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();

$dbus->send_call(
    path => '/org/freedesktop/DBus',
    interface => 'org.freedesktop.DBus.Properties',
    member => 'GetAll',
    destination => 'org.freedesktop.DBus',
    signature => 's',
    body => [ 'org.freedesktop.DBus' ],
    on_return => sub { my ($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 (!$dbus->initialize()) {
    if ($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 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.

• EXTERNAL and DBUS_COOKIE_SHA1 authentication is supported.

TODO

• Add conveniences like match rule logic.

• Improve parsing of bus paths in environment variables.

• 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.