最近开始整理 WordPress 的插件，发现有些插件功能越来越重，比如 Yoast SEO 的插件，出于个人洁癖就把他删除了。但是目前网站原来的 Breadcrumbs 导航功能是这个插件提供的，所以就开始查找替换方案。网上搜索发现一片文章介绍的比较具体 --- 《WordPress实现面包屑导航的方法》，博主其实也是参考了国外网友的非插件实现。
以下代码都是基于 Dimox 的原创，我只是在他基础上做了微调，改动不大：
/*
* Show breadcrumb by Dimox
* URL: http://dimox.net/wordpress-breadcrumbs-without-a-plugin/
* Version: 2017.21.01
* License: MIT
*/
function dangopress_breadcrumb()
{
/* === OPTIONS === */
$text['home'] = '首页'; // text for the 'Home' link
$text['category'] = '%s'; // text for a category page
$text['search'] = '"%s" 的搜索结果'; // text for a search results page
$text['tag'] = '包含标签 "%s" 的文章'; // text for a tag page
$text['404'] = '页面未到到'; // text for the 404 page
$text['page'] = 'Page %s'; // text 'Page N'
$text['cpage'] = 'Comment Page %s'; // text 'Comment Page N'
$prefix = '<i class="icon-windows"></i>'; // Prefix the breadcrumb
$wrap_before = '<div class="breadcrumbs" id="site-breadcrumbs" itemscope itemtype="http://schema.org/BreadcrumbList">'; // the opening wrapper tag
$wrap_after = '</div><!-- .breadcrumbs -->'; // the closing wrapper tag
$sep = '<i class="icon-caret-right"></i>'; // separator between crumbs
$sep_before = '<span class="sep">'; // tag before separator
$sep_after = '</span>'; // tag after separator
$show_home_link = 0; // 1 - show the 'Home' link, 0 - don't show
$show_current = 1; // 1 - show current page title, 0 - don't show
$before = '<h1 class="current-crumb">'; // tag before the current crumb
$after = '</h1>'; // tag after the current crumb
/* === END OF OPTIONS === */
global $post;
$home_url = home_url('/');
$link_before = '<span itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem">';
$link_after = '</span>';
$link_attr = ' itemprop="item"';
$link_in_before = '<span itemprop="name">';
$link_in_after = '</span>';
$link = $link_before . '<a href="%1$s"' . $link_attr . '>' . $link_in_before . '%2$s' . $link_in_after . '</a>' . $link_after;
$frontpage_id = get_option('page_on_front');
$parent_id = ($post) ? $post->post_parent : '';
$sep = ' ' . $sep_before . $sep . $sep_after . ' ';
$home_link = $link_before . '<a rel="nofollow" href="' . $home_url . '"' . $link_attr . ' class="home">' . $link_in_before . $text['home'] . $link_in_after . '</a>' . $link_after;
if (is_home() || is_front_page()) {
return;
} else {
echo $wrap_before . $prefix;
if ($show_home_link) echo $home_link;
if ( is_category() ) {
$cat = get_category(get_query_var('cat'), false);
if ($cat->parent != 0) {
$cats = get_category_parents($cat->parent, TRUE, $sep);
$cats = preg_replace("#^(.+)$sep$#", "$1", $cats);
$cats = preg_replace('#<a([^>]+)>([^<]+)<\/a>#', $link_before . '<a$1' . $link_attr .'>' . $link_in_before . '$2' . $link_in_after .'</a>' . $link_after, $cats);
if ($show_home_link) echo $sep;
echo $cats;
}
if ( get_query_var('paged') ) {
$cat = $cat->cat_ID;
echo $sep . sprintf($link, get_category_link($cat), get_cat_name($cat)) . $sep . $before . sprintf($text['page'], get_query_var('paged')) . $after;
} else {
if ($show_current) echo $sep . $before . sprintf($text['category'], single_cat_title('', false)) . $after;
}
} elseif ( is_search() ) {
if (have_posts()) {
if ($show_home_link && $show_current) echo $sep;
if ($show_current) echo $before . sprintf($text['search'], get_search_query()) . $after;
} else {
if ($show_home_link) echo $sep;
echo $before . sprintf($text['search'], get_search_query()) . $after;
}
} elseif ( is_day() ) {
if ($show_home_link) echo $sep;
echo sprintf($link, get_year_link(get_the_time('Y')), get_the_time('Y')) . $sep;
echo sprintf($link, get_month_link(get_the_time('Y'), get_the_time('m')), get_the_time('F'));
if ($show_current) echo $sep . $before . get_the_time('d') . $after;
} elseif ( is_month() ) {
if ($show_home_link) echo $sep;
echo sprintf($link, get_year_link(get_the_time('Y')), get_the_time('Y'));
if ($show_current) echo $sep . $before . get_the_time('F') . $after;
} elseif ( is_year() ) {
if ($show_home_link && $show_current) echo $sep;
if ($show_current) echo $before . get_the_time('Y') . $after;
} elseif ( is_single() && !is_attachment() ) {
if ($show_home_link) echo $sep;
if ( get_post_type() != 'post' ) {
$post_type = get_post_type_object(get_post_type());
$slug = $post_type->rewrite;
printf($link, $home_url . $slug['slug'] . '/', $post_type->labels->singular_name);
if ($show_current) echo $sep . $before . get_the_title() . $after;
} else {
$cat = get_the_category(); $cat = $cat[0];
$cats = get_category_parents($cat, TRUE, $sep);
if (!$show_current || get_query_var('cpage')) $cats = preg_replace("#^(.+)$sep$#", "$1", $cats);
$cats = preg_replace('#<a([^>]+)>([^<]+)<\/a>#', $link_before . '<a$1' . $link_attr .'>' . $link_in_before . '$2' . $link_in_after .'</a>' . $link_after, $cats);
echo $cats;
if ( get_query_var('cpage') ) {
echo $sep . sprintf($link, get_permalink(), get_the_title()) . $sep . $before . sprintf($text['cpage'], get_query_var('cpage')) . $after;
} else {
if ($show_current) echo $before . get_the_title() . $after;
}
}
// custom post type
} elseif ( !is_single() && !is_page() && get_post_type() != 'post' && !is_404() ) {
$post_type = get_post_type_object(get_post_type());
if ( get_query_var('paged') ) {
echo $sep . sprintf($link, get_post_type_archive_link($post_type->name), $post_type->label) . $sep . $before . sprintf($text['page'], get_query_var('paged')) . $after;
} else {
if ($show_current) echo $sep . $before . $post_type->label . $after;
}
} elseif ( is_attachment() ) {
if ($show_home_link) echo $sep;
$parent = get_post($parent_id);
$cat = get_the_category($parent->ID); $cat = $cat[0];
if ($cat) {
$cats = get_category_parents($cat, TRUE, $sep);
$cats = preg_replace('#<a([^>]+)>([^<]+)<\/a>#', $link_before . '<a$1' . $link_attr .'>' . $link_in_before . '$2' . $link_in_after .'</a>' . $link_after, $cats);
echo $cats;
}
printf($link, get_permalink($parent), $parent->post_title);
if ($show_current) echo $sep . $before . get_the_title() . $after;
} elseif ( is_page() && !$parent_id ) {
if ($show_current) echo $sep . $before . get_the_title() . $after;
} elseif ( is_page() && $parent_id ) {
if ($show_home_link) echo $sep;
if ($parent_id != $frontpage_id) {
$breadcrumbs = array();
while ($parent_id) {
$page = get_page($parent_id);
if ($parent_id != $frontpage_id) {
$breadcrumbs[] = sprintf($link, get_permalink($page->ID), get_the_title($page->ID));
}
$parent_id = $page->post_parent;
}
$breadcrumbs = array_reverse($breadcrumbs);
for ($i = 0; $i < count($breadcrumbs); $i++) {
echo $breadcrumbs[$i];
if ($i != count($breadcrumbs)-1) echo $sep;
}
}
if ($show_current) echo $sep . $before . get_the_title() . $after;
} elseif ( is_tag() ) {
if ( get_query_var('paged') ) {
$tag_id = get_queried_object_id();
$tag = get_tag($tag_id);
echo $sep . sprintf($link, get_tag_link($tag_id), $tag->name) . $sep . $before . sprintf($text['page'], get_query_var('paged')) . $after;
} else {
if ($show_current) echo $sep . $before . sprintf($text['tag'], single_tag_title('', false)) . $after;
}
} elseif ( is_404() ) {
if ($show_home_link && $show_current) echo $sep;
if ($show_current) echo $before . $text['404'] . $after;
} elseif ( has_post_format() && !is_singular() ) {
if ($show_home_link) echo $sep;
echo get_post_format_string( get_post_format() );
}
echo $wrap_after;
}
}
同时，我也把这个很棒的功能引入到 dangopress 主题 里面了，有兴趣的同学可以下载下来尝试下效果，这个主题接下来我还会继续维护。
我的网站效果：
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