How to set the meta description of a WooCommerce product as its primary category description?

Question

I asked Yoast SEO support about this as I'm using their plugin, but they don't have this feature:

Instead of having to set a meta description for each WooCommerce product I sell, I'd like to set it automatically to the description of the product's category (or primary category, if it has several).

I found some code to retrieve the product's category description (https://stackoverflow.com/questions/19249756/how-to-display-woocommerce-category-description), but I don't know how to set it as this product's meta description.

Can you please help? :)

Thank you very much.

Answer 1

Use the wpseo_metadesc filter:

function wpse_406559_product_meta_description_from_category( $description ) {
    if ( ! is_singular( 'product' ) || $description ) {
        // Bail early if not single product, or custom meta description is already set
        return $description;
    }

    $product_cats = get_the_terms( get_queried_object_id(), 'product_cat' );

    // Get first product category
    $product_cat = is_array( $product_cats ) ? current( $product_cats ) : null;

    if ( $product_cat ) {
        // Get Yoast SEO term meta
        $meta = get_option( 'wpseo_taxonomy_meta' );

        // Try to get Yoast SEO meta description for this product category
        $description = $meta['product_cat'][ $product_cat->term_id ]['wpseo_desc'] ?? null;

        if ( ! $description ) {
            // Fallback to default product category description field
            $description = wp_strip_all_tags( $product_cat->description );
        }
    }

    return $description;
}

add_filter( 'wpseo_metadesc', 'wpse_406559_product_meta_description_from_category' );