Attribute Macro zbus::dbus_interface [−][src]
#[dbus_interface]
Expand description
Attribute macro for implementing a D-Bus interface.
The macro must be applied on an impl T
. All methods will be exported, either as methods,
properties or signal depending on the item attributes. It will implement the Interface
trait
for T
on your behalf, to handle the message dispatching and introspection support.
The methods accepts the dbus_interface
attributes:
-
name
- override the D-Bus name (pascal case form of the method by default) -
property
- expose the method as a property. If the method takes an argument, it must be a setter, with aset_
prefix. Otherwise, it’s a getter. -
signal
- the method is a “signal”. It must be a method declaration (without body). Its code block will be expanded to emit the signal from the object path associated with the interface instance.You can call a signal method from a an interface method, or from an
ObjectServer::with
function. -
struct_return
- This attribute is depcrecated and a noop. If you want to return a single structure from a method, simply declare it to return a named structure or a tuple with a tuple as the only field.Since it is not possible for zbus to differentiate between the case of a single structure being returned from the case of multiple out arguments returned as a named structure, nor to introspect the named structure type, the latter is not supported. you must use tuples for returning multiple values from a method.
-
out_args
- When returning multiple values from a method, naming the out arguments become important. You can useout_args
for specifying names for your out arguments.
Note: a <property_name_in_snake_case>_changed
method is generated for each property: this
method emits the “PropertiesChanged” signal for the associated property. The setter (if it
exists) will automatically call this method.
For instance, a property setter named set_foo
will be called to set the property “Foo”, and
will emit the “PropertiesChanged” signal with the new value for “Foo”. Other changes to the
“Foo” property can be signaled manually with the generated foo_changed
method.
The method arguments offers some the following zbus
attributes:
header
- This marks the method argument to receive the message header associated with the D-Bus method call being handled.
Example
use zbus_macros::dbus_interface; use zbus::MessageHeader; struct Example { some_data: String, } #[dbus_interface(name = "org.myservice.Example")] impl Example { // "Quit" method. A method may throw errors. fn quit(&self, #[zbus(header)] hdr: MessageHeader<'_>) -> zbus::fdo::Result<()> { let path = hdr.path()?.unwrap(); let msg = format!("You are leaving me on the {} path?", path); Err(zbus::fdo::Error::Failed(msg)) } // "TheAnswer" property (note: the "name" attribute), with its associated getter. // A `the_answer_changed` method has also been generated to emit the // "PropertiesChanged" signal for this property. #[dbus_interface(property, name = "TheAnswer")] fn answer(&self) -> u32 { 2 * 3 * 7 } // "Notify" signal (note: no implementation body). #[dbus_interface(signal)] fn notify(&self, message: &str) -> zbus::Result<()>; #[dbus_interface(out_args("answer", "question"))] fn meaning_of_life(&self) -> zbus::Result<(i32, String)> { Ok((42, String::from("Meaning of life"))) } }
See also ObjectServer
documentation to learn how to export an interface over a Connection
.