make csrf_token() usable without forms

The Twig function `csrf_token()` is currently only registered when the Form component is installed. However, this function is also useful, for example, when creating simple login forms for which you do not need the full Form component.
symfony · fabpot · Mar 21, 2018 · Nov 28, 2017 · Nov 30, 2017 · 709efa30fc4b4e67e14ffb60ac004187703c90c6
commit 709efa30fc4b4e67e14ffb60ac004187703c90c6
diff --git a/src/Symfony/Bridge/Twig/Extension/CsrfExtension.php b/src/Symfony/Bridge/Twig/Extension/CsrfExtension.php
@@ -0,0 +1,44 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Twig\Extension;
+
+use Symfony\Component\Security\Csrf\CsrfTokenManagerInterface;
+use Twig\Extension\AbstractExtension;
+use Twig\TwigFunction;
+
+/**
+ * @author Christian Flothmann <christian.flothmann@sensiolabs.de>
+ */
+class CsrfExtension extends AbstractExtension
+{
+    private $csrfTokenManager;
+
+    public function __construct(CsrfTokenManagerInterface $csrfTokenManager)
+    {
+        $this->csrfTokenManager = $csrfTokenManager;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getFunctions(): array
+    {
+        return array(
+            new TwigFunction('csrf_token', array($this, 'getCsrfToken')),
+        );
+    }
+
+    public function getCsrfToken(string $tokenId): string
+    {
+        return $this->csrfTokenManager->getToken($tokenId)->getValue();
+    }
+}
diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/security_csrf.xml b/src/Symfony/Bundle/FrameworkBundle/Resources/config/security_csrf.xml
@@ -21,5 +21,10 @@
            <argument type="service" id="request_stack" on-invalid="ignore" />
        </service>
        <service id="Symfony\Component\Security\Csrf\CsrfTokenManagerInterface" alias="security.csrf.token_manager" />
+
+        <service id="twig.extension.security_csrf" class="Symfony\Bridge\Twig\Extension\CsrfExtension">
+            <tag name="twig.extension" />
+            <argument type="service" id="security.csrf.token_manager" />
+        </service>
    </services>
 </container>