/// <summary>
/// Simple handler for the NATS protocol state-machine
/// </summary>
/// <param name="segment"></param>
/// <param name="op"></param>
private void NotifyOperationHandler(
ArraySegment <byte> segment,
int op
)
{
switch (this._workerStage)
{
case StageWaitInfo:
if (op == Parser.INFO_ARG)
{
this._info = this.ProcessInfo(segment, false);
// This will check to see if the connection should be
// secure. This can be dictated from either end and should
// only be called after the INIT protocol has been received.
// Check to see if we need to engage TLS
// Check for mismatch in setups
bool currentIsSecured = this._srvPool.CurrentServer.EndPoint.Secured;
if (currentIsSecured && this._info.TlsRequired == false)
{
throw new NATSSecureConnWantedException();
}
else if (this._info.TlsRequired && currentIsSecured == false)
{
throw new NATSSecureConnRequiredException();
}
// Need to rewrap with bufio
if (currentIsSecured)
{
// makeSecureConn will wrap an existing Conn using TLS
this._tcp.MakeTLS();
}
}
break;
case StageSendConnectVerbose:
if (op == Parser.OP_PLUS_OK)
{
this._workerStage = StageSendConnectNormal;
}
break;
case StageSendConnectNormal:
if (op == Parser.OP_PONG)
{
this._workerStage = StageLogicallyConnected;
}
break;
case StageLogicallyConnected:
if (op == Parser.OP_PING)
{
this.ProcessPing();
}
else if (op == Parser.OP_PONG)
{
this.ProcessPong();
}
break;
default:
throw new NotSupportedException("worker-stage not supported: " + this._workerStage);
}
}
/// <summary>
/// The "inner" worker
/// </summary>
/// <remarks>
/// This method can raise any kind of exception, which will be caught by the <see cref="OuterWorker(object)"/>.
/// </remarks>
/// <param name="ctx"></param>
private void InnerWorker(
WorkerContext ctx
)
{
this._info = null;
/**
* Initial connection to a server
**/
try
{
this._tcp = this._srvPool.ConnectToAServer(
this._workerStage == StageServerInitialConnection,
ctx.CancToken
);
if (this._tcp == null)
{
throw new Exception();
}
}
catch (OperationCanceledException ex)
{
throw ex;
}
catch (Exception)
{
throw new NATSNoServersException("Unable to connect to a server.");
}
/**
* Waiting for the "INFO" data issued by the server
**/
this._workerStage = StageWaitInfo;
this.ReadThenParseSegment(null, null, ReadTimeout, ctx.CancToken);
if (this._info == null)
{
throw new NATSConnectionException("Protocol exception, INFO not received");
}
/**
* Send "CONNECT" to the server
**/
this._workerStage = this._options.Verbose
? StageSendConnectVerbose
: StageSendConnectNormal;
try
{
this._tcp.SocketSendTimeout = 0;
this._tcp.WriteString(this.ConnectProto());
this.SendPing();
}
catch (Exception ex)
{
throw new NATSException("Error sending connect protocol message", ex);
}
this.ReadThenParseSegment(
ex => throw new NATSConnectionException("Connect read error", ex),
null,
ReadTimeout,
ctx.CancToken
);
if (this._workerStage != StageLogicallyConnected)
{
throw new NATSConnectionException("Connect read protocol error");
}
/**
* Main processing loop
**/
this._tcp.SocketReceiveTimeout = ReadTimeout; //for safety
this.SetStatus(ConnState.CONNECTED);
this.PingStart();
this._owner.RequestReplyManager.Start();
int readCount = 0;
while (ctx.CancToken.IsCancellationRequested == false)
{
if (this._writePending)
{
//something to send is pending
lock (this._writeLocker)
{
//is PING, maybe?
if (this._pingSendPending)
{
this.SendPing();
}
//are one or more SUB messages, maybe?
if (this._subPending)
{
for (int i = 0, sublen = this._subQueue.Count; i < sublen; i++)
{
this._tcp.WriteString(this._subQueue[i]);
}
this._subQueue.Clear();
this._tcp.WriteFlush();
this._subPending = false;
}
this._writePending = false;
}
}
else if (this._isLogicalStarted)
{
if (readCount == 0)
{
//no operation was perfomed: no data in, no data out.
//the cycle would be too tight, then.
//give the OS a breathe of fresh air...
Thread.Sleep(1);
}
}
else
{
//the initial NATS handshake with the server is complete:
//if the start was async, then consider its task as terminated
this._isLogicalStarted = true;
ctx.TaskCompletion?.SetResult(null);
}
//listen to incoming data
readCount = this.ReadThenParseSegment(
this.ProcessOpError,
this.ProcessOpError,
0,
ctx.CancToken
);
}
}
