global carbon serialization

src/Illuminate/Support/Carbon.php

@@ -2,10 +2,47 @@
 
 namespace Illuminate\Support;
 
+use JsonSerializable;
 use Carbon\Carbon as BaseCarbon;
 use Illuminate\Support\Traits\Macroable;
 
-class Carbon extends BaseCarbon
+class Carbon extends BaseCarbon implements JsonSerializable
 {
     use Macroable;
+
+    /**
+     * The custom Carbon JSON serializer.
+     *
+     * @var callable|null
+     */
+    protected static $serializer;
+
+    /**
+     * Prepare the object for JSON serialization.
+     *
+     * @return array|string
+     */
+    public function jsonSerialize()
+    {
+        if (static::$serializer) {
+            return call_user_func(static::$serializer, $this);
+        }
+
+        $carbon = $this;
+
+        return call_user_func(function () use ($carbon) {
+            return get_object_vars($carbon);
+        });
+    }
+
+    /**
+     * JSON serialize all Carbon instances using the given callback.
+     *
+     * @param  callable  $callback
+     * @return void
+     */
+    public static function serializeUsing($callback)
+    {
+        static::$serializer = $callback;
+    }
 }

tests/Support/SupportCarbonTest.php

@@ -56,4 +56,19 @@ public function testCarbonRaisesExceptionWhenMacroIsNotFound()
     {
         Carbon::now()->nonExistingMacro();
     }
+
+    public function testCarbonAllowsCustomSerializer()
+    {
+        Carbon::serializeUsing(function ($carbon) {
+            return $carbon->getTimestamp();
+        });
+
+        $carbon = Carbon::now();
+
+        $result = json_decode(json_encode(['carbon' => $carbon]), true);
+
+        $this->assertTrue(is_numeric($result['carbon']));
+
+        Carbon::serializeUsing(null);
+    }
 }