filter: begin work on a new filter API

[public-inbox.git] / lib / PublicInbox / Filter / Base.pm

diff --git a/lib/PublicInbox/Filter/Base.pm b/lib/PublicInbox/Filter/Base.pm
new file mode 100644 (file)
index 0000000..0991e87
--- /dev/null
+++ b/lib/PublicInbox/Filter/Base.pm
@@ -0,0 +1,100 @@
+# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+#
+# base class for creating per-list or per-project filters
+package PublicInbox::Filter::Base;
+use strict;
+use warnings;
+use PublicInbox::MsgIter;
+use constant MAX_MID_SIZE => 244; # max term size - 1 in Xapian
+
+my $NO_HTML = '*** We only accept plain-text mail, no HTML ***';
+our %DEFAULTS = (
+       reject_suffix => [ qw(exe bat cmd com pif scr vbs cpl zip) ],
+       reject_type => [ "text/html:$NO_HTML", "text/xhtml:$NO_HTML",
+               'application/vnd.ms-*:No proprietary data formats' ],
+);
+our $INVALID_FN = qr/\0/;
+
+sub REJECT () { 100 }
+sub ACCEPT { scalar @_ > 1 ? $_[1] : 1 }
+sub IGNORE () { 0 }
+
+my %patmap = ('*' => '.*', '?' => '.', '[' => '[', ']' => ']');
+sub glob2pat {
+       my ($glob) = @_;
+        $glob =~ s!(.)!$patmap{$1} || "\Q$1"!ge;
+        $glob;
+}
+
+sub new {
+       my ($class, %opts) = @_;
+       my $self = bless { err => '', %opts }, $class;
+       foreach my $f (qw(reject_suffix reject_type)) {
+               # allow undef:
+               $self->{$f} = $DEFAULTS{$f} unless exists $self->{$f};
+       }
+       if (defined $self->{reject_suffix}) {
+               my $tmp = $self->{reject_suffix};
+               $tmp = join('|', map { glob2pat($_) } @$tmp);
+               $self->{reject_suffix} = qr/\.($tmp)\s*\z/i;
+       }
+       my $rt = [];
+       if (defined $self->{reject_type}) {
+               my $tmp = $self->{reject_type};
+               @$rt = map {
+                       my ($type, $msg) = split(':', $_, 2);
+                       $type = lc $type;
+                       $msg ||= "Unacceptable Content-Type: $type";
+                       my $re = glob2pat($type);
+                       [ qr/\b$re\b/i, $msg ];
+               } @$tmp;
+       }
+       $self->{reject_type} = $rt;
+       $self;
+}
+
+sub reject ($$) {
+       my ($self, $reason) = @_;
+       $self->{err} = $reason;
+       REJECT;
+}
+
+sub err ($) { $_[0]->{err} }
+
+# for MDA
+sub delivery {
+       my ($self, $mime) = @_;
+
+       my $rt = $self->{reject_type};
+       my $reject_suffix = $self->{reject_suffix} || $INVALID_FN;
+       my (%sfx, %type);
+
+       msg_iter($mime, sub {
+               my ($part, $depth, @idx) = @{$_[0]};
+
+               my $ct = $part->content_type || 'text/plain';
+               foreach my $p (@$rt) {
+                       if ($ct =~ $p->[0]) {
+                               $type{$p->[1]} = 1;
+                       }
+               }
+
+               my $fn = $part->filename;
+               if (defined($fn) && $fn =~ $reject_suffix) {
+                       $sfx{$1} = 1;
+               }
+       });
+
+       my @r;
+       if (keys %type) {
+               push @r, sort keys %type;
+       }
+       if (keys %sfx) {
+               push @r, 'Rejected suffixes(s): '.join(', ', sort keys %sfx);
+       }
+
+       @r ? $self->reject(join("\n", @r)) : $self->ACCEPT;
+}
+
+1;