feat: implement pure-go RIFF EXIF injector

This commit is contained in:
Fd
2026-07-15 18:02:47 +07:00
parent 6228cb2733
commit 68f964f810
+120 -65
View File
@@ -1,15 +1,11 @@
package helper
import (
"bytes"
"encoding/binary"
"encoding/json"
"fmt"
"log"
"math/big"
"os"
"path/filepath"
"strings"
"github.com/google/uuid"
)
type StickerMetadata struct {
@@ -19,7 +15,6 @@ type StickerMetadata struct {
Emojis []string `json:"emojis,omitempty"`
}
// Added matching writeUIntLE from F-BOT_GO reference
func writeUIntLE(buffer []byte, value, offset, byteLength int64) {
slice := make([]byte, byteLength)
val := new(big.Int)
@@ -36,7 +31,7 @@ func writeUIntLE(buffer []byte, value, offset, byteLength int64) {
func createMetadataBytes(packName, publisher string) []byte {
exifObj := StickerMetadata{
PackId: "com.wa.bot.sticker", // or generic ID
PackId: "com.wa.bot.sticker",
Name: packName,
Publisher: publisher,
Emojis: []string{"😀"},
@@ -44,83 +39,143 @@ func createMetadataBytes(packName, publisher string) []byte {
exifJson, err := json.Marshal(exifObj)
if err != nil {
log.Printf("Failed to marshal EXIF: %v", err)
return nil
}
// WebP EXIF JSON string representation inside the file
bit := []byte{0x49, 0x49, 0x2A, 0x00, 0x08, 0x00, 0x00, 0x00, 0x01, 0x00, 0x41, 0x57, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x16, 0x00, 0x00, 0x00}
bit = append(bit, exifJson...)
// Crucial fix: Inject JSON string length at offset 14 (4 bytes)
writeUIntLE(bit, int64(len(exifJson)), 14, 4)
return bit
}
func getOrCreateDefaultExif() string {
defaultExifPath := "temp/default.exif"
if err := os.MkdirAll("temp", 0755); err != nil {
log.Printf("Failed to create temp directory: %v", err)
return ""
// InjectExif takes raw WebP bytes and constructs a new WebP RIFF byte slice containing the EXIF metadata
func InjectExif(webpData []byte, packName, publisher string) ([]byte, error) {
if len(webpData) < 12 || string(webpData[0:4]) != "RIFF" || string(webpData[8:12]) != "WEBP" {
return nil, fmt.Errorf("not a valid WEBP file")
}
// ALWAYS recreate temp/default.exif just in case previous boots were corrupted
// This corrects broken instances locally instantly
packName := os.Getenv("STICKER_NAME")
if packName == "" {
packName = "Bot"
var width, height uint32
hasVP8X := false
var vp8xFlags byte
var vp8xBytes []byte
var chunks [][]byte
// Default defaults for VP8X canvas sizes
width = 512
height = 512
offset := 12
for offset < len(webpData) {
if offset+8 > len(webpData) {
break
}
chunkID := string(webpData[offset : offset+4])
chunkSize := binary.LittleEndian.Uint32(webpData[offset+4 : offset+8])
paddedSize := chunkSize
if paddedSize%2 != 0 {
paddedSize++
}
if offset+8+int(paddedSize) > len(webpData) {
break
}
chunkData := webpData[offset+8 : offset+8+int(paddedSize)]
switch chunkID {
case "VP8X":
hasVP8X = true
vp8xFlags = chunkData[0]
vp8xBytes = chunkData
// extract dimensions
wBytes := []byte{chunkData[4], chunkData[5], chunkData[6], 0}
hBytes := []byte{chunkData[7], chunkData[8], chunkData[9], 0}
width = binary.LittleEndian.Uint32(wBytes) + 1
height = binary.LittleEndian.Uint32(hBytes) + 1
case "VP8 ":
if !hasVP8X {
// extract 14 bit scale block
w := uint32(chunkData[6]) | (uint32(chunkData[7]) << 8)
width = w & 0x3FFF
h := uint32(chunkData[8]) | (uint32(chunkData[9]) << 8)
height = h & 0x3FFF
}
chunks = append(chunks, webpData[offset:offset+8+int(paddedSize)])
case "VP8L":
if !hasVP8X {
// Parse bits 1-28 for w/h
b0 := uint32(chunkData[1])
b1 := uint32(chunkData[2])
b2 := uint32(chunkData[3])
b3 := uint32(chunkData[4])
width = 1 + (((b1 & 0x3F) << 8) | b0)
height = 1 + (((b3 & 0xF) << 10) | (b2 << 2) | ((b1 & 0xC0) >> 6))
}
chunks = append(chunks, webpData[offset:offset+8+int(paddedSize)])
default:
if chunkID != "EXIF" {
chunks = append(chunks, webpData[offset:offset+8+int(paddedSize)])
}
}
offset += 8 + int(paddedSize)
}
publisher := os.Getenv("STICKER_PUBLISHER")
if publisher == "" {
publisher = "Bot"
exifMeta := createMetadataBytes(packName, publisher)
if exifMeta == nil {
return nil, fmt.Errorf("failed to create exif byte payload")
}
exifContent := createMetadataBytes(packName, publisher)
if exifContent == nil {
return ""
// Turn on EXIF flag (bit 3) in VP8X
if !hasVP8X {
vp8xBytes = make([]byte, 10)
vp8xFlags = 0x08 // EXIF flag is bit 3
vp8xBytes[0] = vp8xFlags
w := width - 1
h := height - 1
vp8xBytes[4] = byte(w)
vp8xBytes[5] = byte(w >> 8)
vp8xBytes[6] = byte(w >> 16)
vp8xBytes[7] = byte(h)
vp8xBytes[8] = byte(h >> 8)
vp8xBytes[9] = byte(h >> 16)
} else {
vp8xBytes[0] = vp8xFlags | 0x08
}
if err := os.WriteFile(defaultExifPath, exifContent, 0644); err != nil {
log.Printf("Failed to write default EXIF: %v", err)
return ""
var buf bytes.Buffer
buf.WriteString("RIFF")
buf.Write([]byte{0, 0, 0, 0}) // Total size placeholder
buf.WriteString("WEBP")
// Write VP8X
buf.WriteString("VP8X")
vp8xSize := make([]byte, 4)
binary.LittleEndian.PutUint32(vp8xSize, 10)
buf.Write(vp8xSize)
buf.Write(vp8xBytes)
// Write existing chunks
for _, chunk := range chunks {
buf.Write(chunk)
}
return defaultExifPath
}
func ResolveExif(args []string) (string, bool) {
if len(args) == 0 {
return getOrCreateDefaultExif(), false
// Write EXIF
buf.WriteString("EXIF")
exifSize := uint32(len(exifMeta))
exifSizeSlice := make([]byte, 4)
binary.LittleEndian.PutUint32(exifSizeSlice, exifSize)
buf.Write(exifSizeSlice)
buf.Write(exifMeta)
if exifSize%2 != 0 {
buf.WriteByte(0)
}
argStr := strings.Join(args, " ")
parts := strings.Split(argStr, "|")
result := buf.Bytes()
totalSize := uint32(len(result) - 8)
binary.LittleEndian.PutUint32(result[4:8], totalSize)
packName := strings.TrimSpace(parts[0])
publisher := "Bot"
if len(parts) > 1 {
publisher = strings.TrimSpace(parts[1])
}
if packName == "" && publisher == "Bot" {
return getOrCreateDefaultExif(), false
}
exifContent := createMetadataBytes(packName, publisher)
if exifContent == nil {
return getOrCreateDefaultExif(), false
}
id := uuid.New().String()
tempPath := filepath.Join("temp", fmt.Sprintf("%s.exif", id))
if err := os.WriteFile(tempPath, exifContent, 0644); err != nil {
log.Printf("Failed to write dynamic EXIF: %v", err)
return getOrCreateDefaultExif(), false
}
return tempPath, true
}
return result, nil
}