private string CreateOauthSignature(string resourceUrl, TwitterMethod method, string oauthNonce, string oauthTimestamp, SortedDictionary <string, string> requestParameters)
{
//Add the standard oauth parameters to the sorted list
requestParameters.Add("oauth_consumer_key", ConsumerKey);
requestParameters.Add("oauth_nonce", oauthNonce);
requestParameters.Add("oauth_signature_method", OauthSignatureMethod);
requestParameters.Add("oauth_timestamp", oauthTimestamp);
requestParameters.Add("oauth_token", AccessToken);
requestParameters.Add("oauth_version", OauthVersion);
var sigBaseString = requestParameters.ToTwitterWebString();
var signatureBaseString = string.Concat(method.ToString(), "&", Uri.EscapeDataString(resourceUrl), "&", Uri.EscapeDataString(sigBaseString.ToString()));
//Using this base string, we then encrypt the data using a composite of the
//secret keys and the HMAC-SHA1 algorithm.
var compositeKey = string.Concat(Uri.EscapeDataString(ConsumerKeySecret), "&",
Uri.EscapeDataString(AccessTokenSecret));
string oauthSignature;
using (var hasher = new HMACSHA1(Encoding.ASCII.GetBytes(compositeKey)))
{
oauthSignature = Convert.ToBase64String(
hasher.ComputeHash(Encoding.ASCII.GetBytes(signatureBaseString)));
}
return(oauthSignature);
}
/// <summary>
/// Get POST response from HTTPWebMethod
/// </summary>
/// <param name="resourceUrl"></param>
/// <param name="method"></param>
/// <param name="requestParameters"></param>
/// <returns></returns>
private string GetResponse(string resourceUrl, TwitterMethod method, SortedDictionary <string, string> requestParameters)
{
ServicePointManager.Expect100Continue = false;
WebRequest request = null;
string resultString = string.Empty;
if (method == TwitterMethod.GET)
{
request = (HttpWebRequest)WebRequest.Create(resourceUrl + "?" + requestParameters.ToTwitterWebString());
request.Method = method.ToString();
}
if (request != null)
{
var authHeader = CreateHeader(resourceUrl, method, requestParameters);//Twitter API - auth token
request.Headers.Add("Authorization", authHeader);
var response = request.GetResponse();
using (var sd = new StreamReader(response.GetResponseStream()))
{
resultString = sd.ReadToEnd();
response.Close();
}
}
return(resultString);
}
/// <summary>
/// Authorize the Twitter API - request
/// </summary>
/// <param name="resourceUrl"></param>
/// <param name="method"></param>
/// <param name="requestParameters"></param>
/// <returns></returns>
private string CreateHeader(string resourceUrl, TwitterMethod method, SortedDictionary <string, string> requestParameters)
{
var oauthNonce = CreateOauthNonce();
var oauthTimestamp = CreateOAuthTimestamp();
var oauthSignature = CreateOauthSignature(resourceUrl, method, oauthNonce, oauthTimestamp, requestParameters);
//The oAuth signature is then used to generate the Authentication header.
const string headerFormat = "OAuth oauth_nonce=\"{0}\", oauth_signature_method =\"{1}\", " + "oauth_timestamp=\"{2}\", oauth_consumer_key =\"{3}\", " + "oauth_token=\"{4}\", oauth_signature =\"{5}\", " + "oauth_version=\"{6}\"";
var authHeader = string.Format(headerFormat,
Uri.EscapeDataString(oauthNonce),
Uri.EscapeDataString(OauthSignatureMethod),
Uri.EscapeDataString(oauthTimestamp),
Uri.EscapeDataString(ConsumerKey),
Uri.EscapeDataString(AccessToken),
Uri.EscapeDataString(oauthSignature),
Uri.EscapeDataString(OauthVersion)
);
return(authHeader);
}
