Experience

EE Gotchas: Nested ‘No_results’ Tags (Redux)

Published on 23rd July, 2012

Last week I published a post about a bug in the ExpressionEngine Template parser, which causes problems with nested no_results tags.

Said post includes a couple of quick fixes: one suitable for use by general ExpressionEngine developers; the other intended for add-on developers.

The “general” fix remains unchanged, so if you’re not an add-on developer your work here is done.

If you are an add-on developer, continue reading for a much better solution than the one I originally presented.

The original fix

Here’s the original fix, in case you’ve forgotten it:

$tagdata  = $this->EE->TMPL->tagdata;
$tag_name = 'no_soup_for_you';
$pattern  = '#' .LD .'if ' .$tag_name .RD .'(.*?)' .LD .'/if' .RD .'#s';

if (is_string($tagdata) && is_string($tag_name)
  && preg_match($pattern, $tagdata, $matches)
)
{
  return $matches[1];
}

It’s a simple solution, but has an obvious limitation: it won’t handle any {if} statements inside the {if no_soup_for_you}…{/if} block.

A better solution

Low was quick to point this out on Twitter, and after a brief but undignified scuffle, he agreed to furnish me with his superior solution.

Here it is:

private function _prep_no_results()
{
  // Shortcut to tagdata
  $td    =& $this->EE->TMPL->tagdata;
  $open  = "if no_soup_for_you";
  $close = '/if';

  // Check if there is a custom no_results conditional
  if (strpos($td, $open) !== FALSE
    && preg_match('#' .LD .$open .RD .'(.*?)' .LD .$close .RD .'#s', $td, $match)
  )
  {
    $this->EE->TMPL->log_item("Prepping {$open} conditional");

    // Check if there are conditionals inside of that
    if (stristr($match[1], LD.'if'))
    {
      $match[0] = $this->EE->functions->full_tag($match[0], $td, LD.'if', LD.'\/if'.RD);
    }

    // Set template's no_results data to found chunk
    $this->EE->TMPL->no_results = substr($match[0], strlen(LD.$open.RD), -strlen(LD.$close.RD));

    // Remove no_results conditional from tagdata
    $td = str_replace($match[0], '', $td);
  }
}

Usage

Call the _prep_no_results method before you start processing your module or plugin tag. It will search the current tag data for your custom “no results” block (in this case {if no_soup_for_you}...{/if}).

So far, so similar, but here’s where it gets clever.

Firstly, Low explicitly checks for any conditionals inside the “no results” block. Secondly, he assigns the contents of the custom “no results” block to $this->EE->TMPL->no_results.

This is really smart. I’ll let the man himself explain why:

I frequently call Channel::entries() from within my add-ons (Alphabet, Reorder, Search and Events), so I can’t just return the no_results bit. It’s very well possible that, when I call Channel::entries(), there are entries to be displayed, but because of other params set, no_results is triggered. To make sure it does so with the right content, I need to set the $EE->TMPL->no_results property.

Lodewijk Schutte

So there you have it. Thank you to Low for sharing this much better solution, and for being far too lazy to blog about it.