BlueZ bluetooth backend implementation

#64 non-breaking

Author: rickjansen-dev

README.md

@@ -38,6 +38,7 @@ var serviceProvider = new ServiceCollection()
     .AddLogging()
     .AddPoweredUp()
     .AddWinRTBluetooth() // using WinRT Bluetooth on Windows
+    //.AddBlueZBluetooth() // using BlueZ Bluetooth on Linux
     .BuildServiceProvider();
 
 var host = serviceProvider.GetService<PoweredUpHost>();
@@ -155,6 +156,7 @@ var serviceProvider = new ServiceCollection()
     .AddLogging()
     .AddPoweredUp()
     .AddWinRTBluetooth() // using WinRT Bluetooth on Windows
+    //.AddBlueZBluetooth() // using BlueZ Bluetooth on Linux
     .BuildServiceProvider();
 
 using (var scope = serviceProvider.CreateScope()) // create a scoped DI container per intented active connection/protocol. If disposed, disposes all disposable artifacts.
@@ -236,6 +238,8 @@ DI Container Elements
   - [X] .NET Core 3.1 (on Windows 10 using WinRT)
     - Library uses `Span<T>` / C# 8.0 and is therefore not supported in .NET Framework 1.0 - 4.8 and UWP Apps until arrival of .NET 5 (WinForms and WPF work in .NET Core 3.1)
     - Library uses WinRT for communication therefore only Windows 10
+  - [X] .NET Core 3.1 / .NET 5 on Linux using BlueZ
+    - Requires `bluez` to be installed and configured.
   - [ ] Xamarin (on iOS / Android using ?)
   - [ ] Blazor (on Browser using WebBluetooth)
 - Hub Model

examples/SharpBrick.PoweredUp.Examples/BaseExample.cs

@@ -86,7 +86,7 @@ public void InitHost(bool enableTrace)
                         builder.AddFilter("SharpBrick.PoweredUp.Bluetooth.BluetoothKernel", LogLevel.Debug);
                     }
                 })
-                .AddWinRTBluetooth()
+                .AddBlueZBluetooth()
                 ;
 
             Configure(serviceCollection);

examples/SharpBrick.PoweredUp.Examples/Program.cs

@@ -18,7 +18,7 @@ static async Task Main(string[] args)
             //example = new Example.ExampleMotorVirtualPort();
             //example = new Example.ExampleHubActions();
             //example = new Example.ExampleTechnicMediumHubAccelerometer();
-            //example = new Example.ExampleTechnicMediumHubGyroSensor();
+            example = new Example.ExampleTechnicMediumHubGyroSensor();
             //example = new Example.ExampleVoltage();
             //example = new Example.ExampleTechnicMediumTemperatureSensor();
             //example = new Example.ExampleMotorInputCombinedMode();
@@ -33,7 +33,7 @@ static async Task Main(string[] args)
             //example = new Example.ExampleHubPropertyObserving();
             //example = new Example.ExampleDiscoverByType();
             //example = new Example.ExampleCalibrationSteering();
-            example = new Example.ExampleTechnicMediumHubGestSensor();
+            //example = new Example.ExampleTechnicMediumHubGestSensor();
 
             // NOTE: Examples are programmed object oriented style. Base class implements methods Configure, DiscoverAsync and ExecuteAsync to be overwriten on demand.
             await example.InitHostAndDiscoverAsync(enableTrace);

examples/SharpBrick.PoweredUp.Examples/SharpBrick.PoweredUp.Examples.csproj

@@ -9,6 +9,7 @@
   <ItemGroup>
     <ProjectReference Include="..\..\src\SharpBrick.PoweredUp\SharpBrick.PoweredUp.csproj" />
     <ProjectReference Include="..\..\src\SharpBrick.PoweredUp.WinRT\SharpBrick.PoweredUp.WinRT.csproj" />
+    <ProjectReference Include="..\..\src\SharpBrick.PoweredUp.BlueZ\SharpBrick.PoweredUp.BlueZ.csproj" />
   </ItemGroup>
 
   <ItemGroup>

src/SharpBrick.PoweredUp.BlueZ/BlueZConstants.cs

@@ -0,0 +1,8 @@
+namespace SharpBrick.PoweredUp.BlueZ
+{
+    internal class BlueZConstants
+    {
+        public const string BlueZDBusServiceName = "org.bluez";
+    }
+}
+

src/SharpBrick.PoweredUp.BlueZ/BlueZPoweredUpBluetoothAdapter.cs

@@ -0,0 +1,139 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using SharpBrick.PoweredUp.Bluetooth;
+using SharpBrick.PoweredUp.BlueZ.Utilities;
+using Tmds.DBus;
+
+namespace SharpBrick.PoweredUp.BlueZ
+{
+    public class BlueZPoweredUpBluetoothAdapter : IPoweredUpBluetoothAdapter
+    {
+        private readonly ILogger<BlueZPoweredUpBluetoothAdapter> _logger;
+        private readonly string _adapterObjectPath;
+        private readonly Dictionary<ulong, IPoweredUpBluetoothDevice> _devices = new Dictionary<ulong, IPoweredUpBluetoothDevice>();
+        private IAdapter1 _adapter;
+
+        public bool Discovering { get; set; } = false;
+
+        public BlueZPoweredUpBluetoothAdapter( 
+            ILogger<BlueZPoweredUpBluetoothAdapter> logger,
+            string adapterObjectPath = null) //"/org/bluez/hci0")
+        {
+            _logger = logger;
+            _adapterObjectPath = adapterObjectPath;
+        }
+
+        private async Task<IAdapter1> GetAdapterAsync()
+        {
+            var adapter = !string.IsNullOrEmpty(_adapterObjectPath) ? Connection.System.CreateProxy<IAdapter1>(BlueZConstants.BlueZDBusServiceName, _adapterObjectPath) : await FindFirstAdapter();
+            
+            // validate the adapter
+            await adapter.GetAliasAsync();
+
+            await adapter.WatchPropertiesAsync(AdapterPropertyChangedHandler);
+
+            return adapter;
+        }
+
+        private async Task<IAdapter1> FindFirstAdapter()
+        {
+            var adapters = await Connection.System.FindProxies<IAdapter1>();
+            return adapters.FirstOrDefault();
+        }
+
+        private void AdapterPropertyChangedHandler(PropertyChanges changes)
+        {
+            _logger.LogDebug("Property changed {ChangedProperties}", changes.Changed);
+
+            foreach (var propertyChanged in changes.Changed)
+            {
+                switch (propertyChanged.Key)
+                {
+                    case "Discovering":
+                        Discovering = (bool)propertyChanged.Value;
+                        break;
+                }
+            }
+        }
+
+        private async Task<ICollection<IDevice1>> GetExistingDevicesAsync()
+            => await Connection.System.FindProxies<IDevice1>();
+
+        private IDevice1 GetSpecificDeviceAsync(ObjectPath objectPath)
+            => Connection.System.CreateProxy<IDevice1>(BlueZConstants.BlueZDBusServiceName, objectPath);
+
+        //private IPoweredUpBluetoothDevice ConstructDevice(IDevice1 device, Func<PoweredUpBluetoothDeviceInfo, Task> discoveryHandler = null)
+        //    => new BlueZPoweredUpBluetoothDevice(device, discoveryHandler);
+
+        private async Task<bool> IsLegoWirelessProcotolDevice(IDevice1 device)
+            => (await device.GetUUIDsAsync()).NullToEmpty().Any(x => x.ToUpperInvariant() == PoweredUpBluetoothConstants.LegoHubService);
+
+        public async void Discover(Func<PoweredUpBluetoothDeviceInfo, Task> discoveryHandler, CancellationToken cancellationToken = default)
+        {
+            _adapter ??= await GetAdapterAsync();
+
+            var existingDevices = await GetExistingDevicesAsync();
+
+            foreach (var device in existingDevices)
+            {
+                if (await IsLegoWirelessProcotolDevice(device))
+                {
+                    var poweredUpDevice = new BlueZPoweredUpBluetoothDevice(device, discoveryHandler);
+                    await poweredUpDevice.Initialize();
+
+                    _devices.Add(poweredUpDevice.DeviceInfo.BluetoothAddress, poweredUpDevice);
+
+                    await poweredUpDevice.GetManufacturerDataAndInvokeHandlerAsync();
+                }
+            }
+
+            await Connection.System.WatchInterfacesAdded(NewDeviceAddedHandler);
+
+            await _adapter.SetDiscoveryFilterAsync(new Dictionary<string,object>()
+            {
+                { "UUIDs", new string[] { PoweredUpBluetoothConstants.LegoHubService } }
+            });
+
+            cancellationToken.Register(async () =>
+            {
+                if (Discovering)
+                {
+                    await _adapter.StopDiscoveryAsync();
+                }
+            });
+
+            await _adapter.StartDiscoveryAsync();
+
+            async void NewDeviceAddedHandler((ObjectPath objectPath, IDictionary<string, IDictionary<string, object>> interfaces) args)
+            {
+                if (!args.interfaces.ContainsKey("org.bluez.Device1"))
+                {
+                    return;
+                }
+
+                var device = GetSpecificDeviceAsync(args.objectPath);
+                var poweredUpDevice = new BlueZPoweredUpBluetoothDevice(device, discoveryHandler);
+
+                await poweredUpDevice.Initialize();
+                
+                _devices.Add(poweredUpDevice.DeviceInfo.BluetoothAddress, poweredUpDevice);
+
+                await poweredUpDevice.GetManufacturerDataAndInvokeHandlerAsync();
+            }
+        }
+
+        public Task<IPoweredUpBluetoothDevice> GetDeviceAsync(ulong bluetoothAddress)
+        {
+            if (!_devices.ContainsKey(bluetoothAddress))
+            {
+                throw new ArgumentOutOfRangeException("Requested bluetooth device is not available from this adapter");
+            }
+
+            return Task.FromResult<IPoweredUpBluetoothDevice>(_devices[bluetoothAddress]);
+        }
+    }
+}

src/SharpBrick.PoweredUp.BlueZ/BlueZPoweredUpBluetoothCharacteristic.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Polly;
+using SharpBrick.PoweredUp.Bluetooth;
+using Tmds.DBus;
+
+namespace SharpBrick.PoweredUp.BlueZ
+{
+    internal class BlueZPoweredUpBluetoothCharacteristic : IPoweredUpBluetoothCharacteristic
+    {
+        private IGattCharacteristic1 _characteristic;
+
+        public BlueZPoweredUpBluetoothCharacteristic(IGattCharacteristic1 characteristic, Guid uuid)
+        {
+            Uuid = uuid;
+            _characteristic = characteristic ?? throw new ArgumentNullException(nameof(characteristic));
+        }
+
+        public Guid Uuid { get; } 
+
+        public async Task<bool> NotifyValueChangeAsync(Func<byte[], Task> notificationHandler)
+        {
+            if (notificationHandler is null)
+            {
+                 throw new ArgumentNullException(nameof(notificationHandler));
+            }
+
+            await _characteristic.WatchPropertiesAsync(PropertyChangedHandler);
+
+            await _characteristic.StartNotifyAsync();
+            
+            return true;
+
+            void PropertyChangedHandler(PropertyChanges propertyChanges)
+            {
+                foreach (var propertyChanged in propertyChanges.Changed)
+                {
+                    if (propertyChanged.Key == "Value")
+                    {
+                        notificationHandler((byte[])propertyChanged.Value);
+                    }
+                }
+            }
+        }
+
+        public async Task<bool> WriteValueAsync(byte[] data)
+        {
+            if (data is null)
+            {
+                throw new ArgumentNullException(nameof(data));
+            }
+
+            await Policy
+              .Handle<Tmds.DBus.DBusException>()
+              .WaitAndRetryForeverAsync(_ => TimeSpan.FromMilliseconds(10))
+              .ExecuteAsync(() => _characteristic.WriteValueAsync(data, new Dictionary<string, object>()));
+
+            return true;
+        }
+    }
+}

src/SharpBrick.PoweredUp.BlueZ/BlueZPoweredUpBluetoothDevice.cs

@@ -0,0 +1,124 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpBrick.PoweredUp.Bluetooth;
+using Tmds.DBus;
+
+namespace SharpBrick.PoweredUp.BlueZ
+{
+    internal class BlueZPoweredUpBluetoothDevice : IPoweredUpBluetoothDevice
+    {
+        private readonly Func<PoweredUpBluetoothDeviceInfo, Task> _discoveryHandler;
+        private IDevice1 _device;
+
+        internal PoweredUpBluetoothDeviceInfo DeviceInfo { get; private set; } = new PoweredUpBluetoothDeviceInfo();
+        internal bool Connected { get; private set; } = false;
+        internal bool ServicesResolved { get; private set;} = false;
+
+        internal BlueZPoweredUpBluetoothDevice(IDevice1 device, Func<PoweredUpBluetoothDeviceInfo, Task> discoveryHandler = null)
+        {
+            _discoveryHandler = discoveryHandler;
+            _device = device;
+        }
+
+        public string Name { get; private set; } = string.Empty;
+
+        internal async Task Initialize()
+        {
+            await _device.WatchPropertiesAsync(DevicePropertyChangedHandler);
+
+            await GetSafeDeviceInfoAsync();
+        }
+
+        internal async Task GetManufacturerDataAndInvokeHandlerAsync()
+        {
+            try 
+            {
+                var manufacturerData = await _device.GetManufacturerDataAsync();
+                DeviceInfo.ManufacturerData = (byte[])manufacturerData.First().Value;
+
+                await _discoveryHandler(DeviceInfo);
+            } 
+            catch 
+            {
+                // we can ignore errors here, this will throw an exception for existing devices (only after reboot)
+                // manufacturer data will be returned when discovery is turned on
+            }
+        }
+
+        private async void DevicePropertyChangedHandler(PropertyChanges changes)
+        {
+            foreach (var propertyChanged in changes.Changed)
+            {
+                switch (propertyChanged.Key)
+                {
+                    case "ManufacturerData":
+                        DeviceInfo.ManufacturerData = (byte[])((IDictionary<ushort,object>)propertyChanged.Value).First().Value;
+                        await _discoveryHandler(DeviceInfo);
+                        break;
+                    case "Connected":
+                        Connected = (bool)propertyChanged.Value;
+                        break;
+                    case "ServicesResolved":
+                        ServicesResolved = (bool)propertyChanged.Value;
+                        break;
+                }
+            }
+        }
+
+        internal async Task GetSafeDeviceInfoAsync()
+        {
+            var btAddress = await _device.GetAddressAsync();
+            DeviceInfo.BluetoothAddress = Utilities.BluetoothAddressFormatter.ConvertToInteger(btAddress);
+            DeviceInfo.Name = Name = await _device.GetNameAsync();
+        }
+
+        ~BlueZPoweredUpBluetoothDevice() => Dispose(false);
+        public void Dispose() { Dispose(true); GC.SuppressFinalize(this); }
+
+        protected virtual async void Dispose(bool disposing)
+        {
+            if (Connected)
+                await _device?.DisconnectAsync(); // dangerous to await here, try to find a better way
+
+            _device = null;
+        }
+
+        private async Task WaitForConnectionAndServicesResolved(CancellationToken token)
+        {
+            while (!Connected || !ServicesResolved) 
+            { 
+                await Task.Delay(25, token); 
+            }
+        }
+
+        public async Task<IPoweredUpBluetoothService> GetServiceAsync(Guid serviceId)
+        {
+            var connectionTimeout = TimeSpan.FromSeconds(5);
+
+            var cancellationTokenSource = new CancellationTokenSource();
+
+            await _device.ConnectAsync();
+
+            cancellationTokenSource.CancelAfter(connectionTimeout);
+
+            await WaitForConnectionAndServicesResolved(cancellationTokenSource.Token);
+
+            var gattServices = await Connection.System.FindProxies<IGattService1>();
+
+            foreach (var gattService in gattServices)
+            {
+                var gattUuid = Guid.Parse(await gattService.GetUUIDAsync());
+
+                if (gattUuid == serviceId) 
+                {
+                    return new BlueZPoweredUpBluetoothService(gattService, gattUuid);
+                }
+            }
+
+            throw new ArgumentOutOfRangeException(nameof(serviceId), $"Service with id {serviceId} not found");
+        }
+    }
+}