pipewire/Rust: How to list all Audio/Source nodes and those properties by using pipewire-rs

Question

I want to list all "Audio/Source" pipewire nodes and those properties in my Rust program with pipewire Rust library.

By using event handler, this can be done. But event handler requires a running main loop, which is weird.

Is there any idiomatic way to get list of nodes in Rust program?

Thank you in advance.

Answer 1

i tried to research a lot in this subject but you can't get a way from running a main loop, so i created a thread for it.

i created a code that prints all the devices and all the ports in the system.

use std::thread;
use std::thread::JoinHandle;
use gtk::glib::ExitCode;
use pipewire::{Context, MainLoop};
use pipewire::spa::ReadableDict;
use pipewire::types::ObjectType;

pub fn mypipewrite_spawn_mainloop() -> JoinHandle<ExitCode> {
    let pw_thread = thread::spawn(|| {
        // Initialize PipeWire and run the main loop
        // ...
        let mainloop = MainLoop::new().expect("failed to get mail loop");
        let context = Context::new(&mainloop).expect("failed to get context");
        let core = context.connect(None).expect("failed to get core");
        let registry = core.get_registry().expect("failed to get registry");

        let _listener = registry
            .add_listener_local()
            .global(|global|
                {
                    if global.type_ == ObjectType::Port {
                        let props = global.props.as_ref().unwrap();
                        let port_name = props.get("port.name");
                        let port_alias = props.get("port.alias");
                        let object_path = props.get("object.path");
                        let format_dsp = props.get("format.dsp");
                        let audio_channel = props.get("audio.channel");
                        let port_id = props.get("port.id");
                        let port_direction = props.get("port.direction");
                        println!("Port: Name: {:?} Alias: {:?}  Id: {:?} Direction: {:?} AudioChannel: {:?} Object Path: {:?} FormatDsp: {:?}",
                        port_name,
                        port_alias,
                            port_id,port_direction,audio_channel,object_path,format_dsp
                            );
                    } else if global.type_ == ObjectType::Device {
                            let props = global.props.as_ref().unwrap();
                            let device_name = props.get("device.name");
                            let device_nick = props.get("device.nick");
                            let device_description = props.get("device.description");
                            let device_api = props.get("device.api");
                            let media_class = props.get("media.class");
                            println!("Device: Name: {:?} Nick: {:?} Desc: {:?} Api: {:?} MediaClass: {:?}",
                                     device_name, device_nick, device_description, device_api, media_class);
                    }
                }
                            )
            .register();

        // Calling the `destroy_global` method on the registry will destroy the object with the specified id on the remote.
        // We don't have a specific object to destroy now, so this is commented out.
        // registry.destroy_global(313).into_result()?;


        mainloop.run();
        return ExitCode::FAILURE; // not sure
    });
    return pw_thread;
}