Custom CSS in the REST API?

Hey @chriscoyier,

It’s not possible but you can write a PHP function to scrap the attributes of blocks, like this: https://github.com/Codeinwp/gutenberg-css/blob/master/class-gutenberg-css.php#L131

You can use this function ^ to hook the CSS into the REST API with https://developer.wordpress.org/reference/functions/register_rest_field/.

I wrote this roughly but it works:

add_action( 'rest_api_init', 'add_post_css_rest_field' );

function add_post_css_rest_field() {
    register_rest_field( 'post', 'customCSS', array(
           'get_callback'    => 'get_post_css',
           'schema'          => null,
        )
    );
}

function get_post_css( $object ) {
    //get the id of the post object array
    $post_id = $object['id'];
    if ( class_exists( '\ThemeIsle\GutenbergCSS' ) ) {
        $content = get_the_content( $post_id );
        $content = parse_blocks( $content );
        if ( ! is_array( $content ) || empty( $content ) ) {
	    return null;
        }
        $class = new \ThemeIsle\GutenbergCSS();
        $css = $class->cycle_through_blocks( $content );
        if ( ! empty ( $css ) ) {
            return $css;
        }
    }

    return null;
}

This will add a customCSS field to Rest API with all the CSS. Let me know if it helps.

And keep the good work up, learned a lot from you! 🙂

• This reply was modified 2 years, 12 months ago by Hardeep Asrani.
• This reply was modified 2 years, 12 months ago by Hardeep Asrani.

Hey @chriscoyier,

I tried this on my end and the classes also appear in REST response, as you can see here: https://pasteboard.co/JcNJRir.png or live at this demo link: https://round-palm.jurassic.ninja/wp-json/wp/v2/posts/1

Let me know how it goes on your end! 🙂

You’re welcome, @chriscoyier. I’m marking this as resolved. Thank you for using our plugin. I hope you enjoy using it as much as we enjoy making it. 🙂