/// <summary>
/// Read Next Line
/// </summary>
/// <returns></returns>
private string ReadLine()
{
try
{
Reader.BaseStream.ReadTimeout = ReadTimeout;
var line = "[S]: " + SMTPResponse.FixMessage(Reader.ReadLine());
Log.Add(line);
return(line);
}
catch (Exception excp)
{
return(null);
}
}
/// <summary>
/// Send Data and read to end. Returns TRUE if expected code is equals to the actual response code.
/// </summary>
/// <param name="data">Data to send</param>
/// <param name="expectedResponse">Expected Response Code</param>
/// <returns></returns>
private bool SendAndReadAll(string data, SMTPResponse.ResponseCode expectedResponse)
{
Send(data);
return(SMTPResponse.GetResponseCode(Read(), expectedResponse));
}
/// <summary>
/// Send Email. Returns TRUE if succeeds. Returns FALSE if fails.
/// </summary>
/// <param name="email"></param>
/// <returns></returns>
public bool SendEmail(Email email)
{
Client = new Socket(IPAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
Client.Connect(Hostname, Port);
Stream = new NetworkStream(Client);
if (UseSSL)
{
Log.Add($"<Connecting via SSL to {Hostname}:{Port}>");
SSLStream = new SslStream(Stream, true, new RemoteCertificateValidationCallback(ValidateSSLCertificate), null);
try
{
SSLStream.AuthenticateAsClient(Hostname);
}
catch (Exception excp)
{
Log.Add($"<Invalid SSL Certificate {Hostname}:{Port} ({Enum.GetName(typeof(SslPolicyErrors), SSLError)})>");
return(false);
}
Reader = new StreamReader(SSLStream);
Writer = new StreamWriter(SSLStream)
{
AutoFlush = true
};
}
else
{
Log.Add($"<Connecting to {Hostname}:{Port}>");
Reader = new StreamReader(Stream);
Writer = new StreamWriter(Stream)
{
AutoFlush = true
};
}
// Connection Message
// Expecting 220
if (!SMTPResponse.GetResponseCode(ReadLine(), SMTPResponse.ResponseCode.ServiceReady))
{
Log.Add($"<Cannot establish connection to {Hostname}:{Port}>");
return(false);
}
// Send greetings
// Expecting 250
if (!SendAndReadAll("EHLO " + Hostname, SMTPResponse.ResponseCode.OK))
{
Log.Add($"<Error after greetings {Hostname}:{Port}>");
return(false);
}
// Do Login if required
if (DoLogin)
{
switch (Authentication)
{
case AuthType.Login:
if (!AuthLogin())
{
Log.Add($"<Authentication Error {Hostname}:{Port}>");
return(false);
}
break;
}
}
// Send MAIL FROM
// Send RCPT TO
if (!SendSenderAndRecipientAddresses(email))
{
Log.Add($"<Error after MAIL FROM & RCPT TO {Hostname}:{Port}>");
return(false);
}
// Send DATA
// Expecting 354
if (!SendAndReadLine("DATA", SMTPResponse.ResponseCode.StartMailInput))
{
Log.Add($"<Error after DATA {Hostname}:{Port}>");
return(false);
}
// Send Headers
// Expecting nothing
var headers = email.Headers.GetAllHeaders(email.Headers);
foreach (var header in headers)
{
Send(header);
}
// Send Email body
// Expecting nothing
Send(email.EmailBody);
// Send the end of message
// Expecting 250
var emailSent = SendEndOfMessage();
if (emailSent)
{
Log.Add("<E-Mail sent>");
}
else
{
Log.Add("<E-Mail not sent>");
}
// Send QUIT
// Expecting nothing
Send("QUIT");
return(emailSent);
}
