nix-generate-from-cpan: generate SRI hashes

maintainers/scripts/nix-generate-from-cpan.pl

···
 
 use CPAN::Meta();
 use CPANPLUS::Backend();
+use MIME::Base64;
 use Module::CoreList;
 use Getopt::Long::Descriptive qw( describe_options );
 use JSON::PP qw( encode_json );
···
     return $license_line;
 }
 
+sub sha256_to_sri {
+    my ($sha256) = @_;
+    return "sha256-" . encode_base64(pack("H*", $sha256), '');
+}
+
 my ( $opt, $module_name ) = handle_opts();
 
 Log::Log4perl->easy_init(
···
 INFO( "path: ",    $module->path );
 
 my $tar_path = $module->fetch();
+my $sri_hash = sha256_to_sri($module->status->checksum_value);
 INFO( "downloaded to: ", $tar_path );
-INFO( "sha-256: ",       $module->status->checksum_value );
+INFO( "hash: ", $sri_hash );
 
 my $pkg_path = $module->extract();
 INFO( "unpacked to: ", $pkg_path );
···
     version = "$pkg_version";
     src = fetchurl {
       url = "mirror://cpan/${\$module->path}/${\$module->package}";
-      sha256 = "${\$module->status->checksum_value}";
+      hash = "$sri_hash";
     };
 EOF
 print <<EOF if scalar @build_deps > 0;