/// <summary>
/// Retrieves the next EFT response from the client
/// </summary>
/// <param name="cancellationToken">The token to monitor for cancellation requests</param>
/// <returns> An EFTResponse if one could be read, otherwise null </returns>
/// <exception cref="ConnectionException">The socket is closed.</exception>
/// <exception cref="TaskCanceledException">The task was cancelled by cancellationToken</exception>
public async Task <EFTResponse> ReadResponseAsync(System.Threading.CancellationToken cancellationToken)
{
// Clear the receive buffer if we have been waiting for more than
// 5 seconds for the remaining parts of the message to arrive
var tc = System.Environment.TickCount;
if (_recvBufWaiting && tc - _recvTickCount > 5000 && _recvBuf.Length > 0)
{
Log(LogLevel.Debug, tr => tr.Set($"Data is being cleared from the buffer due to a timeout. Content {_recvBuf.ToString()}"));
_recvBufWaiting = false;
_recvBuf.Clear();
}
// Only try to read more data if our receive buffer is empty
Log(LogLevel.Debug, tr => tr.Set($"ReadResponseAsync() _recvBuf.Length={_recvBuf.Length} _recvBufWaiting={_recvBufWaiting}"));
if (_recvBuf.Length == 0 || _recvBufWaiting == true)
{
var bytesRead = 0;
try
{
bytesRead = await _clientStream.ReadResponseAsync(_buffer, cancellationToken);
_recvTickCount = System.Environment.TickCount;
}
catch (TaskCanceledException e)
{
Log(LogLevel.Debug, tr => tr.Set($"Socket read cancelled", e));
throw e;
}
catch (Exception e)
{
Log(LogLevel.Error, tr => tr.Set($"An error occured sending the request", e));
Disconnect();
throw new ConnectionException(e.Message, e.InnerException);
}
// Check for socket closed
if (bytesRead <= 0)
{
Log(LogLevel.Error, tr => tr.Set("Recv 0 bytes. Socket closed"));
Disconnect();
throw new ConnectionException("Socket closed.");
}
var msgString = DirectEncoding.DIRECT.GetString(_buffer, 0, bytesRead);
Log(LogLevel.Info, tr => tr.Set($"Rx {msgString}"));
// Append receive data to our buffer
_recvBuf.Append(msgString);
}
// Keep parsing until no more characters
try
{
bool isXMLFormatted = false;
int index = 0;
while (index < _recvBuf.Length)
{
// If the current char isn't #/& then keep cycling through the message until we find one
if (_recvBuf[index] != (byte)'#' && !(isXMLFormatted = _recvBuf[index] == (byte)'&'))
{
index++;
continue;
}
// We have a valid start char, check for length.
index++;
int lengthSize = isXMLFormatted ? 6 : 4;
// Check that we have enough bytes to validate length, if not wait for more
if (_recvBuf.Length < index + lengthSize)
{
Log(LogLevel.Debug, tr => tr.Set($"Unable to validate message header. Waiting for more data. Length:{_recvBuf.Length} Required:{index + lengthSize + 1}"));
_recvBufWaiting = true;
break;
}
// Try to get the length of the new message. If it's not a valid length
// we might have some corrupt data, keep checking for a valid message
var lengthStr = _recvBuf.Substring(index, lengthSize);
if (!int.TryParse(lengthStr, out int length) || length <= (lengthSize + 1))
{
Log(LogLevel.Error, tr => tr.Set($"Invalid length. Content:{lengthStr}"));
continue;
}
// We have a valid length
index += lengthSize;
// If the defined message length is > our current buffer size, wait for more data
if (_recvBuf.Length < index + length - (lengthSize + 1))
{
Log(LogLevel.Debug, tr => tr.Set($"Buffer is less than the indicate length. Waiting for more data. Length:{_recvBuf.Length < index} Required:{length - (lengthSize + 1)}"));
_recvBuf = _recvBuf.Remove(0, index - (lengthSize + 1));
_recvBufWaiting = true;
break;
}
// We have a valid response
_recvBufWaiting = false;
var response = _recvBuf.Substring(index, length - (lengthSize + 1));
index += (length - (lengthSize + 1));
_recvBuf.Remove(0, index);
// Process the response
EFTResponse eftResponse = null;
try
{
//if (response.Equals("3M") || response.Equals("3C")) // FOR PREPRINT TIMEOUT
//if (response.Substring(0,2).Equals("3R")) // FOR PRINT TIMEOUT
// System.Threading.Thread.Sleep(61000);
eftResponse = (isXMLFormatted) ? _parser.XMLStringToEFTResponse(response) : _parser.StringToEFTResponse(response);
// If we have an EFTResponse we need to return it.
if (eftResponse != null)
{
// Print requests need a response
if (eftResponse is EFTReceiptResponse)
{
await WriteRequestAsync(new EFTReceiptRequest());
}
//DialogUIHandler needs to be notified of display messages
else if (eftResponse is EFTDisplayResponse && DialogUIHandlerAsync != null)
{
await DialogUIHandlerAsync.HandleDisplayResponseAsync(eftResponse as EFTDisplayResponse);
}
else if (eftResponse.GetType() == _currentStartTxnRequest?.GetPairedResponseType() && DialogUIHandlerAsync != null)
{
await DialogUIHandlerAsync.HandleCloseDisplayAsync();
}
return(eftResponse);
}
}
catch (Exception e)
{
Log(LogLevel.Error, tr => tr.Set("Error parsing response string", e));
}
}
// Clear our buffer if we are all done (this shouldn't happen)
if (index == _recvBuf.Length)
{
_recvBufWaiting = false;
_recvBuf.Clear();
}
}
catch (Exception ex)
{
Log(LogLevel.Error, tr => tr.Set($"Exception (ReceiveEFTResponse): {ex.Message}", ex));
throw ex;
}
return(null);
}
