private async Task <ReceiveMessageResult> receiveMessageAsync(ProtocolType protocol, int timeout, CancellationToken cancellationToken)
{
ReceiveMessageResult result = new ReceiveMessageResult
{
Bytes = 0,
Packets = 0,
Message = new Memory <byte>(),
};
try
{
List <byte> receivedData = new List <byte>();
DateTime startTimestamp = DateTime.UtcNow;
while (DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds < timeout && receivedData.Count < TCPHeaderLength)
{
Memory <byte> buffer = new byte[1500];
TimeSpan receiveTimeout = TimeSpan.FromMilliseconds(timeout).Subtract(DateTime.UtcNow.Subtract(startTimestamp));
if (receiveTimeout.TotalMilliseconds >= 50)
{
int receivedBytes = await _client.ReceiveAsync(buffer, receiveTimeout, cancellationToken);
if (receivedBytes > 0)
{
receivedData.AddRange(buffer.Slice(0, receivedBytes).ToArray());
result.Bytes += receivedBytes;
result.Packets += 1;
}
}
}
if (receivedData.Count == 0)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "' - No Data was Received");
}
if (receivedData.Count < TCPHeaderLength)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message within the Timeout Period from Unitronics PLC '" + RemoteHost + ":" + Port + "'");
}
if (receivedData[3] != 0)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "' - The TCP Header was Invalid");
}
if (BitConverter.ToUInt16(receivedData.GetRange(0, 2).ToArray(), 0) != _requestId)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "' - The TCP Header Transaction ID did not Match");
}
if (receivedData[2] != (byte)protocol)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "' - The TCP Header Protocol Type did not Match");
}
int tcpMessageDataLength = BitConverter.ToUInt16(new byte[] { receivedData[4], receivedData[5] });
if (tcpMessageDataLength <= 0 || tcpMessageDataLength > 1009)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "' - The TCP Message Length was Invalid");
}
receivedData.RemoveRange(0, TCPHeaderLength);
if (receivedData.Count < tcpMessageDataLength - TCPHeaderLength)
{
startTimestamp = DateTime.UtcNow;
while (DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds < timeout && receivedData.Count < tcpMessageDataLength)
{
Memory <byte> buffer = new byte[1024];
TimeSpan receiveTimeout = TimeSpan.FromMilliseconds(timeout).Subtract(DateTime.UtcNow.Subtract(startTimestamp));
if (receiveTimeout.TotalMilliseconds >= 50)
{
int receivedBytes = await _client.ReceiveAsync(buffer, receiveTimeout, cancellationToken);
if (receivedBytes > 0)
{
receivedData.AddRange(buffer.Slice(0, receivedBytes).ToArray());
}
result.Bytes += receivedBytes;
result.Packets += 1;
}
}
}
if (receivedData.Count == 0)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "' - No Data was Received after TCP Header");
}
if (receivedData.Count < tcpMessageDataLength - TCPHeaderLength)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message within the Timeout Period from Unitronics PLC '" + RemoteHost + ":" + Port + "'");
}
result.Message = receivedData.ToArray();
}
catch (ObjectDisposedException)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "' - The underlying Socket Connection has been Closed");
}
catch (TimeoutException)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message within the Timeout Period from Unitronics PLC '" + RemoteHost + ":" + Port + "'");
}
catch (System.Net.Sockets.SocketException e)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC '" + RemoteHost + ":" + Port + "'", e);
}
return(result);
}
public async Task <ProcessMessageResult> ProcessMessageAsync(ReadOnlyMemory <byte> requestMessage, ProtocolType protocol, byte unitId, int timeout, int retries, CancellationToken cancellationToken)
{
int attempts = 0;
Memory <byte> responseMessage = new Memory <byte>();
int bytesSent = 0;
int packetsSent = 0;
int bytesReceived = 0;
int packetsReceived = 0;
DateTime startTimestamp = DateTime.UtcNow;
while (attempts <= retries)
{
try
{
if (!_semaphore.Wait(0))
{
await _semaphore.WaitAsync(cancellationToken);
}
if (attempts > 0)
{
await destroyAndInitializeClient(timeout, cancellationToken);
}
// Send the Message
SendMessageResult sendResult = await sendMessageAsync(requestMessage, protocol, timeout, cancellationToken);
bytesSent += sendResult.Bytes;
packetsSent += sendResult.Packets;
// Receive a Response
ReceiveMessageResult receiveResult = await receiveMessageAsync(protocol, timeout, cancellationToken);
bytesReceived += receiveResult.Bytes;
packetsReceived += receiveResult.Packets;
responseMessage = receiveResult.Message;
break;
}
catch (Exception)
{
if (attempts >= retries)
{
throw;
}
}
finally
{
_semaphore.Release();
}
// Increment the Attempts
attempts++;
}
return(new ProcessMessageResult
{
BytesSent = bytesSent,
PacketsSent = packetsSent,
BytesReceived = bytesReceived,
PacketsReceived = packetsReceived,
Duration = DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds,
ResponseMessage = responseMessage,
});
}
private async Task <ReceiveMessageResult> receiveMessageAsync(ProtocolType protocol, byte unitId, int timeout, CancellationToken cancellationToken)
{
ReceiveMessageResult result = new ReceiveMessageResult
{
Bytes = 0,
Packets = 0,
Message = new Memory <byte>(),
};
try
{
List <byte> receivedData = new List <byte>();
DateTime startTimestamp = DateTime.UtcNow;
bool receiveCompleted = false;
while (DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds < timeout && receiveCompleted == false)
{
Memory <byte> buffer = new byte[1500];
TimeSpan receiveTimeout = TimeSpan.FromMilliseconds(timeout).Subtract(DateTime.UtcNow.Subtract(startTimestamp));
if (receiveTimeout.TotalMilliseconds >= 50)
{
int receivedBytes = await _client.ReceiveAsync(buffer, receiveTimeout, cancellationToken);
if (receivedBytes > 0)
{
receivedData.AddRange(buffer.Slice(0, receivedBytes).ToArray());
result.Bytes += receivedBytes;
result.Packets += 1;
}
}
receiveCompleted = isReceiveCompleted(protocol, receivedData);
}
if (receivedData.Count == 0)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC ID '" + unitId + "' on '" + RemoteHost + ":" + Port + "' - No Data was Received");
}
if (receiveCompleted == false)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message within the Timeout Period from Unitronics PLC ID '" + unitId + "' on '" + RemoteHost + ":" + Port + "'");
}
result.Message = trimReceivedData(protocol, receivedData);
}
catch (ObjectDisposedException)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC ID '" + unitId + "' on '" + RemoteHost + ":" + Port + "' - The underlying Socket Connection has been Closed");
}
catch (TimeoutException)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message within the Timeout Period from Unitronics PLC ID '" + unitId + "' on '" + RemoteHost + ":" + Port + "'");
}
catch (System.Net.Sockets.SocketException e)
{
throw new UnitronicsException("Failed to Receive " + protocol + " Message from Unitronics PLC ID '" + unitId + "' on '" + RemoteHost + ":" + Port + "'", e);
}
return(result);
}