#8 Hack to suppress duplicate messages from Gmail.

When Gmail is configured to deliver via DAVmail SMTP, and more than one domain appears in the recipient list, it appears to create (at most?) one SMTP connection per recipient, which OWA then interprets as multiple mails to all recipients. The result is a mess.

This is a huge hack. Possibly a better approach is to filter the recipient list of each connection based on RCPT TOs seen, but I think that creates another problem: the Message-IDs will be distinct for each set of recipients (in my local IT's Exchange setup, Gmail's Message-ID is replaced by some Exchange-specified message ID).

Patch is against davmail-src-3.6.6-1032

[Anonymous]

Patch against davmail-src-3.6.6-1032

[Mickael Guessant]

This one is tricky: DavMail first creates a draft message on Exchange and moves it to the submission URI, there is no RCPT TO: fields involved. I don't like the idea of keeping a cache of all sent message ids in memory forever, but there must be another way to adjust recipients

[Mickael Guessant]

Fixed by searching for existing message with same Message-id in Sent folder