explorer: adding another sample app

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

explorer.go

@@ -0,0 +1,166 @@
+// +build
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/paypal/gatt"
+	"github.com/paypal/gatt/examples/option"
+)
+
+var done = make(chan struct{})
+
+func onStateChanged(d gatt.Device, s gatt.State) {
+	fmt.Println("State:", s)
+	switch s {
+	case gatt.StatePoweredOn:
+		fmt.Println("Scanning...")
+		d.Scan([]gatt.UUID{}, false)
+		return
+	default:
+		d.StopScanning()
+	}
+}
+
+func onPeriphDiscovered(p gatt.Peripheral, a *gatt.Advertisement, rssi int) {
+	id := strings.ToUpper(flag.Args()[0])
+	if strings.ToUpper(p.ID()) != id {
+		return
+	}
+
+	// Stop scanning once we've got the peripheral we're looking for.
+	p.Device().StopScanning()
+
+	fmt.Printf("\nPeripheral ID:%s, NAME:(%s)\n", p.ID(), p.Name())
+	fmt.Println("  Local Name        =", a.LocalName)
+	fmt.Println("  TX Power Level    =", a.TxPowerLevel)
+	fmt.Println("  Manufacturer Data =", a.ManufacturerData)
+	fmt.Println("  Service Data      =", a.ServiceData)
+	fmt.Println("")
+
+	p.Device().Connect(p)
+}
+
+func onPeriphConnected(p gatt.Peripheral, err error) {
+	fmt.Println("Connected")
+	defer p.Device().CancelConnection(p)
+
+	if err := p.SetMTU(500); err != nil {
+		fmt.Printf("Failed to set MTU, err: %s\n", err)
+	}
+
+	// Discovery services
+	ss, err := p.DiscoverServices(nil)
+	if err != nil {
+		fmt.Printf("Failed to discover services, err: %s\n", err)
+		return
+	}
+
+	for _, s := range ss {
+		msg := "Service: " + s.UUID().String()
+		if len(s.Name()) > 0 {
+			msg += " (" + s.Name() + ")"
+		}
+		fmt.Println(msg)
+
+		// Discovery characteristics
+		cs, err := p.DiscoverCharacteristics(nil, s)
+		if err != nil {
+			fmt.Printf("Failed to discover characteristics, err: %s\n", err)
+			continue
+		}
+
+		for _, c := range cs {
+			msg := "  Characteristic  " + c.UUID().String()
+			if len(c.Name()) > 0 {
+				msg += " (" + c.Name() + ")"
+			}
+			msg += "\n    properties    " + c.Properties().String()
+			fmt.Println(msg)
+
+			// Read the characteristic, if possible.
+			if (c.Properties() & gatt.CharRead) != 0 {
+				b, err := p.ReadCharacteristic(c)
+				if err != nil {
+					fmt.Printf("Failed to read characteristic, err: %s\n", err)
+					continue
+				}
+				fmt.Printf("    value         %x | %q\n", b, b)
+			}
+
+			// Discovery descriptors
+			ds, err := p.DiscoverDescriptors(nil, c)
+			if err != nil {
+				fmt.Printf("Failed to discover descriptors, err: %s\n", err)
+				continue
+			}
+
+			for _, d := range ds {
+				msg := "  Descriptor      " + d.UUID().String()
+				if len(d.Name()) > 0 {
+					msg += " (" + d.Name() + ")"
+				}
+				fmt.Println(msg)
+
+				// Read descriptor (could fail, if it's not readable)
+				b, err := p.ReadDescriptor(d)
+				if err != nil {
+					fmt.Printf("Failed to read descriptor, err: %s\n", err)
+					continue
+				}
+				fmt.Printf("    value         %x | %q\n", b, b)
+			}
+
+			// Subscribe the characteristic, if possible.
+			if (c.Properties() & (gatt.CharNotify | gatt.CharIndicate)) != 0 {
+				f := func(c *gatt.Characteristic, b []byte, err error) {
+					fmt.Printf("notified: % X | %q\n", b, b)
+				}
+				if err := p.SetNotifyValue(c, f); err != nil {
+					fmt.Printf("Failed to subscribe characteristic, err: %s\n", err)
+					continue
+				}
+			}
+
+		}
+		fmt.Println()
+	}
+
+	fmt.Printf("Waiting for 5 seconds to get some notifiations, if any.\n")
+	time.Sleep(5 * time.Second)
+}
+
+func onPeriphDisconnected(p gatt.Peripheral, err error) {
+	fmt.Println("Disconnected")
+	close(done)
+}
+
+func main() {
+	flag.Parse()
+	if len(flag.Args()) != 1 {
+		log.Fatalf("usage: %s [options] peripheral-id\n", os.Args[0])
+	}
+
+	d, err := gatt.NewDevice(option.DefaultClientOptions...)
+	if err != nil {
+		log.Fatalf("Failed to open device, err: %s\n", err)
+		return
+	}
+
+	// Register handlers.
+	d.Handle(
+		gatt.PeripheralDiscovered(onPeriphDiscovered),
+		gatt.PeripheralConnected(onPeriphConnected),
+		gatt.PeripheralDisconnected(onPeriphDisconnected),
+	)
+
+	d.Init(onStateChanged)
+	<-done
+	fmt.Println("Done")
+}