Add Device Information Service support

The Pybricks firmware now includes the BLE Device Information Service
to provide firmware and Pybricks protocol versions.

For now, checking that the service is present is enough to know that the
firmware is up to date. But we will need to add additional checks as
soon as the protocol is changed.

src/ble-uart/sagas.ts

@@ -15,6 +15,11 @@ import {
     takeEvery,
     takeMaybe,
 } from 'typed-redux-saga/macro';
+import {
+    serviceUUID as deviceInfoServiceUUID,
+    firmwareRevisionStringUUID,
+    softwareRevisionStringUUID,
+} from '../ble-device-info-service/protocol';
 import {
     BlePybricksServiceActionType,
     didFailToWriteCommand,
@@ -53,6 +58,8 @@ import {
     TxCharUUID as uartTxCharUUID,
 } from './protocol';
 
+const decoder = new TextDecoder();
+
 function disconnect(
     server: BluetoothRemoteGATTServer,
     _action: BleDeviceDisconnectAction,
@@ -109,7 +116,11 @@ function* connect(_action: BleDeviceConnectAction): Generator {
         device = yield* call(() =>
             navigator.bluetooth.requestDevice({
                 filters: [{ services: [pybricksServiceUUID] }],
-                optionalServices: [pybricksServiceUUID, uartServiceUUID],
+                optionalServices: [
+                    pybricksServiceUUID,
+                    deviceInfoServiceUUID,
+                    uartServiceUUID,
+                ],
             }),
         );
     } catch (err) {
@@ -145,6 +156,79 @@ function* connect(_action: BleDeviceConnectAction): Generator {
 
     yield* takeEvery(BLEDeviceActionType.Disconnect, disconnect, server);
 
+    let deviceInfoService: BluetoothRemoteGATTService;
+    try {
+        deviceInfoService = yield* call(
+            [server, 'getPrimaryService'],
+            deviceInfoServiceUUID,
+        );
+    } catch (err) {
+        server.disconnect();
+        yield* takeMaybe(disconnectChannel);
+        if (err instanceof DOMException && err.code === DOMException.NOT_FOUND_ERR) {
+            yield* put(didFailToConnect({ reason: Reason.NoDeviceInfoService }));
+        } else {
+            yield* put(didFailToConnect({ reason: Reason.Unknown, err }));
+        }
+        return;
+    }
+
+    let firmwareVersionChar: BluetoothRemoteGATTCharacteristic;
+    try {
+        firmwareVersionChar = yield* call(
+            [deviceInfoService, 'getCharacteristic'],
+            firmwareRevisionStringUUID,
+        );
+    } catch (err) {
+        server.disconnect();
+        yield* takeMaybe(disconnectChannel);
+        yield* put(didFailToConnect({ reason: Reason.Unknown, err }));
+        return;
+    }
+
+    let firmwareVersion: string;
+    try {
+        firmwareVersion = decoder.decode(
+            yield* call([firmwareVersionChar, 'readValue']),
+        );
+    } catch (err) {
+        server.disconnect();
+        yield* takeMaybe(disconnectChannel);
+        yield* put(didFailToConnect({ reason: Reason.Unknown, err }));
+        return;
+    }
+
+    // TODO: save firmware version for later use
+    console.log(`Hub firmware version: ${firmwareVersion}`);
+
+    let softwareVersionChar: BluetoothRemoteGATTCharacteristic;
+    try {
+        softwareVersionChar = yield* call(
+            [deviceInfoService, 'getCharacteristic'],
+            softwareRevisionStringUUID,
+        );
+    } catch (err) {
+        server.disconnect();
+        yield* takeMaybe(disconnectChannel);
+        yield* put(didFailToConnect({ reason: Reason.Unknown, err }));
+        return;
+    }
+
+    let protocolVersion: string;
+    try {
+        protocolVersion = decoder.decode(
+            yield* call([softwareVersionChar, 'readValue']),
+        );
+    } catch (err) {
+        server.disconnect();
+        yield* takeMaybe(disconnectChannel);
+        yield* put(didFailToConnect({ reason: Reason.Unknown, err }));
+        return;
+    }
+
+    // TODO: verify that minimum protocol version is met
+    console.log(`Pybricks protocol version: ${protocolVersion}`);
+
     let pybricksService: BluetoothRemoteGATTService;
     try {
         pybricksService = yield* call(
@@ -155,7 +239,7 @@ function* connect(_action: BleDeviceConnectAction): Generator {
         server.disconnect();
         yield* takeMaybe(disconnectChannel);
         if (err instanceof DOMException && err.code === DOMException.NOT_FOUND_ERR) {
-            yield* put(didFailToConnect({ reason: Reason.NoService }));
+            yield* put(didFailToConnect({ reason: Reason.NoPybricksService }));
         } else {
             yield* put(didFailToConnect({ reason: Reason.Unknown, err }));
         }
@@ -231,7 +315,7 @@ function* connect(_action: BleDeviceConnectAction): Generator {
         server.disconnect();
         yield* takeMaybe(disconnectChannel);
         if (err instanceof DOMException && err.code === DOMException.NOT_FOUND_ERR) {
-            yield* put(didFailToConnect({ reason: Reason.NoService }));
+            yield* put(didFailToConnect({ reason: Reason.NoPybricksService }));
         } else {
             yield* put(didFailToConnect({ reason: Reason.Unknown, err }));
         }