[Dovecot] Unique message IDs?

[Patrick Domack]

Quoting Alexander Chekalin <achekalin at lazurit.com>:

>>>> With Maildir the message GUID is typically the same as the  
>>>> Maildir base filename (i.e. everything before ':' character).
>>>
>>> But what if I one day decide to convert my maildir's to mbox'es?
>>> I really plan to do such conversion in a while (as soon as I finish the
>>> indexing system).
>>
>> mbox? or mdbox? With mbox there are no proper GUIDs, but Dovecot kind of
>> fakes it by returning MD5 of specific headers as GUIDs (so not 100%
>> reliable). With mdbox GUIDs work even better than with Maildir, the GUID
>> is always stored in the message's metadata.
>
> I'd like to use the best optimized one (mdbox), but there is a  
> reason not to do that is when I use mbox or maildir I can see where  
> given IMAP folder mails are stored, so, say, if I want to copy only  
> one IMAP folder to some remote site, I just copy know dir or file.  
> With mdbox this is different, I simply can not guess where my  
> messages exactly are.
>
> If it be possible to have per-IMAP-folders mdboxes, I love to use  
> it. But from what I know and tried this is not way mdbox used to  
> work, right?
>

You can always use the info from the wiki, I took some code from it to  
create this little script, that dumps my spam folder and uses it to  
learn. Basically dumps a mailfolder back into maildir format.

doveadm search -u $useraccount mailbox Spam | while read guid uid; do  
doveadm fetch -u $useraccount text mailbox-guid $guid uid $uid >  
msg.$uid; done

If your using mdbox on the other end, you could reimport them I  
suppose, I haven't looked into doing that, since I haven't needed that  
yet.