Gazelle/sections/tools/development/clear_cache.php

<?php
#declare(strict_types=1);

if (!check_perms('users_mod') || !check_perms('admin_clear_cache')) {
    error(403);
}

View::show_header('Clear a cache key');

// Make sure the form was sent
if (!empty($_GET['key'])) {
    $Keys = array_map('trim', preg_split('/\s+/', $_GET['key']));
}

if (isset($Keys) && $_GET['type'] === 'clear') {
    foreach ($Keys as $Key) {
        if (preg_match('/(.*?)(\d+)\.\.(\d+)$/', $Key, $Matches) && is_number($Matches[2]) && is_number($Matches[3])) {
            for ($i = $Matches[2]; $i <= $Matches[3]; $i++) {
                $Cache->delete_value($Matches[1].$i);
            }
        } else {
            $Cache->delete_value($Key);
        }
    }
    echo '<div class="save_message">Key(s) ' . implode(', ', array_map('display_str', $Keys)) . ' cleared!</div>';
}
$MultiKeyTooltip = 'Enter cache keys delimited by any amount of whitespace.';
?>

<div class="header">
  <h2>Clear a cache key</h2>
</div>

<table class="layout" cellpadding="2" cellspacing="1" border="0" align="center">
  <tr class="tooltip" title="<?=$MultiKeyTooltip?>">
    <td>Keys</td>
    <td>
      <form class="manage_form" name="cache" method="get" action="">
        <input type="hidden" name="action" value="clear_cache" />

        <select name="type">
          <option value="view">View</option>
          <option value="clear">Clear</option>
        </select>

        <textarea type="text" name="key" id="key"
          class="inputtext"><?=((isset($_GET['key']) && (isset($_GET['submit']))) ? display_str($_GET['key']) : '')?></textarea>
        <input type="submit" name="submit" class="submit" />
      </form>
    </td>
  </tr>
</table>

<?php
if (isset($Keys) && $_GET['type'] === 'view') {
    ?>
<table class="layout" cellpadding="2" cellspacing="1" border="0" align="center" style="margin-top: 1em;">
  <?php
  foreach ($Keys as $Key) {
      ?>
  <tr>
    <td>
      <?=display_str($Key)?>
    </td>

    <td>
      <pre>
      <?php var_dump($Cache->get_value($Key)); ?>
      </pre>
    </td>
  </tr>
  <?php
  } ?>
</table>
<?php
}
View::show_footer();