递归函数返回数组始终为null

Question

Trying to return an array of items from api call, the var_dump spits out the array that I want, but the return is always null. What am I missing? Many thanks

function get_all_opened($mailgun, $domain, $list_address, $items, $page_advance = false, $next_url = false) 
{

    $end_point = "{$domain}/events";
    if($page_advance) {
        $end_point = "{$domain}/events/{$next_url}";
    }

    //API Call
    $stats = $mailgun->get($end_point, array(
        'event' => 'opened',
        'limit' => 25,
        'list' => $list_address
    ));

    $item_count = count($stats->http_response_body->items);

    if($item_count > 0) {
        $items[] = $stats->http_response_body->items;
    }
    if($item_count < 25) {
        var_dump($items); //Correct result set
        return $items; //Always NULL
    }

    if($item_count > 24) {
        $next_parts = explode ('/', $stats->http_response_body->paging->next);
        $next_url = end($next_parts);
        get_all_opened($mailgun, $domain, $list_address, $items, true, $next_url);
     }
}

$items = array();
get_all_opened($mailgun, $domain, $list_address, $items);

Answer 1

Fixed and working function below

function get_all_opened($mailgun, $domain, $list_address, $items, $page_advance = false, $next_url = false) {

  $end_point = "{$domain}/events";
  if($page_advance) {
    $end_point = "{$domain}/events/{$next_url}";
  }

  //API Call
  $stats = $mailgun->get($end_point, array(
      'event' => 'opened',
      'limit' => 25,
      'list' => $list_address
  ));


  $item_count = count($stats->http_response_body->items);

//add items to return array
  if($item_count > 0) {
    $items[] = $stats->http_response_body->items;
  }


  if($item_count > 24) {
    $next_parts = explode ('/', $stats->http_response_body->paging->next);
    $next_url = end($next_parts);
    return get_all_opened($mailgun, $domain, $list_address, $items, true, $next_url);
  } else {
    return $items;
  }

}