Amazon error message

I want to update quantity on amazon using Feed Api->Sumbit Feed (_POST_INVENTORY_AVAILABILITY_DATA_)

Here is my code:

$action = 'SubmitFeed';
$path = $_SERVER['DOCUMENT_ROOT'].'/resources/amazon_xml/quantity.xml';

$feed = '<?xml version="1.0" ?><AmazonEnvelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="amzn-envelope.xsd">
                <Header>
                    <DocumentVersion>1.01</DocumentVersion>
                    <MerchantIdentifier>A3QPCC6I4V1QU3</MerchantIdentifier>
                </Header>
                    <MessageType>Inventory</MessageType>
                    <Message>
                        <MessageID>1</MessageID>
                        <OperationType>Update</OperationType>
                        <Inventory>
                            <SKU>6000013953</SKU>
                            <Quantity>1</Quantity>
                        </Inventory>
                    </Message>
                </AmazonEnvelope>';

$feedHandle = fopen($path, 'rw+');
fwrite($feedHandle, $feed);
rewind($feedHandle);

$params = array(
                    'AWSAccessKeyId' => $data['aws_access_key'],
                    'Action' => $action,
                    'Merchant' => $data['merchant_id'],
                    'SignatureMethod' => "HmacSHA256",
                    'SignatureVersion' => "2",
                    'Timestamp'=> gmdate("Y-m-d\TH:i:s.\\0\\0\\0\\Z", time()),
                    'Version'=> "2009-10-01",
                    'MarketplaceIdList.Id.1' => $data['marketplace_id'],
                    'FeedType'=> "_POST_INVENTORY_AVAILABILITY_DATA_",
                    'PurgeAndReplace'=> 'false',
                    'ContentMd5' => base64_encode(md5(stream_get_contents($feedHandle), true))
                );


        // Sort the URL parameters
        $url_parts = array();
        foreach(array_keys($params) as $key)
            $url_parts[] = $key . "=" . str_replace('%7E', '~', rawurlencode($params[$key]));

        sort($url_parts);

        // Construct the string to sign
        $url_string = implode("&", $url_parts);
        $string_to_sign = "GET\nmws.amazonservices.in\n" . $url_string;

        // Sign the request
        $signature = hash_hmac("sha256", $string_to_sign, $data['aws_secret_key'], TRUE);

        // Base64 encode the signature and make it URL safe
        $signature = urlencode(base64_encode($signature));



$url = "https://mws.amazonservices.in" . '?' . $url_string . "&Signature=" . $signature;

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL,$url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_TIMEOUT, 15);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    $response = curl_exec($ch); 

        //echo $url;exit;

        echo '<pre>';
        print_r($response);
        echo '</pre>';
        exit;

      

        
        
        
      

    

But I am getting the following response: -

<ErrorResponse xmlns="https://mws.amazonservices.com/">
<Error>
<Type>Sender</Type>
<Code>SignatureDoesNotMatch</Code>
<Message>
The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.
</Message>
</Error>
<RequestID>105f88cb-76e2-49c0-9d33-83d6069dd119</RequestID>
</ErrorResponse>

      

        
        
        
      

    

Can someone please tell me how to send XML file to api? Or am I doing something wrong?

quantity.xml

correct file

Update: -

Code works fine on Amazon Scratchpad