feature #28477 [Validator] Add new json Validator (zairigimad)

This PR was squashed before being merged into the 4.3-dev branch (closes #28477).

Discussion
----------

[Validator] Add new json Validator

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT
| Doc PR        | https://github.com/symfony/symfony-docs/pull/10351

Hi,

in so many cases we want to test if a value is a valid json or not, so I propose this new ~~NotJson~~  `Json` constraint for this need.

cordially,

Commits
-------

131febc7be [Validator] Add new json Validator

src/Symfony/Component/Validator/CHANGELOG.md

@@ -7,7 +7,8 @@ CHANGELOG
  * added options `iban` and `ibanPropertyPath` to Bic constraint
  * added UATP cards support to `CardSchemeValidator`
  * added option `allowNull` to NotBlank constraint
-
+ * added `Json` constraint
+ 
 4.2.0
 -----
 

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

@@ -0,0 +1,31 @@
+<?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 Imad ZAIRIG <imadzairig@gmail.com>
+ */
+class Json extends Constraint
+{
+    const INVALID_JSON_ERROR = '0789c8ad-2d2b-49a4-8356-e2ce63998504';
+
+    protected static $errorNames = [
+        self::INVALID_JSON_ERROR => 'INVALID_JSON_ERROR',
+    ];
+
+    public $message = 'This value should be valid JSON.';
+}

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

@@ -0,0 +1,51 @@
+<?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;
+
+/**
+ * @author Imad ZAIRIG <imadzairig@gmail.com>
+ */
+class JsonValidator extends ConstraintValidator
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function validate($value, Constraint $constraint)
+    {
+        if (!$constraint instanceof Json) {
+            throw new UnexpectedTypeException($constraint, Json::class);
+        }
+
+        if (null === $value || '' === $value) {
+            return;
+        }
+
+        if (!is_scalar($value) && !(\is_object($value) && method_exists($value, '__toString'))) {
+            throw new UnexpectedTypeException($value, 'string');
+        }
+
+        $value = (string) $value;
+
+        json_decode($value);
+
+        if (JSON_ERROR_NONE !== json_last_error()) {
+            $this->context->buildViolation($constraint->message)
+                ->setParameter('{{ value }}', $this->formatValue($value))
+                ->setCode(Json::INVALID_JSON_ERROR)
+                ->addViolation();
+        }
+    }
+}

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

@@ -330,6 +330,10 @@
                 <source>This Business Identifier Code (BIC) is not associated with IBAN {{ iban }}.</source>
                 <target>This Business Identifier Code (BIC) is not associated with IBAN {{ iban }}.</target>
             </trans-unit>
+            <trans-unit id="85">
+                <source>This value should be valid JSON.</source>
+                <target>This value should be valid JSON.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>

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

@@ -330,6 +330,10 @@
                 <source>This Business Identifier Code (BIC) is not associated with IBAN {{ iban }}.</source>
                 <target>Ce code d'identification d'entreprise (BIC) n'est pas associé à l'IBAN {{ iban }}.</target>
             </trans-unit>
+            <trans-unit id="85">
+                <source>This value should be valid JSON.</source>
+                <target>Cette valeur doit être un JSON valide.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>

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

@@ -0,0 +1,77 @@
+<?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\Json;
+use Symfony\Component\Validator\Constraints\JsonValidator;
+use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
+
+class JsonValidatorTest extends ConstraintValidatorTestCase
+{
+    protected function createValidator()
+    {
+        return new JsonValidator();
+    }
+
+    /**
+     * @dataProvider getValidValues
+     */
+    public function testJsonIsValid($value)
+    {
+        $this->validator->validate($value, new Json());
+
+        $this->assertNoViolation();
+    }
+
+    /**
+     * @dataProvider getInvalidValues
+     */
+    public function testInvalidValues($value)
+    {
+        $constraint = new Json([
+            'message' => 'myMessageTest',
+        ]);
+
+        $this->validator->validate($value, $constraint);
+
+        $this->buildViolation('myMessageTest')
+            ->setParameter('{{ value }}', '"'.$value.'"')
+            ->setCode(Json::INVALID_JSON_ERROR)
+            ->assertRaised();
+    }
+
+    public function getValidValues()
+    {
+        return [
+            ['{"planet":"earth", "country": "Morocco","city": "Rabat" ,"postcode" : 10160, "is_great": true,
+			  "img" : null, "area": 118.5, "foo": 15 }'],
+            [null],
+            [''],
+            ['"null"'],
+            ['null'],
+            ['"string"'],
+            ['1'],
+            ['true'],
+            [1],
+        ];
+    }
+
+    public function getInvalidValues()
+    {
+        return [
+            ['{"foo": 3 "bar": 4}'],
+            ['{"foo": 3 ,"bar": 4'],
+            ['{foo": 3, "bar": 4}'],
+            ['foo'],
+        ];
+    }
+}