getDeviceByMulticast: set deviceID as di query parameter to mcast request

Author: jkralik

client/core/getDevice.go

@@ -86,7 +86,7 @@ func (c *Client) GetDeviceByMulticast(ctx context.Context, deviceID string, disc
 
 	h := newDeviceHandler(c.getDeviceConfiguration(), deviceID, cancel)
 	// we want to just get "oic.wk.d" resource, because links will be get via unicast to /oic/res
-	err = DiscoverDevices(findCtx, multicastConn, h, coap.WithResourceType(device.ResourceType))
+	err = DiscoverDevices(findCtx, multicastConn, h, coap.WithResourceType(device.ResourceType), coap.WithDeviceID(deviceID))
 	if err != nil {
 		return nil, MakeDataLoss(fmt.Errorf("could not get the device %s: %w", deviceID, err))
 	}

pkg/net/coap/client.go

@@ -157,6 +157,15 @@ func WithResourceType(in string) OptionFunc {
 	}
 }
 
+func WithDeviceID(in string) OptionFunc {
+	return func(opts message.Options) message.Options {
+		v := "di=" + in
+		buf := make([]byte, len(v))
+		opts, _, _ = opts.AddString(buf, message.URIQuery, v)
+		return opts
+	}
+}
+
 func WithAccept(contentFormat message.MediaType) OptionFunc {
 	return func(opts message.Options) message.Options {
 		buf := make([]byte, 4)