return $expires - $date;
}


sub is_fresh
{
    my $self = shift;
    $self->freshness_lifetime > $self->current_age;
}


sub fresh_until
{
    my $self = shift;
    return $self->freshness_lifetime - $self->current_age + time;
}

1;


__END__

=head1 NAME

HTTP::Response - HTTP style response message

=head1 SYNOPSIS

Response objects are returned by the request() method of the C<LWP::UserAgent>:

    # ...
    $response = $ua->request($request)
    if ($response->is_success) {
        print $response->content;
    }
    else {
        print STDERR $response->status_line, "\n";
    }

=head1 DESCRIPTION

The C<HTTP::Response> class encapsulates HTTP style responses.  A
response consists of a response line, some headers, and a content
body. Note that the LWP library uses HTTP style responses even for
non-HTTP protocol schemes.  Instances of this class are usually
created and returned by the request() method of an C<LWP::UserAgent>
object.

C<HTTP::Response> is a subclass of C<HTTP::Message> and therefore
inherits its methods.  The following additional methods are available:

=over 4

=item $r = HTTP::Response->new( $code )

=item $r = HTTP::Response->new( $code, $msg )

=item $r = HTTP::Response->new( $code, $msg, $header )

=item $r = HTTP::Response->new( $code, $msg, $header, $content )

Constructs a new C<HTTP::Response> object describing a response with
response code $code and optional message $msg.  The optional $header
argument should be a reference to an C<HTTP::Headers> object or a
plain array reference of key/value pairs.  The optional $content
argument should be a string of bytes.  The meaning these arguments are
described below.

=item $r = HTTP::Response->parse( $str )

This constructs a new response object by parsing the given string.

=item $r->code

=item $r->code( $code )

This is used to get/set the code attribute.  The code is a 3 digit
number that encode the overall outcome of a HTTP response.  The
C<HTTP::Status> module provide constants that provide mnemonic names
for the code attribute.

=item $r->message

=item $r->message( $message )

This is used to get/set the message attribute.  The message is a short
human readable single line string that explains the response code.

=item $r->header( $field )

=item $r->header( $field => $value )

This is used to get/set header values and it is inherited from
C<HTTP::Headers> via C<HTTP::Message>.  See L<HTTP::Headers> for
details and other similar methods that can be used to access the
headers.

=item $r->content

=item $r->content( $bytes )