Felipe Gasper
and 1 contributors

NAME

Protocol::DBus - D-Bus in pure Perl

SYNOPSIS

    my $dbus = Protcol::DBus::Client::system();

For blocking I/O:

    $dbus->do_authn();

    $dbus->send_call(
        path => '/org/freedesktop/DBus',
        interface => 'org.freedesktop.DBus.Properties',
        member => 'GetAll',
        destination => 'org.freedesktop.DBus',
        signature => 's',
        body => [ 'org.freedesktop.DBus' ],
        on_return => sub { my ($msg) = @_ },
    );

    my $msg = $dbus->get_message();

For non-blocking I/O:

    $dbus->blocking(0);

    my $fileno = $dbus->fileno();

    # You can use whatever polling method you prefer;
    # the following is just for demonstration:
    vec( my $mask, $fileno, 1 ) = 1;

    while (!$dbus->do_authn()) {
        if ($dbus->authn_pending_send()) {
            select( undef, my $wout = $mask, undef, undef );
        }
        else {
            select( my $rout = $mask, undef, undef, undef );
        }
    }

    $dbus->send_call( .. );     # same parameters as above

    while (1) {
        my $wout = $dbus->pending_send() || q<>;
        $wout &&= $mask;

        select( my $rout = $mask, $wout, undef, undef );

        if ($wout =~ tr<\0><>c) {
            $dbus->flush_write_queue();
        }

        if ($rout =~ tr<\0><>c) {

            # It’s critical to get_message() until undef is returned.
            1 while $dbus->get_message();
        }
    }

DESCRIPTION

This is an original, pure-Perl implementation of client logic for the D-Bus protocol.

It’s not much more than an implementation of the wire protocol; it doesn’t know about objects, services, or anything else besides the actual messages. That said, what’s here already should allow implementation of anything you can do with D-Bus; moreover, it would not be difficult to implement convenience logic—e.g., to mimic interfaces like Net::DBus—on top of what is here now.

Right now this distribution is an experimental effort. If you use it in your project, be sure to check the changelog before deploying a new version. Please file bug reports as appropriate.

See Protocol::DBus::Client and the above sample for a starting point.

EXAMPLES

See the distribution’s examples/ directory.

NOTES

  • UNIX FD support requires that Socket::MsgHdr be loaded at authentication time.

  • Currently EXTERNAL is the only supported authentication mechanism.

TODO

  • Add conveniences like match rule logic.

  • Improve parsing of bus paths in environment variables.

  • Add DBUS_COOKIE_SHA1 authentication.

  • Add more tests.

SEE ALSO

Net::DBus uses libdbus (via XS) as its backend. It’s more mature and more idiomatic as to how a D-Bus application is normally written, but it’s also heavier, and it doesn’t appear to support passing filehandles.