How to return results of a get_posts() in explicitly defined order

Question

I'm trying to create a loop of explicity ordered posts, for example:

<?php $args = array(
    'include'         => '1,3,8,4,12' ); ?>

<?php get_posts( $args ); ?> 

The results are ordered by date by default, and there is no orderby option to return the posts in the order they were entered. There have been multiple bug/feature requests posted about this in Trac, but so far no luck. I've mucked around in the core files a bit but haven't gotten anywhere with it.

Can anyone suggest a workaround for this behavior?

Cheers, Dalton

Answer 1

Okay, I was determined to find a way to do this, and I think I've got it. I had hoped to find a simpler solution and avoid having to use a new WP_Query object, but it's just too ingrained into how the loop works. First, we have a couple of utility functions:

// Set post menu order based on our list  
function set_include_order(&$query, $list) {
    // Map post ID to its order in the list:
    $map = array_flip($list);

    // Set menu_order according to the list     
    foreach ($query->posts as &$post) {
      if (isset($map[$post->ID])) {
        $post->menu_order = $map[$post->ID];
      }
    }  
}

// Sort posts by $post->menu_order.                                 
function menu_order_sort($a, $b) {
  if ($a->menu_order == $b->menu_order) {
    return 0;
  }
  return ($a->menu_order < $b->menu_order) ? -1 : 1;
}

These will allow us to set the menu_order property based on our own list, and then sort the posts in a query object based on that.

Here's how we query and sort the posts:

$plist = array(21, 43, 8, 44, 12);
$args = array(
  'post_type' => 'attachment',
  'post_status' => 'any',
  'post__in' => $plist 
);

// Create a new query  
$myquery = new WP_Query($args);

// set the menu_order
set_include_order($myquery, $plist);

// and actually sort the posts in our query
usort($myquery->posts, 'menu_order_sort');

So now we have our own query object, and the $myquery->posts is sorted according to our custom menu_order_sort function. The only tricky part now, is that we must construct our loop using our custom query object:

while($myquery->have_posts()) : $myquery->the_post();
  ?>
    <div><a id="post_id_<?php the_ID(); ?>" class="nb" href="<?php the_permalink(); ?>"><?php the_title(); ?></a> Post ID: <?php the_ID(); ?>
    </div>
  <?php

endwhile;
wp_reset_postdata();

Obviously, you'd fix up the loop template code there.

I was hoping to find a solution that didn't require the use of a custom query object, perhaps by using query_posts() and replacing the posts propery on the global $wp_query, but I just couldn't get it to work right. With a little more time to work on it, that might have been doable.

Anyhow, see if that will get you where you need to go?

Answer 2

You can try this:

add_filter('posts_orderby', 'enforce_specific_order');
$posts = get_posts($args);
remove_filter( current_filter(), __FUNCTION__ );

function enforce_specific_order($orderby) {
    global $wpdb;
    return "FIND_IN_SET(".$wpdb->posts.".ID, '1,3,8,4,12') ASC";
}

Answer 3

I think this is the fastest way to return the results of a get_posts in a defined order. And besides that, it's a native solution, without hacks

<?php

$posts_order = array('1,3,8,4,12');
$args = array(
    'post__in' => $posts_order,
    'orderby' => 'post__in'
); 
get_posts( $args ); 

?> 

Answer 4

As of WordPress 3.5, this feature is now in core. You can explicitly order posts using the "post__in" parameter. http://core.trac.wordpress.org/ticket/13729

Answer 5

How about just clearing the orderby with a filter? Right before you query your posts, put in:

add_filter('posts_orderby', '__return_false');

Then, after your loop is done:

remove_filter('posts_orderby', '__return_false');

The reason for removing the filter again is in case you have other loops on the page (such as from widgets) that will need their normal explicit ordering.