WordPress 添加面包屑导航 Breadcrumb

/**
 * WordPress 添加面包屑导航 
 * https://www.wpdaxue.com/wordpress-add-a-breadcrumb.html
 */
function cmp_breadcrumbs() {
	$delimiter = '»'; // 分隔符
	$before = '<span class="current">'; // 在当前链接前插入
	$after = '</span>'; // 在当前链接后插入
	if ( !is_home() && !is_front_page() || is_paged() ) {
		echo '<div itemscope itemtype="http://schema.org/WebPage" id="crumbs">'.__( 'You are here:' , 'cmp' );
		global $post;
		$homeLink = home_url();
		echo ' <a itemprop="breadcrumb" rel="nofollow noopener noreferrer" href="' . $homeLink . '">' . __( 'Home' , 'cmp' ) . '</a> ' . $delimiter . ' ';
		if ( is_category() ) { // 分类 存档
			global $wp_query;
			$cat_obj = $wp_query->get_queried_object();
			$thisCat = $cat_obj->term_id;
			$thisCat = get_category($thisCat);
			$parentCat = get_category($thisCat->parent);
			if ($thisCat->parent != 0){
				$cat_code = get_category_parents($parentCat, TRUE, ' ' . $delimiter . ' ');
				echo $cat_code = str_replace ('<a','<a itemprop="breadcrumb"', $cat_code );
			}
			echo $before . '' . single_cat_title('', false) . '' . $after;
		} elseif ( is_day() ) { // 天 存档
			echo '<a itemprop="breadcrumb" rel="nofollow noopener noreferrer" href="' . get_year_link(get_the_time('Y')) . '">' . get_the_time('Y') . '</a> ' . $delimiter . ' ';
			echo '<a itemprop="breadcrumb"  rel="nofollow noopener noreferrer" href="' . get_month_link(get_the_time('Y'),get_the_time('m')) . '">' . get_the_time('F') . '</a> ' . $delimiter . ' ';
			echo $before . get_the_time('d') . $after;
		} elseif ( is_month() ) { // 月 存档
			echo '<a itemprop="breadcrumb" rel="nofollow noopener noreferrer" href="' . get_year_link(get_the_time('Y')) . '">' . get_the_time('Y') . '</a> ' . $delimiter . ' ';
			echo $before . get_the_time('F') . $after;
		} elseif ( is_year() ) { // 年 存档
			echo $before . get_the_time('Y') . $after;
		} elseif ( is_single() && !is_attachment() ) { // 文章
			if ( get_post_type() != 'post' ) { // 自定义文章类型
				$post_type = get_post_type_object(get_post_type());
				$slug = $post_type->rewrite;
				echo '<a itemprop="breadcrumb" rel="nofollow noopener noreferrer" href="' . $homeLink . '/' . $slug['slug'] . '/">' . $post_type->labels->singular_name . '</a> ' . $delimiter . ' ';
				echo $before . get_the_title() . $after;
			} else { // 文章 post
				$cat = get_the_category(); $cat = $cat[0];
				$cat_code = get_category_parents($cat, TRUE, ' ' . $delimiter . ' ');
				echo $cat_code = str_replace ('<a','<a itemprop="breadcrumb"', $cat_code );
				echo $before . get_the_title() . $after;
			}
		} elseif ( !is_single() && !is_page() && get_post_type() != 'post' ) {
			$post_type = get_post_type_object(get_post_type());
			echo $before . $post_type->labels->singular_name . $after;
		} elseif ( is_attachment() ) { // 附件
			$parent = get_post($post->post_parent);
			$cat = get_the_category($parent->ID); $cat = $cat[0];
			echo '<a itemprop="breadcrumb" rel="nofollow noopener noreferrer" href="' . get_permalink($parent) . '">' . $parent->post_title . '</a> ' . $delimiter . ' ';
			echo $before . get_the_title() . $after;
		} elseif ( is_page() && !$post->post_parent ) { // 页面
			echo $before . get_the_title() . $after;
		} elseif ( is_page() && $post->post_parent ) { // 父级页面
			$parent_id  = $post->post_parent;
			$breadcrumbs = array();
			while ($parent_id) {
				$page = get_page($parent_id);
				$breadcrumbs[] = '<a itemprop="breadcrumb" rel="nofollow noopener noreferrer" href="' . get_permalink($page->ID) . '">' . get_the_title($page->ID) . '</a>';
				$parent_id  = $page->post_parent;
			}
			$breadcrumbs = array_reverse($breadcrumbs);
			foreach ($breadcrumbs as $crumb) echo $crumb . ' ' . $delimiter . ' ';
			echo $before . get_the_title() . $after;
		} elseif ( is_search() ) { // 搜索结果
			echo $before ;
			printf( __( 'Search Results for: %s', 'cmp' ),  get_search_query() );
			echo  $after;
		} elseif ( is_tag() ) { //标签 存档
			echo $before ;
			printf( __( 'Tag Archives: %s', 'cmp' ), single_tag_title( '', false ) );
			echo  $after;
		} elseif ( is_author() ) { // 作者存档
			global $author;
			$userdata = get_userdata($author);
			echo $before ;
			printf( __( 'Author Archives: %s', 'cmp' ),  $userdata->display_name );
			echo  $after;
		} elseif ( is_404() ) { // 404 页面
			echo $before;
			_e( 'Not Found', 'cmp' );
			echo  $after;
		}
		if ( get_query_var('paged') ) { // 分页
			if ( is_category() || is_day() || is_month() || is_year() || is_search() || is_tag() || is_author() )
				echo sprintf( __( '( Page %s )', 'cmp' ), get_query_var('paged') );
		}
		echo '</div>';
	}
}

<?php if(function_exists('cmp_breadcrumbs')) cmp_breadcrumbs();?>