cleanup mdns files

registry/mdns_registry.go

@@ -2,8 +2,13 @@
 package registry
 
 import (
+	"bytes"
+	"compress/zlib"
 	"context"
+	"encoding/hex"
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"net"
 	"strconv"
 	"strings"
@@ -49,6 +54,68 @@ type mdnsRegistry struct {
 	listener chan *mdns.ServiceEntry
 }
 
+func encode(txt *mdnsTxt) ([]string, error) {
+	b, err := json.Marshal(txt)
+	if err != nil {
+		return nil, err
+	}
+
+	var buf bytes.Buffer
+	defer buf.Reset()
+
+	w := zlib.NewWriter(&buf)
+	if _, err := w.Write(b); err != nil {
+		return nil, err
+	}
+	w.Close()
+
+	encoded := hex.EncodeToString(buf.Bytes())
+
+	// individual txt limit
+	if len(encoded) <= 255 {
+		return []string{encoded}, nil
+	}
+
+	// split encoded string
+	var record []string
+
+	for len(encoded) > 255 {
+		record = append(record, encoded[:255])
+		encoded = encoded[255:]
+	}
+
+	record = append(record, encoded)
+
+	return record, nil
+}
+
+func decode(record []string) (*mdnsTxt, error) {
+	encoded := strings.Join(record, "")
+
+	hr, err := hex.DecodeString(encoded)
+	if err != nil {
+		return nil, err
+	}
+
+	br := bytes.NewReader(hr)
+	zr, err := zlib.NewReader(br)
+	if err != nil {
+		return nil, err
+	}
+
+	rbuf, err := ioutil.ReadAll(zr)
+	if err != nil {
+		return nil, err
+	}
+
+	var txt *mdnsTxt
+
+	if err := json.Unmarshal(rbuf, &txt); err != nil {
+		return nil, err
+	}
+
+	return txt, nil
+}
 func newRegistry(opts ...Option) Registry {
 	options := Options{
 		Context: context.Background(),