Fred Boyle // September 9, 2010

ExpressionEngine and previous/next

Recently ExpressionEngine developer Ryan Masuga complained on Twitter about the lack of ordering when using EE’s next/previous tags. I had actually solved this troublesome issue a while back but never thought of sharing my solution until then. So since sharing this solution with Ryan and receiving his adoration for it I thought I’d share with the rest of the world.

So without further ado I’ll present the code and walk through the various bits and considerations when using this code.

{exp:channel:entries channel="projects" dynamic="off" orderby="entry_date" sort="desc"}
<?php
  // Store entries in order
  $projects['{entry_id}'] = '{page_uri}'; 
?>
{/exp:channel:entries}
<?php
  $current = '{embed:id}';
  $keys = array_keys($projects);
  $offset = array_search($current, $keys);
  $prev_key = @$keys[$offset - 1];
  $next_key = @$keys[$offset + 1];
  $prev = ($prev_key) ? '<a href="' . $projects[$prev_key] . '" class="previous">⟨ Previous</a>' : "";
  $next = ($next_key) ? '<a href="' . $projects[$next_key] . '" class="next">Next ⟩</a>' : "";
?>
<div class="side-block tungsten upper prev-next">
  <?= $prev ?><?= $next ?>
</div>

So what’s going on here? Let’s explore each section of code.

{exp:channel:entries channel="projects" dynamic="off" orderby="entry_date" sort="desc"}
<?php
  // Store entries in order
  $projects['{entry_id}'] = '{page_uri}'; 
?>
{/exp:channel:entries}

This first block sets up a standard {exp:channel:entries}* tag with the proper ordering parameters we want. The difference though is we’re actually storing the output in a PHP array for later use instead of out to the browser. In this case I’m using the page_uri as what I’ll want to use later and the entry_id is the index to my array. In order for this to function properly the template should be set to allow PHP and parse at output.

Next we need to do some magic to calculate which entry is next and which is the previous one to our current entry.

<?php
  $current = '{embed:id}';
  $keys = array_keys($projects);
  $offset = array_search($current, $keys);
  $prev_key = @$keys[$offset - 1];
  $next_key = @$keys[$offset + 1];
  $prev = ($prev_key) ? '<a href="' . $projects[$prev_key] . '" class="previous">⟨ Previous</a>' : "";
  $next = ($next_key) ? '<a href="' . $projects[$next_key] . '" class="next">Next ⟩</a>' : "";
?>

So with this we store our current entry_id for the page/entry from which this embed was requested. Then we find the keys of our previously stored array and calculating the previous and next values.

Once we have those I build a link to the previous as well as the next entry. Which I then output in this code:

<div class="side-block tungsten upper prev-next">
  <?= $prev ?><?= $next ?>
</div>

So that’s the magic of the embed itself. In order to make sure it all functions properly you would use an embed tag similar to this:

{embed="template_group/prev-next-template" id="{entry_id}"}

That’s it! Let me know your thoughts or questions in the comments.