SmtpServer.StartAsync cannot be cancelled.

[everttimmer1963]

The following problem has been bugging me for a while.

Problem:

When I cancel the cancellationToken passed in with SmtpServer.StartAsync, it doesn't work as expected. The cancellation token should trigger the mailserver to terminate but it doesn't.

Cause:

Inside the ListenAsync task, the code enters a loop for accepting client connections. The loop will finish as soon as a combined token, that is created from the cancellationToken and internal shutDownToken, has it's IsCancellationRequested property set to false. Inside the loop, however, the cancellationToken is passed to endpointListener.GetPipeAsync instead of the combined token. Because of that, the combinedToken.IsCancellationRequested will never become false, and the code won't exit the loop.

Passing the combined token to endpointListener.GetPipeAsync will solve the problem.

Solution:

Replace cancellationToken by cancellationTokenSource.Tokem in the call to endppointListener.GetPipeAsync

Original Code: sessionContext.Pipe = await endpointListener.GetPipeAsync(sessionContext, cancellationToken).ConfigureAwait(false);

Fixed Code: sessionContext.Pipe = await endpointListener.GetPipeAsync(sessionContext, cancellationTokenSource.Token).ConfigureAwait(false);

[nefarius]

Made #192 for this case.

[MarkFl12]

This PR looks good to me, and I think it'll fix #183 as well?

[nefarius]

Agreed! Hopefully the maintainer will see soon enough and merge 🙏

[nefarius]

For those who can't wait for an official update feel free to use my fork in the meantime.