1 files changed, 33 insertions, 0 deletions
diff --git a/lib/PublicInbox/Filter/SubjectTag.pm b/lib/PublicInbox/Filter/SubjectTag.pm
new file mode 100644
index 00000000..1d281425
--- /dev/null
+++ b/lib/PublicInbox/Filter/SubjectTag.pm
@@ -0,0 +1,33 @@
+# Copyright (C) 2017 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# Filter for various [tags] in subjects
+package PublicInbox::Filter::SubjectTag;
+use strict;
+use warnings;
+use base qw(PublicInbox::Filter::Base);
+
+sub new {
+        my ($class, %opts) = @_;
+        my $tag = delete $opts{-tag};
+        die "tag not defined!\n" unless defined $tag && $tag ne '';
+        my $self = $class->SUPER::new(%opts);
+        $self->{tag_re} = qr/\A\s*(re:\s+|)\Q$tag\E\s*/i;
+        $self;
+}
+
+sub scrub {
+        my ($self, $mime) = @_;
+        my $subj = $mime->header('Subject');
+        $subj =~ s/$self->{tag_re}/$1/; # $1 is "Re: "
+        $mime->header_str_set('Subject', $subj);
+        $self->ACCEPT($mime);
+}
+
+# no suffix/article rejection for mirrors
+sub delivery {
+        my ($self, $mime) = @_;
+        $self->scrub($mime);
+}
+
+1;