/// <summary>
/// Sends a command to the device and wait for an <c>ack</c>.
/// </summary>
/// <param name="parameters">Command name, optional parameters.</param>
/// <returns>Whether the command was sent successfully.</returns>
private async Task <bool> SendCommandWaitForAck(params string[] parameters)
{
if (parameters == null || parameters.Length == 0)
{
throw new ArgumentException("Invalid command");
}
string commandString = string.Join(ProtocolConstants.FieldSeparator, parameters);
RetailLogger.Log.HardwareStationPeripheralInteraction(VerifoneDeviceProtocol.Name, "--> " + commandString);
var envelope = ProtocolUtilities.CreateEnvelope(commandString);
var ackResponse = await this.SendMessage(envelope);
return(ackResponse);
}
/// <summary>
/// Validates the envelope format is valid and the LRC matches.
/// </summary>
/// <param name="envelope">Buffer containing message envelope.</param>
/// <param name="length">Length of envelope in buffer.</param>
/// <returns>True if valid, false otherwise.</returns>
public static bool ValidateEnvelope(byte[] envelope, int length)
{
if (envelope == null)
{
throw new ArgumentNullException("envelope");
}
if (envelope.Length <= 3 || length < 3)
{
return(false);
}
// Ignore STX, ETX and LRC bytes.
byte lrc = ProtocolUtilities.GetLrc(envelope, 1, length - 3);
return(lrc == envelope[length - 1] && envelope[0] == ProtocolConstants.StartMessage && envelope[length - 2] == ProtocolConstants.EndMessage);
}
/// <summary>
/// Creates an envelope from the command string.
/// </summary>
/// <param name="commandValue">Command to send.</param>
/// <returns>Byte array containing envelope.</returns>
public static byte[] CreateEnvelope(string commandValue)
{
if (string.IsNullOrEmpty(commandValue))
{
throw new ArgumentNullException("commandValue");
}
byte[] command = Encoding.Default.GetBytes(commandValue);
byte[] envelope = new byte[command.Length + EmptyEnvelopeLength];
envelope[0] = ProtocolConstants.StartMessage;
Array.Copy(command, 0, envelope, 1, command.Length);
envelope[command.Length + 1] = ProtocolConstants.EndMessage;
envelope[command.Length + 2] = ProtocolUtilities.GetLrc(command);
return(envelope);
}
/// <summary>
/// Parse a message from a buffer.
/// </summary>
/// <param name="data">Buffer containing message.</param>
/// <param name="length">Length of message in buffer.</param>
/// <returns>A message object.</returns>
public static ResponseMessage Parse(byte[] data, int length)
{
if (data == null)
{
throw new ArgumentNullException("data");
}
var message = new ResponseMessage();
if (data[0] == ProtocolConstants.Ack)
{
message.IsAck = true;
message.IsValid = true;
return(message);
}
if (data[0] == ProtocolConstants.Nak)
{
message.IsNak = true;
message.IsValid = true;
return(message);
}
message.IsValid = ProtocolUtilities.ValidateEnvelope(data, length);
if (!message.IsValid)
{
return(message);
}
// Handle signature data packets which do not have a field seperator.
if (HeaderEquals(data, 0, ProtocolCommands.SignatureStart))
{
// Format is "S01xxxxxyyyyzerrr"
message.Command = Encoding.Default.GetString(data, 1, 3);
message.ResponseValues = new[]
{
Encoding.Default.GetString(data, 4, 5),
Encoding.Default.GetString(data, 9, 4),
Encoding.Default.GetString(data, 13, 1),
Encoding.Default.GetString(data, 14, 1),
Encoding.Default.GetString(data, 15, 3)
};
}
else if (HeaderEquals(data, 0, ProtocolCommands.SignatureDataReceived))
{
// Format is "S02Muuuu{sigdata}"
message.Command = Encoding.Default.GetString(data, 1, 3);
message.ResponseValues = new[]
{
Encoding.Default.GetString(data, 4, 1),
Encoding.Default.GetString(data, 5, 4)
};
message.RawData = data;
}
else if (HeaderEquals(data, 0, ProtocolCommands.CreditCardDataReceived))
{
// Format is "81.<Track1><FS><Track2><FS><Track3><FS>M"
message.Command = Encoding.Default.GetString(data, 1, 3);
if (length > 6)
{
string responseString = Encoding.Default.GetString(data, 4, length - 6);
var responseValues = responseString.Split(new[] { ProtocolConstants.FieldSeparator }, StringSplitOptions.None);
message.ResponseValues = responseValues.ToArray();
}
}
else if (HeaderEquals(data, 0, ProtocolCommands.PinDataReceived))
{
// Format is "73.00000KKKKKKKKKKKKKKKKKKKKPPPPPPPPPPPPPPPP"
message.Command = Encoding.Default.GetString(data, 1, 3);
if (length > 26)
{
string pinLength = Encoding.Default.GetString(data, 4, 5);
string key = Encoding.Default.GetString(data, 9, length - 27);
string pinData = Encoding.Default.GetString(data, length - 18, 16);
message.ResponseValues = new[] { pinLength, key, pinData };
}
}
else if (HeaderEquals(data, 0, ProtocolCommands.PinDataError1) || HeaderEquals(data, 0, ProtocolCommands.PinDataError2))
{
message.Command = ProtocolCommands.PinDataReceived;
message.ResponseValues = new string[0];
}
else
{
if (length > 3)
{
// Format is "<Command><FS><Response1><FS><Response2>..."
string responseString = Encoding.Default.GetString(data, 1, length - 3);
var responseValues = responseString.Split(new[] { ProtocolConstants.FieldSeparator }, StringSplitOptions.RemoveEmptyEntries);
message.Command = responseValues[0];
message.ResponseValues = responseValues.Skip(1).ToArray();
}
}
message.RawData = data;
return(message);
}
