/// <summary>
/// Resolve a Web Bluetooth GATT "name" to a canonical UUID, using an assigned numbers table if necessary.
/// See <a href="https://webbluetoothcg.github.io/web-bluetooth/#resolveuuidname">here</a> for more info.
/// </summary>
/// <param name="nameToken">A short UUID in integer form, a full UUID, or the name of an assigned number</param>
/// <param name="assignedNumbersTable">The table of assigned numbers to resolve integer names</param>
/// <returns>The UUID associated with the token. Throws if not possible.</returns>
public static Guid ResolveUuidName(JToken nameToken, IReadOnlyDictionary <string, short> assignedNumbersTable)
{
if (nameToken.Type == JTokenType.Integer)
{
return(CanonicalUuid(nameToken.ToObject <int>()));
}
var name = nameToken.ToObject <string>();
// Web Bluetooth demands an exact match to this regex but the .NET Guid constructor is more permissive.
// See https://webbluetoothcg.github.io/web-bluetooth/#valid-uuid
var validGuidRegex = new Regex("^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$");
if (validGuidRegex.IsMatch(name))
{
return(new Guid(name));
}
// TODO: does Windows / .NET really have no built-in call for this?
if (assignedNumbersTable.TryGetValue(name, out var id))
{
return(CanonicalUuid(id));
}
throw JsonRpcException.InvalidParams($"unknown or invalid GATT name: {nameToken}");
}
/// <summary>
/// Encode `data` using `encoding`, either into `destination` or a new JSON object.
/// </summary>
/// <param name="data">The data to encode</param>
/// <param name="encoding">The type of encoding to use, or null to "encode" as a Unicode string</param>
/// <param name="destination">
/// The optional object to encode into.
/// If not null, the "message" and "encoding" properties will be adjusted as necessary.
/// If null, a new object will be created with "message" and (possibly) "encoding" properties.
/// </param>
/// <returns>The object to which the encoded message was written, regardless of source</returns>
public static JObject EncodeBuffer(byte[] data, string encoding, JObject destination = null)
{
if (destination == null)
{
destination = new JObject();
}
switch (encoding)
{
case "base64":
destination["encoding"] = encoding;
destination["message"] = Convert.ToBase64String(data);
break;
case null:
destination.Remove("encoding");
destination["message"] = Encoding.UTF8.GetString(data);
break;
default:
throw JsonRpcException.InvalidParams($"unsupported encoding: {encoding}");
}
return(destination);
}
private void Discover(JObject parameters)
{
var major = parameters["majorDeviceClass"]?.ToObject <BluetoothMajorClass>();
var minor = parameters["minorDeviceClass"]?.ToObject <BluetoothMinorClass>();
if (major == null || minor == null)
{
throw JsonRpcException.InvalidParams("majorDeviceClass and minorDeviceClass required");
}
var deviceClass = BluetoothClassOfDevice.FromParts(major.Value, minor.Value,
BluetoothServiceCapabilities.None);
var selector = BluetoothDevice.GetDeviceSelectorFromClassOfDevice(deviceClass);
try
{
_watcher = DeviceInformation.CreateWatcher(selector, new List <String>
{
SignalStrengthPropertyName,
IsPresentPropertyName,
BluetoothAddressPropertyName
});
_watcher.Added += PeripheralDiscovered;
_watcher.EnumerationCompleted += EnumerationCompleted;
_watcher.Updated += PeripheralUpdated;
_watcher.Stopped += EnumerationStopped;
_watcher.Start();
}
catch (ArgumentException)
{
throw JsonRpcException.ApplicationError("Failed to create device watcher");
}
}
internal BLEDataFilter(JToken dataFilter)
{
var filterObject = (JObject)dataFilter;
JToken token;
if (filterObject.TryGetValue("dataPrefix", out token))
{
dataPrefix = token.ToObject <List <byte> >();
}
else
{
dataPrefix = new List <byte>();
}
if (filterObject.TryGetValue("mask", out token))
{
mask = token.ToObject <List <byte> >();
}
else
{
mask = Enumerable.Repeat <byte>(0xFF, dataPrefix.Count).ToList();
}
if (dataPrefix.Count != mask.Count)
{
throw JsonRpcException.InvalidParams(
$"length of data prefix ({dataPrefix.Count}) does not match length of mask ({mask.Count})");
}
}
/// <summary>
/// Handle the client's request to connect to a particular peripheral.
/// Valid in the discovery state; transitions to connected state on success.
/// </summary>
/// <param name="parameters">
/// A JSON object containing the UUID of a peripheral found by the most recent discovery request
/// </param>
private async Task Connect(JObject parameters)
{
if (_services != null)
{
throw JsonRpcException.InvalidRequest("already connected to peripheral");
}
var peripheralId = parameters["peripheralId"].ToObject <ulong>();
if (!_reportedPeripherals.Contains(peripheralId))
{
// the client may only connect to devices that were returned by the current discovery request
throw JsonRpcException.InvalidParams($"invalid peripheral ID: {peripheralId}");
}
_peripheral = await BluetoothLEDevice.FromBluetoothAddressAsync(peripheralId);
var servicesResult = await _peripheral.GetGattServicesAsync(BluetoothCacheMode.Uncached);
if (servicesResult.Status != GattCommunicationStatus.Success)
{
throw JsonRpcException.ApplicationError($"failed to enumerate GATT services: {servicesResult.Status}");
}
_peripheral.ConnectionStatusChanged += OnPeripheralStatusChanged;
_services = servicesResult.Services;
// cache all characteristics in all services
foreach (var service in _services)
{
var characteristicsResult = await service.GetCharacteristicsAsync(BluetoothCacheMode.Uncached);
if (characteristicsResult.Status != GattCommunicationStatus.Success)
{
continue;
}
foreach (var characteristic in characteristicsResult.Characteristics)
{
_cachedCharacteristics.Add(characteristic.Uuid, characteristic);
}
}
// collect optional services plus all services from all filters
// Note: this modifies _optionalServices for convenience since we know it'll go away soon.
_allowedServices = _optionalServices ?? new HashSet <Guid>();
_allowedServices = _filters
.Where(filter => filter.RequiredServices?.Count > 0)
.Aggregate(_allowedServices, (result, filter) =>
{
result.UnionWith(filter.RequiredServices);
return(result);
});
// clean up resources used by discovery
_watcher.Stop();
_watcher = null;
_reportedPeripherals.Clear();
_optionalServices = null;
}
/// <summary>
/// Search for peripherals which match the filter information provided in the parameters.
/// Valid in the initial state; transitions to discovery state on success.
/// </summary>
/// <param name="parameters">
/// JSON object containing at least one filter, and optionally an "optionalServices" list. See
/// <a href="https://webbluetoothcg.github.io/web-bluetooth/#dictdef-requestdeviceoptions">here</a> for more
/// information, but note that the "acceptAllDevices" property is ignored.
/// </param>
private void Discover(JObject parameters)
{
if (_services != null)
{
throw JsonRpcException.InvalidRequest("cannot discover when connected");
}
var jsonFilters = parameters["filters"]?.ToObject <JArray>();
if (jsonFilters == null || jsonFilters.Count < 1)
{
throw JsonRpcException.InvalidParams("discovery request must include filters");
}
var newFilters = jsonFilters.Select(filter => new BLEScanFilter(filter)).ToList();
if (newFilters.Any(filter => filter.IsEmpty))
{
throw JsonRpcException.InvalidParams("discovery request includes empty filter");
}
HashSet <Guid> newOptionalServices = null;
if (parameters.TryGetValue("optionalServices", out var optionalServicesToken))
{
var optionalServicesArray = (JArray)optionalServicesToken;
newOptionalServices = new HashSet <Guid>(optionalServicesArray.Select(GattHelpers.GetServiceUuid));
}
if (_watcher?.Status == BluetoothLEAdvertisementWatcherStatus.Started)
{
_watcher.Received -= OnAdvertisementReceived;
_watcher.Stop();
}
_watcher = new BluetoothLEAdvertisementWatcher()
{
SignalStrengthFilter =
{
InRangeThresholdInDBm = MinimumSignalStrength,
OutOfRangeThresholdInDBm = MinimumSignalStrength - SignalStrengthMargin,
OutOfRangeTimeout = TimeSpan.FromMilliseconds(OutOfRangeTimeout)
}
};
_reportedPeripherals.Clear();
_filters = newFilters;
_optionalServices = newOptionalServices;
_watcher.Received += OnAdvertisementReceived;
_watcher.ScanningMode = BluetoothLEScanningMode.Active;
_watcher.Start();
}
/// <summary>
/// Decode the "message" property of `jsonBuffer` into bytes.
/// If the buffer has an `encoding` property, use that method. Otherwise, assume the message is Unicode text.
/// </summary>
/// <param name="jsonBuffer">
/// A JSON object containing a "message" property and optionally an "encoding" property.
/// </param>
/// <returns>An array of bytes containing the decoded data</returns>
public static byte[] DecodeBuffer(JObject jsonBuffer)
{
var message = jsonBuffer["message"].ToObject <string>();
var encoding = jsonBuffer["encoding"]?.ToObject <string>();
switch (encoding)
{
case "base64": // "message" is encoded with Base64
return(Convert.FromBase64String(message));
case null: // "message" is a Unicode string with no additional encoding
return(Encoding.UTF8.GetBytes(message));
default:
throw JsonRpcException.InvalidParams($"unsupported encoding: {encoding}");
}
}
// See https://webbluetoothcg.github.io/web-bluetooth/#bluetoothlescanfilterinit-canonicalizing
internal BLEScanFilter(JToken filter)
{
var filterObject = (JObject)filter;
JToken token;
if (filterObject.TryGetValue("name", out token))
{
Name = token.ToString();
}
if (filterObject.TryGetValue("namePrefix", out token))
{
NamePrefix = token.ToString();
}
if (filterObject.TryGetValue("services", out token))
{
var serviceArray = (JArray)token;
RequiredServices = new HashSet <Guid>(serviceArray.Select(GattHelpers.GetServiceUuid));
if (RequiredServices.Count < 1)
{
throw JsonRpcException.InvalidParams($"filter contains empty or invalid services list: {filter}");
}
}
if (filterObject.TryGetValue("manufacturerData", out token))
{
ManufacturerData = new Dictionary <int, BLEDataFilter>();
var manufacturerData = (JObject)token;
foreach (var kv in manufacturerData)
{
var manufacturerId = int.Parse(kv.Key);
var dataFilter = new BLEDataFilter(kv.Value);
ManufacturerData.Add(manufacturerId, dataFilter);
}
}
if (filterObject.TryGetValue("serviceData", out token))
{
throw JsonRpcException.ApplicationError("filtering on serviceData is not currently supported");
}
}
// See https://webbluetoothcg.github.io/web-bluetooth/#bluetoothlescanfilterinit-canonicalizing
internal BLEScanFilter(JToken filter)
{
var filterObject = (JObject)filter;
JToken token;
if (filterObject.TryGetValue("name", out token))
{
Name = token.ToString();
}
if (filterObject.TryGetValue("namePrefix", out token))
{
NamePrefix = token.ToString();
}
if (filterObject.TryGetValue("services", out token))
{
var serviceArray = (JArray)token;
RequiredServices = new HashSet <Guid>(serviceArray.Select(GattHelpers.GetServiceUuid));
if (RequiredServices.Count < 1)
{
throw JsonRpcException.InvalidParams($"filter contains empty or invalid services list: {filter}");
}
}
if (filterObject.TryGetValue("manufacturerData", out token))
{
throw JsonRpcException.ApplicationError("filtering on manufacturerData is not currently supported");
}
if (filterObject.TryGetValue("serviceData", out token))
{
throw JsonRpcException.ApplicationError("filtering on serviceData is not currently supported");
}
}
/// <summary>
/// Fetch the characteristic referred to in the endpointInfo object and perform access verification.
/// </summary>
/// <param name="errorContext">
/// A string to include in error reporting, if an error is encountered
/// </param>
/// <param name="endpointInfo">
/// A JSON object which may contain a 'serviceId' property and a 'characteristicId' property
/// </param>
/// <param name="checkFlag">
/// Check if this flag is set for this service or characteristic in the block list. If so, throw.
/// </param>
/// <returns>
/// The specified GATT service characteristic, if it can be resolved and all checks pass.
/// Otherwise, a JSON-RPC exception is thrown indicating what went wrong.
/// </returns>
private async Task <GattCharacteristic> GetEndpoint(string errorContext, JObject endpointInfo,
GattHelpers.BlockListStatus checkFlag)
{
GattDeviceService service;
Guid?serviceId;
if (_peripheral.ConnectionStatus != BluetoothConnectionStatus.Connected)
{
throw JsonRpcException.ApplicationError($"Peripheral is not connected for {errorContext}");
}
if (endpointInfo.TryGetValue("serviceId", out var serviceToken))
{
serviceId = GattHelpers.GetServiceUuid(serviceToken);
service = _services?.FirstOrDefault(s => s.Uuid == serviceId);
}
else
{
service = _services?.FirstOrDefault(); // could in theory be null
serviceId = service?.Uuid;
}
if (!serviceId.HasValue)
{
throw JsonRpcException.InvalidParams($"Could not determine service UUID for {errorContext}");
}
//if (_allowedServices?.Contains(serviceId.Value) != true)
//{
// throw JsonRpcException.InvalidParams($"attempt to access unexpected service: {serviceId}");
//}
var blockStatus = GattHelpers.GetBlockListStatus(serviceId.Value);
if (blockStatus.HasFlag(checkFlag))
{
throw JsonRpcException.InvalidParams($"service is block-listed with {blockStatus}: {serviceId}");
}
if (service == null)
{
throw JsonRpcException.InvalidParams($"could not find service {serviceId}");
}
GattCharacteristic characteristic;
Guid?characteristicId;
if (endpointInfo.TryGetValue("characteristicId", out var characteristicToken))
{
characteristic = null; // we will attempt to collect this below
characteristicId = GattHelpers.GetCharacteristicUuid(characteristicToken);
}
else
{
if (!_cachedServiceCharacteristics.TryGetValue(service.Uuid, out var characteristics))
{
var characteristicsResult = await service.GetCharacteristicsAsync(BluetoothCacheMode.Uncached);
if (characteristicsResult.Status != GattCommunicationStatus.Success)
{
throw JsonRpcException.ApplicationError(
$"failed to collect characteristics from service: {characteristicsResult.Status}");
}
characteristics = characteristicsResult.Characteristics;
_cachedServiceCharacteristics.Add(service.Uuid, characteristics);
}
characteristic = characteristics.FirstOrDefault(); // could in theory be null
characteristicId = characteristic?.Uuid;
}
if (!characteristicId.HasValue)
{
throw JsonRpcException.InvalidParams($"Could not determine characteristic UUID for {errorContext}");
}
blockStatus = GattHelpers.GetBlockListStatus(characteristicId.Value);
if (blockStatus.HasFlag(checkFlag))
{
throw JsonRpcException.InvalidParams(
$"characteristic is block-listed with {blockStatus}: {characteristicId}");
}
// collect the characteristic if we didn't do so above
if (characteristic == null &&
!_cachedCharacteristics.TryGetValue(characteristicId.Value, out characteristic))
{
var characteristicsResult =
await service.GetCharacteristicsForUuidAsync(characteristicId.Value, BluetoothCacheMode.Uncached);
if (characteristicsResult.Status != GattCommunicationStatus.Success)
{
throw JsonRpcException.ApplicationError(
$"failed to collect characteristics from service: {characteristicsResult.Status}");
}
if (characteristicsResult.Characteristics.Count < 1)
{
throw JsonRpcException.InvalidParams(
$"could not find characteristic {characteristicId} on service {serviceId}");
}
// TODO: why is this a list?
characteristic = characteristicsResult.Characteristics[0];
_cachedCharacteristics.Add(characteristicId.Value, characteristic);
}
try
{
// Unfortunately there's no direct way to test if the peripheral object has been disposed. The
// `connectionState` property still indicates that the peripheral is connected in some cases, for
// example when Bluetooth is turned off in Bluetooth settings / Control Panel. However, trying to
// access the `Service` property of the `Characteristic` will throw an `ObjectDisposedException` in
// this case, so that's the hack being used here to check for a disposed peripheral.
var tempDisposalProbe = characteristic.Service;
}
catch (ObjectDisposedException e)
{
// This could mean that Bluetooth was turned off or the computer resumed from sleep
throw JsonRpcException.ApplicationError($"Peripheral is disposed for {errorContext}");
}
return(characteristic);
}
/// <summary>
/// Fetch the characteristic referred to in the endpointInfo object and perform access verification.
/// </summary>
/// <param name="errorContext">
/// A string to include in error reporting, if an error is encountered
/// </param>
/// <param name="endpointInfo">
/// A JSON object which may contain a 'serviceId' property and a 'characteristicId' property
/// </param>
/// <param name="checkFlag">
/// Check if this flag is set for this service or characteristic in the block list. If so, throw.
/// </param>
/// <returns>
/// The specified GATT service characteristic, if it can be resolved and all checks pass.
/// Otherwise, a JSON-RPC exception is thrown indicating what went wrong.
/// </returns>
private async Task <GattCharacteristic> GetEndpoint(string errorContext, JObject endpointInfo,
GattHelpers.BlockListStatus checkFlag)
{
GattDeviceService service;
Guid?serviceId;
if (endpointInfo.TryGetValue("serviceId", out var serviceToken))
{
serviceId = GattHelpers.GetServiceUuid(serviceToken);
service = _services?.FirstOrDefault(s => s.Uuid == serviceId);
}
else
{
service = _services?.FirstOrDefault(); // could in theory be null
serviceId = service?.Uuid;
}
if (!serviceId.HasValue)
{
throw JsonRpcException.InvalidParams($"Could not determine service UUID for {errorContext}");
}
if (_allowedServices?.Contains(serviceId.Value) != true)
{
throw JsonRpcException.InvalidParams($"attempt to access unexpected service: {serviceId}");
}
var blockStatus = GattHelpers.GetBlockListStatus(serviceId.Value);
if (blockStatus.HasFlag(checkFlag))
{
throw JsonRpcException.InvalidParams($"service is block-listed with {blockStatus}: {serviceId}");
}
if (service == null)
{
throw JsonRpcException.InvalidParams($"could not find service {serviceId}");
}
GattCharacteristic characteristic;
Guid?characteristicId;
if (endpointInfo.TryGetValue("characteristicId", out var characteristicToken))
{
characteristic = null; // we will attempt to collect this below
characteristicId = GattHelpers.GetCharacteristicUuid(characteristicToken);
}
else
{
if (!_cachedServiceCharacteristics.TryGetValue(service.Uuid, out var characteristics))
{
var characteristicsResult = await service.GetCharacteristicsAsync(BluetoothCacheMode.Uncached);
if (characteristicsResult.Status != GattCommunicationStatus.Success)
{
throw JsonRpcException.ApplicationError(
$"failed to collect characteristics from service: {characteristicsResult.Status}");
}
characteristics = characteristicsResult.Characteristics;
_cachedServiceCharacteristics.Add(service.Uuid, characteristics);
}
characteristic = characteristics.FirstOrDefault(); // could in theory be null
characteristicId = characteristic?.Uuid;
}
if (!characteristicId.HasValue)
{
throw JsonRpcException.InvalidParams($"Could not determine characteristic UUID for {errorContext}");
}
blockStatus = GattHelpers.GetBlockListStatus(characteristicId.Value);
if (blockStatus.HasFlag(checkFlag))
{
throw JsonRpcException.InvalidParams(
$"characteristic is block-listed with {blockStatus}: {characteristicId}");
}
// collect the characteristic if we didn't do so above
if (characteristic == null &&
!_cachedCharacteristics.TryGetValue(characteristicId.Value, out characteristic))
{
var characteristicsResult =
await service.GetCharacteristicsForUuidAsync(characteristicId.Value, BluetoothCacheMode.Uncached);
if (characteristicsResult.Status != GattCommunicationStatus.Success)
{
throw JsonRpcException.ApplicationError(
$"failed to collect characteristics from service: {characteristicsResult.Status}");
}
if (characteristicsResult.Characteristics.Count < 1)
{
throw JsonRpcException.InvalidParams(
$"could not find characteristic {characteristicId} on service {serviceId}");
}
// TODO: why is this a list?
characteristic = characteristicsResult.Characteristics[0];
_cachedCharacteristics.Add(characteristicId.Value, characteristic);
}
return(characteristic);
}