Struct zbus::Connection [−][src]
pub struct Connection { /* fields omitted */ }
Expand description
A D-Bus connection.
A connection to a D-Bus bus, or a direct peer.
Once created, the connection is authenticated and negotiated and messages can be sent or received, such as method calls or signals.
For higher-level message handling (typed functions, introspection, documentation reasons etc),
it is recommended to wrap the low-level D-Bus messages into Rust functions with the
dbus_proxy
and dbus_interface
macros instead of doing it directly on a Connection
.
Typically, a connection is made to the session bus with Connection::session
, or to the
system bus with Connection::system
. Then the connection is used with crate::Proxy
instances or the on-demand ObjectServer
instance that can be accessed through
Connection::object_server
.
Connection
implements Clone
and cloning it is a very cheap operation, as the underlying
data is not cloned. This makes it very convenient to share the connection between different
parts of your code. Connection
also implements std::marker::Sync
andstd::marker::Send
so you can send and share a connection instance across threads as well.
Connection
keeps an internal queue of incoming message. The maximum capacity of this queue
is configurable through the set_max_queued
method. The default size is 64. When the queue is
full, no more messages can be received until room is created for more. This is why it’s
important to ensure that all crate::MessageStream
and crate::blocking::MessageIterator
instances are continuously polled and iterated on, respectively.
For sending messages you can either use Connection::send_message
method or make use of the
Sink
implementation. For latter, you might find SinkExt
API very useful. Keep in mind
that Connection
will not manage the serial numbers (cookies) on the messages for you when
they are sent through the Sink
implementation. You can manually assign unique serial numbers
to them using the Connection::assign_serial_num
method before sending them off, if needed.
Having said that, the Sink
is mainly useful for sending out signals, as they do not expect
a reply, and serial numbers are not very useful for signals either for the same reason.
Since you do not need exclusive access to a zbus::Connection
to send messages on the bus,
Sink
is also implemented on &Connection
.
Caveats
At the moment, a simultaneous flush request from multiple tasks/threads could potentially create a busy loop, thus wasting CPU time. This limitation may be removed in the future.
Examples
Get the session bus ID
use zbus::Connection;
let mut connection = Connection::session().await?;
let reply = connection
.call_method(
Some("org.freedesktop.DBus"),
"/org/freedesktop/DBus",
Some("org.freedesktop.DBus"),
"GetId",
&(),
)
.await?;
let id: &str = reply.body()?;
println!("Unique ID of the bus: {}", id);
Monitoring all messages
Let’s eavesdrop on the session bus 😈 using the Monitor interface:
use futures_util::stream::TryStreamExt;
use zbus::{Connection, MessageStream};
let connection = Connection::session().await?;
connection
.call_method(
Some("org.freedesktop.DBus"),
"/org/freedesktop/DBus",
Some("org.freedesktop.DBus.Monitoring"),
"BecomeMonitor",
&(&[] as &[&str], 0u32),
)
.await?;
let mut stream = MessageStream::from(connection);
while let Some(msg) = stream.try_next().await? {
println!("Got message: {}", msg);
}
This should print something like:
Got message: Signal NameAcquired from org.freedesktop.DBus
Got message: Signal NameLost from org.freedesktop.DBus
Got message: Method call GetConnectionUnixProcessID from :1.1324
Got message: Error org.freedesktop.DBus.Error.NameHasNoOwner:
Could not get PID of name ':1.1332': no such name from org.freedesktop.DBus
Got message: Method call AddMatch from :1.918
Got message: Method return from org.freedesktop.DBus
Implementations
Send msg
to the peer.
Unlike our Sink
implementation, this method sets a unique (to this connection) serial
number on the message before sending it off, for you.
On successfully sending off msg
, the assigned serial number is returned.
pub async fn call_method<'d, 'p, 'i, 'm, D, P, I, M, B>(
&self,
destination: Option<D>,
path: P,
interface: Option<I>,
method_name: M,
body: &B
) -> Result<Arc<Message>> where
D: TryInto<BusName<'d>>,
P: TryInto<ObjectPath<'p>>,
I: TryInto<InterfaceName<'i>>,
M: TryInto<MemberName<'m>>,
D::Error: Into<Error>,
P::Error: Into<Error>,
I::Error: Into<Error>,
M::Error: Into<Error>,
B: Serialize + DynamicType,
pub async fn call_method<'d, 'p, 'i, 'm, D, P, I, M, B>(
&self,
destination: Option<D>,
path: P,
interface: Option<I>,
method_name: M,
body: &B
) -> Result<Arc<Message>> where
D: TryInto<BusName<'d>>,
P: TryInto<ObjectPath<'p>>,
I: TryInto<InterfaceName<'i>>,
M: TryInto<MemberName<'m>>,
D::Error: Into<Error>,
P::Error: Into<Error>,
I::Error: Into<Error>,
M::Error: Into<Error>,
B: Serialize + DynamicType,
Send a method call.
Create a method-call message, send it over the connection, then wait for the reply.
On successful reply, an Ok(Message)
is returned. On error, an Err
is returned. D-Bus
error replies are returned as Error::MethodError
.
pub async fn emit_signal<'d, 'p, 'i, 'm, D, P, I, M, B>(
&self,
destination: Option<D>,
path: P,
interface: I,
signal_name: M,
body: &B
) -> Result<()> where
D: TryInto<BusName<'d>>,
P: TryInto<ObjectPath<'p>>,
I: TryInto<InterfaceName<'i>>,
M: TryInto<MemberName<'m>>,
D::Error: Into<Error>,
P::Error: Into<Error>,
I::Error: Into<Error>,
M::Error: Into<Error>,
B: Serialize + DynamicType,
pub async fn emit_signal<'d, 'p, 'i, 'm, D, P, I, M, B>(
&self,
destination: Option<D>,
path: P,
interface: I,
signal_name: M,
body: &B
) -> Result<()> where
D: TryInto<BusName<'d>>,
P: TryInto<ObjectPath<'p>>,
I: TryInto<InterfaceName<'i>>,
M: TryInto<MemberName<'m>>,
D::Error: Into<Error>,
P::Error: Into<Error>,
I::Error: Into<Error>,
M::Error: Into<Error>,
B: Serialize + DynamicType,
Emit a signal.
Create a signal message, and send it over the connection.
Reply to a message.
Given an existing message (likely a method call), send a reply back to the caller with the
given body
.
Returns the message serial number.
Reply an error to a message.
Given an existing message (likely a method call), send an error reply back to the caller
with the given error_name
and body
.
Returns the message serial number.
pub async fn reply_dbus_error(
&self,
call: &MessageHeader<'_>,
err: impl DBusError
) -> Result<u32>
pub async fn reply_dbus_error(
&self,
call: &MessageHeader<'_>,
err: impl DBusError
) -> Result<u32>
Reply an error to a message.
Given an existing message (likely a method call), send an error reply back to the caller using one of the standard interface reply types.
Returns the message serial number.
pub async fn request_name<'w, W>(&self, well_known_name: W) -> Result<()> where
W: TryInto<WellKnownName<'w>>,
W::Error: Into<Error>,
pub async fn request_name<'w, W>(&self, well_known_name: W) -> Result<()> where
W: TryInto<WellKnownName<'w>>,
W::Error: Into<Error>,
Register a well-known name for this service on the bus.
You can request multiple names for the same ObjectServer
. Use Connection::release_name
for deregistering names registered through this method.
Note that exclusive ownership without queueing is requested (using
fdo::RequestNameFlags::ReplaceExisting
and fdo::RequestNameFlags::DoNotQueue
flags)
since that is the most typical case. If that is not what you want, you should use
fdo::DBusProxy::request_name
instead (but make sure then that name is requested
after you’ve setup your service implementation with the ObjectServer
).
Errors
Fails with zbus::Error::NameTaken
if the name is already owned by another peer.
pub async fn release_name<'w, W>(&self, well_known_name: W) -> Result<bool> where
W: TryInto<WellKnownName<'w>>,
W::Error: Into<Error>,
pub async fn release_name<'w, W>(&self, well_known_name: W) -> Result<bool> where
W: TryInto<WellKnownName<'w>>,
W::Error: Into<Error>,
Deregister a previously registered well-known name for this service on the bus.
Use this method to deregister a well-known name, registered through
Connection::request_name
.
Unless an error is encountered, returns Ok(true)
if name was previously registered with
the bus through self
and it has now been successfully deregistered, Ok(false)
if name
was not previously registered or already deregistered.
Checks if self
is a connection to a message bus.
This will return false
for p2p connections.
Assigns a serial number to msg
that is unique to this connection.
This method can fail if msg
is corrupted.
The unique name as assigned by the message bus or None
if not a message bus connection.
Max number of messages to queue.
Set the max number of messages to queue.
The server’s GUID.
The underlying executor.
When a connection is built with internal_executor set to false, zbus will not spawn a thread to run the executor. You’re responsible to continuously tick the executor. Failure to do so will result in hangs.
Examples
Here is how one would typically run the zbus executor through tokio’s single-threaded scheduler:
use zbus::ConnectionBuilder;
use tokio::runtime;
runtime::Builder::new_current_thread()
.build()
.unwrap()
.block_on(async {
let conn = ConnectionBuilder::session()
.unwrap()
.internal_executor(false)
.build()
.await
.unwrap();
{
let conn = conn.clone();
tokio::task::spawn(async move {
loop {
conn.executor().tick().await;
}
});
}
// All your other async code goes here.
});
Get a reference to the associated ObjectServer
.
The ObjectServer
is created on-demand.
Returns a listener, notified on various connection activity.
This function is meant for the caller to implement idle or timeout on inactivity.
Trait Implementations
Performs the conversion.
Performs the conversion.
Performs the conversion.
Performs the conversion.
Auto Trait Implementations
impl !RefUnwindSafe for Connection
impl Send for Connection
impl Sync for Connection
impl Unpin for Connection
impl !UnwindSafe for Connection
Blanket Implementations
Mutably borrows from an owned value. Read more
Composes a function in front of the sink. Read more
fn with_flat_map<U, St, F>(self, f: F) -> WithFlatMap<Self, Item, U, St, F> where
F: FnMut(U) -> St,
St: Stream<Item = Result<Item, Self::Error>>,
fn with_flat_map<U, St, F>(self, f: F) -> WithFlatMap<Self, Item, U, St, F> where
F: FnMut(U) -> St,
St: Stream<Item = Result<Item, Self::Error>>,
Composes a function in front of the sink. Read more
Transforms the error returned by the sink.
Map this sink’s error to a different error type using the Into
trait. Read more
Adds a fixed-size buffer to the current sink. Read more
Fanout items to multiple sinks. Read more
Flush the sink, processing all pending items. Read more
A future that completes after the given item has been fully processed into the sink, including flushing. Read more
A future that completes after the given item has been received by the sink. Read more
A future that completes after the given stream has been fully processed into the sink, including flushing. Read more
Wrap this sink in an Either
sink, making it the left-hand variant
of that Either
. Read more
Wrap this stream in an Either
stream, making it the right-hand variant
of that Either
. Read more
A convenience method for calling Sink::poll_ready
on Unpin
sink types. Read more
A convenience method for calling Sink::start_send
on Unpin
sink types. Read more
A convenience method for calling Sink::poll_flush
on Unpin
sink types. Read more