install go2rtc on bob

installs_on_host/go2rtc/pkg/gopro/discovery.go

@@ -0,0 +1,43 @@
+package gopro
+
+import (
+	"net"
+	"net/http"
+	"regexp"
+)
+
+func Discovery() (urls []string) {
+	ints, err := net.Interfaces()
+	if err != nil {
+		return nil
+	}
+
+	// The socket address for USB connections is 172.2X.1YZ.51:8080
+	// https://gopro.github.io/OpenGoPro/http_2_0#socket-address
+	re := regexp.MustCompile(`^172\.2\d\.1\d\d\.`)
+
+	for _, itf := range ints {
+		addrs, err := itf.Addrs()
+		if err != nil {
+			continue
+		}
+
+		for _, addr := range addrs {
+			host := addr.String()
+			if !re.MatchString(host) {
+				continue
+			}
+
+			host = host[:11] + "51" // 172.2x.1xx.xxx
+			res, err := http.Get("http://" + host + ":8080/gopro/webcam/status")
+			if err != nil {
+				continue
+			}
+			_ = res.Body.Close()
+
+			urls = append(urls, host)
+		}
+	}
+
+	return
+}

installs_on_host/go2rtc/pkg/gopro/producer.go

@@ -0,0 +1,124 @@
+package gopro
+
+import (
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/AlexxIT/go2rtc/pkg/mpegts"
+)
+
+func Dial(rawURL string) (*mpegts.Producer, error) {
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		return nil, err
+	}
+
+	r := &listener{host: u.Host}
+
+	if err = r.command("/gopro/webcam/stop"); err != nil {
+		return nil, err
+	}
+
+	if err = r.listen(); err != nil {
+		return nil, err
+	}
+
+	if err = r.command("/gopro/webcam/start"); err != nil {
+		return nil, err
+	}
+
+	prod, err := mpegts.Open(r)
+	if err != nil {
+		return nil, err
+	}
+
+	prod.FormatName = "gopro"
+	prod.RemoteAddr = u.Host
+
+	return prod, nil
+}
+
+type listener struct {
+	conn    net.PacketConn
+	host    string
+	packet  []byte
+	packets chan []byte
+}
+
+func (r *listener) Read(p []byte) (n int, err error) {
+	if r.packet == nil {
+		var ok bool
+		if r.packet, ok = <-r.packets; !ok {
+			return 0, io.EOF // channel closed
+		}
+	}
+
+	n = copy(p, r.packet)
+
+	if n < len(r.packet) {
+		r.packet = r.packet[n:]
+	} else {
+		r.packet = nil
+	}
+
+	return
+}
+
+func (r *listener) Close() error {
+	return r.conn.Close()
+}
+
+func (r *listener) command(api string) error {
+	client := &http.Client{Timeout: 5 * time.Second}
+
+	res, err := client.Get("http://" + r.host + ":8080" + api)
+	if err != nil {
+		return err
+	}
+
+	_ = res.Body.Close()
+
+	if res.StatusCode != http.StatusOK {
+		return errors.New("gopro: wrong response: " + res.Status)
+	}
+
+	return nil
+}
+
+func (r *listener) listen() (err error) {
+	if r.conn, err = net.ListenPacket("udp4", ":8554"); err != nil {
+		return
+	}
+
+	r.packets = make(chan []byte, 1024)
+	go r.worker()
+
+	return
+}
+
+func (r *listener) worker() {
+	b := make([]byte, 1500)
+	for {
+		if err := r.conn.SetReadDeadline(time.Now().Add(3 * time.Second)); err != nil {
+			break
+		}
+
+		n, _, err := r.conn.ReadFrom(b)
+		if err != nil {
+			break
+		}
+
+		packet := make([]byte, n)
+		copy(packet, b)
+
+		r.packets <- packet
+	}
+
+	close(r.packets)
+
+	_ = r.command("/gopro/webcam/stop")
+}