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Vm-pop3d
========

*WARNING: Badly done migration will cause your IMAP and/or POP3 clients to
re-download all mails. Read <Migration.txt> page first carefully.*

Vm-pop3d uses the Message-ID: header data for UIDL, Dovecot does not support
this as it is not unique enough. The following Perl script will take the
Message-ID: data from all mails in a mbox and put the data into the X-UIDL:
header which Dovecot can use with the 'pop3_reuse_xuidl' setting:

---%<-------------------------------------------------------------------------
#!/usr/bin/env perl
use Email::Simple;
my @totalmail=<STDIN>;
my $mail = join("",@totalmail);
my $email = Email::Simple->new($mail);
my $msg_id = $email->header("Message-Id");
$msg_id =~ s#<##g;
$msg_id =~ s#>##g;
$email->header_set("X-UIDL", $msg_id);
print $email->as_string;
---%<-------------------------------------------------------------------------

Requires email::simple, though the default setting in email::simple is to wrap
headers at 77 characters, which then causes problems when Outlook clients issue
UIDL, the workaround for this is to edit the Perl module, on Debian Etch this
involves editing '/usr/share/perl5/Email/Simple.pm', find "sub _fold" and
change {0,77} to a suitably higher value. On more recent versions of
email::simple, you may need to edit 'Headers.pm' instead, with the line to look
for being "_default_fold_at"

You then run the script like so:

---%<-------------------------------------------------------------------------
formail -q- -s perl script.pl < inbox > newinbox
---%<-------------------------------------------------------------------------

When Dovecot now looks at newinbox, it will use the X-UIDL: header and clients
will not redownload mail.

(This file was created from the wiki on 2019-06-19 12:42)