DanielEScherzer · DanielEScherzer · Dec 2, 2025 · Dec 2, 2025 · Dec 2, 2025 · Dec 2, 2025
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -43,6 +43,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ env.PHP_VERSION }}
+          ini-values: zend.exception_ignore_args=Off,zend.exception_string_param_max_len=15
           tools: composer
 
       - name: Install composer dependencies

diff --git a/src/Pages/InternalErrorPage.php b/src/Pages/InternalErrorPage.php
@@ -0,0 +1,143 @@
+<?php
+declare( strict_types = 1 );
+
+namespace DanielWebsite\Pages;
+
+use DanielEScherzer\HTMLBuilder\FluentHTML;
+use Throwable;
+
+class InternalErrorPage extends BasePage {
+
+	private Throwable $error;
+
+	public function __construct( Throwable $error ) {
+		parent::__construct();
+		$this->head->append(
+			FluentHTML::fromTag( 'title' )->addChild( 'Internal Error' )
+		);
+		$this->error = $error;
+		$this->setResponseCode( 500 );
+	}
+
+	protected function build(): void {
+		$this->addStyleSheet( 'error-styles.css' );
+		$this->head->append(
+			FluentHTML::make(
+				'style',
+				[],
+				[
+					'pre { overflow-x: auto; padding-bottom: 10px; }',
+					'.error-box { width: fit-content; max-width: 100%; }',
+				]
+			)
+		);
+		$error = $this->error;
+		$file = self::formatFile( $error->getFile() );
+		$this->contentWrapper->append(
+			FluentHTML::make(
+				'div',
+				[ 'class' => 'error-box' ],
+				[
+					FluentHTML::make( 'h1', [], 'Internal Error' ),
+					FluentHTML::make(
+						'p',
+						[],
+						'[' . get_class( $error ) . '] ' . $error->getMessage(),
+					),
+					FluentHTML::make(
+						'p',
+						[],
+						[
+							'From ',
+							FluentHTML::make( 'code', [], $file ),
+							' line ',
+							FluentHTML::make( 'code', [], (string)$error->getLine() ),
+						]
+					),
+					FluentHTML::make( 'p', [], 'Backtrace:' ),
+					FluentHTML::make(
+						'pre',
+						[],
+						self::formatTrace( $error )
+					),
+				]
+			)
+		);
+	}
+
+	public static function handleException( Throwable $error ) {
+		try {
+			$page = new InternalErrorPage( $error );
+			$page->getResponse()->applyResponse();
+		} catch ( Throwable $error2 ) {
+			self::handleManually( $error, $error2 );
+		}
+	}
+
+	public static function handleManually( Throwable $error1, Throwable $error2 ) {
+		http_response_code( 500 );
+		echo "<!DOCTYPE html>\n";
+		echo "<html lang='en'>\n";
+		echo "<head>\n";
+		echo "<title>Internal Error</title>\n";
+		echo "<style> .content-wrapper { margin: auto; width: 80%; } </style>\n";
+		echo "</head>\n<body>\n";
+		echo "<div class='content-wrapper'>\n";
+
+		echo "<h1>Internal Error</h1>\n";
+		echo '<p>[' . get_class( $error1 ) . '] ' . $error1->getMessage() . "</p>\n";
+		$file = self::formatFile( $error1->getFile() );
+		echo "<p>From: <code>$file</code> line " . $error1->getLine() . "</p>\n";
+		echo "<p>Backtrace:</p>\n";
+		echo "<pre>" . self::formatTrace( $error1 ) . "</pre>\n";
+
+		echo "<p><b>While trying to handle that error, the handler also had an error:</b></p>\n";
+		echo '<p>[' . get_class( $error2 ) . '] ' . $error2->getMessage() . "</p>\n";
+		$file = self::formatFile( $error2->getFile() );
+		echo "<p>From: <code>$file</code> line " . $error2->getLine() . "</p>\n";
+		echo "<p>Backtrace:</p>\n";
+		echo "<pre>" . self::formatTrace( $error2 ) . "</pre>\n";
+
+		echo "</div></body></html>";
+	}
+
+	/**
+	 * Like Exception::getTraceAsString() but
+	 * - the `/var/www/html/` is removed from the start of files
+	 */
+	private static function formatTrace( Throwable $error ): string {
+		// Don't want to try and reimplement the entirety of the exception
+		// formatting
+		$trace = $error->getTraceAsString();
+		$lines = explode( "\n", $trace );
+		$betterLines = array_map(
+			static fn ( $line ) => preg_replace_callback(
+				"/^(#\d+) ([^\(]+)(\(\d+\): .*$)/",
+				static fn ( array $matches ): string => $matches[1]
+					. ' '
+					. self::formatFile( $matches[2] )
+					. $matches[3],
+				$line
+			),
+			$lines
+		);
+		return implode( "\n", $betterLines );
+	}
+
+	/**
+	 * Nicely format file names, removing common leading prefixes
+	 */
+	private static function formatFile( string $file ): string {
+		// Within docker container
+		if ( str_starts_with( $file, '/var/www/html/' ) ) {
+			return '.../' . substr( $file, strlen( '/var/www/html/' ) );
+		}
+		// Within GitHub actions
+		$ghPrefix = '/home/runner/work/website-content/website-content/';
+		if ( str_starts_with( $file, $ghPrefix ) ) {
+			return '.../' . substr( $file, strlen( $ghPrefix ) );
+		}
+		return $file;
+	}
+
+}
diff --git a/src/setup.php b/src/setup.php
@@ -20,3 +20,5 @@
 
 // Autoloading from composer
 require_once __DIR__ . '/../vendor/autoload.php';
+
+set_exception_handler( [ \DanielWebsite\Pages\InternalErrorPage::class, 'handleException' ] );
diff --git a/tests/StaticOutputTest.php b/tests/StaticOutputTest.php
@@ -13,13 +13,15 @@
 use DanielWebsite\Pages\BlogPostPage;
 use DanielWebsite\Pages\Error404Page;
 use DanielWebsite\Pages\Error405Page;
+use DanielWebsite\Pages\InternalErrorPage;
 use DanielWebsite\Pages\LandingPage;
 use DanielWebsite\Pages\OpenSourcePage;
 use DanielWebsite\Pages\RedirectPage;
 use DanielWebsite\Pages\ThesisPage;
 use DanielWebsite\Pages\ToolPage;
 use DanielWebsite\Pages\WorkPage;
 use DanielWebsite\Router;
+use Exception;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
@@ -30,6 +32,7 @@
 #[CoversClass( BlogPostPage::class )]
 #[CoversClass( Error404Page::class )]
 #[CoversClass( Error405Page::class )]
+#[CoversClass( InternalErrorPage::class )]
 #[CoversClass( LandingPage::class )]
 #[CoversClass( OpenSourcePage::class )]
 #[CoversClass( RedirectPage::class )]
@@ -98,4 +101,41 @@ public function testRedirect() {
 		$this->assertInstanceOf( RedirectPage::class, $page );
 	}
 
+	public function testErrorNice() {
+		ob_start();
+		InternalErrorPage::handleException( new Exception( 'testing' ) );
+		$output = ob_get_clean();
+		// Different include paths in docker and on GitHub
+		$output = preg_replace(
+			"/(\/vendor\/bin\/phpunit\(122\):) include\([^\)]+\)/",
+			"$1 include({path})",
+			$output
+		);
+		$filePath = __DIR__ . '/data/errors-nice.html';
+		if ( getenv( 'TESTS_UPDATE_EXPECTED' ) === '1' ) {
+			file_put_contents( $filePath, $output );
+		}
+		$this->assertStringEqualsFile( $filePath, $output );
+	}
+
+	public function testErrorManual() {
+		ob_start();
+		InternalErrorPage::handleManually(
+			new Exception( 'first' ),
+			new Exception( 'second' )
+		);
+		$output = ob_get_clean();
+		// Different include paths in docker and on GitHub
+		$output = preg_replace(
+			"/(\/vendor\/bin\/phpunit\(122\):) include\([^\)]+\)/",
+			"$1 include({path})",
+			$output
+		);
+		$filePath = __DIR__ . '/data/errors-manual.html';
+		if ( getenv( 'TESTS_UPDATE_EXPECTED' ) === '1' ) {
+			file_put_contents( $filePath, $output );
+		}
+		$this->assertStringEqualsFile( $filePath, $output );
+	}
+
 }
diff --git a/tests/data/errors-manual.html b/tests/data/errors-manual.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<html lang='en'>
+<head>
+<title>Internal Error</title>
+<style> .content-wrapper { margin: auto; width: 80%; } </style>
+</head>
+<body>
+<div class='content-wrapper'>
+<h1>Internal Error</h1>
+<p>[Exception] first</p>
+<p>From: <code>.../tests/StaticOutputTest.php</code> line 124</p>
+<p>Backtrace:</p>
+<pre>#0 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(1317): DanielWebsite\Tests\StaticOutputTest->testErrorManual()
+#1 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(517): PHPUnit\Framework\TestCase->runTest()
+#2 .../vendor/phpunit/phpunit/src/Framework/TestRunner/TestRunner.php(99): PHPUnit\Framework\TestCase->runBare()
+#3 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(357): PHPUnit\Framework\TestRunner->run(Object(DanielWebsite\Tests\StaticOutputTest))
+#4 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestCase->run()
+#5 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestSuite->run()
+#6 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestSuite->run()
+#7 .../vendor/phpunit/phpunit/src/TextUI/TestRunner.php(64): PHPUnit\Framework\TestSuite->run()
+#8 .../vendor/phpunit/phpunit/src/TextUI/Application.php(229): PHPUnit\TextUI\TestRunner->run(Object(PHPUnit\TextUI\Configuration\Configuration), Object(PHPUnit\Runner\ResultCache\DefaultResultCache), Object(PHPUnit\Framework\TestSuite))
+#9 .../vendor/phpunit/phpunit/phpunit(104): PHPUnit\TextUI\Application->run(Array)
+#10 .../vendor/bin/phpunit(122): include({path})
+#11 {main}</pre>
+<p><b>While trying to handle that error, the handler also had an error:</b></p>
+<p>[Exception] second</p>
+<p>From: <code>.../tests/StaticOutputTest.php</code> line 125</p>
+<p>Backtrace:</p>
+<pre>#0 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(1317): DanielWebsite\Tests\StaticOutputTest->testErrorManual()
+#1 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(517): PHPUnit\Framework\TestCase->runTest()
+#2 .../vendor/phpunit/phpunit/src/Framework/TestRunner/TestRunner.php(99): PHPUnit\Framework\TestCase->runBare()
+#3 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(357): PHPUnit\Framework\TestRunner->run(Object(DanielWebsite\Tests\StaticOutputTest))
+#4 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestCase->run()
+#5 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestSuite->run()
+#6 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestSuite->run()
+#7 .../vendor/phpunit/phpunit/src/TextUI/TestRunner.php(64): PHPUnit\Framework\TestSuite->run()
+#8 .../vendor/phpunit/phpunit/src/TextUI/Application.php(229): PHPUnit\TextUI\TestRunner->run(Object(PHPUnit\TextUI\Configuration\Configuration), Object(PHPUnit\Runner\ResultCache\DefaultResultCache), Object(PHPUnit\Framework\TestSuite))
+#9 .../vendor/phpunit/phpunit/phpunit(104): PHPUnit\TextUI\Application->run(Array)
+#10 .../vendor/bin/phpunit(122): include({path})
+#11 {main}</pre>
+</div></body></html>
diff --git a/tests/data/errors-nice.html b/tests/data/errors-nice.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html lang="en"><head><link rel="icon" href="data:,"><meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1"><link rel="stylesheet" type="text/css" href="/resources/default-styles.css"><title>Internal Error</title><link rel="stylesheet" type="text/css" href="/resources/error-styles.css"><style>pre { overflow-x: auto; padding-bottom: 10px; }.error-box { width: fit-content; max-width: 100%; }</style></head><body><div class="des-navbar"><a href="/Home">Home</a><a href="/files/Resume.pdf">Résumé</a><a href="/OpenSource">Open Source</a><a href="/Work">Work</a><a href="/Blog">Blog</a></div><div class="content-wrapper"><div class="error-box"><h1>Internal Error</h1><p>[Exception] testing</p><p>From <code>.../tests/StaticOutputTest.php</code> line <code>106</code></p><p>Backtrace:</p><pre>#0 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(1317): DanielWebsite\Tests\StaticOutputTest-&gt;testErrorNice()
+#1 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(517): PHPUnit\Framework\TestCase-&gt;runTest()
+#2 .../vendor/phpunit/phpunit/src/Framework/TestRunner/TestRunner.php(99): PHPUnit\Framework\TestCase-&gt;runBare()
+#3 .../vendor/phpunit/phpunit/src/Framework/TestCase.php(357): PHPUnit\Framework\TestRunner-&gt;run(Object(DanielWebsite\Tests\StaticOutputTest))
+#4 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestCase-&gt;run()
+#5 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestSuite-&gt;run()
+#6 .../vendor/phpunit/phpunit/src/Framework/TestSuite.php(374): PHPUnit\Framework\TestSuite-&gt;run()
+#7 .../vendor/phpunit/phpunit/src/TextUI/TestRunner.php(64): PHPUnit\Framework\TestSuite-&gt;run()
+#8 .../vendor/phpunit/phpunit/src/TextUI/Application.php(229): PHPUnit\TextUI\TestRunner-&gt;run(Object(PHPUnit\TextUI\Configuration\Configuration), Object(PHPUnit\Runner\ResultCache\DefaultResultCache), Object(PHPUnit\Framework\TestSuite))
+#9 .../vendor/phpunit/phpunit/phpunit(104): PHPUnit\TextUI\Application-&gt;run(Array)
+#10 .../vendor/bin/phpunit(122): include({path})
+#11 {main}</pre></div></div><div class="des-footer"><div class="des-footer--content">Content is © 2025 Daniel Scherzer</div></div></body></html>
Original file line number	Diff line number	Diff line change
Expand Up		@@ -20,3 +20,5 @@

		// Autoloading from composer
		require_once __DIR__ . '/../vendor/autoload.php';

		set_exception_handler( [ \DanielWebsite\Pages\InternalErrorPage::class, 'handleException' ] );