/// <summary>
/// Sends the given data to the EVL device.
/// </summary>
/// <param name="data">Data to send to EVL</param>
/// <returns></returns>
public async Task SendAsync(string data)
{
byte[] buffer = Encoding.UTF8.GetBytes(data + "\r\n");
await writeStream.WriteAsync(buffer, 0, buffer.Length);
lastSentCommand = Tpi.GetCommandPart(data);
}
/// <summary>
/// Processes a login command with the given data.
/// </summary>
/// <param name="data">Data sent with login command.</param>
private async Task ProcessLoginAsync(string data)
{
var loginType = (Command.LoginType) int.Parse(data);
if (loginType == Command.LoginType.IncorrectPassword)
{
// Login failed - throw exception
throw new Exception("Invalid password.");
}
else if (loginType == Command.LoginType.TimeOut)
{
// Login timed out - throw exception
throw new Exception("Login to EVL timed out.");
}
else if (loginType == Command.LoginType.PasswordRequest)
{
// Login request - send credentials
string command = Command.NetworkLogin + Password;
await SendAsync(command + Tpi.CalculateChecksum(command));
}
}
/// <summary>
/// Reads data from the EVL connection and processes commands until connection is terminated.
/// </summary>
/// <param name="stream">Stream from EVL connection</param>
private async Task ReadAsync(NetworkStream stream)
{
using (stream)
{
string separator = string.Join("", Separators);
byte[] buffer = new byte[1024];
string incomplete = "";
bool read = true;
while (read)
{
int result = await stream.ReadAsync(buffer, 0, 1024);
if (result == 0)
{
break;
}
string incoming = Encoding.UTF8.GetString(buffer, 0, result);
string[] packets;
if (incoming.EndsWith(separator))
{
// Incoming contains complete command(s)
// Append new data to stored incomplete command
incomplete += incoming;
packets = incomplete.Split(Separators, StringSplitOptions.RemoveEmptyEntries);
// Clear incomplete buffer
incomplete = string.Empty;
}
else
{
// Incoming contains partial command
incomplete += incoming;
// Separate into individual packets
string[] partial = incomplete.Split(Separators, StringSplitOptions.RemoveEmptyEntries);
// Store complete packets in packets array
packets = new string[partial.Length - 1];
Array.Copy(partial, packets, partial.Length - 1);
// Store incomplete command to use when rest of data arrives
incomplete = partial[partial.Length - 1];
}
// Process each complete command received
foreach (string packet in packets)
{
bool valid = Tpi.VerifyChecksum(packet);
if (!valid)
{
// TODO: Expand on this.
Console.WriteLine("Incorrect checksum!");
break;
}
string command = Tpi.GetCommandPart(packet);
string data = Tpi.GetDataPart(packet);
try
{
await ProcessAsync(command, data);
}
catch (Exception e)
{
Console.WriteLine("Error: " + e.Message);
read = false;
break;
}
}
}
}
// Disconnected, clean up connection and other stuff.
Console.WriteLine("Disconnected from EVL!");
Disconnect();
}
