www: fix absolute URLs when mounted under a subdir

While we avoid generating absolute URLs in most cases, our
"git clone" instructions and URL headers in mboxrd files
contain full URLs.

So do the same thing we do for WwwAtomStream and pre-generate
the full URL before Plack::App::URLMap changes $env->{PATH_INFO}
and $env->{SCRIPT_NAME} back to their original values.

Reported-by: edef <edef@edef.eu>
Link: https://public-inbox.org/meta/cover.0f97c47bb88db8b875be7497289d8fedd3b11991.1569296942.git-series.edef@edef.eu/

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/PublicInbox/Mbox.pm b/lib/PublicInbox/Mbox.pm
index 6d902e6c..67b671f5 100644
--- a/lib/PublicInbox/Mbox.pm
+++ b/lib/PublicInbox/Mbox.pm
@@ -60,10 +60,12 @@ sub getline {
 
 sub close {} # noop
 
+# /$INBOX/$MESSAGE_ID/raw
 sub emit_raw {
         my ($ctx) = @_;
         my $mid = $ctx->{mid};
         my $ibx = $ctx->{-inbox};
+        $ctx->{base_url} = $ibx->base_url($ctx->{env});
         my ($mref, $more, $id, $prev, $next);
         if (my $over = $ibx->over) {
                 my $smsg = $over->next_by_mid($mid, \$id, \$prev) or return;
@@ -97,7 +99,7 @@ sub msg_hdr ($$;$) {
                 $header_obj->header_set($d);
         }
         my $ibx = $ctx->{-inbox};
-        my $base = $ibx->base_url($ctx->{env});
+        my $base = $ctx->{base_url};
         $mid = $ctx->{mid} unless defined $mid;
         $mid = mid_escape($mid);
         my @append = (
@@ -246,6 +248,7 @@ use PublicInbox::Hval qw/to_filename/;
 sub new {
         my ($class, $ctx, $cb) = @_;
         my $buf = '';
+        $ctx->{base_url} = $ctx->{-inbox}->base_url($ctx->{env});
         bless {
                 buf => \$buf,
                 gz => IO::Compress::Gzip->new(\$buf, Time => 0),