Add spam secure filter

README.md

@@ -39,6 +39,33 @@ return [
 ];
 ```
 
+### Twig text spam protection
+
+The Twig filter `spamsecure` replaces all dot and @-signs.
+
+```twig
+{# Replace plain text #}
+{{ text|spamsecure }}
+
+{# Replace rich text mails #}
+{{ htmlText|spamsecure(true) }}
+```
+
+
+### Configure the Bundle
+
+Create a configuration file called `nucleos_twig.yaml`:
+
+```yaml
+# config/packages/nucleos_twig.yaml
+
+nucleos_twig:
+    secure:
+        mail:
+            at_text:   [ ' [AT] ', ' (AT) ', ' [ÄT] ' ]
+            dot_text:  [ ' [DOT] ', ' (DOT) ', ' [.] ' ]
+```
+
 ## License
 
 This library is under the [MIT license](LICENSE.md).

src/Bridge/Symfony/DependencyInjection/Configuration.php

@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * (c) Christian Gripp <mail@core23.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Nucleos\Twig\Bridge\Symfony\DependencyInjection;
+
+use Symfony\Component\Config\Definition\Builder\NodeDefinition;
+use Symfony\Component\Config\Definition\Builder\TreeBuilder;
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+
+final class Configuration implements ConfigurationInterface
+{
+    public function getConfigTreeBuilder(): TreeBuilder
+    {
+        $treeBuilder = new TreeBuilder('nucleos_twig');
+
+        $rootNode = $treeBuilder->getRootNode();
+
+        $rootNode->append($this->getSecureNode());
+
+        return $treeBuilder;
+    }
+
+    private function getSecureNode(): NodeDefinition
+    {
+        $node = (new TreeBuilder('secure'))->getRootNode();
+
+        $node
+            ->addDefaultsIfNotSet()
+            ->children()
+                ->arrayNode('mail')
+                    ->addDefaultsIfNotSet()
+                    ->children()
+                        ->arrayNode('dot_text')
+                             ->useAttributeAsKey('id')
+                             ->requiresAtLeastOneElement()
+                             ->defaultValue([' [DOT] ', ' (DOT) ', ' [.] '])
+                             ->prototype('scalar')->end()
+                        ->end()
+                        ->arrayNode('at_text')
+                             ->useAttributeAsKey('id')
+                             ->requiresAtLeastOneElement()
+                             ->defaultValue([' [AT] ', ' (AT) ', ' [ÄT] '])
+                             ->prototype('scalar')->end()
+                        ->end()
+                    ->end()
+                ->end()
+            ->end()
+        ;
+
+        return $node;
+    }
+}

src/Bridge/Symfony/DependencyInjection/NucleosTwigExtension.php

@@ -11,6 +11,7 @@
 
 namespace Nucleos\Twig\Bridge\Symfony\DependencyInjection;
 
+use Nucleos\Twig\Runtime\StringRuntime;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Loader;
@@ -20,7 +21,20 @@ final class NucleosTwigExtension extends Extension
 {
     public function load(array $configs, ContainerBuilder $container): void
     {
+        $configuration = new Configuration();
+        $config        = $this->processConfiguration($configuration, $configs);
+
         $loader = new Loader\PhpFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
         $loader->load('services.php');
+
+        $this->configureSecure($config['secure'], $container);
+    }
+
+    private function configureSecure(array $config, ContainerBuilder $container): void
+    {
+        $container->getDefinition(StringRuntime::class)
+            ->replaceArgument(0, $config['mail']['at_text'])
+            ->replaceArgument(1, $config['mail']['dot_text'])
+        ;
     }
 }

src/Bridge/Symfony/Resources/config/services.php

@@ -34,6 +34,10 @@
 
         ->set(StringRuntime::class)
             ->tag('twig.runtime')
+            ->args([
+                [],
+                [],
+            ])
 
         ->set(RouterRuntime::class)
             ->tag('twig.runtime')

src/Extension/StringExtension.php

@@ -22,6 +22,9 @@ public function getFilters(): array
         return [
             new TwigFilter('format_bytes', [StringRuntime::class, 'formatBytes']),
             new TwigFilter('obfuscate', [StringRuntime::class, 'obfuscate']),
+            new TwigFilter('spamsecure', [StringRuntime::class, 'spamsecure'], [
+                'is_safe' => ['html'],
+            ]),
         ];
     }
 }

src/Runtime/StringRuntime.php

@@ -16,6 +16,29 @@
 
 final class StringRuntime implements RuntimeExtensionInterface
 {
+    private const MAIL_HTML_PATTERN = '/\<a(?:[^>]+)href\=\"mailto\:([^">]+)\"(?:[^>]*)\>(.*?)\<\/a\>/ism';
+    private const MAIL_TEXT_PATTERN = '/(([A-Z0-9._%+-]+)@([A-Z0-9.-]+)\.([A-Z]{2,4})(\((.+?)\))?)/i';
+
+    /**
+     * @var string[]
+     */
+    private readonly array $mailAtText;
+
+    /**
+     * @var string[]
+     */
+    private readonly array $mailDotText;
+
+    /**
+     * @param string[] $mailAtText
+     * @param string[] $mailDotText
+     */
+    public function __construct(array $mailAtText, array $mailDotText)
+    {
+        $this->mailAtText   = $mailAtText;
+        $this->mailDotText  = $mailDotText;
+    }
+
     public function formatBytes(float $bytes, bool $si = true, int $fractionDigits = 0, ?string $locale = null): string
     {
         if (null === $locale) {
@@ -55,6 +78,93 @@ public function obfuscate(string $string, array $options = []): string
         return StringUtils::obfuscate($string, (int) $options['start'], (int) $options['end'], (string) $options['replacement']);
     }
 
+    /**
+     * Replaces email addresses with an alternative text representation.
+     *
+     * @param string $text   input string
+     * @param bool   $isHtml Secure html or text
+     *
+     * @return string with replaced links
+     */
+    public function spamsecure(string $text, bool $isHtml = true): string
+    {
+        if ($isHtml) {
+            return preg_replace_callback(self::MAIL_HTML_PATTERN, [$this, 'encryptMail'], $text) ?? '';
+        }
+
+        return preg_replace_callback(self::MAIL_TEXT_PATTERN, [$this, 'encryptMailText'], $text) ?? '';
+    }
+
+    /**
+     * @param string[] $matches
+     */
+    private function encryptMailText(array $matches): string
+    {
+        [$original, $email] = $matches;
+
+        return $this->getSecuredName($email).
+            $this->hashedArrayValue($this->mailAtText, $original).
+            $this->getSecuredName($email, true);
+    }
+
+    /**
+     * @param string[] $matches
+     */
+    private function encryptMail(array $matches): string
+    {
+        [$original, $email, $text] = $matches;
+
+        if ($text === $email) {
+            return sprintf(
+                '%s%s%s',
+                $this->getSecuredName($email),
+                $this->hashedArrayValue($this->mailAtText, $original),
+                $this->getSecuredName($email, true)
+            );
+        }
+
+        return sprintf(
+            '%s%s%s (%s)',
+            $this->getSecuredName($email),
+            $this->hashedArrayValue($this->mailAtText, $original),
+            $this->getSecuredName($email, true),
+            $text
+        );
+    }
+
+    private function getSecuredName(string $name, bool $isDomain = false): string
+    {
+        $index = strpos($name, '@');
+
+        \assert(false !== $index);
+
+        if ($isDomain) {
+            $name = substr($name, $index + 1);
+        } else {
+            $name = substr($name, 0, $index);
+        }
+
+        return str_replace('.', $this->hashedArrayValue($this->mailDotText, $name), $name);
+    }
+
+    /**
+     * @param string[] $list
+     */
+    private function hashedArrayValue(array $list, string $name): string
+    {
+        $count = \count($list);
+        $index = $this->numericHash($name) % $count;
+
+        return $list[$index];
+    }
+
+    private function numericHash(string $name): int
+    {
+        $hash = hash('sha256', $name);
+
+        return \intval(substr($hash, 0, 6), 16);
+    }
+
     private function getPrefix(bool $si, int $exp): string
     {
         $prefixes = ($si ? 'kMGTPE' : 'KMGTPE');

tests/Bridge/Symfony/DependencyInjection/ConfigurationTest.php

@@ -0,0 +1,61 @@
+<?php
+
+/*
+ * (c) Christian Gripp <mail@core23.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Nucleos\Twig\Tests\Bridge\Symfony\DependencyInjection;
+
+use Nucleos\Twig\Bridge\Symfony\DependencyInjection\Configuration;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Config\Definition\Processor;
+
+final class ConfigurationTest extends TestCase
+{
+    public function testDefaultOptions(): void
+    {
+        $processor = new Processor();
+
+        $config = $processor->processConfiguration(new Configuration(), [[
+        ]]);
+
+        $expected = [
+            'secure' => [
+                'mail' => [
+                    'dot_text'  => [' [DOT] ', ' (DOT) ', ' [.] '],
+                    'at_text'   => [' [AT] ', ' (AT) ', ' [ÄT] '],
+                ],
+            ],
+        ];
+
+        self::assertSame($expected, $config);
+    }
+
+    public function testOptions(): void
+    {
+        $processor = new Processor();
+
+        $config = $processor->processConfiguration(new Configuration(), [[
+            'secure' => [
+                'mail' => [
+                    'dot_text'  => ['[DOT]'],
+                    'at_text'   => ['[AT'],
+                ],
+            ],
+        ]]);
+
+        $expected = [
+            'secure' => [
+                'mail' => [
+                    'dot_text'  => ['[DOT]'],
+                    'at_text'   => ['[AT'],
+                ],
+            ],
+        ];
+
+        self::assertSame($expected, $config);
+    }
+}

tests/Bridge/Symfony/DependencyInjection/NucleosTwigExtensionTest.php

@@ -16,6 +16,7 @@
 use Nucleos\Twig\Extension\RouterExtension;
 use Nucleos\Twig\Extension\StringExtension;
 use Nucleos\Twig\Extension\UrlAutoConverterExtension;
+use Nucleos\Twig\Runtime\StringRuntime;
 
 final class NucleosTwigExtensionTest extends AbstractExtensionTestCase
 {
@@ -26,6 +27,13 @@ public function testLoadDefault(): void
         $this->assertContainerBuilderHasService(UrlAutoConverterExtension::class);
         $this->assertContainerBuilderHasService(StringExtension::class);
         $this->assertContainerBuilderHasService(RouterExtension::class);
+
+        $this->assertContainerBuilderHasServiceDefinitionWithArgument(StringRuntime::class, 0, [
+            ' [AT] ', ' (AT) ', ' [ÄT] ',
+        ]);
+        $this->assertContainerBuilderHasServiceDefinitionWithArgument(StringRuntime::class, 1, [
+            ' [DOT] ', ' (DOT) ', ' [.] ',
+        ]);
     }
 
     protected function getContainerExtensions(): array

tests/Extension/StringExtensionTest.php

@@ -32,13 +32,11 @@ public function testGetFilters(): void
             self::assertCallable($filter->getCallable());
         }
 
-        self::assertSame(
-            [
-                'format_bytes',
-                'obfuscate',
-            ],
-            array_map(static fn (TwigFilter $filter): string => $filter->getName(), $filters)
-        );
+        self::assertSame([
+            'format_bytes',
+            'obfuscate',
+            'spamsecure',
+        ], array_map(static fn (TwigFilter $filter): string => $filter->getName(), $filters));
     }
 
     private static function assertCallable(mixed $callable): void