add helper methods to get IPv4 and IPv6 peer

chihaya.go

@@ -34,6 +34,28 @@ type AnnounceRequest struct {
 	Params Params
 }
 
+// Peer4 returns a Peer using the IPv4 endpoint of the Announce.
+// Note that, if the Announce does not contain an IPv4 address, the IP field of
+// the returned Peer can be nil.
+func (r *AnnounceRequest) Peer4() Peer {
+	return Peer{
+		IP:   r.IPv4,
+		Port: r.Port,
+		ID:   r.PeerID,
+	}
+}
+
+// Peer6 returns a Peer using the IPv6 endpoint of the Announce.
+// Note that, if the Announce does not contain an IPv6 address, the IP field of
+// the returned Peer can be nil.
+func (r *AnnounceRequest) Peer6() Peer {
+	return Peer{
+		IP:   r.IPv6,
+		Port: r.Port,
+		ID:   r.PeerID,
+	}
+}
+
 // AnnounceResponse represents the parameters used to create an announce
 // response.
 type AnnounceResponse struct {

server/store/middleware/response/response.go

@@ -27,16 +27,14 @@ func (f FailedToRetrievePeers) Error() string { return string(f) }
 func responseAnnounceClient(next tracker.AnnounceHandler) tracker.AnnounceHandler {
 	return func(cfg *chihaya.TrackerConfig, req *chihaya.AnnounceRequest, resp *chihaya.AnnounceResponse) (err error) {
 		storage := store.MustGetStore()
-		peer4 := chihaya.Peer{ID: req.PeerID, IP: req.IPv4, Port: req.Port}
-		peer6 := chihaya.Peer{ID: req.PeerID, IP: req.IPv6, Port: req.Port}
 
 		resp.MinInterval = cfg.MinAnnounceInterval
 		resp.Compact = req.Compact
 		resp.Complete = int32(storage.NumSeeders(req.InfoHash))
 		resp.Incomplete = int32(storage.NumLeechers(req.InfoHash))
-		resp.IPv4Peers, resp.IPv6Peers, err = storage.AnnouncePeers(req.InfoHash, req.Left == 0, int(req.NumWant), peer4, peer6)
+		resp.IPv4Peers, resp.IPv6Peers, err = storage.AnnouncePeers(req.InfoHash, req.Left == 0, int(req.NumWant), req.Peer4(), req.Peer6())
 		if err != nil {
-			return err.(FailedToRetrievePeers)
+			return FailedToRetrievePeers(err.Error())
 		}
 
 		return next(cfg, req, resp)