Payments API - Execute Charge

Payments-ExecuteCharge

//string body = "{\"amount\": \"10.55\",\"token\": \"s2ZJuHhJQkZMXBngU7fP00At21c\",\"currency\": \"USD\"}";
//string responseXML = ExecutePaymentsCharge(consumerKey, consumerSecret, accessToken, accessSecret, realmId, body);
            
        public static string ExecutePaymentsCharge(string consumerKey, string consumerSecret, string accessToken, string accessTokenSecret, string realmId, string body)
        {
            string uri = string.Format("https://sandbox.api.intuit.com/quickbooks/v4/payments/charges");
            HttpWebRequest httpWebRequest = WebRequest.Create(uri) as HttpWebRequest;
            httpWebRequest.Headers.Add("Request-Id", "iuy87t79t3861796t87r670");
            httpWebRequest.Method = "POST";
            httpWebRequest.Accept = "application/json";
            httpWebRequest.ContentType = "application/json";
            httpWebRequest.Headers.Add("Authorization", GetDevDefinedOAuthHeader(consumerKey, consumerSecret, accessToken, accessTokenSecret, httpWebRequest, body));
            UTF8Encoding encoding = new UTF8Encoding();
            byte[] content = encoding.GetBytes(body);
            using (var stream = httpWebRequest.GetRequestStream())
            {
                stream.Write(content, 0, content.Length);
            }
            HttpWebResponse httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse;
            using (Stream data = httpWebResponse.GetResponseStream())
            {
                //return XML response
                return new StreamReader(data).ReadToEnd();
            }
        }
        
        private static string GetDevDefinedOAuthHeader(string consumerKey, string consumerSecret, string accessToken, string accessTokenSecret, HttpWebRequest webRequest, string requestBody)
        {

            OAuthConsumerContext consumerContext = new OAuthConsumerContext
            {
                ConsumerKey = consumerKey,
                SignatureMethod = SignatureMethod.HmacSha1,
                ConsumerSecret = consumerSecret,
                UseHeaderForOAuthParameters = true
            };

            //We already have OAuth tokens, so OAuth URIs below are not used - set to example.com
            OAuthSession oSession = new OAuthSession(consumerContext, "https://www.example.com",
                                    "https://www.example.com",
                                    "https://www.example.com");

            oSession.AccessToken = new TokenBase
            {
                Token = accessToken,
                ConsumerKey = consumerKey,
                TokenSecret = accessTokenSecret
            };

            IConsumerRequest consumerRequest = oSession.Request();
            consumerRequest = ConsumerRequestExtensions.ForMethod(consumerRequest, webRequest.Method);
            if (requestBody != null)
            {
                consumerRequest = consumerRequest.Post().WithRawContentType(webRequest.ContentType).WithRawContent(System.Text.Encoding.ASCII.GetBytes(requestBody));
            }
            consumerRequest = ConsumerRequestExtensions.ForUri(consumerRequest, webRequest.RequestUri);
            consumerRequest = consumerRequest.SignWithToken();
            return consumerRequest.Context.GenerateOAuthParametersForHeader();
        }