if article is part of category or any of it's children

Question

I know I can get the category id and parent category id, but what I really want is a category and any child categories.

I'm making a group of articles and I want to do an override to add a class to all articles in a category and all child categories, no matter how many child categories I add.

Is that possible? I don't want to do IF parent category id OR parent category id OR parent category id because if I do that I'll have to update it every time I add a new category.

I want to know an article categories and all subcategories

I checked out this article but it's not really the whole solution https://stackoverflow.com/questions/43647327/get-joomla-parent-category-id

Thanks in advance.

Answer 1

I faced a similar problem a while ago and not coming up with a good answer I came up with a straight forward messy answer. Behold:

public static function isArticleIdInThisCategoryId($article_id,$category_id)
{
    if(!$article_id){return false;}

    $db = JFactory::getDbo();
    $query = $db->getQuery(true);
    $query->select('a.catid AS parent1,b.parent_id AS parent2,c.parent_id AS parent3,d.parent_id AS parent4,');
    $query->from($db->qn('#__content','a'));
    $query->join('LEFT',$db->qn('#__categories', 'b') . ' ON (' . $db->qn('a.catid') . ' = ' . $db->qn('b.id') . ')');
    $query->join('LEFT',$db->qn('#__categories', 'c') . ' ON (' . $db->qn('b.parent_id') . ' = ' . $db->qn('c.id') . ')');
    $query->join('LEFT',$db->qn('#__categories', 'd') . ' ON (' . $db->qn('c.parent_id') . ' = ' . $db->qn('d.id') . ')');
    $query->where($db->qn('a.id') . " = " . $db->q($article_id));
    $db->setQuery($query);
    $result = $db->loadAssoc();

    if(empty($result)){
        return false;
    }

    for ($i=1; $i <= 4; $i++) { 
        if(!empty($result['parent' . $i]) && $result['parent' . $i] == $category_id){
            return true;
        }
    }
    return false;
}

It's a public static function because i had it in a helper class, but hopefully you can see the idea. Also note it only goes 4 parent categories deep, but should be easier enough to make deeper if needed.

Answer 2

Database method when you want to check against one category and all its children. Where $categoryId is your specified category.

// Get child category IDs
$db = JFactory::getDbo();
$query = $db->getQuery(true)
    ->select('sub.id')
    ->from('#__categories as sub')
    ->join('INNER', '#__categories as this ON sub.lft > this.lft AND sub.rgt < this.rgt')
    ->where('this.id = ' . (int) $categoryId);
$db->setQuery($query);
$categoryIds = $db->loadColumn();
// Add top category too.
$categoryIds[] = $categoryId;

Then, when displaying the article, add this check:

<?php if (in_array($this->item->catid, $categoryIds)) : ?>
    <?php // Article is in one of the categories, do stuff ?>
<?php endif; ?>