udp: Implement announces

udp/writer.go

@@ -0,0 +1,49 @@
+// Copyright 2015 The Chihaya Authors. All rights reserved.
+// Use of this source code is governed by the BSD 2-Clause license,
+// which can be found in the LICENSE file.
+
+package udp
+
+import (
+	"bytes"
+	"encoding/binary"
+
+	"github.com/chihaya/chihaya/tracker/models"
+)
+
+type Writer struct {
+	buf *bytes.Buffer
+
+	transactionID []byte
+}
+
+func (w *Writer) WriteError(err error) error {
+	w.writeHeader(3)
+	w.buf.WriteString(err.Error())
+	w.buf.WriteRune('\000')
+	return nil
+}
+
+func (w *Writer) WriteAnnounce(res *models.AnnounceResponse) error {
+	w.writeHeader(1)
+	binary.Write(w.buf, binary.BigEndian, uint32(res.Interval))
+	binary.Write(w.buf, binary.BigEndian, uint32(res.Incomplete))
+	binary.Write(w.buf, binary.BigEndian, uint32(res.Complete))
+
+	for _, peer := range res.IPv4Peers {
+		w.buf.Write(peer.IP)
+		binary.Write(w.buf, binary.BigEndian, peer.Port)
+	}
+
+	return nil
+}
+
+func (w *Writer) WriteScrape(res *models.ScrapeResponse) error {
+	w.writeHeader(2)
+	return nil
+}
+
+func (w *Writer) writeHeader(action uint32) {
+	binary.Write(w.buf, binary.BigEndian, action)
+	w.buf.Write(w.transactionID)
+}