/// <summary>
/// Opens the connection
/// </summary>
private async Task OpenAsyncInternal(Logger logger)
{
//switch state to connecting if not done so
int state = Interlocked.CompareExchange(ref _connectionState, 1, 0);
if (state == 1)
return;
if (state == 2)
throw new ObjectDisposedException("Connection disposed before opening!");
try
{
//create TCP connection
_client = new TcpClient();
await _client.ConnectAsync(_address, _cluster.Config.Port).ConfigureAwait(false);
_writeStream = _client.GetStream();
_readStream = _client.GetStream();
logger.LogVerbose("TCP connection to {0} is opened", Address);
//start readloop
StartReadingAsync();
//get compression option
_allowCompression = false; //assume false unless
if (_cluster.Config.AllowCompression)
{
//check wether compression is supported by getting compression options from server
var options = new OptionsFrame();
var supported =
await SendRequestAsync(options, logger, 1, true).ConfigureAwait(false) as SupportedFrame;
if (supported == null)
throw new ProtocolException(0, "Expected Supported frame not received");
IList<string> compressionOptions;
//check if options contain compression
if (supported.SupportedOptions.TryGetValue("COMPRESSION", out compressionOptions))
{
//check wether snappy is supported
_allowCompression = compressionOptions.Contains("snappy");
}
//dispose supported frame
supported.Dispose();
}
//submit startup frame
var startup = new StartupFrame(_cluster.Config.CqlVersion);
if (_allowCompression)
{
logger.LogVerbose("Enabling Snappy Compression.");
startup.Options["COMPRESSION"] = "snappy";
}
Frame response = await SendRequestAsync(startup, logger, 1, true).ConfigureAwait(false);
//authenticate if required
var auth = response as AuthenticateFrame;
if (auth != null)
{
logger.LogVerbose("Authentication requested, attempting to provide credentials", Address);
//check if _username is actually set
if (_cluster.Config.Username == null || _cluster.Config.Password == null)
throw new UnauthorizedException("No credentials provided");
//dispose AuthenticateFrame
response.Dispose();
var cred = new CredentialsFrame(_cluster.Config.Username, _cluster.Config.Password);
response = await SendRequestAsync(cred, logger, 1, true).ConfigureAwait(false);
}
//check if ready
if (!(response is ReadyFrame))
throw new ProtocolException(0, "Expected Ready frame not received");
//dispose ready frame
response.Dispose();
using (logger.ThreadBinding())
{
if (OnConnectionChange != null)
OnConnectionChange(this, new ConnectionChangeEvent { Connected = true });
}
logger.LogInfo("{0} is opened and ready for use", this);
}
catch (Exception ex)
{
using (logger.ThreadBinding())
{
Dispose(true, ex);
throw;
}
}
}
/// <summary>
/// Negotiates the connection options.
/// </summary>
/// <param name="logger">The logger.</param>
/// <returns></returns>
/// <exception cref="ProtocolException">0;Expected Supported frame not received</exception>
private async Task NegotiateConnectionOptionsAsync(Logger logger)
{
//get options from server
var options = new OptionsFrame();
var frame =
await SendRequestAsyncInternal(options, logger, 1, CancellationToken.None).AutoConfigureAwait();
var supported = frame as SupportedFrame;
if (supported == null)
throw new ProtocolException(frame.ProtocolVersion, 0, "Expected Supported frame not received");
//setup concurrent calls depending on frameversion
_frameSubmitLock = new SemaphoreSlim(supported.ProtocolVersion <= 2 ? sbyte.MaxValue : short.MaxValue);
//setuo compression
_allowCompression = false;
if (_config.AllowCompression)
{
IList<string> compressionOptions;
//check if options contain compression
if (supported.SupportedOptions.TryGetValue("COMPRESSION", out compressionOptions))
{
//check wether snappy is supported
_allowCompression = compressionOptions.Contains("snappy");
}
}
//dispose supported frame
supported.Dispose();
}
