feat(blob): fix bug when blob decode with 0 (#627)

pkg/rpc/tx_blob.go

@@ -2,6 +2,7 @@ package rpc
 
 import (
 	"errors"
+	"math/big"
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
@@ -11,6 +12,10 @@ import (
 	"github.com/holiman/uint256"
 )
 
+var (
+	preLenBlob = 32
+)
+
 var (
 	errBlobInvalid = errors.New("invalid blob encoding")
 )
@@ -124,7 +129,7 @@ func MakeSidecar(data []byte) (*types.BlobTxSidecar, error) {
 }
 
 func encode(origin []byte) []byte {
-	var res []byte
+	var res = make([]byte, preLenBlob, len(origin)/31*32+32)
 	for ; len(origin) >= 31; origin = origin[31:] {
 		data := [32]byte{}
 		copy(data[1:], origin[:31])
@@ -135,9 +140,20 @@ func encode(origin []byte) []byte {
 		copy(data[1:], origin)
 		res = append(res, data...)
 	}
+
+	// Add length prefix
+	blobLen := big.NewInt(int64(len(res))).Bytes()
+	copy(res[preLenBlob-len(blobLen):preLenBlob], blobLen)
+
 	return res
 }
 
+func decode(data []byte) []byte {
+	blobLen := new(big.Int).SetBytes(data[:preLenBlob])
+	var lenBytes = blobLen.Uint64()
+	return data[preLenBlob:lenBytes]
+}
+
 // EncodeBlobs encodes bytes into a EIP-4844 blob.
 func EncodeBlobs(origin []byte) []kzg4844.Blob {
 	data := encode(origin)
@@ -160,13 +176,7 @@ func DecodeBlob(blob []byte) ([]byte, error) {
 	if len(blob) != BlobBytes {
 		return nil, errBlobInvalid
 	}
-	var i = len(blob) - 1
-	for ; i >= 0; i-- {
-		if blob[i] != 0 {
-			break
-		}
-	}
-	blob = blob[:i+1]
+	blob = decode(blob)
 
 	var res []byte
 	for ; len(blob) >= 32; blob = blob[32:] {

pkg/rpc/tx_blob_test.go

@@ -2,6 +2,7 @@ package rpc
 
 import (
 	"context"
+	"encoding/json"
 	"os"
 	"testing"
 	"time"
@@ -10,6 +11,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/stretchr/testify/assert"
 
 	"github.com/taikoxyz/taiko-client/internal/utils"
@@ -69,3 +71,24 @@ func TestMakeSideCar(t *testing.T) {
 	assert.NoError(t, dErr)
 	assert.Equal(t, origin, origin1)
 }
+
+func TestSpecialEndWith0(t *testing.T) {
+	// nolint: lll
+	var txsData = `
+[{"type":"0x2","chainId":"0x28c59","nonce":"0x1cca","to":"0x0167001000000000000000000000000000010099","gas":"0x86b3","gasPrice":null,"maxPriorityFeePerGas":"0x59682f00","maxFeePerGas":"0x59682f02","value":"0x0","input":"0xa9059cbb00000000000000000000000001670010000000000000000000000000000100990000000000000000000000000000000000000000000000000000000000000001","accessList":[],"v":"0x0","r":"0x2d554e149d15575030f271403a3b359cd9d5df8acb47ae7df5845aadc54b1ee2","s":"0x39b7ce8e803c443d8fd33679948fbd0a485d88b6a55812a53d9a03a922142100","yParity":"0x0","hash":"0x27aa02a44ea343a72131fc67734c67d410ab6f65429637fbb17a08f781e77f7e"}]
+`
+
+	var txs types.Transactions
+	err := json.Unmarshal([]byte(txsData), &txs)
+	assert.NoError(t, err)
+
+	origin, err := rlp.EncodeToBytes(txs)
+	assert.NoError(t, err)
+
+	blobs := EncodeBlobs(origin)
+
+	data, dErr := DecodeBlobs(blobs)
+	assert.NoError(t, dErr)
+
+	assert.Equal(t, crypto.Keccak256Hash(origin), crypto.Keccak256Hash(data))
+}