Functions.php snippets

// remove junk from head
remove_action('wp_head', 'rsd_link');
remove_action('wp_head', 'wp_generator');
remove_action('wp_head', 'feed_links', 2);
remove_action('wp_head', 'index_rel_link');
remove_action('wp_head', 'wlwmanifest_link');
remove_action('wp_head', 'feed_links_extra', 3);
remove_action('wp_head', 'start_post_rel_link', 10, 0);
remove_action('wp_head', 'parent_post_rel_link', 10, 0);
remove_action('wp_head', 'adjacent_posts_rel_link', 10, 0);

// add custom post content
function add_post_content($content) {
    if(!is_feed() && !is_home()) {
        $content .= '<p>This article is copyright &copy; '.date('Y').'&nbsp;'.bloginfo('name').'</p>';
    }
    return $content;
}
add_filter('the_content', 'add_post_content');

// delay feed update
function publish_later_on_feed($where) {
    global $wpdb;

    if (is_feed()) {
        // timestamp in WP-format
        $now = gmdate('Y-m-d H:i:s');

        // value for wait; + device
        $wait = '5'; // integer

        // http://dev.mysql.com/doc/refman/5.0/en/date-and-time-functions.html#function_timestampdiff
        $device = 'MINUTE'; // MINUTE, HOUR, DAY, WEEK, MONTH, YEAR

        // add SQL-sytax to default $where
        $where .= " AND TIMESTAMPDIFF($device, $wpdb->posts.post_date_gmt, '$now') > $wait ";
    }
    return $where;
}
add_filter('posts_where', 'publish_later_on_feed');

// add custom dashboard widget
add_action('wp_dashboard_setup', 'my_custom_dashboard_widgets');

function my_custom_dashboard_widgets() {
global $wp_meta_boxes;

wp_add_dashboard_widget('custom_help_widget', 'Theme Support', 'custom_dashboard_help');
}

function custom_dashboard_help() {
echo '<p>Welcome to Custom Blog Theme! Need help? Contact the developer <a href="mailto:yourusername@gmail.com">here</a>. For WordPress Tutorials visit: <a href="https://www.wpbeginner.com" target="_blank">WPBeginner</a></p>';
}

// Featured image in feed
function rss_post_thumbnail($content) {
global $post;
if(has_post_thumbnail($post->ID)) {
$content = '<p>' . get_the_post_thumbnail($post->ID) .
'</p>' . get_the_content();
}
return $content;
}
add_filter('the_excerpt_rss', 'rss_post_thumbnail');
add_filter('the_content_feed', 'rss_post_thumbnail');

//add admin user (if forgot password)
function wpb_admin_account(){
$user = 'Username';
$pass = 'Password';
$email = 'email@domain.com';
if ( !username_exists( $user )  && !email_exists( $email ) ) {
$user_id = wp_create_user( $user, $pass, $email );
$user = new WP_User( $user_id );
$user->set_role( 'administrator' );
} }
add_action('init','wpb_admin_account');

//Exclude categories from RSS
function exclude_category($query) {
    if ( $query->is_feed ) {
        $query->set('cat', '-5, -2, -3');
    }
return $query;
}
add_filter('pre_get_posts', 'exclude_category');