private static HttpRequestMessage CreateLtiOutcomesRequest(imsx_POXEnvelopeType imsxEnvelope, string url, string consumerKey, string consumerSecret)
{
var webRequest = new HttpRequestMessage(HttpMethod.Post, url);
var parameters = new NameValueCollection();
parameters.AddParameter(OAuthConstants.ConsumerKeyParameter, consumerKey);
parameters.AddParameter(OAuthConstants.NonceParameter, Guid.NewGuid().ToString());
parameters.AddParameter(OAuthConstants.SignatureMethodParameter, OAuthConstants.SignatureMethodHmacSha1);
parameters.AddParameter(OAuthConstants.VersionParameter, OAuthConstants.Version10);
// Calculate the timestamp
var ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
var timestamp = Convert.ToInt64(ts.TotalSeconds);
parameters.AddParameter(OAuthConstants.TimestampParameter, timestamp);
// Calculate the body hash
var ms = new MemoryStream();
using (var sha1 = PlatformSpecific.GetSha1Provider())
{
ImsxRequestSerializer.Serialize(ms, imsxEnvelope);
ms.Position = 0;
webRequest.Content = new StreamContent(ms);
webRequest.Content.Headers.ContentType = HttpContentType.Xml;
var hash = sha1.ComputeHash(ms.ToArray());
var hash64 = Convert.ToBase64String(hash);
parameters.AddParameter(OAuthConstants.BodyHashParameter, hash64);
}
// Calculate the signature
var signature = OAuthUtility.GenerateSignature(webRequest.Method.Method.ToUpper(), webRequest.RequestUri, parameters,
consumerSecret);
parameters.AddParameter(OAuthConstants.SignatureParameter, signature);
// Build the Authorization header
var authorization = new StringBuilder(OAuthConstants.AuthScheme).Append(" ");
foreach (var key in parameters.AllKeys)
{
authorization.AppendFormat("{0}=\"{1}\",", key, WebUtility.UrlEncode(parameters[key]));
}
webRequest.Headers.Add(OAuthConstants.AuthorizationHeader, authorization.ToString(0, authorization.Length - 1));
return(webRequest);
}
private static void SignRequest(HttpRequestMessage request, byte[] body, string consumerKey, string consumerSecret)
{
if (body == null)
{
body = new byte[0];
}
if (body.Length > 0 && request.Content.Headers.ContentLength != body.Length)
{
throw new ArgumentException("body length does not match request.ContentLength", "body");
}
var parameters = new NameValueCollection();
parameters.AddParameter(OAuthConstants.ConsumerKeyParameter, consumerKey);
parameters.AddParameter(OAuthConstants.NonceParameter, Guid.NewGuid().ToString());
parameters.AddParameter(OAuthConstants.SignatureMethodParameter, OAuthConstants.SignatureMethodHmacSha1);
parameters.AddParameter(OAuthConstants.VersionParameter, OAuthConstants.Version10);
// Calculate the timestamp
var ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
var timestamp = Convert.ToInt64(ts.TotalSeconds);
parameters.AddParameter(OAuthConstants.TimestampParameter, timestamp);
// Calculate the body hash
using (var sha1 = PlatformSpecific.GetSha1Provider())
{
var hash = sha1.ComputeHash(body);
var hash64 = Convert.ToBase64String(hash);
parameters.AddParameter(OAuthConstants.BodyHashParameter, hash64);
}
// Calculate the signature
var signature = OAuthUtility.GenerateSignature(request.Method.Method.ToUpper(), request.RequestUri, parameters,
consumerSecret);
parameters.AddParameter(OAuthConstants.SignatureParameter, signature);
// Build the Authorization header
var authorization = new StringBuilder(OAuthConstants.AuthScheme).Append(" ");
foreach (var key in parameters.AllKeys)
{
authorization.AppendFormat("{0}=\"{1}\",", key, WebUtility.UrlEncode(parameters[key]));
}
request.Headers.Add(OAuthConstants.AuthorizationHeader, authorization.ToString(0, authorization.Length - 1));
}