Get next and previous 3 posts in a term in single post page

Question

I have a the following

• Custom post type: episode

• Custom taxonomy: series

  • sub terms real deal -> season 1, season 2, season 3, etc.

The terms are hierarchical, and the entire thing is intended to be structured like a TV series (each "series" has "seasons").

On the single-episode.php page, I want to display the current episode, AS WELL AS links to the next 3 episodes and previous 3 episodes in that season.

As an example, if on the "Season 1 - Episode 5" page, I need to get content for Season 1,

Episodes 4,3,2 + Season 1 Episodes 6,7,8.

I'm having trouble figuring out how to do this inside the loop on a single episode page.

Here's what I currently have, however it does not work -- it just repeats the current page episode title over and over with a

trying to get property of non-object

error.

<?php
  $args = array(
      'post-type'      => 'episode',
      'post-status'    => 'publish',
      'posts_per_page' => 6,
      'tax_query'      => array(
          'relation' => 'AND',
          array(
              'taxonomy' => 'series',
              'field'    => 'slug',
              /* Name of the "series" (in slug format) */
              'terms'    => array( 'season-1' ),
          ),
          array(
              'taxonomy' => 'series',
              'field'    => 'slug',
              /* Name of the "seasons" (in slug format) DYNAMIC */
              'terms'    => array( $term->slug ),
          )
      )
  );
  $episodes = new WP_Query( $args );
  foreach( $episodes as $episode ) {
    echo get_the_title($episode->id);
  }
?>

---

EDIT:

Here's my updated query, still a work in progress. It does not seem to be getting anything at the moment. I want to get a total of 6 results, 3 posted BEFORE to the current post, 3 posted AFTER the current post. I'm trying to use the post_date for both the before and after properties of date_query but not sure if I'm doing it right.

$args = [
    'tax_query' => [
      'relation' => 'AND', [
        'taxonomy' => 'series',
        'field'    => 'slug',
        /* Name of the "series" (in slug format) */
        'terms'    => ['season-1'],
      ]
    ],
    'posts_per_page' => 6,
    /* make query more efficient */
    'no_found_rows' => true,
    /* dont let filters/pre_get_posts modify query */
    'suppress_filters' => true,
    'date_query' => [
      [
        'before'    => $post_object->post_date,
        'after'     => $post_object->post_date,
      ],
      'inclusive' => false
    ]
];
$q = new WP_Query( $args );
return $q->posts;

---

EDIT 2:

I've gotten my desired effect working using a very inefficient method -- it works, but I'd LOVE to hear some tips to optimize it! seems very expensive in terms of queries right now.

$orig_post = $post;
$orig_terms = wp_get_post_terms($orig_post->ID, 'series');
$current_post = $post;
$adjPost = [
  'prev' => [],
  'next' => []
];

for($i = 1; $i <= 3; $i++){
  $post = get_previous_post(true, '', 'series'); // this uses $post->ID
  if ( $post ) {
    $these_terms = wp_get_post_terms($post->ID, 'series');
    if ( $these_terms[1]->slug === $orig_terms[1]->slug) {
      array_push( $adjPost['prev'], $post );
    }
  }
}
$post = $current_post;

for($i = 1; $i <= 3; $i++){
  $post = get_next_post(true, '', 'series'); // this uses $post->ID
  if ( $post ) {
    $these_terms = wp_get_post_terms($post->ID, 'series');
    if ( $these_terms[1]->slug === $orig_terms[1]->slug) {
      array_push( $adjPost['next'], $post );
    }
  }
}
$post = $current_post;

echo "<h1>Prev:</h1>";
foreach ( $adjPost['prev'] as $prev ) {
  echo '<br>';
  echo $prev->post_title;
}

echo "<h1>Next:</h1>";
foreach ( $adjPost['next'] as $next ) {
  echo '<br>';
  echo $next->post_title;
}

Answer 1

You second approach (EDIT 2) is quite buggy and inefficient unfortunately. Also, you are not going to do this in one query.

As I already stated, you need to look at the approach in this answer I have recently done. You were almost there in your first edit, the only problem is, you cannot do this in one query, you will have to do two, one to get the previous set of posts, the other to get the next set of posts.

I have optimized the code to do only get the necessary info and nothing more. WP_Query results is also cached, so you really don't have to to worry that much about efficiency.

I'm not going to rerun through all the detail again in this answer, you should go through the linked post in detail, but you can try something like this (CAVEAT: Untested. Please see the notes in linked answer)

$post_object = get_queried_object();
$terms = wp_get_post_terms( $post_object->ID, 'series', array( 'fields' => 'ids' ) ); // Set fields to get only term ID's to make this more effient
$args = [
    'post_type' => $post_object->post_type,
    'tax_query' => [
       [
        'taxonomy' => 'series',
        'terms'    => $terms,
      ]
    ],
    'posts_per_page' => 3,
    'order' => 'ASC' // CHANDE TO DESC IF NOT CORRECT
    /* make query more efficient */
    'no_found_rows' => true,
    /* dont let filters modify query */
    'suppress_filters' => true,
    'date_query' => [
      [
        'before'    => $post_object->post_date,
        'inclusive' => false
      ],
    ]
];
$q1 = new WP_Query( $args );
var_dump( $q1->posts );

$args1 = [
    'post_type' => $post_object->post_type,
    'tax_query' => [
       [
        'taxonomy' => 'series',
        'terms'    => $terms,
      ]
    ],
    'posts_per_page' => 3,
    'order' => 'DESC' // CHANDE TO ASC IF NOT CORRECT
    /* make query more efficient */
    'no_found_rows' => true,
    /* dont let filters modify query */
    'suppress_filters' => true,
    'date_query' => [
      [
        'after'    => $post_object->post_date,
        'inclusive' => false
      ],
    ]
];
$q2 = new WP_Query( $args1 );
var_dump( $q2->posts );

Answer 2

Your syntax is slightly off - $episodes is an instance of WP_Query, not an array. If you want a full-blown loop for using all template tags, use:

while ( $episodes->have_posts() ) {
    $episodes->the_post();

    the_title(); // Episode title
    the_content(); // Episode content
}

wp_reset_postdata(); // Restore current episode

Otherwise you can just foreach on the posts property:

foreach ( $episodes->posts as $episode ) {
    echo get_the_title( $episode ); // Most template tags accept a post object
    echo get_the_post_thumbnail( $episode->ID ); // Only accepts post ID
    echo get_the_content(); // Does not accept a post argument, you'd need the loop above to set up the global post object
}