protected async override Task <HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
HttpResponseMessage response = null;
string requestContentBase64String = string.Empty;
string requestUri = System.Net.WebUtility.UrlEncode(request.RequestUri.AbsoluteUri).ToLower();
string requestHttpMethod = request.Method.Method;
//Calculate UNIX time
DateTime epochStart = new DateTime(1970, 01, 01, 0, 0, 0, 0, DateTimeKind.Utc);
TimeSpan timeSpan = DateTime.UtcNow - epochStart;
string requestTimeStamp = Convert.ToUInt64(timeSpan.TotalSeconds).ToString();
//create random nonce for each request
string nonce = Guid.NewGuid().ToString("N");
//Checking if the request contains body, usually will be null wiht HTTP GET and DELETE
if (request.Content != null)
{
requestContentBase64String = CryptographicHelpers.MD5Hash(request.Content.ReadAsStringAsync().Result);
}
//Creating the raw signature string
string signatureRawData = String.Format("{0}{1}{2}{3}{4}{5}", APPId, requestHttpMethod, requestUri, requestTimeStamp, nonce, requestContentBase64String);
var requestSignatureBase64String = CryptographicHelpers.HmacSha256(APIKey, signatureRawData);
request.Headers.Authorization = new AuthenticationHeaderValue("amx", string.Format("{0}:{1}:{2}:{3}", APPId, requestSignatureBase64String, nonce, requestTimeStamp));
response = await base.SendAsync(request, cancellationToken);
return(response);
}
