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完成Web ASM

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This commit is contained in:
Misaki
2026-06-08 22:09:35 +08:00
parent e565b80bc2
commit 36660519c1
28 changed files with 1148 additions and 178 deletions
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ncmcrypt/embed.go
+44
View File
@@ -0,0 +1,44 @@
package ncmcrypt
import (
"fmt"
"os"
)
func EmbedMetadata(audio []byte, format NcmFormat, title, artist, album string, coverData []byte) ([]byte, error) {
tmpFile, err := os.CreateTemp("", "ncmdump-embed-*")
if err != nil {
return nil, fmt.Errorf("create temp file: %w", err)
}
tmpPath := tmpFile.Name()
defer os.Remove(tmpPath)
if _, err := tmpFile.Write(audio); err != nil {
tmpFile.Close()
return nil, fmt.Errorf("write temp: %w", err)
}
tmpFile.Close()
ncm := &NeteaseCloudMusic{
mPng: [8]byte{0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A},
mFormat: format,
mDumpFilePath: tmpPath,
mImageData: coverData,
mMetadata: &NeteaseClousMusicMetadata{
mName: title,
mArtist: artist,
mAlbum: album,
},
}
if _, err := ncm.FixMetadata(false); err != nil {
return nil, fmt.Errorf("write metadata: %w", err)
}
result, err := os.ReadFile(tmpPath)
if err != nil {
return nil, fmt.Errorf("read result: %w", err)
}
return result, nil
}
ncmcrypt/ncmcrypt.go
+130 -94
View File
@@ -20,9 +20,7 @@ import (
type NcmFormat = string
const (
Mp3 NcmFormat = "mp3"
)
const (
Mp3 NcmFormat = "mp3"
Flac NcmFormat = "flac"
)
@@ -31,56 +29,37 @@ type NeteaseCloudMusic struct {
sModifyKey [17]byte
mPng [8]byte
mFilePath string
mFilePath string
mDumpFilePath string
mFormat NcmFormat
mImageData []byte
mFileStream *os.File
mReader io.ReadSeeker
mKeyBox [256]byte
mMetadata *NeteaseClousMusicMetadata
mAlbumPicUrl string
}
func (ncm *NeteaseCloudMusic) Close() {
if closer, ok := ncm.mReader.(io.Closer); ok {
closer.Close()
}
ncm.mReader = nil
}
func (ncm *NeteaseCloudMusic) read(buffer *[]byte, size int) int {
if len(*buffer) < size {
*buffer = make([]byte, size)
}
res, err := ncm.mFileStream.Read(*buffer)
res, err := ncm.mReader.Read((*buffer)[:size])
if err != nil {
return 0
}
return res
}
func (ncm *NeteaseCloudMusic) openFile() bool {
file, err := os.Open(ncm.mFilePath)
if err != nil {
return false
}
ncm.mFileStream = file
return true
}
func (ncm *NeteaseCloudMusic) isNcmFile() bool {
header := make([]byte, 4)
// check magic header 4E455443 4D414446
if ncm.read(&header, 4) != 4 {
return false
}
if int(binary.LittleEndian.Uint32(header)) != 0x4E455443 {
return false
}
if ncm.read(&header, 4) != 4 {
return false
}
if int(binary.LittleEndian.Uint32(header)) != 0x4D414446 {
return false
}
return true
func (ncm *NeteaseCloudMusic) skip(n int64) error {
_, err := ncm.mReader.Seek(n, io.SeekCurrent)
return err
}
func (ncm *NeteaseCloudMusic) buildKeyBox(key []byte, keyLen int) {
@@ -113,7 +92,6 @@ func (ncm *NeteaseCloudMusic) mimeType() string {
return "image/jpeg"
}
// Dump encrypted ncm file to normal music file. If `targetDir` is "", the converted file will be saved to the original directory.
func (ncm *NeteaseCloudMusic) Dump(targetDir string) (bool, error) {
ncm.mDumpFilePath = ncm.mFilePath
var outputStream *os.File
@@ -123,7 +101,6 @@ func (ncm *NeteaseCloudMusic) Dump(targetDir string) (bool, error) {
for {
n := ncm.read(&buffer, len(buffer))
if n == 0 {
break
}
@@ -141,7 +118,7 @@ func (ncm *NeteaseCloudMusic) Dump(targetDir string) (bool, error) {
ncm.mFormat = Flac
ncm.mDumpFilePath = utils.ReplaceExtension(ncm.mDumpFilePath, ".flac")
}
if targetDir != "" { // change save dir
if targetDir != "" {
ncm.mDumpFilePath = filepath.Join(targetDir, filepath.Base(ncm.mDumpFilePath))
}
findFormatFlag = true
@@ -160,12 +137,63 @@ func (ncm *NeteaseCloudMusic) Dump(targetDir string) (bool, error) {
return true, nil
}
// FixMetadata will fix the missing metadata for target music file, the source of the metadata comes from origin ncm file.
// Since NeteaseCloudMusic version 3.0, the album cover image is no longer embedded in the ncm file. If the parameter is true, it means downloading the image from the NetEase server and embedding it into the target music file (network connection required)
func (ncm *NeteaseCloudMusic) DumpStream(w io.Writer, onFormat func(NcmFormat)) error {
buffer := make([]byte, 0x8000)
findFormatFlag := false
for {
n := ncm.read(&buffer, len(buffer))
if n == 0 {
break
}
for i := 0; i < n; i++ {
j := (i + 1) & 0xff
buffer[i] ^= ncm.mKeyBox[(ncm.mKeyBox[j]+ncm.mKeyBox[(int(ncm.mKeyBox[j])+j)&0xff])&0xff]
}
if !findFormatFlag {
if buffer[0] == 0x49 && buffer[1] == 0x44 && buffer[2] == 0x33 {
ncm.mFormat = Mp3
} else {
ncm.mFormat = Flac
}
findFormatFlag = true
if onFormat != nil {
onFormat(ncm.mFormat)
}
}
if _, err := w.Write(buffer[:n]); err != nil {
return fmt.Errorf("stream write failed: %w", err)
}
}
return nil
}
func (ncm *NeteaseCloudMusic) GetFormat() NcmFormat {
return ncm.mFormat
}
func (ncm *NeteaseCloudMusic) GetMetadata() map[string]string {
m := map[string]string{}
if ncm.mMetadata != nil {
m["title"] = ncm.mMetadata.mName
m["artist"] = ncm.mMetadata.mArtist
m["album"] = ncm.mMetadata.mAlbum
}
if ncm.mAlbumPicUrl != "" {
m["coverUrl"] = ncm.mAlbumPicUrl
}
return m
}
func (ncm *NeteaseCloudMusic) FixMetadata(fetchAlbumImageFromRemote bool) (bool, error) {
// only fetch album image from remote when it's not embedded in the ncm file
if ncm.mMetadata == nil {
return true, nil
}
if len(ncm.mImageData) <= 0 && fetchAlbumImageFromRemote {
// get the album pic from url
resp, err := http.Get(ncm.mAlbumPicUrl)
if err != nil {
return false, err
@@ -237,7 +265,6 @@ func (ncm *NeteaseCloudMusic) FixMetadata(fetchAlbumImageFromRemote bool) (bool,
cmts = flacvorbis.New()
}
// flac 可能自带元数据 当且仅当没有该项时才向目标添加元数据
if res, _ := cmts.Get(flacvorbis.FIELD_TITLE); len(res) == 0 {
_ = cmts.Add(flacvorbis.FIELD_TITLE, ncm.mMetadata.mName)
}
@@ -257,7 +284,6 @@ func (ncm *NeteaseCloudMusic) FixMetadata(fetchAlbumImageFromRemote bool) (bool,
}
err = audioFile.Save(ncm.mDumpFilePath)
if err != nil {
return false, err
}
@@ -265,7 +291,6 @@ func (ncm *NeteaseCloudMusic) FixMetadata(fetchAlbumImageFromRemote bool) (bool,
return true, nil
}
// GetDumpFilePath returns the absolute path of dumped music file
func (ncm *NeteaseCloudMusic) GetDumpFilePath() string {
path, err := filepath.Abs(ncm.mDumpFilePath)
if err != nil {
@@ -274,38 +299,32 @@ func (ncm *NeteaseCloudMusic) GetDumpFilePath() string {
return path
}
// NewNeteaseCloudMusic returns a new NeteaseCloudMusic instance, if the format of the file is incorrect, the error will be returned.
func NewNeteaseCloudMusic(filePath string) (*NeteaseCloudMusic, error) {
ncm := &NeteaseCloudMusic{
sCoreKey: [17]byte{0x68, 0x7A, 0x48, 0x52, 0x41, 0x6D, 0x73, 0x6F, 0x35, 0x6B, 0x49, 0x6E, 0x62, 0x61, 0x78, 0x57, 0},
sModifyKey: [17]byte{0x23, 0x31, 0x34, 0x6C, 0x6A, 0x6B, 0x5F, 0x21, 0x5C, 0x5D, 0x26, 0x30, 0x55, 0x3C, 0x27, 0x28, 0},
mPng: [8]byte{0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A},
func parseNcmHeader(ncm *NeteaseCloudMusic) error {
header := make([]byte, 4)
mFilePath: filePath,
if ncm.read(&header, 4) != 4 {
return fmt.Errorf("read header failed")
}
if int(binary.LittleEndian.Uint32(header)) != 0x4E455443 {
return fmt.Errorf("not a ncm file")
}
if ncm.read(&header, 4) != 4 {
return fmt.Errorf("read header failed")
}
if int(binary.LittleEndian.Uint32(header)) != 0x4D414446 {
return fmt.Errorf("not a ncm file")
}
if !ncm.openFile() {
return nil, fmt.Errorf("open file failed")
if err := ncm.skip(2); err != nil {
return fmt.Errorf("seek version failed")
}
if !ncm.isNcmFile() {
return nil, fmt.Errorf("not a ncm file")
}
// actually this 2 bytes is the version, now we just skip it
if _, err := ncm.mFileStream.Seek(2, 1); err != nil {
return nil, fmt.Errorf("seek version failed")
}
// the length of the RC4 key, encrypted by AES128
n := make([]byte, 4)
if ncm.read(&n, len(n)) != 4 {
return nil, fmt.Errorf("read key len failed")
return fmt.Errorf("read key len failed")
}
keyLen := int(binary.LittleEndian.Uint32(n))
keydata := make([]byte, keyLen)
ncm.read(&keydata, keyLen)
@@ -314,25 +333,19 @@ func NewNeteaseCloudMusic(filePath string) (*NeteaseCloudMusic, error) {
}
mKeyData, err := utils.AesEcbDecrypt(ncm.sCoreKey[:16], keydata)
if err != nil {
return nil, fmt.Errorf("decrypt key failed")
return fmt.Errorf("decrypt key failed")
}
// build the key box
ncm.buildKeyBox(mKeyData[17:], len(mKeyData)-17)
if ncm.read(&n, len(n)) != 4 {
return nil, fmt.Errorf("read metadata len failed")
return fmt.Errorf("read metadata len failed")
}
metadataLen := int(binary.LittleEndian.Uint32(n))
if metadataLen <= 0 {
// process meta here
ncm.mMetadata = nil
} else {
// read metadata
if metadataLen > 0 {
modifyData := make([]byte, metadataLen)
ncm.read(&modifyData, metadataLen)
@@ -340,43 +353,32 @@ func NewNeteaseCloudMusic(filePath string) (*NeteaseCloudMusic, error) {
modifyData[i] ^= 0x63
}
// escape `163 key(Don't modify):`
swapModifyData := string(modifyData[22:])
modifyOutData, err := base64.StdEncoding.DecodeString(swapModifyData)
if err != nil {
panic("base64 decode modify data failed")
return fmt.Errorf("base64 decode modify data failed")
}
modifyDecryptData, err := utils.AesEcbDecrypt(ncm.sModifyKey[:16], modifyOutData)
if err != nil {
panic("decrypt modify data failed")
return fmt.Errorf("decrypt modify data failed")
}
// escape `music:`
mMetadataString := string(modifyDecryptData[6:])
// extract the album pic url
ncm.mAlbumPicUrl = GetAlbumPicUrl(mMetadataString)
ncm.mMetadata = NewNeteaseCloudMusicMetadata(mMetadataString)
}
// skip the 5 bytes gap
if _, err := ncm.mFileStream.Seek(5, 1); err != nil {
return nil, fmt.Errorf("seek gap failed")
if err := ncm.skip(5); err != nil {
return fmt.Errorf("seek gap failed")
}
// read the cover frame
coverFrameLen := make([]byte, 4)
if ncm.read(&coverFrameLen, len(coverFrameLen)) != 4 {
return nil, fmt.Errorf("read cover frame len failed")
return fmt.Errorf("read cover frame len failed")
}
if ncm.read(&n, len(n)) != 4 {
return nil, fmt.Errorf("read cover frame data len failed")
return fmt.Errorf("read cover frame data len failed")
}
coverFrameLenInt := int(binary.LittleEndian.Uint32(coverFrameLen))
@@ -386,7 +388,41 @@ func NewNeteaseCloudMusic(filePath string) (*NeteaseCloudMusic, error) {
ncm.read(&ncm.mImageData, coverFrameDataLen)
}
ncm.mFileStream.Seek(int64(coverFrameLenInt)-int64(coverFrameDataLen), 1)
ncm.skip(int64(coverFrameLenInt) - int64(coverFrameDataLen))
return nil
}
func NewNeteaseCloudMusic(filePath string) (*NeteaseCloudMusic, error) {
f, err := os.Open(filePath)
if err != nil {
return nil, fmt.Errorf("open file failed")
}
ncm := &NeteaseCloudMusic{
sCoreKey: [17]byte{0x68, 0x7A, 0x48, 0x52, 0x41, 0x6D, 0x73, 0x6F, 0x35, 0x6B, 0x49, 0x6E, 0x62, 0x61, 0x78, 0x57, 0},
sModifyKey: [17]byte{0x23, 0x31, 0x34, 0x6C, 0x6A, 0x6B, 0x5F, 0x21, 0x5C, 0x5D, 0x26, 0x30, 0x55, 0x3C, 0x27, 0x28, 0},
mPng: [8]byte{0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A},
mFilePath: filePath,
mReader: f,
}
if err := parseNcmHeader(ncm); err != nil {
f.Close()
return nil, err
}
return ncm, nil
}
func NewNeteaseCloudMusicFromBytes(data []byte) (*NeteaseCloudMusic, error) {
ncm := &NeteaseCloudMusic{
sCoreKey: [17]byte{0x68, 0x7A, 0x48, 0x52, 0x41, 0x6D, 0x73, 0x6F, 0x35, 0x6B, 0x49, 0x6E, 0x62, 0x61, 0x78, 0x57, 0},
sModifyKey: [17]byte{0x23, 0x31, 0x34, 0x6C, 0x6A, 0x6B, 0x5F, 0x21, 0x5C, 0x5D, 0x26, 0x30, 0x55, 0x3C, 0x27, 0x28, 0},
mPng: [8]byte{0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A},
mReader: bytes.NewReader(data),
}
if err := parseNcmHeader(ncm); err != nil {
return nil, err
}
return ncm, nil
}