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Implement auto reconnect for BLE devices
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Add auto reconnect feature to the BLE capabilities. As a result of
this, the WebGui is able to reconnect to already paired devices across
page reloads as well as in case of loss of connection to the sensor or
switching between BLE and ANT+
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Abász committed Sep 4, 2023
1 parent 9a02e6e commit 011915e
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Showing 3 changed files with 118 additions and 123 deletions.
230 changes: 112 additions & 118 deletions src/common/services/ble-heart-rate.service.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,22 +3,16 @@ import { MatSnackBar } from "@angular/material/snack-bar";
import { BluetoothCore } from "@manekinekko/angular-web-bluetooth";
import {
BehaviorSubject,
catchError,
combineLatest,
concat,
concatMap,
EMPTY,
filter,
map,
merge,
Observable,
of,
startWith,
switchMap,
take,
takeUntil,
tap,
timer,
withLatestFrom,
} from "rxjs";

Expand All @@ -31,88 +25,70 @@ import {
IHeartRateService,
} from "../common.interfaces";

import { ConfigManagerService } from "./config-manager.service";

@Injectable({
providedIn: "root",
})
export class BLEHeartRateService implements IHeartRateService {
private batteryCharacteristic: BehaviorSubject<BluetoothRemoteGATTCharacteristic | undefined> =
new BehaviorSubject<BluetoothRemoteGATTCharacteristic | undefined>(undefined);
private bluetoothDevice: BluetoothDevice | undefined;
private cancellationToken: AbortController = new AbortController();
private heartRateCharacteristic: BehaviorSubject<BluetoothRemoteGATTCharacteristic | undefined> =
new BehaviorSubject<BluetoothRemoteGATTCharacteristic | undefined>(undefined);

constructor(
private configManager: ConfigManagerService,
private snackBar: MatSnackBar,
private ble: BluetoothCore,
) {}

disconnectDevice(): void {
if (
this.batteryCharacteristic.value !== undefined ||
this.heartRateCharacteristic.value !== undefined
) {
this.ble.disconnectDevice();
this.batteryCharacteristic.next(undefined);
this.heartRateCharacteristic.next(undefined);
if (this.bluetoothDevice !== undefined) {
this.bluetoothDevice.ongattserverdisconnected = (): void => {
return;
};
this.bluetoothDevice = undefined;
}
this.ble.disconnectDevice();
this.cancellationToken.abort();
this.batteryCharacteristic.next(undefined);
this.heartRateCharacteristic.next(undefined);
}

// TODO: Reconnect feature:
// a new function in the heart rate service is needed that routes to either ant+ or ble depending on the setting so the right reconnect is done
// need to handle the change of setting which should trigger a reconnect of the other
// 1) this has been only tested in chrome
// 2) need to enable the chrome://flags/#enable-web-bluetooth-new-permissions-backend in chrome

// need to check if getDevices API is available
// it needs to save the last connected device id in local storage and then search getDevvices().
// const devices = (await navigator.bluetooth.getDevices())
// register the onadverisementreceived event (only once)
// devices[0].onadvertisementreceived = (event) =>{console.log(event)
// event.device.gatt.connect()
// }
async discover(): Promise<void> {
this.disconnectDevice();

// switch on advertisement watch
// await devices[0].watchAdvertisements()
// get the heartratecharacteristic and do next. everything should be a go then.
const device = await this.ble.discover({
acceptAllDevices: false,
filters: [{ services: [HEART_RATE_SERVICE] }],
optionalServices: [BATTERY_LEVEL_SERVICE],
});
if (device?.gatt === undefined) {
await this.reconnect();

discover$(): Observable<Array<Observable<never> | BluetoothRemoteGATTCharacteristic>> {
return this.ble
.discover$({
acceptAllDevices: false,
filters: [{ services: [HEART_RATE_SERVICE] }],
optionalServices: [BATTERY_LEVEL_SERVICE],
})
.pipe(
concatMap(
(
gatt: void | BluetoothRemoteGATTServer,
): Observable<Array<Observable<never> | BluetoothRemoteGATTCharacteristic>> => {
if (gatt === undefined) {
return EMPTY;
}
return;
}
await this.connect(device);
}

return combineLatest([
merge(
timer(15 * 1000).pipe(
tap((): void => {
this.snackBar.open("Getting battery info timed out", "Dismiss");
}),
map((): Observable<never> => EMPTY),
),
this.connectToBattery(gatt),
),
this.connectToHearRate(gatt),
]);
},
),
tap({
error: (error: unknown): void => {
if (error) {
this.snackBar.open(`${error}`, "Dismiss");
}
},
}),
catchError((): Observable<never> => EMPTY),
);
async reconnect(): Promise<void> {
this.disconnectDevice();
const device = (await navigator.bluetooth.getDevices()).filter(
(device: BluetoothDevice): boolean => device.id === this.configManager.getItem("bleDeviceId"),
)?.[0];
if (device === undefined) {
return;
}

device.onadvertisementreceived = this.reconnectHandler;
this.cancellationToken = new AbortController();
await device.watchAdvertisements({ signal: this.cancellationToken.signal });
}

streamHRMonitorBatteryLevel$(): Observable<number | undefined> {
Expand Down Expand Up @@ -148,68 +124,78 @@ export class BLEHeartRateService implements IHeartRateService {
);
}

private connectToBattery(gatt: BluetoothRemoteGATTServer): Observable<BluetoothRemoteGATTCharacteristic> {
return this.ble.getPrimaryService$(gatt, BATTERY_LEVEL_SERVICE).pipe(
concatMap(
(
primaryService: BluetoothRemoteGATTService,
): Observable<void | BluetoothRemoteGATTCharacteristic> => {
return this.ble.getCharacteristic$(primaryService, BATTERY_LEVEL_CHARACTERISTIC).pipe(
tap((): void => {
this.snackBar.open("Battery service is available", "Dismiss");
}),
);
},
),
concatMap(
(
characteristic: void | BluetoothRemoteGATTCharacteristic,
): Observable<BluetoothRemoteGATTCharacteristic> => {
if (characteristic === undefined) {
return EMPTY;
}
this.batteryCharacteristic.next(characteristic);
private async connect(device: BluetoothDevice): Promise<void> {
try {
this.bluetoothDevice = device;
const gatt = await this.ble.connectDevice(device);

return of(characteristic);
},
),
catchError((): Observable<never> => EMPTY),
take(1),
);
if (this.bluetoothDevice === undefined) {
return;
}

await Promise.all([this.connectToBattery(gatt), this.connectToHearRate(gatt)]);
this.configManager.setItem("bleDeviceId", device.id);
device.ongattserverdisconnected = this.disconnectHandler;
} catch (error) {
this.snackBar.open(`${error}`, "Dismiss");
}
}

private connectToHearRate(
private async connectToBattery(
gatt: BluetoothRemoteGATTServer,
): Observable<BluetoothRemoteGATTCharacteristic> {
return this.ble.getPrimaryService$(gatt, HEART_RATE_SERVICE).pipe(
concatMap(
(
primaryService: BluetoothRemoteGATTService,
): Observable<void | BluetoothRemoteGATTCharacteristic> => {
return this.ble.getCharacteristic$(primaryService, HEART_RATE_CHARACTERISTIC).pipe(
tap((): void => {
this.snackBar.open("Heart Rate monitor is connected", "Dismiss");
}),
);
},
),
concatMap(
(
characteristic: void | BluetoothRemoteGATTCharacteristic,
): Observable<BluetoothRemoteGATTCharacteristic> => {
if (characteristic === undefined) {
return EMPTY;
}
this.heartRateCharacteristic.next(characteristic);
): Promise<void | BluetoothRemoteGATTCharacteristic> {
try {
const primaryService = await this.ble.getPrimaryService(gatt, BATTERY_LEVEL_SERVICE);
const characteristic = await this.ble.getCharacteristic(
primaryService,
BATTERY_LEVEL_CHARACTERISTIC,
);
this.batteryCharacteristic.next(characteristic ?? undefined);

return of(characteristic);
},
),
catchError((): Observable<never> => EMPTY),
take(1),
);
return characteristic;
} catch (error) {
if (this.bluetoothDevice) {
this.snackBar.open("Battery service is unavailable", "Dismiss");
console.warn(error);
}
}

return;
}

private async connectToHearRate(
gatt: BluetoothRemoteGATTServer,
): Promise<void | BluetoothRemoteGATTCharacteristic> {
try {
const primaryService = await this.ble.getPrimaryService(gatt, HEART_RATE_SERVICE);
const characteristic = await this.ble.getCharacteristic(
primaryService,
HEART_RATE_CHARACTERISTIC,
);
this.heartRateCharacteristic.next(characteristic ?? undefined);

return characteristic;
} catch (error) {
if (this.bluetoothDevice) {
this.snackBar.open("Error connecting Heart Rate monitor", "Dismiss");
console.error(error);
}
}

return;
}

private disconnectHandler = async (event: Event): Promise<void> => {
const device: BluetoothDevice = event.target as BluetoothDevice;
device.onadvertisementreceived = this.reconnectHandler;

if (!device.watchingAdvertisements) {
this.cancellationToken = new AbortController();
await device.watchAdvertisements({ signal: this.cancellationToken.signal });
}
this.snackBar.open("Heart Rate Monitor disconnected", "Dismiss");
};

private observeBattery(
batteryCharacteristic: BluetoothRemoteGATTCharacteristic,
): Observable<number | undefined> {
Expand Down Expand Up @@ -298,4 +284,12 @@ export class BLEHeartRateService implements IHeartRateService {

return result;
}

private reconnectHandler: (event: BluetoothAdvertisingEvent) => Promise<void> = async (
event: BluetoothAdvertisingEvent,
): Promise<void> => {
this.cancellationToken.abort();

this.connect(event.device);
};
}
2 changes: 2 additions & 0 deletions src/common/services/config-manager.service.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,9 @@ export class ConfigManagerService {
});
if (!isSecureContext) {
this.config.heartRateMonitor = "off";
this.config.bleDeviceId = "";
localStorage.setItem("heartRateMonitor", "off");
localStorage.setItem("bleDeviceId", "");
}

this.configSubject = new BehaviorSubject(this.config);
Expand Down
9 changes: 4 additions & 5 deletions src/common/services/heart-rate.service.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,12 +22,9 @@ export class HeartRateService {
) {}

async discover(): Promise<void> {
this.ble.disconnectDevice();

switch (this.configManager.getConfig().heartRateMonitor) {
case "ble":
this.ble.discover$().subscribe();
break;
return await this.ble.discover();
case "ant":
return await this.ant.discover();
default:
Expand All @@ -46,19 +43,21 @@ export class HeartRateService {
filter((config: Config): boolean => config.heartRateMonitor !== this.heartRateMonitor),
switchMap((config: Config): Observable<IHeartRate | undefined> => {
this.heartRateMonitor = config.heartRateMonitor;
this.ble.disconnectDevice();

switch (config.heartRateMonitor) {
case "ble":
this.ant.disconnectDevice();
this.ble.reconnect();

return this.ble.streamHeartRate$();
case "ant":
this.ble.disconnectDevice();
this.ant.reconnect();

return this.ant.streamHeartRate$();
default:
this.ant.disconnectDevice();
this.ble.disconnectDevice();

return of(undefined);
}
Expand Down

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