NAME

Protocol::DBus - D-Bus in pure Perl

SYNOPSIS

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

For blocking I/O:

# Authentication and “Hello” call/response:
$dbus->initialize();

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

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 (!$dbus->initialize()) {
    if ($dbus->init_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 messaging 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. This is fine, of course, if all you want to do is, e.g., replace an invocation of gdbus or dbus-send with pure Perl.

If you want an interface that mimics D-Bus’s actual object system, you’ll need to implement it yourself or to look elsewhere. (See "SEE ALSO" below.)

STATUS

This project is in BETA status. While the API should be pretty stable now, breaking changes can still happen. If you use this module in your project, you MUST check the changelog before deploying a new version. Please file bug reports as appropriate.

EXAMPLES

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

Also see the distribution’s examples/ directory.

NOTES

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

• Certain OSes may require Socket::MsgHdr to function. (Linux, notably, does not.) It depends if your OS can send local socket credentials without recourse to sendmsg(2).

• EXTERNAL and DBUS_COOKIE_SHA1 authentication is supported.

TODO

• Improve parsing of bus paths in environment variables.

• Add more tests.

SEE ALSO

The most mature, stable D-Bus implementation in Perl is Net::DBus, an XS binding to libdbus, the reference D-Bus implementation.