search: add YYYYMMDD search range via "d:" prefix

This is similar to mairix in that it uses a "d:" prefix; but
only takes YYYYMMDD, for now.  Using custom date/time parsers
via Perl will be much more work:

	nntp://news.gmane.org/20151005222157.GE5880@survex.com

Anyhow, this ought to be more human-friendly than searching by
Unix timestamps, but it requires reindexing to take advantage of.

3 files changed, 18 insertions, 1 deletions

diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index 61f03383..7561ef44 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -12,6 +12,7 @@ use constant TS => 0; # timestamp
 use constant NUM => 1; # NNTP article number
 use constant BYTES => 2; # :bytes as defined in RFC 3977
 use constant LINES => 3; # :lines as defined in RFC 3977
+use constant YYYYMMDD => 4; # for searching in the WWW UI
 
 use Search::Xapian qw/:standard/;
 use PublicInbox::SearchMsg;
@@ -179,6 +180,8 @@ sub qp {
         $qp->set_database($self->{xdb});
         $qp->set_stemmer($self->stemmer);
         $qp->set_stemming_strategy(STEM_SOME);
+        $qp->add_valuerangeprocessor(
+                Search::Xapian::StringValueRangeProcessor->new(YYYYMMDD, 'd:'));
 
         while (my ($name, $prefix) = each %bool_pfx_external) {
                 $qp->add_boolean_prefix($name, $prefix);
diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index f8155ecc..f54f5f2f 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -17,6 +17,7 @@ use base qw(PublicInbox::Search);
 use PublicInbox::MID qw/mid_clean id_compress mid_mime/;
 use PublicInbox::MsgIter;
 use Carp qw(croak);
+use POSIX qw(strftime);
 require PublicInbox::Git;
 *xpfx = *PublicInbox::Search::xpfx;
 
@@ -128,7 +129,8 @@ sub add_message {
                         $doc->add_term(xpfx('path') . id_compress($path));
                 }
 
-                add_val($doc, &PublicInbox::Search::TS, $smsg->ts);
+                my $ts = $smsg->ts;
+                add_val($doc, &PublicInbox::Search::TS, $ts);
 
                 defined($num) and
                         add_val($doc, &PublicInbox::Search::NUM, $num);
@@ -139,6 +141,9 @@ sub add_message {
                 add_val($doc, &PublicInbox::Search::LINES,
                                 $mime->body_raw =~ tr!\n!\n!);
 
+                my $yyyymmdd = strftime('%Y%m%d', gmtime($ts));
+                $doc->add_value(&PublicInbox::Search::YYYYMMDD, $yyyymmdd);
+
                 my $tg = $self->term_generator;
 
                 $tg->set_document($doc);
diff --git a/t/search.t b/t/search.t
index 2685348c..db94c0a3 100644
--- a/t/search.t
+++ b/t/search.t
@@ -315,6 +315,15 @@ sub filter_mids {
                 'UTF-8 subject preserved');
 }
 
+{
+        my $res = $ro->query('d:19931002..20101002');
+        ok(scalar @{$res->{msgs}} > 0, 'got results within range');
+        $res = $ro->query('d:20101003..');
+        is(scalar @{$res->{msgs}}, 0, 'nothing after 20101003');
+        $res = $ro->query('d:..19931001');
+        is(scalar @{$res->{msgs}}, 0, 'nothing before 19931001');
+}
+
 done_testing();
 
 1;