extmsg: fall back to partial Message-ID matching

In case a URL gets truncated (as is common with long URLs),
we can rely on Xapian for partial matches and bring the user
to their destination.

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index 20650554..e7ea96c7 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -269,4 +269,13 @@ sub enquire {
         $self->{enquire} ||= Search::Xapian::Enquire->new($self->{xdb});
 }
 
+sub mid_prefix {
+        my ($self, $mpfx) = @_;
+        my $query = eval { $self->qp->parse_query("m:$mpfx", FLAG_PARTIAL) };
+        return if $@;
+        my $res = $self->do_enquire($query, { relevance => 1 });
+        return unless $res->{total};
+        [ map { $_->mid } @{$res->{msgs}} ];
+}
+
 1;