[ErrorHandler] help finish the PR

Author: yceruto

CHANGELOG.md

@@ -4,6 +4,7 @@ CHANGELOG
 4.4.0
 -----
 
+ * added a new `TwigErrorRenderer` for `html` format, integrated with the `ErrorHandler` component
  * marked all classes extending twig as `@final`
  * deprecated to pass `$rootDir` and `$fileLinkFormatter` as 5th and 6th argument respectively to the 
    `DebugCommand::__construct()` method, swap the variables position.

ErrorRenderer/TwigErrorRenderer.php

@@ -0,0 +1,97 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Twig\ErrorRenderer;
+
+use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRendererInterface;
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+use Twig\Environment;
+use Twig\Error\LoaderError;
+use Twig\Loader\ExistsLoaderInterface;
+
+/**
+ * Provides the ability to render custom Twig-based HTML error pages
+ * in non-debug mode, otherwise falls back to HtmlErrorRenderer.
+ *
+ * @author Yonel Ceruto <[email protected]>
+ */
+class TwigErrorRenderer implements ErrorRendererInterface
+{
+    private $twig;
+    private $fallbackErrorRenderer;
+    private $debug;
+
+    public function __construct(Environment $twig, HtmlErrorRenderer $fallbackErrorRenderer = null, bool $debug = false)
+    {
+        $this->twig = $twig;
+        $this->fallbackErrorRenderer = $fallbackErrorRenderer ?? new HtmlErrorRenderer();
+        $this->debug = $debug;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function render(\Throwable $exception): FlattenException
+    {
+        $exception = $this->fallbackErrorRenderer->render($exception);
+
+        if ($this->debug || !$template = $this->findTemplate($exception->getStatusCode())) {
+            return $exception;
+        }
+
+        return $exception->setAsString($this->twig->render($template, [
+            'legacy' => false, // to be removed in 5.0
+            'exception' => $exception,
+            'status_code' => $exception->getStatusCode(),
+            'status_text' => $exception->getStatusText(),
+        ]));
+    }
+
+    private function findTemplate(int $statusCode): ?string
+    {
+        $template = sprintf('@Twig/Exception/error%s.html.twig', $statusCode);
+        if ($this->templateExists($template)) {
+            return $template;
+        }
+
+        $template = '@Twig/Exception/error.html.twig';
+        if ($this->templateExists($template)) {
+            return $template;
+        }
+
+        return null;
+    }
+
+    /**
+     * To be removed in 5.0.
+     *
+     * Use instead:
+     *
+     *   $this->twig->getLoader()->exists($template)
+     */
+    private function templateExists(string $template): bool
+    {
+        $loader = $this->twig->getLoader();
+        if ($loader instanceof ExistsLoaderInterface || method_exists($loader, 'exists')) {
+            return $loader->exists($template);
+        }
+
+        try {
+            $loader->getSourceContext($template);
+
+            return true;
+        } catch (LoaderError $e) {
+        }
+
+        return false;
+    }
+}

Tests/ErrorRenderer/TwigErrorRendererTest.php

@@ -0,0 +1,65 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Twig\Tests\ErrorRenderer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Bridge\Twig\ErrorRenderer\TwigErrorRenderer;
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Twig\Environment;
+use Twig\Loader\ArrayLoader;
+
+class TwigErrorRendererTest extends TestCase
+{
+    public function testFallbackToNativeRendererIfDebugOn()
+    {
+        $exception = new \Exception();
+
+        $twig = $this->createMock(Environment::class);
+        $nativeRenderer = $this->createMock(HtmlErrorRenderer::class);
+        $nativeRenderer
+            ->expects($this->once())
+            ->method('render')
+            ->with($exception)
+        ;
+
+        (new TwigErrorRenderer($twig, $nativeRenderer, true))->render(new \Exception());
+    }
+
+    public function testFallbackToNativeRendererIfCustomTemplateNotFound()
+    {
+        $exception = new NotFoundHttpException();
+
+        $twig = new Environment(new ArrayLoader([]));
+
+        $nativeRenderer = $this->createMock(HtmlErrorRenderer::class);
+        $nativeRenderer
+            ->expects($this->once())
+            ->method('render')
+            ->with($exception)
+            ->willReturn(FlattenException::createFromThrowable($exception))
+        ;
+
+        (new TwigErrorRenderer($twig, $nativeRenderer, false))->render($exception);
+    }
+
+    public function testRenderCustomErrorTemplate()
+    {
+        $twig = new Environment(new ArrayLoader([
+            '@Twig/Exception/error404.html.twig' => '<h1>Page Not Found</h1>',
+        ]));
+        $exception = (new TwigErrorRenderer($twig))->render(new NotFoundHttpException());
+
+        $this->assertSame('<h1>Page Not Found</h1>', $exception->getAsString());
+    }
+}

composer.json

@@ -24,10 +24,11 @@
         "egulias/email-validator": "^2.1.10",
         "symfony/asset": "^3.4|^4.0|^5.0",
         "symfony/dependency-injection": "^3.4|^4.0|^5.0",
+        "symfony/error-handler": "^4.4|^5.0",
         "symfony/finder": "^3.4|^4.0|^5.0",
         "symfony/form": "^4.4|^5.0",
         "symfony/http-foundation": "^4.3|^5.0",
-        "symfony/http-kernel": "^3.4|^4.0",
+        "symfony/http-kernel": "^4.4",
         "symfony/mime": "^4.3|^5.0",
         "symfony/polyfill-intl-icu": "~1.0",
         "symfony/routing": "^3.4|^4.0|^5.0",