大多数面包屑函数的问题是它依赖于$post 对象。不仅是$post 全球完全不可靠（参见我的帖子here），它甚至可能不包含我们需要的数据，即使$post 全局未受损
这个$post 全局存档页面（包括类别、标记、日期、分类术语、作者和自定义帖子类型存档）包含循环前的第一篇帖子。第一篇帖子并非总是来自所选的归档文件（您所在的归档文件页面），这意味着您要查找的信息可能不正确，即使$post global未受到损害。第一篇文章可能不来自所选归档的情况是通过自定义粘滞和the_posts 滤器
我最近重写了一个非常旧的breadcrumb函数，它使用$GLOBALS[\'wp_the_query\'] 对象和保存在$GLOBALS[\'wp_the_query\'] 全球的这样，我们就有了99.999%可靠的面包屑，它不依赖于$post 全局或任何泄露的数据。
以下是函数：（需要PHP 5.4+。此外，可以根据需要进行更改）
function get_hansel_and_gretel_breadcrumbs()
{
// Set variables for later use
$here_text = __( \'You are currently here!\' );
$home_link = home_url(\'/\');
$home_text = __( \'Home\' );
$link_before = \'<span typeof="v:Breadcrumb">\';
$link_after = \'</span>\';
$link_attr = \' rel="v:url" property="v:title"\';
$link = $link_before . \'<a\' . $link_attr . \' href="%1$s">%2$s</a>\' . $link_after;
$delimiter = \' » \'; // Delimiter between crumbs
$before = \'<span class="current">\'; // Tag before the current crumb
$after = \'</span>\'; // Tag after the current crumb
$page_addon = \'\'; // Adds the page number if the query is paged
$breadcrumb_trail = \'\';
$category_links = \'\';
/**
* Set our own $wp_the_query variable. Do not use the global variable version due to
* reliability
*/
$wp_the_query = $GLOBALS[\'wp_the_query\'];
$queried_object = $wp_the_query->get_queried_object();
// Handle single post requests which includes single pages, posts and attatchments
if ( is_singular() )
{
/**
* Set our own $post variable. Do not use the global variable version due to
* reliability. We will set $post_object variable to $GLOBALS[\'wp_the_query\']
*/
$post_object = sanitize_post( $queried_object );
// Set variables
$title = apply_filters( \'the_title\', $post_object->post_title );
$parent = $post_object->post_parent;
$post_type = $post_object->post_type;
$post_id = $post_object->ID;
$post_link = $before . $title . $after;
$parent_string = \'\';
$post_type_link = \'\';
if ( \'post\' === $post_type )
{
// Get the post categories
$categories = get_the_category( $post_id );
if ( $categories ) {
// Lets grab the first category
$category = $categories[0];
$category_links = get_category_parents( $category, true, $delimiter );
$category_links = str_replace( \'<a\', $link_before . \'<a\' . $link_attr, $category_links );
$category_links = str_replace( \'</a>\', \'</a>\' . $link_after, $category_links );
}
}
if ( !in_array( $post_type, [\'post\', \'page\', \'attachment\'] ) )
{
$post_type_object = get_post_type_object( $post_type );
$archive_link = esc_url( get_post_type_archive_link( $post_type ) );
$post_type_link = sprintf( $link, $archive_link, $post_type_object->labels->singular_name );
}
// Get post parents if $parent !== 0
if ( 0 !== $parent )
{
$parent_links = [];
while ( $parent ) {
$post_parent = get_post( $parent );
$parent_links[] = sprintf( $link, esc_url( get_permalink( $post_parent->ID ) ), get_the_title( $post_parent->ID ) );
$parent = $post_parent->post_parent;
}
$parent_links = array_reverse( $parent_links );
$parent_string = implode( $delimiter, $parent_links );
}
// Lets build the breadcrumb trail
if ( $parent_string ) {
$breadcrumb_trail = $parent_string . $delimiter . $post_link;
} else {
$breadcrumb_trail = $post_link;
}
if ( $post_type_link )
$breadcrumb_trail = $post_type_link . $delimiter . $breadcrumb_trail;
if ( $category_links )
$breadcrumb_trail = $category_links . $breadcrumb_trail;
}
// Handle archives which includes category-, tag-, taxonomy-, date-, custom post type archives and author archives
if( is_archive() )
{
if ( is_category()
|| is_tag()
|| is_tax()
) {
// Set the variables for this section
$term_object = get_term( $queried_object );
$taxonomy = $term_object->taxonomy;
$term_id = $term_object->term_id;
$term_name = $term_object->name;
$term_parent = $term_object->parent;
$taxonomy_object = get_taxonomy( $taxonomy );
$current_term_link = $before . $taxonomy_object->labels->singular_name . \': \' . $term_name . $after;
$parent_term_string = \'\';
if ( 0 !== $term_parent )
{
// Get all the current term ancestors
$parent_term_links = [];
while ( $term_parent ) {
$term = get_term( $term_parent, $taxonomy );
$parent_term_links[] = sprintf( $link, esc_url( get_term_link( $term ) ), $term->name );
$term_parent = $term->parent;
}
$parent_term_links = array_reverse( $parent_term_links );
$parent_term_string = implode( $delimiter, $parent_term_links );
}
if ( $parent_term_string ) {
$breadcrumb_trail = $parent_term_string . $delimiter . $current_term_link;
} else {
$breadcrumb_trail = $current_term_link;
}
} elseif ( is_author() ) {
$breadcrumb_trail = __( \'Author archive for \') . $before . $queried_object->data->display_name . $after;
} elseif ( is_date() ) {
// Set default variables
$year = $wp_the_query->query_vars[\'year\'];
$monthnum = $wp_the_query->query_vars[\'monthnum\'];
$day = $wp_the_query->query_vars[\'day\'];
// Get the month name if $monthnum has a value
if ( $monthnum ) {
$date_time = DateTime::createFromFormat( \'!m\', $monthnum );
$month_name = $date_time->format( \'F\' );
}
if ( is_year() ) {
$breadcrumb_trail = $before . $year . $after;
} elseif( is_month() ) {
$year_link = sprintf( $link, esc_url( get_year_link( $year ) ), $year );
$breadcrumb_trail = $year_link . $delimiter . $before . $month_name . $after;
} elseif( is_day() ) {
$year_link = sprintf( $link, esc_url( get_year_link( $year ) ), $year );
$month_link = sprintf( $link, esc_url( get_month_link( $year, $monthnum ) ), $month_name );
$breadcrumb_trail = $year_link . $delimiter . $month_link . $delimiter . $before . $day . $after;
}
} elseif ( is_post_type_archive() ) {
$post_type = $wp_the_query->query_vars[\'post_type\'];
$post_type_object = get_post_type_object( $post_type );
$breadcrumb_trail = $before . $post_type_object->labels->singular_name . $after;
}
}
// Handle the search page
if ( is_search() ) {
$breadcrumb_trail = __( \'Search query for: \' ) . $before . get_search_query() . $after;
}
// Handle 404\'s
if ( is_404() ) {
$breadcrumb_trail = $before . __( \'Error 404\' ) . $after;
}
// Handle paged pages
if ( is_paged() ) {
$current_page = get_query_var( \'paged\' ) ? get_query_var( \'paged\' ) : get_query_var( \'page\' );
$page_addon = $before . sprintf( __( \' ( Page %s )\' ), number_format_i18n( $current_page ) ) . $after;
}
$breadcrumb_output_link = \'\';
$breadcrumb_output_link .= \'<div class="breadcrumb">\';
if ( is_home()
|| is_front_page()
) {
// Do not show breadcrumbs on page one of home and frontpage
if ( is_paged() ) {
$breadcrumb_output_link .= $here_text . $delimiter;
$breadcrumb_output_link .= \'<a href="\' . $home_link . \'">\' . $home_text . \'</a>\';
$breadcrumb_output_link .= $page_addon;
}
} else {
$breadcrumb_output_link .= $here_text . $delimiter;
$breadcrumb_output_link .= \'<a href="\' . $home_link . \'" rel="v:url" property="v:title">\' . $home_text . \'</a>\';
$breadcrumb_output_link .= $delimiter;
$breadcrumb_output_link .= $breadcrumb_trail;
$breadcrumb_output_link .= $page_addon;
}
$breadcrumb_output_link .= \'</div><!-- .breadcrumbs -->\';
return $breadcrumb_output_link;
}
您可以简单地如下所示
echo get_hansel_and_gretel_breadcrumbs();
在需要的地方
这个breadcrumb函数还负责自定义帖子类型
