+sub nntp_url {
+ my ($self) = @_;
+ $self->{-nntp_url} ||= do {
+ # no checking for nntp_usable here, we can point entirely
+ # to non-local servers or users run by a different user
+ my $ns = $self->{-pi_config}->{'publicinbox.nntpserver'};
+ my $group = $self->{newsgroup};
+ my @urls;
+ if ($ns && $group) {
+ $ns = [ $ns ] if ref($ns) ne 'ARRAY';
+ @urls = map {
+ my $u = m!\Anntps?://! ? $_ : "nntp://$_";
+ $u .= '/' if $u !~ m!/\z!;
+ $u.$group;
+ } @$ns;
+ }
+
+ my $mirrors = $self->{nntpmirror};
+ if ($mirrors) {
+ my @m;
+ foreach (@$mirrors) {
+ my $u = m!\Anntps?://! ? $_ : "nntp://$_";
+ if ($u =~ m!\Anntps?://[^/]+/?\z!) {
+ if ($group) {
+ $u .= '/' if $u !~ m!/\z!;
+ $u .= $group;
+ } else {
+ warn
+"publicinbox.$self->{name}.nntpmirror=$_ missing newsgroup name\n";
+ }
+ }
+ # else: allow full URLs like:
+ # nntp://news.example.com/alt.example
+ push @m, $u;
+ }
+ my %seen = map { $_ => 1 } @urls;
+ foreach my $u (@m) {
+ next if $seen{$u};
+ $seen{$u} = 1;
+ push @urls, $u;
+ }
+ }
+ \@urls;
+ };
+}
+