GB 2.0 replacement for generateblocks_background_image_url filter?

Or maybe you’ve got a better idea… What I’m trying to do is to take a URL from a postmeta field and dynamically substitute it into a container’s background image. I chose to implement this with a shortcode, which I then enter into the background image’s URL, but maybe you have a better way?

Here’s the code for the shortcode. To use it, I simply enter [hero-background-business] into the background’s “background image” field:

add_shortcode( 'hero-background-business', function( $atts ) {
    $defaultImageUrl = '/wp-content/uploads/2025/06/Contractor-Hero-Background.webp';

	$atts = shortcode_atts( [
        'id'                => false,
		'default-image-url'	=> '',
    ], $atts );

	$id = absint( $atts[ "id" ] );
	if ( $id === 0 ) {
		$id = get_queried_object_id();
	}

	$bkgImageUrl = sanitize_url( $atts[ "default-image-url" ] );
	if ( empty( $bkgImageUrl ) ) {
		error_log( "+++ Missing or empty default image URL, using default URL" );
		$bkgImageUrl = $defaultImageUrl;
	}

	$heroBkgId = get_post_meta( $id, 'af_hero_bg', true );
	if ( empty( $heroBkgId ) ) {
		error_log( "+++ Missing or empty af_hero_bg postmeta for ID {$id}" );
		return $defaultImageUrl;
	}

	$imageAttr = wp_get_attachment_image_src( $heroBkgId , 'full' );
	if ( empty( $imageAttr ) ) {
		error_log( "+++ Missing image attributes for attachment ID {$heroBkgId}" );
		return $defaultImageUrl;
	}

	$imageUrl  = $imageAttr[0];
	if ( ! $imageUrl ) {
		error_log( "+++ Missing or empty image URL for attachment ID {$heroBkgId}" );
		return $defaultImageUrl;
	}

	error_log( "+++ Found hero background image: page ID {$id}, image ID {$heroBkgId}, URL {$imageUrl}" );
	return parse_url( $imageUrl, PHP_URL_PATH );
} );

The problem isn’t in the shortcode itself; the problem is that background image URL is never run through the do_shortcode() function to start with.

This seems to hold a lot of promise. Where can I find out more about writing these dynamic tags?

I put the following code into my customization plugin. It gives me message “+++ Registering Hero Background Business Dynamic Tag”, and nothing else. The code is:

add_action( 'init', '\AcornFinance\Customizations\register_hero_background_business_dynamic_tag', 20 );
function register_hero_background_business_dynamic_tag() {
    error_log( "+++ Registering Hero Background Business Dynamic Tag" );

    // if ( class_exists( 'GenerateBlocks_Register_Dynamic_Tag' ) ) {
        new \GenerateBlocks_Register_Dynamic_Tag(
            [
                'title'       => __( 'Hero Background Business', 'generatepress-child' ),
                'tag'         => 'hero_background_business',
                'type'        => 'post',
                'supports'    => [ 'source' ],
                'description' => __( 'Get the hero background image path for a business page.', 'generatepress-child' ),
                'options'     => [
                    'default-image-url' => [
                        'type'        => 'text',
                        'label'       => __( 'Default Image URL', 'generatepress-child' ),
                        'help'        => __( 'Default image URL to use if no hero background is found.', 'generatepress-child' ),
                    ],
                ],
                'return'      => 'get_hero_background_business_tag',
            ]
        );
    // }
}

function get_hero_background_business_tag( $options, $block, $instance ) {
    error_log( "+++ get_hero_background_business_tag called with options: " . print_r( $options, true ) );

    $defaultImageUrl = '/wp-content/uploads/2025/06/Contractor-Hero-Background.webp';

    $id = isset( $options['id'] ) ? absint( $options['id'] ) : 0;
    if ( $id === 0 ) {
        $id = get_queried_object_id();
    }

    $bkgImageUrl = isset( $options['default-image-url'] ) ? sanitize_url( $options['default-image-url'] ) : '';
    if ( empty( $bkgImageUrl ) ) {
        error_log( "+++ Missing or empty default image URL, using default URL" );
        $bkgImageUrl = $defaultImageUrl;
    }

    $heroBkgId = get_post_meta( $id, 'af_hero_bg', true );
    if ( empty( $heroBkgId ) ) {
        error_log( "+++ Missing or empty af_hero_bg postmeta for ID {$id}" );
        return $bkgImageUrl;
    }

    $imageAttr = wp_get_attachment_image_src( $heroBkgId, 'full' );
    if ( empty( $imageAttr ) ) {
        error_log( "+++ Missing image attributes for attachment ID {$heroBkgId}" );
        return $bkgImageUrl;
    }

    $imageUrl = $imageAttr[0];
    if ( ! $imageUrl ) {
        error_log( "+++ Missing or empty image URL for attachment ID {$heroBkgId}" );
        return $bkgImageUrl;
    }

    return parse_url( $imageUrl, PHP_URL_PATH );
}

So it seems like the line of code 'return' => 'get_hero_background_business_tag' isn’t being processed correctly, but I don’t know how to debug that…

Nevermind the previous comment, I fixed it by simply prefixing the function with the namespace. Now the function gets called, and it outputs the correct value in the text box, but when used in the background’s background image field with value {{hero_background_business}}, I get nothing for the property generated into the CSS. If you look at the URL provided below and inspect gb-element-4d922c3f, you’ll see a teeny bit of CSS for the class, but no background image.