#d-bus #d-bus #ipc

dbus-tree

Framework for writing D-Bus method handlers (legacy)

3 releases

0.9.2 Oct 14, 2021
0.9.1 Mar 24, 2021
0.9.0 Sep 18, 2020

#184 in Unix APIs

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8,928 downloads per month
Used in 12 crates (10 directly)

Apache-2.0/MIT

480KB
9K SLoC

D-Bus bindings for Rust

crates.io API documentation license Github CI

  • Use blocking::Connection to connect to the session or system bus. (Or SyncConnection / LocalConnection)
  • Use Message to send and receive messages. Get and append arguments of all types, see the argument guide for details.
  • Build method dispatching servers using the dbus-crossroads or dbus-tree crates. Standard D-Bus interfaces (introspection, properties, object manager) are supported.

Breaking changes

The main dbus crate is fairly mature and the features you need should be all there. Breaking changes can still happen, but not often.

  • In 0.9, the dbus::tree module moved to the dbus-tree crate (but consider migrating to dbus-crossroads instead).
  • If you're currently using 0.6.x of dbus and want to upgrade to later versions, you can read changes in dbus-rs 0.7.

Additional crates

  • dbus-crossroads for easy building of method dispatching servers. API documentation
  • dbus-tokio integrates D-Bus with Tokio. API documentation
  • dbus-codegen installs a binary tool which generates Rust code from D-Bus XML introspection data. The readme contains an introduction to how to use it.
  • libdbus-sys contains the raw FFI bindings to libdbus.
  • dbus-tree facitilates easy building of method dispatching servers (legacy design). API documentation

Invitation

You are hereby invited to participate in the development of these crates:

  • If you have discovered what you believe is a bug, file an issue.
  • If you have questions or comments that the documentation cannot answer in an easy way, start a discussion.
  • If you have smaller improvements to code, documentation, examples etc, go ahead and submit a pull request. Larger pieces of work are better off discussed first.

The code is Apache 2.0 / MIT dual licensed. Any code submitted in Pull Requests, discussions or issues is assumed to have this license, unless explicitly stated otherwise.

Examples

Client

This example opens a connection to the session bus and asks for a list of all names currently present.

use dbus::blocking::Connection;
use std::time::Duration;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // First open up a connection to the session bus.
    let conn = Connection::new_session()?;

    // Second, create a wrapper struct around the connection that makes it easy
    // to send method calls to a specific destination and path.
    let proxy = conn.with_proxy("org.freedesktop.DBus", "/", Duration::from_millis(5000));

    // Now make the method call. The ListNames method call takes zero input parameters and
    // one output parameter which is an array of strings.
    // Therefore the input is a zero tuple "()", and the output is a single tuple "(names,)".
    let (names,): (Vec<String>,) = proxy.method_call("org.freedesktop.DBus", "ListNames", ())?;

    // Let's print all the names to stdout.
    for name in names { println!("{}", name); }

    Ok(())
}

Examples of client code in the examples directory:

Server

This example grabs the com.example.dbustest bus name, adds the /hello path which implements the com.example.dbustest interface, and specifies that this interface has a Hello method. It then listens for incoming D-Bus method calls on this path and handles them accordingly.

dbus-crossroads:

let c = Connection::new_session()?;
c.request_name("com.example.dbustest", false, true, false)?;
let mut cr = Crossroads::new();
let token = cr.register("com.example.dbustest", |b| {
    b.method("Hello", ("name",), ("reply",), |_, _, (name,): (String,)| {
        Ok(format!("Hello {}!", name))
    });
});
cr.insert("/hello", &[token], ());
cr.serve(&c)?;

Examples of server code using dbus-crossroads in the examples directory:

dbus-tree:

let c = Connection::new_session()?;
c.request_name("com.example.dbustest", false, true, false)?;
let f = Factory::new_fn::<()>();
let tree = f.tree(())
    .add(f.object_path("/hello", ()).introspectable()
        .add(f.interface("com.example.dbustest", ())
            .add_m(f.method("Hello", (), |m| {
                let n: &str = m.msg.read1()?;
                let s = format!("Hello {}!", n);
                Ok(vec!(m.msg.method_return().append1(s)))
            }).inarg::<&str,_>("name")
              .outarg::<&str,_>("reply")
        )
    ).add(f.object_path("/", ()).introspectable());
tree.start_receive(&c);
loop { c.process(Duration::from_millis(1000))?; }

Examples of server code using dbus-tree in the examples directory:

Features

The futures feature makes dbus depend on the futures crate. This enables the nonblock module (used by the dbus-tokio crate).

The no-string-validation feature skips an extra check that a specific string (e g a Path, ErrorName etc) conforms to the D-Bus specification, which might also make things a tiny bit faster. But - if you do so, and then actually send invalid strings to the D-Bus library, you might get a panic instead of a proper error.

Requirements

Libdbus 1.6 or higher, and latest stable release of Rust. If you run Ubuntu (any maintained version should be okay), this means having the libdbus-1-dev and pkg-config packages installed while building, and the libdbus-1-3 package installed while running.

Cross compiling libdbus might be tricky because it binds to a C library, there are some notes here.

Dependencies