Magento Find Category by Path for http://stackoverflow.com/questions/19248041/magento-get-category-by-path

Finder.php

<?php
/**
 * Functionality taken from Mage_ImportExport_Model_Import_Entity_Product
 */
class Your_Module_Model_Category_Finder
{
	/**
	 * Categories text-path to ID hash.
	 *
	 * @var array
	 */
	protected $_categories = array();

	/**
	 * Categories text-path to ID hash with roots checking.
	 *
	 * @var array
	 */
	protected $_categoriesWithRoots = array();

	/**
	 * Populates the models properties with category information.
	 */
	public function __construct()
	{
		$this->_initCategories();
	}


	/**
	 * Finds a subcategory id from a path string
	 *
	 * @param $string
	 * @return bool
	 */
	public function getIdFromPath($string)
	{
		if (in_array($string, array_keys($this->_categories))) {
			return $this->_categories[$string];
		}

		return false;
	}

	/**
	 * Returns all valid path strings
	 *
	 * @return array
	 */
	public function getAllPaths()
	{
		return array_keys($this->_categories);
	}

	/**
	 * Initialize categories text-path to ID hash.
	 *
	 * @return Mage_ImportExport_Model_Import_Entity_Product
	 */
	protected function _initCategories()
	{
		$collection = Mage::getResourceModel('catalog/category_collection')->addNameToResult();
		/* @var $collection Mage_Catalog_Model_Resource_Eav_Mysql4_Category_Collection */
		foreach ($collection as $category) {
			$structure = explode('/', $category->getPath());
			$pathSize = count($structure);
			if ($pathSize > 1) {
				$path = array();
				for ($i = 1; $i < $pathSize; $i++) {
					$path[] = $collection->getItemById($structure[$i])->getName();
				}
				$rootCategoryName = array_shift($path);
				if (!isset($this->_categoriesWithRoots[$rootCategoryName])) {
					$this->_categoriesWithRoots[$rootCategoryName] = array();
				}
				$index = implode('/', $path);
				$this->_categoriesWithRoots[$rootCategoryName][$index] = $category->getId();
				if ($pathSize > 2) {
					$this->_categories[$index] = $category->getId();
				}
			}
		}
		return $this;
	}

}