fix: Validation raises TypeError when invalid JSON comes

system/HTTP/Exceptions/HTTPException.php

@@ -72,6 +72,19 @@ public static function forInvalidNegotiationType(string $type)
         return new static(lang('HTTP.invalidNegotiationType', [$type]));
     }
 
+    /**
+     * Thrown in IncomingRequest when the json_decode() produces
+     *  an error code other than JSON_ERROR_NONE.
+     *
+     * @param string $error The error message
+     *
+     * @return static
+     */
+    public static function forInvalidJSON(?string $error = null)
+    {
+        return new static(lang('HTTP.invalidJSON', [$error]));
+    }
+
     /**
      * For Message
      *

system/HTTP/IncomingRequest.php

@@ -573,10 +573,22 @@ public function getVar($index = null, $filter = null, $flags = null)
      * @see http://php.net/manual/en/function.json-decode.php
      *
      * @return array|bool|float|int|stdClass|null
+     *
+     * @throws HTTPException When the body is invalid as JSON.
      */
     public function getJSON(bool $assoc = false, int $depth = 512, int $options = 0)
     {
-        return json_decode($this->body ?? '', $assoc, $depth, $options);
+        if ($this->body === null) {
+            return null;
+        }
+
+        $result = json_decode($this->body, $assoc, $depth, $options);
+
+        if (json_last_error() !== JSON_ERROR_NONE) {
+            throw HTTPException::forInvalidJSON(json_last_error_msg());
+        }
+
+        return $result;
     }
 
     /**

system/Language/en/HTTP.php

@@ -19,6 +19,7 @@
 
     // IncomingRequest
     'invalidNegotiationType' => '"{0}" is not a valid negotiation type. Must be one of: media, charset, encoding, language.',
+    'invalidJSON'            => 'Failed to parse JSON string. Error: {0}',
 
     // Message
     'invalidHTTPProtocol' => 'Invalid HTTP Protocol Version: {0}',

tests/system/HTTP/IncomingRequestTest.php

@@ -18,6 +18,7 @@
 use CodeIgniter\Test\CIUnitTestCase;
 use Config\App;
 use InvalidArgumentException;
+use JsonException;
 use TypeError;
 
 /**
@@ -528,6 +529,32 @@ public function testGetJSONReturnsNullFromNullBody(): void
         $this->assertNull($request->getJSON());
     }
 
+    public function testGetJSONWithInvalidJSONString(): void
+    {
+        $this->expectException(HTTPException::class);
+        $this->expectExceptionMessage('Failed to parse JSON string. Error: Syntax error');
+
+        $config          = new App();
+        $config->baseURL = 'http://example.com/';
+        $json            = 'Invalid JSON string';
+        $request         = $this->createRequest($config, $json);
+
+        $request->getJSON();
+    }
+
+    public function testGetJSONWithJsonThrowOnErrorAndInvalidJSONString(): void
+    {
+        $this->expectException(JsonException::class);
+        $this->expectExceptionMessage('Syntax error');
+
+        $config          = new App();
+        $config->baseURL = 'http://example.com/';
+        $json            = 'Invalid JSON string';
+        $request         = $this->createRequest($config, $json);
+
+        $request->getJSON(false, 512, JSON_THROW_ON_ERROR);
+    }
+
     public function testCanGrabGetRawInput(): void
     {
         $rawstring = 'username=admin001&role=administrator&usepass=0';

tests/system/Validation/ValidationTest.php

@@ -11,6 +11,7 @@
 
 namespace CodeIgniter\Validation;
 
+use CodeIgniter\HTTP\Exceptions\HTTPException;
 use CodeIgniter\HTTP\IncomingRequest;
 use CodeIgniter\HTTP\URI;
 use CodeIgniter\HTTP\UserAgent;
@@ -789,6 +790,25 @@ public function testJsonInput(): void
         unset($_SERVER['CONTENT_TYPE']);
     }
 
+    public function testJsonInputInvalid(): void
+    {
+        $this->expectException(HTTPException::class);
+        $this->expectExceptionMessage('Failed to parse JSON string. Error: Syntax error');
+
+        $config  = new App();
+        $json    = 'invalid';
+        $request = new IncomingRequest($config, new URI(), $json, new UserAgent());
+        $request->setHeader('Content-Type', 'application/json');
+
+        $rules = [
+            'role' => 'if_exist|max_length[5]',
+        ];
+        $this->validation
+            ->withRequest($request->withMethod('POST'))
+            ->setRules($rules)
+            ->run();
+    }
+
     /**
      * @see https://github.com/codeigniter4/CodeIgniter4/issues/6466
      */

user_guide_src/source/changelogs/v4.4.4.rst

@@ -31,6 +31,8 @@ and Traditional rules validate data of non-string types.
 Message Changes
 ***************
 
+- Added ``HTTP.invalidJSON`` error message.
+
 *******
 Changes
 *******