Get attachments in an array of bytes using MimeKit in C#

Question

How can I get the attachment content when using MimeKit? This is what I have:

var mimeMessage = MimeMessage.Load(@"test.eml");
var attachments = mimeMessage.Attachments.ToList();

foreach (var attachment in attachments)
{
    // how do I get the content here (array of bytes or stream)
}

Palaeozoic

Answer 1

This should do what you need:

var mimeMessage = MimeMessage.Load(@"test.eml");
var attachments = mimeMessage.Attachments.ToList();

foreach (var attachment in attachments)
{
    using (var memory = new MemoryStream ())
    {
        if (attachment is MimePart)
            ((MimePart) attachment).Content.DecodeTo (memory);
        else
            ((MessagePart) attachment).Message.WriteTo (memory);

        var bytes = memory.ToArray ();
    }
}

Exhibitionism

What if the content type is "message/rfc822" (the attachment is an email)? That didn't seem to work with that type of attachments. – Palaeozoic

Just one question, will those two options cover any type of attachment? – Palaeozoic

Is there a way to get the unique id of the attachment? (not the Content Id) – Palaeozoic

Yes, they'll cover all types of attachments. Attachments don't have unique ids, the closest they have is the Content-Id. – Exhibitionism

Answer 2

You can use WriteToStreamAsync method:

foreach (var attachment in message.Attachments)
{
    using var stream = new MemoryStream();
    attachment.WriteToStreamAsync(stream);
    var bytes = stream.ToArray();
}

Synchrotron