Implement one-click image cache purge tool

tools/image_cache.inc.php

@@ -0,0 +1,88 @@
+<?php
+if (!defined('PHPWG_ROOT_PATH'))
+{
+  die('Hacking attempt!');
+}
+
+function bratonien_tools_clear_image_cache()
+{
+  $cache_root = rtrim(PHPWG_ROOT_PATH, '/\\') . '/_data/i';
+
+  if (!is_dir($cache_root))
+  {
+    throw new RuntimeException('Bildcache-Verzeichnis wurde nicht gefunden: ' . $cache_root);
+  }
+
+  $real_cache_root = realpath($cache_root);
+  $expected_root = realpath(rtrim(PHPWG_ROOT_PATH, '/\\') . '/_data/i');
+
+  if ($real_cache_root === false || $expected_root === false || $real_cache_root !== $expected_root)
+  {
+    throw new RuntimeException('Sicherheitspruefung des Bildcache-Pfads fehlgeschlagen.');
+  }
+
+  $deleted_files = 0;
+  $deleted_bytes = 0;
+  $failed_files = 0;
+
+  $iterator = new RecursiveIteratorIterator(
+    new RecursiveDirectoryIterator($real_cache_root, FilesystemIterator::SKIP_DOTS),
+    RecursiveIteratorIterator::CHILD_FIRST
+  );
+
+  foreach ($iterator as $item)
+  {
+    if (!$item->isFile() && !$item->isLink())
+    {
+      continue;
+    }
+
+    if (strtolower($item->getFilename()) === 'index.htm')
+    {
+      continue;
+    }
+
+    $path = $item->getPathname();
+    $size = $item->isFile() ? $item->getSize() : 0;
+
+    if (@unlink($path))
+    {
+      $deleted_files++;
+      $deleted_bytes += $size;
+    }
+    else
+    {
+      $failed_files++;
+    }
+  }
+
+  if ($failed_files > 0)
+  {
+    throw new RuntimeException(
+      sprintf('%d Dateien geloescht, %d Dateien konnten nicht geloescht werden.', $deleted_files, $failed_files)
+    );
+  }
+
+  return array(
+    'message' => sprintf(
+      'Bildcache geleert: %d Dateien (%s) entfernt.',
+      $deleted_files,
+      bratonien_tools_format_bytes($deleted_bytes)
+    ),
+  );
+}
+
+function bratonien_tools_format_bytes($bytes)
+{
+  $units = array('B', 'KB', 'MB', 'GB', 'TB');
+  $value = (float) $bytes;
+  $unit = 0;
+
+  while ($value >= 1024 && $unit < count($units) - 1)
+  {
+    $value /= 1024;
+    $unit++;
+  }
+
+  return number_format($value, $unit === 0 ? 0 : 2, ',', '.') . ' ' . $units[$unit];
+}