private async Task HandleRequestAsync()
{
while (true)
{
#if ModBusDebug
Debug.WriteLine($"Begin reading header from Master at IP: {EndPoint}");
#endif
int readBytes = await Stream.ReadAsync(_mbapHeader, 0, 6).ConfigureAwait(false);
if (readBytes == 0)
{
#if ModBusDebug
Debug.WriteLine($"0 bytes read, Master at {EndPoint} has closed Socket connection.");
#endif
ModbusMasterTcpConnectionClosed?.Invoke(this, new TcpConnectionEventArgs(EndPoint));
return;
}
ushort frameLength = (ushort)IPAddress.HostToNetworkOrder(BitConverter.ToInt16(_mbapHeader, 4));
#if ModBusDebug
Debug.WriteLine($"Master at {EndPoint} sent header: \"{string.Join(", ", _mbapHeader)}\" with {frameLength} bytes in PDU");
#endif
_messageFrame = new byte[frameLength];
readBytes = await Stream.ReadAsync(_messageFrame, 0, frameLength).ConfigureAwait(false);
if (readBytes == 0)
{
#if ModBusDebug
Debug.WriteLine($"0 bytes read, Master at {EndPoint} has closed Socket connection.");
#endif
ModbusMasterTcpConnectionClosed?.Invoke(this, new TcpConnectionEventArgs(EndPoint));
return;
}
#if ModBusDebug
Debug.WriteLine($"Read frame from Master at {EndPoint} completed {readBytes} bytes");
#endif
byte[] frame = _mbapHeader.Concat(_messageFrame).ToArray();
#if ModBusDebug
Debug.WriteLine($"RX from Master at {EndPoint}: {string.Join(", ", frame)}");
#endif
var request = ModbusMessageFactory.CreateModbusRequest(_messageFrame);
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = _slave.ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
#if ModBusDebug
Debug.WriteLine($"TX to Master at {EndPoint}: {string.Join(", ", responseFrame)}");
#endif
await Stream.WriteAsync(responseFrame, 0, responseFrame.Length).ConfigureAwait(false);
}
}
internal void ReadFrameCompleted(IAsyncResult ar)
{
CatchExceptionAndRemoveMasterEndPoint(() =>
{
_log.DebugFormat("Read Frame completed {0} bytes", Stream.EndRead(ar));
byte[] frame = _mbapHeader.Concat(_messageFrame).ToArray();
_log.InfoFormat("RX: {0}", frame.Join(", "));
IModbusMessage request = ModbusMessageFactory.CreateModbusRequest(frame.Slice(6, frame.Length - 6).ToArray());
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = _slave.ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
_log.InfoFormat("TX: {0}", responseFrame.Join(", "));
Stream.BeginWrite(responseFrame, 0, responseFrame.Length, WriteCompleted, null);
}, EndPoint);
}
internal void ReadFrameCompleted(IAsyncResult ar)
{
_log.DebugFormat("Read Frame completed {0} bytes", _stream.EndRead(ar));
byte[] frame = CollectionUtility.Concat(_mbapHeader, _messageFrame);
_log.InfoFormat("RX: {0}", StringUtility.Join(", ", frame));
IModbusMessage request = ModbusMessageFactory.CreateModbusRequest(CollectionUtility.Slice(frame, 6, frame.Length - 6));
request.TransactionID = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// TODO refactor
ModbusTcpTransport transport = new ModbusTcpTransport();
// perform action and build response
IModbusMessage response = _slave.ApplyRequest(request);
response.TransactionID = request.TransactionID;
// write response
byte[] responseFrame = transport.BuildMessageFrame(response);
_log.InfoFormat("TX: {0}", StringUtility.Join(", ", responseFrame));
_stream.BeginWrite(responseFrame, 0, responseFrame.Length, WriteCompleted, null);
}