nntp: append Archived-At and List-Archive headers

For readers using NNTP, we should do our best to advertise the
clonable HTTP/HTTPS URLs and the message permalink URL for
ease-of-referencing messages, since we don't want the NNTP server
and it's sequential article numbers to be relied on.

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/PublicInbox/NewsGroup.pm b/lib/PublicInbox/NewsGroup.pm
index adac919f..98a3595a 100644
--- a/lib/PublicInbox/NewsGroup.pm
+++ b/lib/PublicInbox/NewsGroup.pm
@@ -13,12 +13,21 @@ require PublicInbox::Search;
 require PublicInbox::Git;
 
 sub new {
-        my ($class, $name, $git_dir, $address) = @_;
+        my ($class, $name, $git_dir, $address, $url) = @_;
+
+        # first email address is preferred
         $address = $address->[0] if ref($address);
+        if ($url) {
+                # assume protocol-relative URLs which start with '//' means
+                # the server supports both HTTP and HTTPS, favor HTTPS.
+                $url = "https:$url" if $url =~ m!\A//!;
+                $url .= '/' if $url !~ m!/\z!;
+        }
         my $self = bless {
                 name => $name,
                 git_dir => $git_dir,
                 address => $address,
+                url => $url,
         }, $class;
         $self->{domain} = ($address =~ /\@(\S+)\z/) ? $1 : 'localhost';
         $self;