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lib/Apache/AxKit/Provider/XMLDOMProvider.pm  view on Meta::CPAN

    # debug
    #my $h = $response->server;
    #throw Apache::AxKit::Exception::Error(-text => "Last Modified Header: \"$h\"");

    # some XML validation
    my $parser = XML::LibXML->new();
    $parser->validation(0);
    $parser->load_ext_dtd(0);
    $parser->expand_xinclude(0);
    $parser->expand_entities(0);
    my $dom;
    eval {
	$dom = $parser->parse_string($string);
    };
    if ($@) {
	throw Apache::AxKit::Exception::Error( -text => "Input must be well-formed XML: $@" );
    }

    # if everything went fine, return xml-string-reference
    return \$string;
}

# sub: mtime
# we want to cache our stuff; the mtime is determined
# from the mdate (YYYY-MM-DD hh:mm) element "<mdate></mdate>" placed
# somewhere in the remote XML-DOM;
# CAUTION: do not provide multiple mdate elements in one single XML-DOM;
# if mdate is not provided, we refuse to cache
sub mtime {
    my $self = shift;
    my $mtime_element = $self->{mtime_element};

    # debug
    #print STDERR Dumper( $self->{id} );

    # return cached mtime, if this is the second call per request
    return $self->{mtime}->{$self->{id}} if defined $self->{mtime}->{$self->{id}};

    # mtime stuff
    # twiggle out mdate from string-content
    $self->{response}->content() =~ m/.*\<$mtime_element\>([^\<]*)\<\/$mtime_element\>/;
    my $mdate = $1;

    # debug
    #print STDERR Dumper( "mdate: ", $mdate );

    my $mtime;
    # test if $mdate is provided in xml-dom

    if ( defined $mdate ) {
	# create time-piece object
	# mdate format example: 2007-06-26 02:42
	my $time_obj = Time::Piece->strptime( $mdate, "%Y-%m-%d %H:%M" );
	$mtime = $time_obj->epoch();

	# debug
	#print STDERR Dumper( "mtime in secs: ", $mtime );
    }
    else {
	# else invalidate cache
	$mtime = time();
	
	# debug
	#print STDERR Dumper("now: ", $mtime );
    }

    # cache mtime, since mtime is called twice per request
    $self->{mtime}->{$self->{id}} = $mtime;

    # debug
    #print STDERR Dumper( "return value: ", $mtime );

    return $mtime;
}

# sub: process
# we always answer requests :-)
sub process {
    my $self = shift;
    return 1;
}

# sub: key
# should return a unique identifier for the resource.
# we assume the id from the uri (including query params) is a good one.
sub key {
    my $self = shift;
    return $self->{id};
}

# sub: exists
# returns 1 if remote XML-DOM is accessible
# throws AxKit IO exception otherwise
sub exists {
    my $self = shift;
    my $response = $self->{response};
    my $url = $self->{xmlfile};
    if ( $response->is_success() ) {
	return 1;
    }
    else {
	throw Apache::AxKit::Exception::IO( -text =>  $response->status_line() . ": Cannot access upstream resource: \"$url\"" );
    }
}

1;
__END__
# Below is stub documentation for your module. You'd better edit it!

=head1 NAME

Apache::AxKit::Provider::XMLDOMProvider - AxKit Provider for remote XML-DOMs available via HTTP

=head1 SYNOPSIS

  AxContentProvider Apache::AxKit::Provider::XMLDOMProvider
  PerlSetVar RemoteXML "http://www.example.com/xmlfile.xml"
  PerlSetVar RemoteXMLmTimeElement "mdate"

=head1 DESCRIPTION