Notify IndexNow When Content Is Published

add_action( 'template_redirect', function () {
    $key = get_option( 'wpide_indexnow_key' );

    if ( ! $key ) {
        return;
    }

    $path = isset( $_SERVER['REQUEST_URI'] ) ? (string) wp_parse_url( wp_unslash( $_SERVER['REQUEST_URI'] ), PHP_URL_PATH ) : '';

    if ( '/' . $key . '.txt' === $path ) {
        status_header( 200 );
        header( 'Content-Type: text/plain; charset=utf-8' );
        echo esc_html( $key );
        exit;
    }
}, 0 );

add_action( 'transition_post_status', function ( $new_status, $old_status, $post ) {
    if ( 'publish' !== $new_status || 'production' !== wp_get_environment_type() || wp_is_post_revision( $post ) || ! is_post_publicly_viewable( $post ) ) {
        return;
    }

    if ( get_transient( 'wpide_indexnow_' . $post->ID ) ) {
        return;
    }

    set_transient( 'wpide_indexnow_' . $post->ID, 1, MINUTE_IN_SECONDS );

    $key = get_option( 'wpide_indexnow_key' );

    if ( ! $key ) {
        $key = strtolower( wp_generate_password( 32, false, false ) );
        update_option( 'wpide_indexnow_key', $key, false );
    }

    wp_remote_post( 'https://api.indexnow.org/indexnow', array(
        'blocking' => false,
        'timeout'  => 5,
        'headers'  => array( 'Content-Type' => 'application/json; charset=utf-8' ),
        'body'     => wp_json_encode( array(
            'host'        => wp_parse_url( home_url(), PHP_URL_HOST ),
            'key'         => $key,
            'keyLocation' => home_url( '/' . $key . '.txt' ),
            'urlList'     => array( get_permalink( $post ) ),
        ) ),
    ) );
}, 10, 3 );