mda|learn|watch: support dropUniqueUnsubscribe config

List-Unsubscribe headers with unique identifiers (such as those
generated by our examples/unsubscribe.milter) should not
end up in public archives.  Add a new config knob to strip
List-Unsubscribe headers if they have the
`List-Unsubscribe-Post: List-Unsubscribe=One-Click'
header.

Unfortunately, this breaks DKIM signatures if the signature
covers either of these List-Unsubscribe* headers.  However,
breaking DKIM is the lesser evil compared to any archive reader
being able to stop archival by an independent archivist.

As much as I would like this to be the default, it probably
affects few users at the moment since very few mailing lists
use unique identifiers in List-Unsubscribe (but that number
has grown, recently).

1 files changed, 3 insertions, 0 deletions

diff --git a/script/public-inbox-learn b/script/public-inbox-learn
index 8069d919..6a1bc890 100755
--- a/script/public-inbox-learn
+++ b/script/public-inbox-learn
@@ -28,6 +28,7 @@ use PublicInbox::Spamcheck::Spamc;
 use Getopt::Long qw(:config gnu_getopt no_ignore_case auto_abbrev);
 my %opt = (all => 0);
 GetOptions(\%opt, qw(all help|h)) or die $help;
+use PublicInbox::Import;
 
 my $train = shift or die $help;
 if ($train !~ /\A(?:ham|spam|rm)\z/) {
@@ -37,6 +38,8 @@ die "--all only works with `rm'\n" if $opt{all} && $train ne 'rm';
 
 my $spamc = PublicInbox::Spamcheck::Spamc->new;
 my $pi_cfg = PublicInbox::Config->new;
+local $PublicInbox::Import::DROP_UNIQUE_UNSUB;
+PublicInbox::Import::load_config($pi_cfg);
 my $err;
 my $mime = PublicInbox::Eml->new(do{
         defined(my $data = do { local $/; <STDIN> }) or die "read STDIN: $!\n";