private async Task ReadDataAsync(SerialPort serialPort)
{
var buffer = new byte[4096];
Task<int> readStringTask = serialPort.BaseStream.ReadAsync(buffer, 0, 4096);
var bytesRead = await readStringTask;
_rawData += Encoding.ASCII.GetString(buffer, 0, bytesRead);
// Check if a newline has received, indicating that a complete message should have read
var lastIndexOfPrintln = _rawData.LastIndexOf("\r\n", StringComparison.Ordinal);
if (lastIndexOfPrintln == -1)
return;
var completeMessages = _rawData.Substring(0, lastIndexOfPrintln);
_rawData = _rawData.Remove(0, lastIndexOfPrintln);
// Split message if more than one have been received
var messages = completeMessages.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
foreach (var message in messages)
{
_nrf24State.CountOfReceivedMessages++;
SendRawMessage(message);
// Every message has three parts splitted by a space
// - record length & message type
// - serial header
// - packet data
var parts = message.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
if (parts.Count() != 3)
continue;
var nrf24Structure = new NRF24Structure
{
DateTime = DateTime.Now,
TypeAndLength = parts[0],
Header = parts[1],
Data = parts[2]
};
// Create the NRF24Header part
nrf24Structure.NRF24Header = NRF24Hub.CreateNRF24Header(nrf24Structure);
// Create the NRF24Data part
nrf24Structure.NRF24Data = CreateNRF24Data(nrf24Structure);
SendObject(nrf24Structure);
}
}
private NRF24Data CreateNRF24Data(NRF24Structure nrf24Structure)
{
if (nrf24Structure.NRF24Header == null || nrf24Structure.Data.Length < 5)
return null;
// Set the NRF24 data part
var nrf24Data = new NRF24Data
{
NodeAddress = $"{nrf24Structure.NRF24Header.Address}{nrf24Structure.Data.Substring(0, 2)}"
};
var controlFieldString = nrf24Structure.Data.Substring(2, 4);
var controlFieldBitArray = NRF24Helpers.GetBitArrayFromHexString(controlFieldString);
nrf24Data.PayloadLength = NRF24Helpers.GetPartOfBitArray(controlFieldBitArray, 0, 6);
nrf24Data.Pid = NRF24Helpers.GetPartOfBitArray(controlFieldBitArray, 6, 2);
nrf24Data.NoAck = controlFieldBitArray[9];
nrf24Data.Payload = nrf24Structure.Data.Substring(4, nrf24Structure.Data.Length - 4);
var payloadFieldBitArray = NRF24Helpers.GetBitArrayFromHexString(nrf24Data.Payload);
// For last byte only the MSbit has value; rest will be cleared
payloadFieldBitArray = NRF24Helpers.GetPartOfBitArray(payloadFieldBitArray, 0, payloadFieldBitArray.Length - 7);
// Get the packet crc (the crc is located in last two bytes of the packet)
var crcOffset = payloadFieldBitArray.Length - 16;
nrf24Data.PacketCrc = NRF24Helpers.GetPartOfBitArray(payloadFieldBitArray, crcOffset, 16);
// Remove the crc bits from the bitarray before it is processed further
nrf24Data.PayloadBitArray = NRF24Helpers.GetPartOfBitArray(payloadFieldBitArray, 0, payloadFieldBitArray.Length - 16);
//TODO what about the string payload??
// ****
// Calculate the crc ourselfs
// Get the payload in bits, as the bitArray is already stripped of all unneeded stuff, the length is the amount of bits
//var payloadLengthBits = payloadFieldBitArray.Length;
//var packetLengthBits = 40 + 9 + payloadLengthBits;
// As the crc is calculated over the address, packet control field and payload, attach the two fields
//var combinedString = $"{this.NRF24Header.Address}{this.Data}";
//var combinedString = $"{this.Data}";
// Create the NRF24Mysensor part
nrf24Data.NRF24Mysensor = CreateNRF24Mysensor(nrf24Data);
return nrf24Data;
}
private void SendObject(NRF24Structure nrf24Structure)
{
var context = _connectionManager.GetHubContext<NRF24Hub>();
context.Clients.All.broadcastObject(nrf24Structure);
}
private static NRF24Header CreateNRF24Header(NRF24Structure nrf24Structure)
{
return (nrf24Structure.Header.Length == 18)
? new NRF24Header
{
Timestamp = nrf24Structure.Header.Substring(0, 8),
PacketsLost = nrf24Structure.Header.Substring(8, 2),
Address = nrf24Structure.Header.Substring(10, 8)
}
: null;
}