On MacOS notifications stream freezes forever when computer locked

[dmtrKovalenko]

With the basic provided example for notification stream

use btleplug::api::{Central, CharPropFlags, Manager as _, Peripheral, ScanFilter};
use btleplug::platform::Manager;
use futures::stream::StreamExt;
use std::error::Error;
use std::time::Duration;
use tokio::time;
use uuid::Uuid;

/// Only devices whose name contains this string will be tried.
const PERIPHERAL_NAME_MATCH_FILTER: &str = "CO2CICKA Sensor";
/// UUID of the characteristic for which we should subscribe to notifications.
const NOTIFY_CHARACTERISTIC_UUID: Uuid = Uuid::from_u128(0x0000FFE1_0000_1000_8000_00805F9B34FB);

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    pretty_env_logger::init();

    let manager = Manager::new().await?;
    let adapter_list = manager.adapters().await?;
    if adapter_list.is_empty() {
        eprintln!("No Bluetooth adapters found");
    }

    for adapter in adapter_list.iter() {
        println!("Starting scan...");
        adapter
            .start_scan(ScanFilter::default())
            .await
            .expect("Can't scan BLE adapter for connected devices...");
        time::sleep(Duration::from_secs(2)).await;
        let peripherals = adapter.peripherals().await?;

        if peripherals.is_empty() {
            eprintln!("->>> BLE peripheral devices were not found, sorry. Exiting...");
        } else {
            // All peripheral devices in range.
            for peripheral in peripherals.iter() {
                let properties = peripheral.properties().await?;
                let is_connected = peripheral.is_connected().await?;
                let local_name = properties
                    .unwrap()
                    .local_name
                    .unwrap_or(String::from("(peripheral name unknown)"));
                println!(
                    "Peripheral {:?} is connected: {:?}",
                    &local_name, is_connected
                );
                // Check if it's the peripheral we want.
                if local_name.contains(PERIPHERAL_NAME_MATCH_FILTER) {
                    println!("Found matching peripheral {:?}...", &local_name);
                    if !is_connected {
                        // Connect if we aren't already connected.
                        if let Err(err) = peripheral.connect().await {
                            eprintln!("Error connecting to peripheral, skipping: {}", err);
                            continue;
                        }
                    }
                    let is_connected = peripheral.is_connected().await?;
                    println!(
                        "Now connected ({:?}) to peripheral {:?}.",
                        is_connected, &local_name
                    );
                    if is_connected {
                        println!("Discover peripheral {:?} services...", local_name);
                        peripheral.discover_services().await?;
                        for characteristic in peripheral.characteristics() {
                            println!("Checking characteristic {:?}", characteristic);
                            // Subscribe to notifications from the characteristic with the selected
                            // UUID.
                            if characteristic.uuid == NOTIFY_CHARACTERISTIC_UUID
                                && characteristic.properties.contains(CharPropFlags::NOTIFY)
                            {
                                println!("Subscribing to characteristic {:?}", characteristic.uuid);
                                peripheral.subscribe(&characteristic).await?;
                                // Print the first 4 notifications received.
                                let mut notification_stream = peripheral.notifications().await?;

                                // Process while the BLE connection is not broken or stopped.
                                while let Some(data) = notification_stream.next().await {
                                    println!(
                                        "Received data from {:?} [{:?}]: {:?}",
                                        local_name, data.uuid, data.value
                                    );
                                }
                            }
                        }
                        println!("Disconnecting from peripheral {:?}...", local_name);
                        peripheral.disconnect().await?;
                    }
                } else {
                    println!("Skipping unknown peripheral {:?}", peripheral);
                }
            }
        }
    }
    Ok(())
}

If I remove the .take(4) everything works fine and stream lasts forever unless the computer is locked. Then the connection is dying on the blte plug side (but not at the peripheral side) and peripheral is not scannable anymore until the whole program is killed.

I tried to add timeouts like

        while let Some(data) = timeout(TIMEOUT, notification_stream.next()).await? {
            tracing::debug!("Received data from sensor {data:?}");
            match TData::from_bytes(data.value) {
                Ok(data) => fun(data),
                Err(e) => tracing::error!("Error decodring data from sensor {}", e),
            }

            let is_connected = timeout(TIMEOUT, self.peripheral.is_connected())
                .await
                .map_err(|_| "Connection lost")??;

            if !is_connected {
                return Err("BLE connection was lost".into());
            }
        }

but it doesn't help

[fredrik-jansson-se]

I'm interested in this fix as well. I'll go with @dmtrKovalenko fork in the meantime.