magento - retrieve all children categories given a category id

Question

As said in the title, i'm trying to do this stuff through my custom function:

public function retrieveAllChilds($id = null, $childs = null){

        $childIdsArray = is_null($childs) ? array() : $childs;
        $category = is_null($id) ? $this->getCurrentCategory() : $this->getCategoryFromId($id);
        if (count($this->getChildrenCategories($id)) > 0) {
            $c = count($this->getChildrenCategories($id));
            $tmp_array = array();
            foreach ($this->getChildrenCategories($id) as $category) {
                array_push($tmp_array, $category->getId());             
            }
            $childIdsArray = array_merge($childIdsArray, $tmp_array);
            foreach ($this->getChildrenCategories($id) as $category){
                $this->retrieveAllChilds($category->getId(), $childIdsArray);
            }
        }
        else{
            return array_unique($childIdsArray);
        }

        return array_unique($childIdsArray);
}

but seems that there's something wrong in the stop or in the exit condition. the function retrieve correctly first 16 elements. anybody could help me?

Solution

I think the class Mage_Catalog_Model_Category already includes the function you are searching. It is called getChildren:

public function retrieveAllChilds($id = null, $childs = null) {
    $category = Mage::getModel('catalog/category')->load($id);
    return $category->getChildren();
}

The function getChildren returns children IDs comma-separated, getChildrenCategories returns an array of Mage_Catalog_Model_Category instances.

If you want to get the children categories recursively, you can use:

public function retrieveAllChilds($id = null, $childs = null) {
    $category = Mage::getModel('catalog/category')->load($id);
    return $category->getResource()->getChildren($category, true);
}

Comments

[Daniel Sloof]

You are exactly right, except that by default it will not fetch them recursively (so top level only). He will want to use: $category->getResource()->getChildren($category, true);