AWS SNS HTTP subscription confirmation in PHP

I am unable to get the confirmation of AWS SNS Http connection in PHP. My application is developed on Laravel 5.1

In AWS I have created a Topic and added a subscription. I have selected endpoint as HTTP and provided the URL http://myurl.com/sns.

My PHP code is below

public function getSnsMessage()
{
   $message = Message::fromRawPostData();
   $validator = new MessageValidator();
   // Validate the message and log errors if invalid.
   try {
       $validator->validate($message);
    }catch (InvalidSnsMessageException $e) {
       // Pretend we're not here if the message is invalid.
       http_response_code(404);
        error_log('SNS Message Validation Error: ' . $e->getMessage());
       die();
    }

    // Check the type of the message and handle the subscription.
   if ($message['Type'] === 'SubscriptionConfirmation') {
       // Confirm the subscription by sending a GET request to the SubscribeURL
       file_get_contents(public_path() . '/awssns.txt','SUB URL MESSAGE = '.$message['SubscribeURL'].PHP_EOL, FILE_APPEND );
    }
  }

My route file entry is:

Route::get('/sns', [
'as'   => 'sns',
'uses' => 'SnsEndpointController@getSnsMessage',
]);

In the browser when I call the URL – http://myurl.com/sns, I get the below error.

RuntimeException in Message.php line 35:SNS message type header not provided.
1.    in Message.php line 35
2.    at Message::fromRawPostData() in SnsEndpointController.php line 26
3.    at SnsEndpointController->getSnsMessage(object(Request))
4.    at call_user_func_array(array(object(SnsEndpointController), 
       'getSnsMessage'), array(object(Request))) in Controller.php line 256

I have the following in my composer:

"aws/aws-sdk-php-laravel": "^3.1",
"aws/aws-php-sns-message-validator": "^1.2"

Any help on how to resolve this error and to get confirmation of my subscription?

via Chebli Mohamed