A simple WordPress plugin that adds Open Graph author tags for Facebook

open-graph-author-tags.php

<?php
/**
 * @wordpress-plugin
 * Plugin Name:       Open Graph Author Tags
 * Description:       Adds author Open Graph tags to posts for Facebook
 * Version:           1.0.0
 * Author:            Daniel M. Hendricks
 * Author URI:        https://www.danhendricks.com
 * Plugin URI:        https://gist.github.com/dmhendricks/63e135c22db3857f1dc1e69c5a6cdc16/
 * Requires at least: 4.7
 * Requires PHP:      5.6
 */
namespace CloudVerve;
defined( 'ABSPATH' ) || die();

final class Open_Graph_Author_Tags {

    private static $instance;

    public static function init() {

        if ( !isset( self::$instance ) && !( self::$instance instanceof Open_Graph_Author_Tags ) ) {

            self::$instance = new Open_Graph_Author_Tags;

            // Add author tags
            add_action( 'wp_head', [ self::$instance, 'opengraph_author_tags' ] );

        }

        return self::$instance;

    }

    /*
     * Add author tags to page head
     *
     * @since 1.0.0
     */
    public static function opengraph_author_tags() {

        if( !is_single() ) return;

        printf( '<meta property="author" content="%s" />', esc_attr( get_the_author() ) );

        if( $author_facebook_link = filter_var( get_the_author_meta( 'facebook' ), FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED ) ) {
            printf( '<meta property="article:author" content="%s" />', esc_attr( $author_facebook_link ) );
        }

    }

}

Open_Graph_Author_Tags::init();