Magento right way(performance wise) to get simple products from configurable product

Question

I'm helping a friend out with some REALLY BAD magento code (which placed in a custom-made template).

In a category view I have the following code which should get simple products of a configurable product and query the simple products.

I'm not a big magento expert, but from reading, I have a feeling that looping and loading each product is a bit over-kill.

Any suggestions of how to improve the code and to read about best practices abotu querying and getting only needed data(in this case is simple products images.)

CODE:

$_productCollection=$this->getLoadedProductCollection();
$_helper = $this->helper('catalog/output');
foreach ($_productCollection as $_product):
<div class="item-product-wrap">    
          <?php
          // Get full product object.
          $conf_product = Mage::getModel('catalog/product')->load($_product->getId());

          // Get all simple products.
          $simple_products = $conf_product->getTypeInstance(true)->getUsedProducts(null, $conf_product);

          // Get default simple product ID.
          $default_simple_product_id = $conf_product->getData('default_configuration_id');
          // If default simple product is not set, get the first one.
          $default_simple_product_id = !$default_simple_product_id ? $simple_products[0]->getId() : $default_simple_product_id;

          // Run through all simple products.
          foreach ($simple_products as $simple_product):
            $simple_product_loaded = Mage::getModel('catalog/product')->load($simple_product->getId());

            if ($simple_product_loaded->getStatus() == 2) {
              // Product is disabled.
              continue;
            }

            // Get color. Replace spaces and ampersands with dashes to support URLs.
            $color = str_replace('&', '-', str_replace(' ', '-', $simple_product->getAttributeText('color')));

            // Get image.
            $product_media_config_model = Mage::getModel('catalog/product_media_config');
            $small_image = $product_media_config_model->getMediaUrl($simple_product->getImage());
            ?>
<div class="one-simple-product<?php echo ($default_simple_product_id == $simple_product->getId() ? ' active' : '') ?>">

    <a href="<?php echo $_product->getProductUrl() . '#' . $color ?>" title="<?php echo $this->stripTags($this->getImageLabel($simple_product, 'small_image'), null, true) ?>" class="product-image">
    <img src="<?php echo $small_image; ?>" width="135" height="135" alt="<?php echo $this->stripTags($this->getImageLabel($simple_product, 'small_image'), null, true) ?>" />
    </a>

</div>

Answer 1

You can use the following:

public function getChildrenCollection() {

    $parent = Mage::registry('current_product');
    $parentId = $parent->getId();

    $childrenIds = Mage::getResourceSingleton('catalog/product_type_configurable')
            ->getChildrenIds($parentId);

     $childrenCollection = Mage::getModel('catalog/product')->getCollection()
        ->addIdFilter($childrenIds)
        ->addAttributeToSelect(array_of_attributes_you_want_to_load);

     return $childrenCollection;
}

Remember to put this code in a Block (there shouldn't be any PHP in template files, you can just call $this->getChildrenCollection()) and don't use * in the attribute to select, only specify the attributes you really need

Answer 2

Following extension will be useful to you to display only selected part of simple products (associated products) of configurable product.

You may show/hide simple product's attribute like price, image, name, & description etc.

https://github.com/organicinternet/magento-configurable-simple