my %post_data = map { $_ => param( $_ ) } param;
my %url_data  = map { $_ => url_param( $_) } url_param;
my %data      = merge( \%post_data, \%url_data );

sub merge {
  my %merged;
  for (@_) {
    while (my ($key, $value) = each %$_) {
      push @{$merged{$key}}, $value;
    }
  }
  %merged;
}