/// <summary>
/// Generates a MD5 signature for the Facebook session.
/// </summary>
/// <param name="secret">
/// The app secret.
/// </param>
/// <param name="dictionary">
/// The dictionary.
/// </param>
/// <returns>
/// Returns the generated signature.
/// </returns>
/// <remarks>
/// http://developers.facebook.com/docs/authentication/
/// </remarks>
internal static string GenerateSessionSignature(string secret, IDictionary <string, object> dictionary)
{
if (string.IsNullOrEmpty(secret))
{
throw new ArgumentNullException("secret");
}
if (dictionary == null)
{
throw new ArgumentNullException("dictionary");
}
var payload = new StringBuilder();
// sort by the key and remove "sig" if present
var parts = (from a in dictionary
orderby a.Key
where a.Key != "sig"
select string.Format(CultureInfo.InvariantCulture, "{0}={1}", a.Key, a.Value)).ToList();
parts.ForEach(s => payload.Append(s));
payload.Append(secret);
var hash = FacebookWebUtils.ComputerMd5Hash(Encoding.UTF8.GetBytes(payload.ToString()));
var signature = new StringBuilder();
foreach (var h in hash)
{
signature.Append(h.ToString("x2", CultureInfo.InvariantCulture));
}
return(signature.ToString());
}
public void ItShouldGenerateCorrectMd5Hash()
{
var input = System.Text.Encoding.UTF8.GetBytes("access_token=124973200873702|2.OAaqICOCk_B4sZNv59q8Yg__.3600.1295118000-100001327642026|vz4H9xjlRZPfg2quCv0XOM5g9_oexpires=1295118000secret=lddpssZCuPoEtjcDFcWtoA__session_key=2.OAaqICOCk_B4sZNv59q8Yg__.3600.1295118000-100001327642026uid=1000013276420263b4a872617be2ae1932baa1d4d240272");
var expected = new byte[] { 29, 149, 250, 75, 61, 250, 91, 38, 192, 28, 138, 200, 103, 109, 128, 184 };
var md5Hash = FacebookWebUtils.ComputerMd5Hash(input);
Assert.True(expected.SequenceEqual(md5Hash));
}