change proxy_url validating way See https://github.com/symfony/config/blob/8f551fe22672ac7ab2c95fe46d899f960ed4d979/Definition/VariableNode.php#L87

Author: MasaakiYoshida

src/DependencyInjection/Configuration.php

@@ -38,17 +38,6 @@ public function getConfigTreeBuilder()
                             ->scalarNode('proxy_url')
                                 ->isRequired()
                                 ->cannotBeEmpty()
-                                ->validate()
-                                    ->always(function ($v) {
-                                        try {
-                                            ProxyUrlFactory::parseUrl($v);
-                                        } catch (\UnexpectedValueException $e) {
-                                            throw new \InvalidArgumentException($e->getMessage());
-                                        }
-
-                                        return $v;
-                                    })
-                                ->end()
                             ->end()
                             ->scalarNode('proxy_host_filter_service')
                                 ->defaultNull()

src/DependencyInjection/PHPMentorsProxyURLRewriteExtension.php

@@ -12,6 +12,7 @@
 
 namespace PHPMentors\ProxyURLRewriteBundle\DependencyInjection;
 
+use PHPMentors\ProxyURLRewriteBundle\ProxyUrl\ProxyUrlFactory;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Loader\XmlFileLoader;
@@ -49,6 +50,13 @@ private function transformConfigToContainer(array $config, ContainerBuilder $con
     {
         if ($config['enabled']) {
             foreach ($config['proxy_urls'] as $id => $proxyUrl) {
+
+                try{
+                    ProxyUrlFactory::parseUrl($proxyUrl['path']);
+                } catch (\UnexpectedValueException $e) {
+                    throw new \InvalidArgumentException($e->getMessage());
+                }
+
                 if (class_exists('Symfony\Component\DependencyInjection\ChildDefinition')) {
                     $definitionClass = 'Symfony\Component\DependencyInjection\ChildDefinition';
                 } else {