internal ImapConnection(ImapConnectionOptions options) :
base(options.Host, options.Port, true, options.AllowInvalidRemoteCertificates)
{
if (options == null)
{
throw new ArgumentNullException(nameof(options));
}
ConnectionType = options.ConnectionType;
ComputeDefaultValues();
}
private async Task <bool> UpgradeToSecureConnection()
{
var commandResult = await ExecuteCommand(ImapCommands.StartTLS());
var upgradeSuccess = commandResult.Contains(ImapResponse.OK_TLS_NEGOTIATION);
if (upgradeSuccess)
{
ConnectionType = ImapConnectionType.SSL_TLS;
_stream = GetStream();
return(true);
}
else
{
throw new Exception("Could not upgrade IMAP non SSL connection using STARTTLS handshake");
}
}
private void ComputeDefaultValues()
{
switch (ConnectionType)
{
case ImapConnectionType.AUTO when Port == 993:
ConnectionType = ImapConnectionType.SSL_TLS;
break;
case ImapConnectionType.AUTO when Port == 143:
ConnectionType = ImapConnectionType.STARTTLS;
break;
}
if (ConnectionType == ImapConnectionType.AUTO)
{
throw new Exception($"Port {Port} is not a valid imap port when using automatic configuration");
}
}