Getting Started With ASP.NET MVC3 & Google Checkout: Take 2

Question

This is a follow-up to: https://stackoverflow.com/questions/6285578/getting-started-with-asp-net-mvc3-google-checkout

Now I finally started to know what's going on with the Google Checkout API. I decided to do everything on the server side. So I wrote some code but I could not make a successful call to the API. Here's my code:

        var str = string.Format("{0}:{1}", MERCHANT_ID, MERCHANT_KEY);
        var auth = EncodeTo64(str);
        var request = WebRequest.Create("https://sandbox.google.com/checkout/api/checkout/v2/requestForm/Merchant/747839340759259");
        ((HttpWebRequest) request).Accept = "application/xml;charset=UTF-8";
        request.Headers.Add("Authorization", "Basic " + auth);
        request.ContentType = "application/xml;charset=UTF-8";
        request.Method = "POST";
        string postData = "_type=hello";
        byte[] byteArray = Encoding.UTF8.GetBytes(postData);
        request.ContentLength = byteArray.Length;
        Stream dataStream = request.GetRequestStream();
        dataStream.Write(byteArray, 0, byteArray.Length);
        dataStream.Close();
        // Get the response.
        WebResponse response = request.GetResponse();
        ViewData.Add("status", ((HttpWebResponse)response).StatusDescription);
        dataStream = response.GetResponseStream();
        var reader = new StreamReader(dataStream);
        string responseFromServer = reader.ReadToEnd();
        ViewData.Add("responseFromServer", responseFromServer);
        reader.Close();
        dataStream.Close();
        response.Close();
        return View();

First I was getting a 401 error, but I got that resolved. Now I keep getting The remote server returned an error: (400) Bad Request. on the line that says WebResponse response = request.GetResponse();. So it has to be something wrong with my C# code I guess?

NOTE: The HTTP post should have the following headers.

Authorization: Basic MTIzNDU2Nzg5MDpIc1lYRm9aZkhBcXlMY0NSWWVIOHFR (which is the base64 encoding of Merchant_ID:Merchant_Key

Content-Type: application/xml;charset=UTF-8

Accept: application/xml;charset=UTF-8

So any suggestion on how I could resolve this issue?

UPDATE: I think I figured out the source of the problem, but I cannot figure out how to solve it. Here's a link that explains it: This Stream Does Not Support Seek Operations

UPDATE 2: I finally got fiddler to catch the call, and here's what I found out:

REQUEST:

POST 

https://sandbox.google.com/checkout/api/checkout/v2/requestForm/Merchant/747839340759259

HTTP/1.1

Accept: application/xml;charset=UTF-8

Content-Type: application/x-www-form-urlencoded

Range: bytes=1024-

Authorization: Basic NzQ3ODM5MzQwNzU5MjU5OjVKNS1tRkpIZVBWc25hXzVFOW5mZ2c=

User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)

Host: sandbox.google.com

Content-Length: 257

Expect: 100-continue

Connection: Keep-Alive


_type=checkout-shopping-cart&item_name_1=Baseball&item_description_1=White+baseball&item_currency_1=USD&item_price_1=5.99&item_quantity_1=2&item_name_2=Baseball+Glove&item_description_2=XL+Baseball+Glove&item_currency_2=USD&item_price_2=30&item_quantity_2=1

RESPONSE:

HTTP/1.1 400 Bad Request

Content-Type: application/x-www-form-urlencoded; charset=US-ASCII

Transfer-Encoding: chunked

Date: Thu, 09 Jun 2011 19:32:49 GMT

Expires: Thu, 09 Jun 2011 19:32:49 GMT

Cache-Control: private, max-age=0

X-Content-Type-Options: nosniff

X-Frame-Options: SAMEORIGIN

X-XSS-Protection: 1; mode=block

Set-Cookie: S=payments_api=GWZzws2nBZR-KMGHgKJlTQ; Expires=Thu, 09-Jun-2011 20:02:49 GMT; Path=/; Secure; HttpOnly

Server: GSE

74
_type=error&error-message=Carts+must+contain+at+least+one+item.&serial-number=c8677c3d-3e80-48e8-bd84-f01fa3b02165

0

Answer 1

You state:

The HTTP post should have the following headers.

Content-Type: application/xml;charset=UTF-8

yet that is clearly not xml in your payload, and that isn't an xml header in the trace... it looks to me simply that you aren't sending the right data to the API.

Answer 2

This may be a dumb question, but is there a reason that you're not using Google's .NET DLL?

I realize the example on google code is for a windows form app, but the objects used to post the checkout request should work just fine from your controller.