Topic Tag: Post-relationship

// https://toolset.com/forums/topic/next-and-previous-sibling-posts-in-a-one-to-many-post-relationship/
// get a link to the next or previous sibling post in child post content template
// example: [tssupp-next-prev-child current="[wpv-post-id]" step="1" relslug="book-chapter"][/tssupp-next-prev-child]
// current: current post id, step: 1 for next or -1 for previous, relslug: slug of the post relationship
 
function tssupp_next_prev_child($atts) {
  $a = shortcode_atts( array(
    'current' => 0,
    'step' => '1',
    'relslug' => '',
  ), $atts );
  $link = '';
 
  // get all child posts
  $relationship_slug = $a['relslug'];
  $current_child_id = $a['current'];
  $parent_id = toolset_get_related_post( $current_child_id, $relationship_slug );
  $sibling_args = array(
    'query_by_role'=>'parent',
    'limit'=>1000,
    'role_to_return'=>'child',
    'orderby'=>'title'
  );
  $siblings = toolset_get_related_posts( $parent_id, $relationship_slug, $sibling_args );
 
  // loop over child posts and get index of the current post
  foreach($siblings as $i=>$sibling) {
    if( $sibling == $current_child_id ) {
      break;
    }
  }
 
  // increment or decrement index for next or previous sibling
  $i += $a['step'];
 
  // create link to next/previous sibling
  if(isset($siblings[$i])){
    $perm = get_the_permalink( $siblings[$i] );
    $title = get_the_title( $siblings[$i] );
    $link .= $a['step']=='1' ? "Next: " : "Previous: ";
    $link .= "<a href='" . $perm . "'>" . $title . "</a>";
  }
 
  // output the link, or empty string if not set
  return $link;
}
add_shortcode( 'tssupp-next-prev-child', 'tssupp_next_prev_child' );

[tssupp-next-prev-child step="1" relslug="book-chapter" current="[wpv-post-id]"][/tssupp-next-prev-child]

[tssupp-next-prev-child step="-1" relslug="book-chapter" current="[wpv-post-id]"][/tssupp-next-prev-child]

// create link to next/previous sibling
  if(isset($siblings[$i])){
    $perm = get_the_permalink( $siblings[$i] );
    $title = get_the_title( $siblings[$i] );
    $link .= $a['step']=='1' ? "Next: " : "Previous: ";
    $link .= "<a href='" . $perm . "'>" . $title . "</a>";
  }