make sure to generate valid filenames (#2238)

src/Utils/FileHelper.php

@@ -10,6 +10,7 @@
 namespace App\Utils;
 
 use Symfony\Component\Filesystem\Filesystem;
+use Symfony\Component\String\UnicodeString;
 
 final class FileHelper
 {
@@ -68,4 +69,20 @@ final class FileHelper
     {
         $this->filesystem->remove($filename);
     }
+
+    public static function convertToAsciiFilename(string $filename): string
+    {
+        $filename = new UnicodeString($filename);
+        $filename = (string) $filename->collapseWhitespace()->trim()->replace(PHP_EOL, '')->replace(' ', '_');
+
+        $dangerousCharacters = ['"', "'", '&', '/', '\\', '?', '#', '%'];
+        $filename = str_replace($dangerousCharacters, ' ', $filename);
+
+        $filename = new UnicodeString($filename);
+        $filename = (string) $filename->collapseWhitespace()->replace(' ', '_')->ascii()->trim();
+        $filename = preg_replace('/[^a-zA-Z0-9\x7f-\xff\-]++/', ' ', $filename);
+        $filename = str_replace(' ', '_', trim($filename));
+
+        return $filename;
+    }
 }