId ? $cartService->findItemById($cartItemId) : false),
        );

        return new ViewModel($vars);
    }

    public function imagesAction()
    {
        $productId = $this->params('id');
        $images    = $this->getService('product_image')->getImages('product', $productId);

        return new ViewModel(array('images' => $images));
    }

    public function getViewHelper($helperName)
    {
        return $this->getServiceLocator()->get('viewhelpermanager')->get($helperName);
    }

    public function uomsPartialAction()
    {
        $post = $this->params()->fromPost();
        $pid  = $post['product_id'];
        $builderPid = isset($post['builder_product_id']) ? $post['builder_product_id'] : null;

        $helper  = $this->getViewHelper('speckCatalogUomsToCart');
        $content = $helper->__invoke($pid, $builderPid);

        return $this->getResponse()->setContent($content);
    }

    public function optionsPartialAction()
    {
        $postParams = $this->params()->fromPost();
        $productId  = $postParams['product_id'];

        $options = $this->getService('option')->getByProductId($productId, true, true);

        $renderer = $this->getService('renderer');
        foreach ($options as $option) {
            $vars     = array('option' => $option);
            $html    .= $renderer->render('/catalog/product/option', $vars);
        }

        return $html;
    }
}

RefactoredProductController.php

<?php

namespace SpeckCatalog\Controller;

use Zend\Mvc\Controller\AbstractActionController;
use Zend\View\Model\ViewModel;

class ProductController extends AbstractActionController
{
    private $productService;
    private $cartService;

    public function __construct(CartService $cartService, ProductService $productService)
    {
        $this->cartService = $cartService;
        $this->productService = $productService;
    }

    public function indexAction()
    {
        $cartItemId     = $this->params('cartItemId');
        $product        = $this->productService
            ->setEnabledOnly(true)
            ->getFullProduct($this->params('id'));
        if (!$product) {
            throw new \Exception('no product for that id');
        }

        $this->layout()->crumbs = $this->productService->getCrumbs($product);

        $vars = array(
            'product'     => $product,
            'editingCart' => ($cartItemId ? true : false),
            'cartItem'    => ($cartItemId ? $this->cartService->findItemById($cartItemId) : false),
        );

        return new ViewModel($vars);
    }

    // other actions extracted into separate controllers as they do not share dependencies and responsibilities
}

Line
Responsibility to lookup dependencies is moved out. Controller object is guaranteed to have all required dependencies.

All dependencies are recorded explicitly. Reduced code complexity leads to improved readability and maintainability.

Line
No failure point here anymore, code is simpler and as a result more reliable.