micro/registry/encoding.go

169 lines
2.6 KiB
Go

package registry
import (
"bytes"
"compress/zlib"
"encoding/hex"
"encoding/json"
"io/ioutil"
)
func encode(buf []byte) string {
var b bytes.Buffer
defer b.Reset()
w := zlib.NewWriter(&b)
if _, err := w.Write(buf); err != nil {
return ""
}
w.Close()
return hex.EncodeToString(b.Bytes())
}
func decode(d string) []byte {
hr, err := hex.DecodeString(d)
if err != nil {
return nil
}
br := bytes.NewReader(hr)
zr, err := zlib.NewReader(br)
if err != nil {
return nil
}
rbuf, err := ioutil.ReadAll(zr)
if err != nil {
return nil
}
return rbuf
}
func encodeEndpoints(en []*Endpoint) []string {
var tags []string
for _, e := range en {
if b, err := json.Marshal(e); err == nil {
tags = append(tags, "e-"+encode(b))
}
}
return tags
}
func decodeEndpoints(tags []string) []*Endpoint {
var en []*Endpoint
// use the first format you find
var ver byte
for _, tag := range tags {
if len(tag) == 0 || tag[0] != 'e' {
continue
}
// check version
if ver > 0 && tag[1] != ver {
continue
}
var e *Endpoint
var buf []byte
// Old encoding was plain
if tag[1] == '=' {
buf = []byte(tag[2:])
}
// New encoding is hex
if tag[1] == '-' {
buf = decode(tag[2:])
}
if err := json.Unmarshal(buf, &e); err == nil {
en = append(en, e)
}
// set version
ver = tag[1]
}
return en
}
func encodeMetadata(md map[string]string) []string {
var tags []string
for k, v := range md {
if b, err := json.Marshal(map[string]string{
k: v,
}); err == nil {
// new encoding
tags = append(tags, "t-"+encode(b))
}
}
return tags
}
func decodeMetadata(tags []string) map[string]string {
md := make(map[string]string)
var ver byte
for _, tag := range tags {
if len(tag) == 0 || tag[0] != 't' {
continue
}
// check version
if ver > 0 && tag[1] != ver {
continue
}
var kv map[string]string
var buf []byte
// Old encoding was plain
if tag[1] == '=' {
buf = []byte(tag[2:])
}
// New encoding is hex
if tag[1] == '-' {
buf = decode(tag[2:])
}
// Now unmarshal
if err := json.Unmarshal(buf, &kv); err == nil {
for k, v := range kv {
md[k] = v
}
}
// set version
ver = tag[1]
}
return md
}
func encodeVersion(v string) []string {
return []string{"v-" + encode([]byte(v))}
}
func decodeVersion(tags []string) (string, bool) {
for _, tag := range tags {
if len(tag) < 2 || tag[0] != 'v' {
continue
}
// Old encoding was plain
if tag[1] == '=' {
return tag[2:], true
}
// New encoding is hex
if tag[1] == '-' {
return string(decode(tag[2:])), true
}
}
return "", false
}