Wordpress - related posts by custom taxonomy problem

Question

Hello,

I'm trying to display related posts based on a custum taxonomy. I found a query at wordpress.org that kind of works. However the original post gets duplicated in the results multiple times. (words is the name of the custom taxonomy I use) What seems to happen is that the single post gets duplicated according to what amount showpost is set. Any idea's what could cause this?

The code:

<?php
//for in the loop, display all "content", regardless of post_type,
//that have the same custom taxonomy (e.g. words) terms as the current post
$backup = $post;  // backup the current object
$found_none = '<h2>No related posts found!</h2>';
$taxonomy = 'words';//  e.g. post_tag, category, custom taxonomy
$param_type = 'words'; //  e.g. tag__in, category__in, but genre__in will NOT work
$post_types = get_post_types( array('public' => true), 'names' );
$tax_args=array('orderby' => 'none');
$tags = wp_get_post_terms( $post->ID , $taxonomy, $tax_args);
if ($tags) {
  foreach ($tags as $tag) {
    $args=array(
      "$param_type" => $tag->slug,
      'post__not_in' => array($post->ID),
      'post_type' => $post_types,
      'showposts'=>5,
      'caller_get_posts'=>1
    );
    $my_query = null;
    $my_query = new WP_Query($args);
    if( $my_query->have_posts() ) {
      while ($my_query->have_posts()) : $my_query->the_post(); ?>
        <h3><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title(); ?>"><?php the_title(); ?></a></h3>
        <?php $found_none = '';
      endwhile;
    }
  }
}
if ($found_none) {
echo $found_none;
}
$post = $backup;  // copy it back
wp_reset_query(); // to use the original query again
?>

Answer 1

It's inside the foreach loop that you're getting duplications. That code is effectively saying;

1. Get all the terms for taxonomy type $param_type
2. For each term, get 5 posts that are tagged with that term

So if you have a post that is tagged with more than one term of the same taxonomy, it's likely it will appear more than once.

You can iteratively add queried posts into the post__not_in array to ensure they don't appear again;

1. Add $post_not_in = array($post->ID); just above if ($tags) {

2. Then replace the line post__not_in' => array($post->ID), with post__not_in' => $post_not_in,.

3. Finally, drop $post_not_in[] = get_the_ID(); inside your while loop, after $found_none = '';