bs4breadcrumbs for wp

bs4breadcrumbs.php

<?php

/**
 * Retrieve category parents.
 *
 * @param int $id Category ID.
 * @param array $visited Optional. Already linked to categories to prevent duplicates.
 * @return string|WP_Error A list of category parents on success, WP_Error on failure.
 * 
 * file name: bs4breadcrumbs.php
 * 
 */
function custom_get_category_parents( $id, $visited = array() ) {
    $chain = '';
    $parent = get_term( $id, 'category' );
    
    if ( is_wp_error( $parent ) )
      return $parent;
    
    $name = $parent->name;
    
    if ( $parent->parent && ( $parent->parent != $parent->term_id ) && !in_array( $parent->parent, $visited ) ) {
      $visited[] = $parent->parent;
      $chain .= custom_get_category_parents( $parent->parent, $visited );
    }
    
    $chain .= '<li class="breadcrumb-item"><a href="' . esc_url( get_category_link( $parent->term_id ) ) . '">' . $name. '</a>' . '</li>';
    
    return $chain;
  }
  
  
  function bootstrap_breadcrumb() {
    global $post;
    
    $html = '<ol class="breadcrumb">';
    
    if ( (is_front_page()) || (is_home()) ) {
      $html .= '<li class="breadcrumb-item active">Home</li>';
    }
    
    else {
      $html .= '<li class="breadcrumb-item"><a href="'.esc_url(home_url('/')).'">Home</a></li>';
      
      if ( is_attachment() ) {
        $parent = get_post($post->post_parent);
        $categories = get_the_category($parent->ID);
        
        if ( $categories[0] ) {
          $html .= custom_get_category_parents($categories[0]);
        }
        
        $html .= '<li class="breadcrumb-item"><a href="' . esc_url( get_permalink( $parent ) ) . '">' . $parent->post_title . '</a></li>';
        $html .= '<li class="breadcrumb-item active">' . get_the_title() . '</li>';
      }
      
      elseif ( is_category() ) {
        $category = get_category( get_query_var( 'cat' ) );
        
        if ( $category->parent != 0 ) {
          $html .= custom_get_category_parents( $category->parent );
        }
        
        $html .= '<li class="breadcrumb-item active">' . single_cat_title( '', false ) . '</li>';
      }
      
      elseif ( is_page() && !is_front_page() ) {
        $parent_id = $post->post_parent;
        $parent_pages = array();
        
        while ( $parent_id ) {
          $page = get_page($parent_id);
          $parent_pages[] = $page;
          $parent_id = $page->post_parent;
        }
        
        $parent_pages = array_reverse( $parent_pages );
        
        if ( !empty( $parent_pages ) ) {
          foreach ( $parent_pages as $parent ) {
            $html .= '<li class="breadcrumb-item"><a href="' . esc_url( get_permalink( $parent->ID ) ) . '">' . get_the_title( $parent->ID ) . '</a></li>';
          }
        }
        
        $html .= '<li class="breadcrumb-item active">' . get_the_title() . '</li>';
      }
      
      elseif ( is_singular( ) ) {
        $categories = get_the_category();

        if( !empty( $categories ) ) {
            $html .= custom_get_category_parents($categories[0]);
        } else {
            $html .= '<li class="breadcrumb-item"><a href="'.get_option('home').'/'.get_post_type_object( get_post_type($post) )->name.'">'.get_post_type_object( get_post_type($post) )->label.'</a></li>';
        }
        
        // if ( $categories[0] ) {
        //   $html .= custom_get_category_parents($categories[0]);
        // }
        
        $html .= '<li class="breadcrumb-item active">' . get_the_title() . '</li>';
      }
      
      elseif ( is_tag() ) {
        $html .= '<li class="breadcrumb-item active">' . single_tag_title( '', false ) . '</li>';
      }
      
      elseif ( is_day() ) {
        $html .= '<li class="breadcrumb-item"><a href="' . esc_url( get_year_link( get_the_time( 'Y' ) ) ) . '">' . get_the_time( 'Y' ) . '</a></li>';
        $html .= '<li class="breadcrumb-item"><a href="' . esc_url( get_month_link( get_the_time( 'Y' ), get_the_time( 'm' ) ) ) . '">' . get_the_time( 'm' ) . '</a></li>';
        $html .= '<li class="breadcrumb-item active">' . get_the_time('d') . '</li>';
      }
      
      elseif ( is_month() ) {
        $html .= '<li class="breadcrumb-item"><a href="' . esc_url( get_year_link( get_the_time( 'Y' ) ) ) . '">' . get_the_time( 'Y' ) . '</a></li>';
        $html .= '<li class="breadcrumb-item active">' . get_the_time( 'F' ) . '</li>';
      }
      
      elseif ( is_year() ) {
        $html .= '<li class="breadcrumb-item active">' . get_the_time( 'Y' ) . '</li>';
      }
      
      elseif ( is_author() ) {
        $html .= '<li class="breadcrumb-item active">' . get_the_author() . '</li>';
      }
      
      elseif ( is_search() ) {
        
      }
      
      elseif ( is_404() ) {
        
      }
      
    }
    
    $html .= '</ol>';
    
    echo $html;
}