feature #31518 [Validator] Added HostnameValidator (karser)

This PR was merged into the 5.1-dev branch.

Discussion
----------

[Validator] Added HostnameValidator

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #10088   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->

This PR adds HostnameValidator support. I encountered this need in my project and was surprised that this issue has been open for years.

Here is short example:
```
App\Entity\Acme:
    properties:
        domain:
            - Hostname: ~
        non_tld_domain:
            - Hostname: { requireTld: false }
```
The option `requireTld` is `true` by default and disallows domains like localhost and etc.

Commits
-------

8a08c20 Added HostnameValidator

CHANGELOG-5.0.md

@@ -380,7 +380,7 @@ To get the diff between two versions, go to https://github.com/symfony/symfony/c
  * feature #32446 [Lock] rename and deprecate Factory into LockFactory (Simperfit)
  * feature #31975 Dynamic bundle assets (garak)
  * feature #32429 [VarDumper] Let browsers trigger their own search on double CMD/CTRL + F (ogizanagi)
- * feature #32198 [Lock] Split "StoreInterface" into multiple interfaces with less responsability (Simperfit)
+ * feature #32198 [Lock] Split "StoreInterface" into multiple interfaces with less responsibility (Simperfit)
  * feature #31511 [Validator] Allow to use property paths to get limits in range constraint (Lctrs)
  * feature #32424 [Console] don't redraw progress bar more than every 100ms by default (nicolas-grekas)
  * feature #27905 [MonologBridge] Monolog 2 compatibility (derrabus)

src/Symfony/Component/Validator/CHANGELOG.md

@@ -1,6 +1,10 @@
 CHANGELOG
 =========
 
+5.1.0
+-----
+ * added the `Hostname` constraint and validator
+
 5.0.0
 -----
 

src/Symfony/Component/Validator/Constraints/Hostname.php

@@ -0,0 +1,32 @@
+<?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\Component\Validator\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * @Annotation
+ * @Target({"PROPERTY", "METHOD", "ANNOTATION"})
+ *
+ * @author Dmitrii Poddubnyi <dpoddubny@gmail.com>
+ */
+class Hostname extends Constraint
+{
+    const INVALID_HOSTNAME_ERROR = '7057ffdb-0af4-4f7e-bd5e-e9acfa6d7a2d';
+
+    protected static $errorNames = [
+        self::INVALID_HOSTNAME_ERROR => 'INVALID_HOSTNAME_ERROR',
+    ];
+
+    public $message = 'This value is not a valid hostname.';
+    public $requireTld = true;
+}

src/Symfony/Component/Validator/Constraints/HostnameValidator.php

@@ -0,0 +1,69 @@
+<?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\Component\Validator\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+use Symfony\Component\Validator\Exception\UnexpectedValueException;
+
+/**
+ * @author Dmitrii Poddubnyi <dpoddubny@gmail.com>
+ */
+class HostnameValidator extends ConstraintValidator
+{
+    /**
+     * https://tools.ietf.org/html/rfc2606.
+     */
+    private const RESERVED_TLDS = [
+        'example',
+        'invalid',
+        'localhost',
+        'test',
+    ];
+
+    public function validate($value, Constraint $constraint)
+    {
+        if (!$constraint instanceof Hostname) {
+            throw new UnexpectedTypeException($constraint, Hostname::class);
+        }
+
+        if (null === $value || '' === $value) {
+            return;
+        }
+
+        if (!is_scalar($value) && !(\is_object($value) && method_exists($value, '__toString'))) {
+            throw new UnexpectedValueException($value, 'string');
+        }
+
+        $value = (string) $value;
+        if ('' === $value) {
+            return;
+        }
+        if (!$this->isValid($value) || ($constraint->requireTld && !$this->hasValidTld($value))) {
+            $this->context->buildViolation($constraint->message)
+                ->setParameter('{{ value }}', $this->formatValue($value))
+                ->setCode(Hostname::INVALID_HOSTNAME_ERROR)
+                ->addViolation();
+        }
+    }
+
+    private function isValid(string $domain): bool
+    {
+        return false !== filter_var($domain, FILTER_VALIDATE_DOMAIN, FILTER_FLAG_HOSTNAME);
+    }
+
+    private function hasValidTld(string $domain): bool
+    {
+        return false !== strpos($domain, '.') && !\in_array(substr($domain, strrpos($domain, '.') + 1), self::RESERVED_TLDS, true);
+    }
+}

src/Symfony/Component/Validator/Resources/translations/validators.de.xlf

@@ -366,6 +366,10 @@
                 <source>This value should be between {{ min }} and {{ max }}.</source>
                 <target>Dieser Wert sollte zwischen {{ min }} und {{ max }} sein.</target>
             </trans-unit>
+            <trans-unit id="95">
+                <source>This value is not a valid hostname.</source>
+                <target>Dieser Wert ist kein gültiger Hostname.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>

src/Symfony/Component/Validator/Resources/translations/validators.en.xlf

@@ -366,6 +366,10 @@
                 <source>This value should be between {{ min }} and {{ max }}.</source>
                 <target>This value should be between {{ min }} and {{ max }}.</target>
             </trans-unit>
+            <trans-unit id="95">
+                <source>This value is not a valid hostname.</source>
+                <target>This value is not a valid hostname.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>

src/Symfony/Component/Validator/Resources/translations/validators.fr.xlf

@@ -366,6 +366,10 @@
                 <source>This value should be between {{ min }} and {{ max }}.</source>
                 <target>Cette valeur doit être comprise entre {{ min }} et {{ max }}.</target>
             </trans-unit>
+            <trans-unit id="95">
+                <source>This value is not a valid hostname.</source>
+                <target>Cette valeur n'est pas un nom d'hôte valide.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>

src/Symfony/Component/Validator/Resources/translations/validators.ru.xlf

@@ -366,6 +366,10 @@
                 <source>This value should be between {{ min }} and {{ max }}.</source>
                 <target>Значение должно быть между {{ min }} и {{ max }}.</target>
             </trans-unit>
+            <trans-unit id="95">
+                <source>This value is not a valid hostname.</source>
+                <target>Значение не является корректным именем хоста.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>

src/Symfony/Component/Validator/Tests/Constraints/HostnameValidatorTest.php

@@ -0,0 +1,200 @@
+<?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\Component\Validator\Tests\Constraints;
+
+use Symfony\Component\Validator\Constraints\Hostname;
+use Symfony\Component\Validator\Constraints\HostnameValidator;
+use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
+
+/**
+ * @author Dmitrii Poddubnyi <dpoddubny@gmail.com>
+ */
+class HostnameValidatorTest extends ConstraintValidatorTestCase
+{
+    public function testNullIsValid()
+    {
+        $this->validator->validate(null, new Hostname());
+
+        $this->assertNoViolation();
+    }
+
+    public function testEmptyStringIsValid()
+    {
+        $this->validator->validate('', new Hostname());
+
+        $this->assertNoViolation();
+    }
+
+    public function testExpectsStringCompatibleType()
+    {
+        $this->expectException(\Symfony\Component\Validator\Exception\UnexpectedValueException::class);
+
+        $this->validator->validate(new \stdClass(), new Hostname());
+    }
+
+    /**
+     * @dataProvider getValidMultilevelDomains
+     */
+    public function testValidTldDomainsPassValidationIfTldRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname());
+
+        $this->assertNoViolation();
+    }
+
+    /**
+     * @dataProvider getValidMultilevelDomains
+     */
+    public function testValidTldDomainsPassValidationIfTldNotRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname(['requireTld' => false]));
+
+        $this->assertNoViolation();
+    }
+
+    public function getValidMultilevelDomains()
+    {
+        return [
+            ['symfony.com'],
+            ['example.co.uk'],
+            ['example.fr'],
+            ['example.com'],
+            ['xn--diseolatinoamericano-66b.com'],
+            ['xn--ggle-0nda.com'],
+            ['www.xn--simulateur-prt-2kb.fr'],
+            [sprintf('%s.com', str_repeat('a', 20))],
+        ];
+    }
+
+    /**
+     * @dataProvider getInvalidDomains
+     */
+    public function testInvalidDomainsRaiseViolationIfTldRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname([
+            'message' => 'myMessage',
+        ]));
+
+        $this->buildViolation('myMessage')
+            ->setParameter('{{ value }}', '"'.$domain.'"')
+            ->setCode(Hostname::INVALID_HOSTNAME_ERROR)
+            ->assertRaised();
+    }
+
+    /**
+     * @dataProvider getInvalidDomains
+     */
+    public function testInvalidDomainsRaiseViolationIfTldNotRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname([
+            'message' => 'myMessage',
+            'requireTld' => false,
+        ]));
+
+        $this->buildViolation('myMessage')
+            ->setParameter('{{ value }}', '"'.$domain.'"')
+            ->setCode(Hostname::INVALID_HOSTNAME_ERROR)
+            ->assertRaised();
+    }
+
+    public function getInvalidDomains()
+    {
+        return [
+            ['acme..com'],
+            ['qq--.com'],
+            ['-example.com'],
+            ['example-.com'],
+            [sprintf('%s.com', str_repeat('a', 300))],
+        ];
+    }
+
+    /**
+     * @dataProvider getReservedDomains
+     */
+    public function testReservedDomainsPassValidationIfTldNotRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname(['requireTld' => false]));
+
+        $this->assertNoViolation();
+    }
+
+    /**
+     * @dataProvider getReservedDomains
+     */
+    public function testReservedDomainsRaiseViolationIfTldRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname([
+            'message' => 'myMessage',
+            'requireTld' => true,
+        ]));
+
+        $this->buildViolation('myMessage')
+            ->setParameter('{{ value }}', '"'.$domain.'"')
+            ->setCode(Hostname::INVALID_HOSTNAME_ERROR)
+            ->assertRaised();
+    }
+
+    public function getReservedDomains()
+    {
+        return [
+            ['example'],
+            ['foo.example'],
+            ['invalid'],
+            ['bar.invalid'],
+            ['localhost'],
+            ['lol.localhost'],
+            ['test'],
+            ['abc.test'],
+        ];
+    }
+
+    /**
+     * @dataProvider getTopLevelDomains
+     */
+    public function testTopLevelDomainsPassValidationIfTldNotRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname(['requireTld' => false]));
+
+        $this->assertNoViolation();
+    }
+
+    /**
+     * @dataProvider getTopLevelDomains
+     */
+    public function testTopLevelDomainsRaiseViolationIfTldRequired($domain)
+    {
+        $this->validator->validate($domain, new Hostname([
+            'message' => 'myMessage',
+            'requireTld' => true,
+        ]));
+
+        $this->buildViolation('myMessage')
+            ->setParameter('{{ value }}', '"'.$domain.'"')
+            ->setCode(Hostname::INVALID_HOSTNAME_ERROR)
+            ->assertRaised();
+    }
+
+    public function getTopLevelDomains()
+    {
+        return [
+            ['com'],
+            ['net'],
+            ['org'],
+            ['etc'],
+        ];
+    }
+
+    protected function createValidator()
+    {
+        return new HostnameValidator();
+    }
+}