www: handle name-only publicinbox.*.url entries

Apparently URLs can be configured relatively for HTTP(S) setups,
attempt to support them when linking to cross-posted messages.

This also fixes the top-row (mirror/help/color/Atom feed) links
in /$INBOX_URL/$EXTMSG_MSGID/T/ (and /t/) URLs.

Reported-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Link: https://public-inbox.org/meta/20210902191239.cmbxlmjqcsmdzmqp@meerkat.local/

1 files changed, 12 insertions, 6 deletions

diff --git a/lib/PublicInbox/ExtMsg.pm b/lib/PublicInbox/ExtMsg.pm
index 5c8bf561..b7427b1b 100644
--- a/lib/PublicInbox/ExtMsg.pm
+++ b/lib/PublicInbox/ExtMsg.pm
@@ -117,7 +117,7 @@ sub ext_msg_ALL ($) {
                         $k =~ s/:[0-9]+:$x->{blob}\z// or next;
                         next if $k eq $cur_key;
                         my $ibx = $by_eidx_key->{$k} // next;
-                        my $url = $ibx->base_url or next;
+                        $ibx->base_url or next;
                         push(@{$ctx->{found}}, $ibx) unless $seen{$k}++;
                 }
         }
@@ -188,6 +188,12 @@ sub finalize_exact {
         finalize_partial($ctx);
 }
 
+sub _url_pfx ($$) {
+        my ($ctx, $u) = @_;
+        (index($u, '://') < 0 && index($u, '/') != 0) ?
+                "$ctx->{-upfx}../$u" : $u;
+}
+
 sub partial_response ($) {
         my ($ctx) = @_;
         my $mid = $ctx->{mid};
@@ -196,6 +202,7 @@ sub partial_response ($) {
         my $html = ascii_html($mid);
         my $title = "&lt;$html&gt; not found";
         my $s = "<pre>Message-ID &lt;$html&gt;\nnot found\n";
+        $ctx->{-upfx} //= '../';
         if (my $n_partial = $ctx->{n_partial}) {
                 $code = 300;
                 my $es = $n_partial == 1 ? '' : 'es';
@@ -204,8 +211,8 @@ sub partial_response ($) {
                 my $cur_name = $ctx->{ibx}->{name};
                 foreach my $pair (@{$ctx->{partial}}) {
                         my ($ibx, $res) = @$pair;
-                        my $env = $ctx->{env} if $ibx->{name} eq $cur_name;
-                        my $u = $ibx->base_url($env) or next;
+                        my $e = $ibx->{name} eq $cur_name ? $ctx->{env} : undef;
+                        my $u = _url_pfx($ctx, $ibx->base_url($e) // next);
                         foreach my $m (@$res) {
                                 my $href = mid_href($m);
                                 my $html = ascii_html($m);
@@ -220,7 +227,6 @@ sub partial_response ($) {
         }
         $ctx->{-html_tip} = $s .= '</pre>';
         $ctx->{-title_html} = $title;
-        $ctx->{-upfx} = '../';
         html_oneshot($ctx, $code);
 }
 
@@ -253,13 +259,13 @@ sub exact {
         my $title = "&lt;$html&gt; found in ";
         my $end = @$found == 1 ? 'another inbox' : 'other inboxes';
         $ctx->{-title_html} = $title . $end;
-        $ctx->{-upfx} = '../';
+        $ctx->{-upfx} //= '../';
         my $ext_urls = ext_urls($ctx, $mid, $href, $html);
         my $code = (@$found == 1 && $ext_urls eq '') ? 200 : 300;
         $ctx->{-html_tip} = join('',
                         "<pre>Message-ID: &lt;$html&gt;\nfound in $end:\n\n",
                                 (map {
-                                        my $u = $_->base_url;
+                                        my $u = _url_pfx($ctx, $_->base_url);
                                         qq(<a\nhref="$u$href/">$u$html/</a>\n)
                                 } @$found),
                         $ext_urls, '</pre>');