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Add NCM Decoder

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pull/1/head
Emmm Monster 4 years ago
parent bf2846b950
commit 98a645a45c
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GPG Key ID: C98279C83FB50DB9
2 changed files with 368 additions and 0 deletions
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111
algo/ncm/meta.go
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package ncm
import (
"github.com/umlock-music/cli/algo/common"
"strings"
)
type RawMeta interface {
common.Meta
GetFormat() string
GetAlbumImageURL() string
}
type RawMetaMusic struct {
Format string `json:"format"`
MusicID int `json:"musicId"`
MusicName string `json:"musicName"`
Artist [][]interface{} `json:"artist"`
Album string `json:"album"`
AlbumID int `json:"albumId"`
AlbumPicDocID interface{} `json:"albumPicDocId"`
AlbumPic string `json:"albumPic"`
MvID int `json:"mvId"`
Flag int `json:"flag"`
Bitrate int `json:"bitrate"`
Duration int `json:"duration"`
Alias []interface{} `json:"alias"`
TransNames []interface{} `json:"transNames"`
}
func (m RawMetaMusic) GetAlbumImageURL() string {
return m.AlbumPic
}
func (m RawMetaMusic) GetArtists() (artists []string) {
for _, artist := range m.Artist {
for _, item := range artist {
name, ok := item.(string)
if ok {
artists = append(artists, name)
}
}
}
return
}
func (m RawMetaMusic) GetTitle() string {
return m.MusicName
}
func (m RawMetaMusic) GetAlbum() string {
return m.Album
}
func (m RawMetaMusic) GetFormat() string {
return m.Format
}
type RawMetaDJ struct {
ProgramID int `json:"programId"`
ProgramName string `json:"programName"`
MainMusic RawMetaMusic `json:"mainMusic"`
DjID int `json:"djId"`
DjName string `json:"djName"`
DjAvatarURL string `json:"djAvatarUrl"`
CreateTime int64 `json:"createTime"`
Brand string `json:"brand"`
Serial int `json:"serial"`
ProgramDesc string `json:"programDesc"`
ProgramFeeType int `json:"programFeeType"`
ProgramBuyed bool `json:"programBuyed"`
RadioID int `json:"radioId"`
RadioName string `json:"radioName"`
RadioCategory string `json:"radioCategory"`
RadioCategoryID int `json:"radioCategoryId"`
RadioDesc string `json:"radioDesc"`
RadioFeeType int `json:"radioFeeType"`
RadioFeeScope int `json:"radioFeeScope"`
RadioBuyed bool `json:"radioBuyed"`
RadioPrice int `json:"radioPrice"`
RadioPurchaseCount int `json:"radioPurchaseCount"`
}
func (m RawMetaDJ) GetArtists() []string {
if m.DjName != "" {
return []string{m.DjName}
}
return m.MainMusic.GetArtists()
}
func (m RawMetaDJ) GetTitle() string {
if m.ProgramName != "" {
return m.ProgramName
}
return m.MainMusic.GetTitle()
}
func (m RawMetaDJ) GetAlbum() string {
if m.Brand != "" {
return m.Brand
}
return m.MainMusic.GetAlbum()
}
func (m RawMetaDJ) GetFormat() string {
return m.MainMusic.GetFormat()
}
func (m RawMetaDJ) GetAlbumImageURL() string {
if strings.HasPrefix(m.MainMusic.GetAlbumImageURL(), "http") {
return m.MainMusic.GetAlbumImageURL()
}
return m.DjAvatarURL
}

257
algo/ncm/ncm.go
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package ncm
import (
"bytes"
"encoding/base64"
"encoding/binary"
"encoding/json"
"errors"
"github.com/umlock-music/cli/algo/common"
"github.com/umlock-music/cli/internal/logging"
"github.com/umlock-music/cli/internal/utils"
"go.uber.org/zap"
"io/ioutil"
"net/http"
"strings"
)
var (
magicHeader = []byte{
0x43, 0x54, 0x45, 0x4E, 0x46, 0x44, 0x41, 0x4D}
keyCore = []byte{
0x68, 0x7a, 0x48, 0x52, 0x41, 0x6d, 0x73, 0x6f,
0x35, 0x6b, 0x49, 0x6e, 0x62, 0x61, 0x78, 0x57}
keyMeta = []byte{
0x23, 0x31, 0x34, 0x6C, 0x6A, 0x6B, 0x5F, 0x21,
0x5C, 0x5D, 0x26, 0x30, 0x55, 0x3C, 0x27, 0x28}
)
func NewDecoder(data []byte) *Decoder {
return &Decoder{
data: data,
fileLength: uint32(len(data)),
}
}
type Decoder struct {
data []byte
fileLength uint32
key []byte
box []byte
metaRaw []byte
metaType string
Meta RawMeta
Cover []byte
Audio []byte
offsetKey uint32
offsetMeta uint32
offsetCover uint32
offsetAudio uint32
}
func (f *Decoder) Validate() bool {
if !bytes.Equal(magicHeader, f.data[:len(magicHeader)]) {
return false
}
/*if status.IsDebug {
logging.Log().Info("the unknown field of the header is: \n" + spew.Sdump(f.data[8:10]))
}*/
f.offsetKey = 8 + 2
return true
}
//todo: 读取前进行检查长度，防止越界
func (f *Decoder) readKeyData() error {
if f.offsetKey == 0 || f.offsetKey+4 > f.fileLength {
return errors.New("invalid cover data offset")
}
bKeyLen := f.data[f.offsetKey : f.offsetKey+4]
iKeyLen := binary.LittleEndian.Uint32(bKeyLen)
f.offsetMeta = f.offsetKey + 4 + iKeyLen
bKeyRaw := make([]byte, iKeyLen)
for i := uint32(0); i < iKeyLen; i++ {
bKeyRaw[i] = f.data[i+4+f.offsetKey] ^ 0x64
}
f.key = utils.PKCS7UnPadding(utils.DecryptAes128Ecb(bKeyRaw, keyCore))[17:]
return nil
}
func (f *Decoder) readMetaData() error {
if f.offsetMeta == 0 || f.offsetMeta+4 > f.fileLength {
return errors.New("invalid meta data offset")
}
bMetaLen := f.data[f.offsetMeta : f.offsetMeta+4]
iMetaLen := binary.LittleEndian.Uint32(bMetaLen)
f.offsetCover = f.offsetMeta + 4 + iMetaLen
if iMetaLen == 0 {
return errors.New("no any meta data found")
}
// Why sub 22: Remove "163 key(Don't modify):"
bKeyRaw := make([]byte, iMetaLen-22)
for i := uint32(0); i < iMetaLen-22; i++ {
bKeyRaw[i] = f.data[f.offsetMeta+4+22+i] ^ 0x63
}
cipherText, err := base64.StdEncoding.DecodeString(string(bKeyRaw))
if err != nil {
return errors.New("decode ncm meta failed: " + err.Error())
}
metaRaw := utils.PKCS7UnPadding(utils.DecryptAes128Ecb(cipherText, keyMeta))
sepIdx := bytes.IndexRune(metaRaw, ':')
if sepIdx == -1 {
return errors.New("invalid ncm meta data")
}
f.metaType = string(metaRaw[:sepIdx])
f.metaRaw = metaRaw[sepIdx+1:]
return nil
}
func (f *Decoder) buildKeyBox() {
box := make([]byte, 256)
for i := 0; i < 256; i++ {
box[i] = byte(i)
}
keyLen := len(f.key)
var j byte
for i := 0; i < 256; i++ {
j = box[i] + j + f.key[i%keyLen]
box[i], box[j] = box[j], box[i]
}
f.box = make([]byte, 256)
var _i byte
for i := 0; i < 256; i++ {
_i = byte(i + 1)
si := box[_i]
sj := box[_i+si]
f.box[i] = box[si+sj]
}
}
func (f *Decoder) parseMeta() error {
switch f.metaType {
case "music":
f.Meta = new(RawMetaMusic)
return json.Unmarshal(f.metaRaw, f.Meta)
case "dj":
f.Meta = new(RawMetaDJ)
default:
return errors.New("unknown ncm meta type: " + f.metaType)
}
return nil
}
func (f *Decoder) readCoverData() error {
if f.offsetCover == 0 || f.offsetCover+13 > f.fileLength {
return errors.New("invalid cover data offset")
}
coverLenStart := f.offsetCover + 5 + 4
bCoverLen := f.data[coverLenStart : coverLenStart+4]
/*if status.IsDebug {
logging.Log().Info("the unknown field of the cover is: \n" +
spew.Sdump(f.data[f.offsetCover:f.offsetCover+5]))
coverLen2 := f.data[f.offsetCover+5 : f.offsetCover+5+4] // it seems that always the same
if !bytes.Equal(coverLen2, bCoverLen) {
logging.Log().Warn("special file found! 2 cover length filed no the same!")
}
}*/
iCoverLen := binary.LittleEndian.Uint32(bCoverLen)
f.offsetAudio = coverLenStart + 4 + iCoverLen
if iCoverLen == 0 {
return errors.New("no any cover data found")
}
f.Cover = f.data[coverLenStart+4 : 4+coverLenStart+iCoverLen]
return nil
}
func (f *Decoder) readAudioData() error {
if f.offsetAudio == 0 || f.offsetAudio > f.fileLength {
return errors.New("invalid audio offset")
}
audioRaw := f.data[f.offsetAudio:]
audioLen := len(audioRaw)
f.Audio = make([]byte, audioLen)
for i := uint32(0); i < uint32(audioLen); i++ {
f.Audio[i] = f.box[i&0xff] ^ audioRaw[i]
}
return nil
}
func (f *Decoder) Decode() error {
if err := f.readKeyData(); err != nil {
return err
}
f.buildKeyBox()
err := f.readMetaData()
if err == nil {
err = f.parseMeta()
}
if err != nil {
logging.Log().Warn("parse ncm meta data failed", zap.Error(err))
}
err = f.readCoverData()
if err != nil {
logging.Log().Warn("parse ncm cover data failed", zap.Error(err))
}
return f.readAudioData()
}
func (f Decoder) GetAudioExt() string {
if f.Meta != nil {
return f.Meta.GetFormat()
}
return ""
}
func (f Decoder) GetAudioData() []byte {
return f.Audio
}
func (f Decoder) GetCoverImage() []byte {
if f.Cover != nil {
return f.Cover
}
{
imgURL := f.Meta.GetAlbumImageURL()
if f.Meta != nil && !strings.HasPrefix(imgURL, "http") {
return nil
}
resp, err := http.Get(imgURL)
if err != nil {
logging.Log().Warn("download image failed", zap.Error(err), zap.String("url", imgURL))
return nil
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
logging.Log().Warn("download image failed", zap.String("http", resp.Status),
zap.String("url", imgURL))
return nil
}
data, err := ioutil.ReadAll(resp.Body)
if err != nil {
logging.Log().Warn("download image failed", zap.Error(err), zap.String("url", imgURL))
return nil
}
return data
}
}
func (f Decoder) GetMeta() common.Meta {
return f.Meta
}
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