Is MimeMessage.LoadAsync thread safe?

[ciranmc]

Hi,

I am currently using MimeMessage.LoadAsync inside a Parallel.ForEachAsync. Is this a thread safe operation?
For context, each item in the list is a separate email blob stream. I saw a previous issue "Thread-safety information" which mentioned that MimeParser is not thread safe which MimeMessage.LoadAsync uses internally.

Any help would be appreciated.
Thanks.

[jstedfast]

Is this a thread safe operation?

As long as the streams are not being used from multiple threads, yes. And it sounds like that's the case, so you should be good.

I saw a previous issue "Thread-safety information" which mentioned that MimeParser is not thread safe which MimeMessage.LoadAsync uses internally.

Right, but each call to MimeMessage.Load/LoadAsync() creates its own MimeParser instance, so there's no possibility of multithreaded issues with the MimeParser.

That said, you could probably improve performance of your code if you instantiated 1 MimeParer per thread in your Parallel.ForEachAsync() logic and used parser.SetStream() and parser.ParseMessageAsync() instead of calling MimeMessage.LoadAsync().

[ciranmc]

That's great. Thank you for clarifying.

[jstedfast]

FWIW, as a general rule, static methods are generally safe to call from multiple threads while instance methods are not.