public void OpenReadAsync(Uri apiUrl, XHttpRequestParamters paramter, HttpResponseHandler handler, bool isAddAuthenticationHead = false)
{
var request = new WebClient();
foreach (var headerString in paramter.HeaderStrings)
{
request.Headers.Add(headerString.Key, headerString.Value);
}
if (isAddAuthenticationHead)
{
AddAuthenticationHead(request, apiUrl, "GET", paramter);
}
request.OpenReadCompleted += OpenReadCallBack;
request.OpenReadAsync(apiUrl, handler);
}
private void AddAuthenticationHead(WebClient request, Uri apiUrl, string method, XHttpRequestParamters paramter)
{
var requestContentBase64String = string.Empty;
//HttpUtility需要引用System.Web
var requestUri = HttpUtility.UrlEncode(apiUrl.ToString().ToLower());
var requestHttpMethod = method;
//Calculate UNIX time
var epochStart = new DateTime(1970, 01, 01, 0, 0, 0, 0, DateTimeKind.Utc);
var timeSpan = DateTime.UtcNow - epochStart;
var requestTimeStamp = Convert.ToUInt64(timeSpan.TotalSeconds).ToString();
//create random nonce for each request
var nonce = Guid.NewGuid().ToString("N");
if (paramter.BodyParamters.Count > 0)
{
var builder = new StringBuilder();
foreach (var bodyParamter in paramter.BodyParamters)
{
builder.Append(bodyParamter.Key);
builder.Append("=");
builder.Append(bodyParamter.Value);
builder.Append("&");
}
builder.Remove(builder.Length, 1);
var content = Encoding.UTF8.GetBytes(builder.ToString());
var md5 = MD5.Create();
//Hashing the request body, any change in request body will result in different hash, we'll incure message integrity
var requestContentHash = md5.ComputeHash(content);
requestContentBase64String = Convert.ToBase64String(requestContentHash);
}
var signatureRawData = "{AppId}{requestHttpMethod}{requestUri}{requestTimeStamp}{nonce}{requestContentBase64String}";
var secretKeyByteArray = Convert.FromBase64String(ApiKey);
var signature = Encoding.UTF8.GetBytes(signatureRawData);
using (var hmac = new HMACSHA256(secretKeyByteArray))
{
var signatureBytes = hmac.ComputeHash(signature);
var requestSignatureBase64String = Convert.ToBase64String(signatureBytes);
request.Headers.Add("Authorization", string.Format(" {0} {1}", "cpx", string.Format("{0}:{1}:{2}:{3}", AppId, requestSignatureBase64String, nonce, requestTimeStamp)));
}
}
