PHP 遞迴掃描目錄並依副檔名過濾儲存至陣列

基本掃描：glob()

$files = glob("*.{jpg,png,gif,webp}", GLOB_BRACE);
print_r($files);

遞迴掃描：RecursiveDirectoryIterator (SPL)

$dir = new RecursiveDirectoryIterator(__DIR__, FilesystemIterator::SKIP_DOTS);
$iter = new RecursiveIteratorIterator($dir);
$regex = new RegexIterator($iter, '/\.(jpg|png|gif|webp)$/i');

$files = [];
foreach ($regex as $file) {
    if ($file->isFile()) {
        $files[] = $file->getPathname();
    }
}
print_r($files);

自訂函式：scan_dir($path, $extensions, $recursive)

/**
 * 掃描目錄回傳符合副檔名的檔案陣列
 * @param string $path 目錄路徑
 * @param array $extensions 允許副檔名 ['jpg','png'] 或 null=全部
 * @param bool $recursive 是否遞迴子目錄
 * @return array 絕對路徑陣列
 */
function scan_dir($path, $extensions = null, $recursive = true) {
    $path = rtrim($path, '/\\');
    $flags = FilesystemIterator::KEY_AS_PATHNAME | FilesystemIterator::CURRENT_AS_FILEINFO | FilesystemIterator::SKIP_DOTS;
    
    $iterator = $recursive 
        ? new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path, $flags))
        : new FilesystemIterator($path, $flags);
    
    $allowed = $extensions ? array_flip(array_map('strtolower', $extensions)) : null;
    $files = [];
    
    foreach ($iterator as $file) {
        if (!$file->isFile()) continue;
        if ($allowed) {
            $ext = strtolower($file->getExtension());
            if (!isset($allowed[$ext])) continue;
        }
        $files[] = $file->getPathname();
    }
    return $files;
}

// 使用
$images = scan_dir('/var/www/uploads', ['jpg','png','webp'], true);
print_r($images);

效能比較 (10 萬檔案測試)

常見需求擴充

• 依修改時間排序：usort($files, fn($a,$b) => filemtime($b) - filemtime($a))
• 分頁處理：array_slice($files, $offset, $limit)
• 計算總大小：array_sum(array_map('filesize', $files))
• 輸出 JSON 供前端樹狀選單：遞迴建立巢狀陣列