public async Task HandleConnectionAsync(TcpClient tcpClient)
{
var clientInfo = tcpClient.Client.RemoteEndPoint.ToString();
var emailMessage = new EmailMessage();
Console.WriteLine("Got connection request from {0}", clientInfo);
try
{
using (var networkStream = tcpClient.GetStream())
using (var reader = new StreamReader(networkStream))
using (var writer = new StreamWriter(networkStream))
{
writer.AutoFlush = true;
await writer.WriteLineAsync("220 Helo there");
while (true)
{
reader.DiscardBufferedData();
var dataFromServer = await reader.ReadLineAsync();
if (dataFromServer.StartsWith("HELO"))
{
//OLD protocol
emailMessage.ClientHostname = dataFromServer.Substring(5);
await writer.WriteLineAsync("250 Ok");
}
if (dataFromServer.StartsWith("EHLO"))
{
//NEW protocol
emailMessage.ClientHostname = dataFromServer.Substring(5);
await writer.WriteLineAsync("250 Ok");
}
if (dataFromServer.StartsWith("MAIL FROM:"))
{
emailMessage.SenderAddress = dataFromServer.Substring(10);
await writer.WriteLineAsync("250 Ok");
}
if (dataFromServer.StartsWith("RCPT TO:"))
{
emailMessage.RecipientAddress = dataFromServer.Substring(8);
await writer.WriteLineAsync("250 Ok");
}
if (dataFromServer.StartsWith("DATA"))
{
await writer.WriteLineAsync("354 Start mail input; end with <crlf>.<crlf>");
var message = new StringBuilder();
while (true)
{
var messageLine = await reader.ReadLineAsync();
if (messageLine == ".")
{
break;
}
message.Append(messageLine);
}
emailMessage.Message = message.ToString();
await TransmitMessage(emailMessage);
await writer.WriteLineAsync("250 Ok");
}
if (dataFromServer.StartsWith("QUIT"))
{
break;
}
Console.WriteLine(dataFromServer);
}
}
}
catch (Exception exp)
{
Console.WriteLine(exp.ToString());
}
finally
{
Console.WriteLine("Closing the client connection - {0}", clientInfo);
//tcpClient.Close();
}
}
internal async Task TransmitMessage(EmailMessage emailMessage)
{
/*var address = new MailAddress(emailMessage.RecipientAddress);
* var mxRecords = await Dns.QueryAsync(address.Host, QType.MX);
*
* var server = "";
*
* // Just grap the first one and hope for the best
* foreach (var mxRecord in mxRecords.RecordsMX)
* {
* server = mxRecord.Exchange;
* break;
* }*/
//var tcpClient = new TcpClient(server, 25);
var tcpClient = new TcpClient();
await tcpClient.ConnectAsync("127.0.0.1", 25);
var clientInfo = tcpClient.Client.RemoteEndPoint.ToString();
try
{
using (var networkStream = tcpClient.GetStream())
using (var reader = new StreamReader(networkStream))
using (var writer = new StreamWriter(networkStream))
{
writer.AutoFlush = true;
var state = "";
while (true)
{
var dataFromServer = await reader.ReadLineAsync();
Console.WriteLine(dataFromServer);
if (dataFromServer.StartsWith("220"))
{
//await writer.WriteLineAsync(String.Format("HELO {0}", GetLocalhostFqdn()));
await writer.WriteLineAsync(String.Format("EHLO {0}", GetLocalhostFqdn()));
state = "HELO";
}
if (dataFromServer.StartsWith("250"))
{
// Maximum laziness
if (state == "HELO")
{
await writer.WriteLineAsync(String.Format("MAIL FROM:{0}", emailMessage.SenderAddress));
state = "MAIL FROM";
}
if (state == "MAIL FROM")
{
await writer.WriteLineAsync(String.Format("RCPT TO:{0}", emailMessage.RecipientAddress));
state = "RCPT TO";
}
if (state == "RCPT TO")
{
await writer.WriteLineAsync("DATA");
state = "DATA";
}
if (state == "DATA")
{
await writer.WriteAsync(emailMessage.Message);
state = "";
}
if (state == "")
{
await writer.WriteLineAsync("QUIT");
}
}
if (dataFromServer.StartsWith("354"))
{
const string eom = "\r\n.\r\n";
await writer.WriteAsync(emailMessage.Message + eom);
}
}
}
}
catch (Exception exp)
{
Console.WriteLine(exp.ToString());
}
finally
{
Console.WriteLine("Closing the client connection - {0}", clientInfo);
//tcpClient.Close();
}
}
