fix: Fix downloading a playlist as a TAR archive

This is the only time where youtube-dl returning an empty URL is not a problem.

classes/EmptyUrlException.php

@@ -0,0 +1,15 @@
+<?php
+/**
+ * EmptyUrlException class.
+ */
+
+namespace Alltube;
+
+use Exception;
+
+/**
+ * Exception thrown when youtube-dl returns an empty URL.
+ */
+class EmptyUrlException extends Exception
+{
+}

classes/VideoDownload.php

@@ -155,7 +155,7 @@ class VideoDownload
         $urls = explode("\n", $this->getProp($url, $format, 'get-url', $password));
 
         if (empty($urls[0])) {
-            throw new Exception(_('youtube-dl returned an empty URL.'));
+            throw new EmptyUrlException(_('youtube-dl returned an empty URL.'));
         }
 
         return $urls;

controllers/FrontController.php

@@ -6,6 +6,7 @@
 namespace Alltube\Controller;
 
 use Alltube\Config;
+use Alltube\EmptyUrlException;
 use Alltube\Locale;
 use Alltube\LocaleManager;
 use Alltube\PasswordException;
@@ -456,11 +457,19 @@ class FrontController
      */
     private function getRedirectResponse($url, $format, Response $response, Request $request)
     {
+        try {
             $videoUrls = $this->download->getURL(
                 $url,
                 $format,
                 $this->sessionSegment->getFlash($url)
             );
+        } catch (EmptyUrlException $e) {
+            /*
+            If this happens it is probably a playlist
+            so it will either be handle by getStream() or throw an exception anyway.
+             */
+            $videoUrls = [];
+        }
         if (count($videoUrls) > 1) {
             return $this->getRemuxStream($videoUrls, $format, $response, $request);
         } elseif ($this->config->stream) {