/// <summary>Creates a message representation as follows:
/// HTTP method\n +
/// Content-MD5\n +
/// Response content type (accept header)\n +
/// Canonicalized URI\n
/// ISO-8601 UTC timestamp including milliseconds (e.g. 2013-09-23T09:24:43.5395441Z)\n
/// Public-Key
/// </summary>
public string CreateMessageRepresentation(WebApiRequestContext context, string contentMd5Hash, string timestamp)
{
if (context == null || !context.IsValid)
{
return(null);
}
string result = string.Join(_delimiterRepresentation,
context.HttpMethod.ToLower(),
contentMd5Hash ?? "",
context.HttpAcceptType.ToLower(),
context.Url.ToLower(),
timestamp,
context.PublicKey.ToLower()
);
return(result);
}
public HttpWebRequest StartRequest(WebApiRequestContext context, string content, StringBuilder requestContent)
{
if (context == null || !context.IsValid)
{
return(null);
}
// client system time must not be too far away from api server time! check response header.
// ISO-8601 utc timestamp with milliseconds (e.g. 2013-09-23T09:24:43.5395441Z)
string timestamp = DateTime.UtcNow.ToString("o");
byte[] data = null;
string contentMd5Hash = "";
var request = (HttpWebRequest)WebRequest.Create(context.Url);
SetTimeout(request);
request.UserAgent = _consumerName; // optional
request.Method = context.HttpMethod;
request.Headers.Add(HttpRequestHeader.Pragma, "no-cache");
request.Headers.Add(HttpRequestHeader.CacheControl, "no-cache, no-store");
request.Accept = context.HttpAcceptType;
request.Headers.Add(HttpRequestHeader.AcceptCharset, "UTF-8");
request.Headers.Add(WebApiGlobal.HeaderName.PublicKey, context.PublicKey);
request.Headers.Add(WebApiGlobal.HeaderName.Date, timestamp);
if (!string.IsNullOrWhiteSpace(content) && BodySupported(request.Method))
{
data = Encoding.UTF8.GetBytes(content);
request.ContentLength = data.Length;
request.ContentType = "application/json; charset=utf-8";
contentMd5Hash = CreateContentMd5Hash(data);
// optional... provider returns HmacResult.ContentMd5NotMatching if there's no match
request.Headers.Add(HttpRequestHeader.ContentMd5, contentMd5Hash);
}
else if (BodySupported(request.Method))
{
request.ContentLength = 0;
}
string messageRepresentation = CreateMessageRepresentation(context, contentMd5Hash, timestamp);
//Debug.WriteLine(messageRepresentation);
string signature = CreateSignature(context.SecretKey, messageRepresentation);
request.Headers.Add(HttpRequestHeader.Authorization, CreateAuthorizationHeader(signature));
if (data != null)
{
using (var stream = request.GetRequestStream())
{
stream.Write(data, 0, data.Length);
}
requestContent.Append(content);
}
requestContent.Insert(0, request.Headers.ToString());
return(request);
}