public async Task AuthenticateAsync(CancellationToken ct)
{
_sender.RequestText =
$"{SmtpCommandNames.AUTH} {SmtpDefinitions.SmtpAuthMethods.Login} {Convert.ToBase64String(Encoding.UTF8.GetBytes(_credentials.UserName))}";
await _connection.WriteLineAsync(_sender.RequestText, ct);
_sender.ReplyText = await _connection.ReadLineAsync(ct);
_sender.ValidateReply();
_sender.RequestText = Convert.ToBase64String(Encoding.UTF8.GetBytes(_credentials.Password));
await _connection.WriteLineAsync(_sender.RequestText, ct);
_sender.ReplyText = await _connection.ReadLineAsync(ct);
_sender.ValidateReply();
}
/// <summary>
/// Sends an array of email messages using a session state object.
/// Credentials, Enable SSL and Client Hostname are NOT taken from the state object but
/// rather from the properties of this class.
/// </summary>
/// <param name="sessionStates">The session states.</param>
/// <param name="sessionId">The session identifier.</param>
/// <param name="ct">The cancellation token.</param>
/// <returns>
/// A task that represents the asynchronous of send email operation.
/// </returns>
/// <exception cref="ArgumentNullException">sessionStates.</exception>
/// <exception cref="SecurityException">Could not upgrade the channel to SSL.</exception>
/// <exception cref="SmtpException">Defines an SMTP Exceptions class.</exception>
public async Task SendMailAsync(
IEnumerable <SmtpSessionState> sessionStates,
string sessionId = null,
CancellationToken ct = default)
{
if (sessionStates == null)
{
throw new ArgumentNullException(nameof(sessionStates));
}
using (var tcpClient = new TcpClient())
{
await tcpClient.ConnectAsync(Host, Port);
using (var connection = new Connection(tcpClient, Encoding.UTF8, "\r\n", true, 1000))
{
var sender = new SmtpSender(sessionId);
try
{
// Read the greeting message
sender.ReplyText = await connection.ReadLineAsync(ct);
// EHLO 1
sender.RequestText = $"{SmtpCommandNames.EHLO} {ClientHostname}";
await connection.WriteLineAsync(sender.RequestText, ct);
do
{
sender.ReplyText = await connection.ReadLineAsync(ct);
}while (!sender.IsReplyOk);
sender.ValidateReply();
// STARTTLS
if (EnableSsl)
{
sender.RequestText = $"{SmtpCommandNames.STARTTLS}";
await connection.WriteLineAsync(sender.RequestText, ct);
sender.ReplyText = await connection.ReadLineAsync(ct);
sender.ValidateReply();
if (await connection.UpgradeToSecureAsClientAsync() == false)
{
throw new SecurityException("Could not upgrade the channel to SSL.");
}
}
{
// EHLO 2
sender.RequestText = $"{SmtpCommandNames.EHLO} {ClientHostname}";
await connection.WriteLineAsync(sender.RequestText, ct);
do
{
sender.ReplyText = await connection.ReadLineAsync(ct);
}while (!sender.IsReplyOk);
sender.ValidateReply();
}
// AUTH
if (Credentials != null)
{
var auth = new ConnectionAuth(connection, sender, Credentials);
await auth.AuthenticateAsync(ct);
}
foreach (var sessionState in sessionStates)
{
{
// MAIL FROM
sender.RequestText = $"{SmtpCommandNames.MAIL} FROM:<{sessionState.SenderAddress}>";
await connection.WriteLineAsync(sender.RequestText, ct);
sender.ReplyText = await connection.ReadLineAsync(ct);
sender.ValidateReply();
}
// RCPT TO
foreach (var recipient in sessionState.Recipients)
{
sender.RequestText = $"{SmtpCommandNames.RCPT} TO:<{recipient}>";
await connection.WriteLineAsync(sender.RequestText, ct);
sender.ReplyText = await connection.ReadLineAsync(ct);
sender.ValidateReply();
}
{
// DATA
sender.RequestText = $"{SmtpCommandNames.DATA}";
await connection.WriteLineAsync(sender.RequestText, ct);
sender.ReplyText = await connection.ReadLineAsync(ct);
sender.ValidateReply();
}
{
// CONTENT
var dataTerminator = sessionState.DataBuffer
.Skip(sessionState.DataBuffer.Count - 5)
.ToText();
sender.RequestText = $"Buffer ({sessionState.DataBuffer.Count} bytes)";
await connection.WriteDataAsync(sessionState.DataBuffer.ToArray(), true, ct);
if (dataTerminator.EndsWith(SmtpDefinitions.SmtpDataCommandTerminator) == false)
{
await connection.WriteTextAsync(SmtpDefinitions.SmtpDataCommandTerminator, ct);
}
sender.ReplyText = await connection.ReadLineAsync(ct);
sender.ValidateReply();
}
}
{
// QUIT
sender.RequestText = $"{SmtpCommandNames.QUIT}";
await connection.WriteLineAsync(sender.RequestText, ct);
sender.ReplyText = await connection.ReadLineAsync(ct);
sender.ValidateReply();
}
}
catch (Exception ex)
{
var errorMessage =
$"Could not send email. {ex.Message}\r\n Last Request: {sender.RequestText}\r\n Last Reply: {sender.ReplyText}";
errorMessage.Error(typeof(SmtpClient).FullName, sessionId);
throw new SmtpException(errorMessage);
}
}
}
}