internal static byte[] EncodeToken(GitHubTokenData token)
{
using (var stream = new MemoryStream())
using (var writer = new BinaryWriter(stream))
{
writer.Write(token.UserId);
writer.Write(token.TokenId);
writer.Write(token.Expiration.Ticks);
writer.Write(token.AccessToken);
writer.Flush();
return(stream.ToArray());
}
}
private bool TryDecodeToken(string protectedToken, out GitHubTokenData token)
{
Span <byte> tokenBytes = stackalloc byte[1024];
if (!Convert.TryFromBase64String(protectedToken, tokenBytes, out int bytesWritten))
{
token = default;
return(false);
}
// DataProtector can't handle spans, so we have to copy out the value
var toUnprotect = new byte[bytesWritten];
tokenBytes.Slice(0, bytesWritten).CopyTo(toUnprotect.AsSpan());
byte[] unprotected;
try
{
unprotected = _dataProtector.Unprotect(toUnprotect);
}
catch (Exception e)
{
Logger.LogWarning("IDataProtector.Unprotect exception: {exception}", e);
token = default;
return(false);
}
if (!GitHubTokenEncoder.TryDecodeToken(unprotected, Logger, out GitHubTokenData candidateToken))
{
Logger.LogWarning("Malformed token, aborting");
token = default;
return(false);
}
if (candidateToken.Expiration < DateTimeOffset.UtcNow)
{
Logger.LogInformation("Expired token used, expired on {expiration}, from user {user}, with id {id}",
candidateToken.Expiration,
candidateToken.UserId,
candidateToken.TokenId);
token = default;
return(false);
}
token = candidateToken;
return(true);
}
internal static bool TryDecodeToken(byte[] encoded, ILogger logger, out GitHubTokenData token)
{
try
{
using (MemoryStream stream = new MemoryStream(encoded))
using (BinaryReader reader = new BinaryReader(stream))
{
long userId = reader.ReadInt64();
long tokenId = reader.ReadInt64();
var expiration = new DateTimeOffset(reader.ReadInt64(), TimeSpan.Zero);
string accessToken = reader.ReadString();
token = new GitHubTokenData(userId, tokenId, expiration, accessToken);
}
return(true);
}
catch (Exception e)
{
logger.LogWarning("Invalid token: {exception}", e);
token = default;
return(false);
}
}