Guidance for how query loop block treats IDs for custom shortcode

Hi Gary,

Can you share the code you used to create the shortcode?

Let me know!

Hi Ying

Sure, here’s the code that works in an Elements template when using the shortcode but doesn’t in a query loop block:

function gt_get_parent_terms($taxonomy = 'category') {
    global $post;
    $post_id = $post->ID;
    $catName = "";
    foreach((get_the_category($post_id)) as $category){
        if ($category->parent == 0) {
			$catName .= $category->name;	
		}
    }
    return $catName;
}
add_shortcode('parent_cat', 'gt_get_parent_terms');

Note I tried changing the above $post_id variable to equal get_the_id() for use in the query loop but this doesn’t seem to work either, so I’m stumped as to why the ID part isn’t working when the shortcode is used within the query loop block?

Thanks

Hi Gary,

This is a core WordPress thing. When you use get_the_ID() in a GenerateBlocks or WordPress Query Loop, the returned ID will always be the ID of the current page/post viewed, not the one in the current loop.

To address this, filter render_block() is used. You'll need the add a Headline Block for instance and alter it via render_block() as get_the_ID() would work with that method.

Reference: https://developer.wordpress.org/reference/functions/render_block/

Hi Fernando

Thanks for letting me know about how the ID is treated by Wordpress, I had wondered if what I had was just grabbing the ID of the page rather than the query loop item.

You reminded me I have previously used the render_block function based on using a unique class attribute to alter the content of a block, so I'll use that as starting point and hopefully I can get the top level category to show correctly.

Thanks

Great! You're welcome Gary! Just reach out anytime if you'll need further assistance!