initial commit

scratchlink/ble.go

@@ -0,0 +1,92 @@
+package scratchlink
+
+import (
+	"encoding/base64"
+
+	"github.com/google/uuid"
+	"github.com/rs/zerolog/log"
+	"golang.org/x/net/websocket"
+	"tinygo.org/x/bluetooth"
+
+	"github.com/lucarin91/scratch-link4linux/jsonrpc"
+)
+
+func matchDevice(device bluetooth.ScanResult, filters []DiscoverFilter) bool {
+	//TODO: implement match device
+
+	for _, filter := range filters {
+		if len(filter.Name) != 0 && filter.Name != device.LocalName() {
+			return false
+		}
+
+		for _, service := range filter.Services {
+			if !device.HasServiceUUID(bluetooth.NewUUID(service)) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+func getDeviceCharacteristic(device bluetooth.Device, serviceID, characteristicID bluetooth.UUID) (bluetooth.DeviceCharacteristic, error) {
+	services, err := device.DiscoverServices([]bluetooth.UUID{serviceID})
+	if err != nil {
+		return bluetooth.DeviceCharacteristic{}, err
+	}
+
+	chars, err := services[0].DiscoverCharacteristics([]bluetooth.UUID{characteristicID})
+	if err != nil {
+		return bluetooth.DeviceCharacteristic{}, err
+	}
+
+	return chars[0], nil
+}
+
+func notificationCallback(c *websocket.Conn, serviceID, characteristicID uuid.UUID) func(buf []byte) {
+	return func(buf []byte) {
+		_ = jsonrpc.WsSend(c, jsonrpc.NewMsg("characteristicDidChange", UpdateParams{
+			ServiceID:        serviceID,
+			CharacteristicID: characteristicID,
+			Message:          base64.StdEncoding.EncodeToString(buf),
+			Encoding:         "base64",
+		}))
+	}
+}
+
+func startAsyncScan(adapter *bluetooth.Adapter, filter []DiscoverFilter) <-chan Device {
+	// Stop previus scan (if any).
+	_ = adapter.StopScan()
+
+	devices := make(chan Device, 10)
+
+	go func() {
+		defer close(devices)
+
+		err := adapter.Scan(func(adapter *bluetooth.Adapter, device bluetooth.ScanResult) {
+			if len(device.LocalName()) == 0 {
+				return
+			}
+
+			log.Debug().
+				Str("name", device.LocalName()).
+				Str("address", device.Address.String()).
+				Int16("RSSI", device.RSSI).
+				Msg("found device")
+
+			if !matchDevice(device, filter) {
+				return
+			}
+
+			devices <- Device{
+				PeripheralID: device.Address.String(),
+				Name:         device.LocalName(),
+				RSSI:         device.RSSI,
+			}
+		})
+		if err != nil {
+			log.Error().Err(err).Msg("scan error")
+		}
+	}()
+
+	return devices
+}