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I am posting data to the Amazon MerchantFullfillment uri using the WebRequest class (as detailed in https://msdn.microsoft.com/en-us/library/debx8sh9.aspx)

I get 

<?xml version="1.0"?>
<ErrorResponse xmlns="http://mws.amazonservices.com/MerchantFulfillment/2015-06-01">
  <Error>
    <Type>Sender</Type>
    <Code>InvalidParameterValue</Code>
    <Message>Either Action or Operation query parameter must be present.</Message>
  </Error>
  <RequestID>03f0e2ca-4c30-4012-9888-c33acc83446f</RequestID>
</ErrorResponse>

I am sending the Action query parameter "&Action=GetEligibleShippingServices" in the postData. Here is my code--I changed the endpoint url to try to see the request.

public void CreateAWSMessage(DateTime timestamp, ShipmentRequestDetails srd)
{
    NameValueCollection awsField = new NameValueCollection();

    string stringToSign = StringToSign(timestamp, srd, awsField);

    string signature = CreateMessageSignature(srd, awsField, stringToSign);

    string signedString = stringToSign + "&Signature=" + signature;

    //string url = @"https://mws.amazonaws.com/MerchantFulfillment/2015-06-01";
    string url = @"http://localhost/WebApplication1/Service.aspx";

    WebRequest gess = WebRequest.Create(url);
    HttpWebRequest httpGESS = (HttpWebRequest)gess;
    string tmp = gess.Method;

    httpGESS.Method = "POST";

    httpGESS.ContentType = "x-www-form-urlencoded";

    byte[] bytes = Encoding.UTF8.GetBytes(signedString);
    httpGESS.ContentLength = bytes.Length;
    using (Stream stream = httpGESS.GetRequestStream())            
    {
        stream.Write(bytes, 0, bytes.Length);
    }

    string responseString;
    using (StreamReader streamResponse = new StreamReader(httpGESS.GetResponse().GetResponseStream()))
    {
        responseString = streamResponse.ReadToEnd();
    }
}

When I look at the request in debugging WebApplication1 (the endpoint), it shows the content as empty, and the method as "GET". That explains why the API is not receiving the Action query parameter. Why does the endpoint not see the request payload, or that it's a "POST"?

Here is the sanitized signedString:

AWSAccessKeyId=myAWSAccessKeyID&Action=GetEligibleShippingServices&MWSAuthToken=myMWSAuthToken&SellerId=mySellerID&ShipmentRequestDetails.AmazonOrderId=TST-1234567-1234568&ShipmentRequestDetails.ItemList.Item.1.OrderItemId=Item1&ShipmentRequestDetails.ItemList.Item.1.Quantity=2&ShipmentRequestDetails.MustArriveByDate=2016-12-31T01%3a15%3a52Z&ShipmentRequestDetails.PackageDimensions.Height=9&ShipmentRequestDetails.PackageDimensions.Length=7&ShipmentRequestDetails.PackageDimensions.Unit=inches&ShipmentRequestDetails.PackageDimensions.Width=8&ShipmentRequestDetails.SellerOrderId=TST-1234567-1234568&ShipmentRequestDetails.ShipDate=2016-12-27T01%3a15%3a52Z&ShipmentRequestDetails.ShipFromAddress.AddressLine1=799%20Central%20Ave&ShipmentRequestDetails.ShipFromAddress.AddressLine2=&ShipmentRequestDetails.ShipFromAddress.AddressLine3=&ShipmentRequestDetails.ShipFromAddress.City=Los%20Angeles&ShipmentRequestDetails.ShipFromAddress.CountryCode=US&ShipmentRequestDetails.ShipFromAddress.Email=jp%40example.com&ShipmentRequestDetails.ShipFromAddress.Name=JP%20test&ShipmentRequestDetails.ShipFromAddress.Phone=310-555-1212&ShipmentRequestDetails.ShipFromAddress.PostalCode=90021&ShipmentRequestDetails.ShipFromAddress.StateOrProvinceCode=CA&ShipmentRequestDetails.ShippingServiceOptions.CarrierWillPickUp=False&ShipmentRequestDetails.ShippingServiceOptions.DeliveryExperience=DeliveryConfirmationWithoutSignature&ShipmentRequestDetails.Weight.Unit=ounces&ShipmentRequestDetails.Weight.Value=120&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2016-12-26T21%3a53%3a05Z&Version=2015-06-01&Signature=d9rvl0XO7CbKuR+wNvCwh56ux5oNY/wv3I6z79+fG1M
Jean Paul
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  • Why don't you use HttpClient? – zmbq Dec 26 '16 at 20:20
  • If may be that your StringToSign method is already doing this, but try encoding the string before you write it to the Stream. var urlEncodedString = HttpUtility.UrlEncode(signedString); Something like that otherwise it might not be properly included in your post. – Woot Dec 26 '16 at 21:10
  • @Woot signedString included. – Jean Paul Dec 26 '16 at 22:05
  • This does not seem to be a problem with MWS, but rather with using HttpWebRequest in C#. You might want to look a this: http://stackoverflow.com/questions/14702902/post-form-data-using-httpwebrequest – Hazzit Dec 29 '16 at 15:18

0 Answers0