view: support SHA-1 of Message-IDs for message links

Some Message-IDs are crazy long, so support SHA-1s for them
instead.  This allows shorter URLs to be generated and are
less likely

However, we'll still favor short Message-IDs whenever possible.

1 files changed, 11 insertions, 5 deletions

diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index f67e72ce..1814286b 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -130,13 +130,19 @@ sub get_index {
 # just returns a string ref for the blob in the current ctx
 sub mid2blob {
         my ($ctx) = @_;
-        require Digest::SHA;
-        my $hex = Digest::SHA::sha1_hex($ctx->{mid});
-        $hex =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/i or
-                        die "BUG: not a SHA-1 hex: $hex";
+        my $hex = $ctx->{mid};
+        my ($x2, $x38) = ($hex =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/);
+
+        unless (defined $x38) {
+                # compatibility with old links
+                require Digest::SHA;
+                $hex = Digest::SHA::sha1_hex($hex);
+                ($x2, $x38) = ($hex =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/);
+                defined $x38 or die "BUG: not a SHA-1 hex: $hex";
+        }
 
         my @cmd = ('git', "--git-dir=$ctx->{git_dir}",
-                        qw(cat-file blob), "HEAD:$1/$2");
+                        qw(cat-file blob), "HEAD:$x2/$x38");
         my $cmd = join(' ', @cmd);
         my $pid = open my $fh, '-|';
         defined $pid or die "fork failed: $!\n";