Added twig extension to format file size, links to download and delete files attached to the book.

src/Twig/AppExtension.php

@@ -4,6 +4,7 @@
 namespace App\Twig;
 
 use Twig\Extension\AbstractExtension;
+use Twig\TwigFilter;
 use Twig\TwigFunction;
 
 class AppExtension extends AbstractExtension
@@ -15,8 +16,22 @@ class AppExtension extends AbstractExtension
         ];
     }
 
+    public function getFilters()
+    {
+        return [
+            new TwigFilter('bytes_format', [$this, 'bytes_format']),
+        ];
+    }
+
     public function file_exists(string $file): bool
     {
         return file_exists(ltrim($file, '/'));
     }
+
+    public function bytes_format(int $bytes): string
+    {
+        $base = log($bytes) / log(1024);
+        $suffix = array("B", "KB", "MB", "GB", "TB")[floor($base)];
+        return round(pow(1024, $base - floor($base)), 2) . $suffix;
+    }
 }