gistfile1.txt

        enable sub {                                          
            my $app = shift;                                  
            return sub {                                      
                my $env = shift;                              
                my $res = $app->($env);                       
                my $control = $env->{PATH_INFO} =~ /\.(css|js)$/
                    ? 'max-age=42'                            
                    : 'no-cache';
                Plack::Util::header_set($res->[1], 'Cache-Control', $control);
                return $res;
            };
        };