Merge pull request #356 from bloxbean/fix_353_main

fix: #353 Directly extract tx body bytes from tx bytes

Author: satran004

transaction-spec/src/main/java/com/bloxbean/cardano/client/transaction/util/TransactionUtil.java

@@ -1,16 +1,16 @@
 package com.bloxbean.cardano.client.transaction.util;
 
-import co.nstant.in.cbor.model.Array;
-import co.nstant.in.cbor.model.DataItem;
-import com.bloxbean.cardano.client.common.cbor.CborSerializationUtil;
+import co.nstant.in.cbor.CborDecoder;
+import co.nstant.in.cbor.CborException;
 import com.bloxbean.cardano.client.crypto.Blake2bUtil;
 import com.bloxbean.cardano.client.exception.CborDeserializationException;
 import com.bloxbean.cardano.client.exception.CborRuntimeException;
 import com.bloxbean.cardano.client.exception.CborSerializationException;
 import com.bloxbean.cardano.client.transaction.spec.Transaction;
-import com.bloxbean.cardano.client.transaction.spec.TransactionBody;
 import com.bloxbean.cardano.client.util.HexUtil;
 
+import java.io.ByteArrayInputStream;
+
 public class TransactionUtil {
 
     /**
@@ -36,8 +36,8 @@ public static Transaction createCopy(Transaction transaction) {
      */
     public static String getTxHash(Transaction transaction) {
         try {
-            transaction.serialize(); //Just to trigger fill body.setAuxiliaryDataHash(), might be removed later.
-            return safeGetTxHash(transaction.getBody());
+            byte[] txBytes = transaction.serialize(); //Just to trigger fill body.setAuxiliaryDataHash(), might be removed later.
+            return getTxHash(txBytes);
         } catch (Exception ex) {
             throw new RuntimeException("Get transaction hash failed. ", ex);
         }
@@ -51,19 +51,44 @@ public static String getTxHash(Transaction transaction) {
      */
     public static String getTxHash(byte[] transactionBytes) {
         try {
-            Array array = (Array) CborSerializationUtil.deserialize(transactionBytes);
-            DataItem txBodyDI = array.getDataItems().get(0);
-            return safeGetTxHash(CborSerializationUtil.serialize(txBodyDI, false));
+            byte[] txBodyBytes = extractTransactionBodyFromTx(transactionBytes);
+            return safeGetTxHash(txBodyBytes);
         } catch (Exception ex) {
             throw new RuntimeException("Get transaction hash failed. ", ex);
         }
     }
 
-    private static String safeGetTxHash(byte[] txBodyBytes) throws Exception {
-        return HexUtil.encodeHexString(Blake2bUtil.blake2bHash256(txBodyBytes));
+    /**
+     * Extract transaction body bytes from transaction bytes.
+     * @param txBytes transaction bytes
+     * @return transaction body bytes
+     */
+    public static byte[] extractTransactionBodyFromTx(byte[] txBytes) {
+        if (txBytes == null || txBytes.length == 0)
+            throw new IllegalArgumentException("Transaction bytes can't be null or empty");
+
+        ByteArrayInputStream bais = new ByteArrayInputStream(txBytes);
+        CborDecoder decoder = new CborDecoder(bais);
+
+        //Extract transaction body
+        bais.read(); //Skip the first byte as it is a tag
+        try {
+            decoder.decodeNext();
+        } catch (CborException e) {
+            throw new CborRuntimeException(e);
+        }
+
+        int available = bais.available();
+        byte[] txBodyRaw = new byte[txBytes.length - available -1]; // -1 for the first byte
+
+        //Copy tx body bytes to txBodyRaw
+        System.arraycopy(txBytes,1,txBodyRaw,0,txBodyRaw.length);
+
+        return txBodyRaw;
     }
 
-    private static String safeGetTxHash(TransactionBody safeTransactionBody) throws Exception {
-        return safeGetTxHash(CborSerializationUtil.serialize(safeTransactionBody.serialize()));
+    private static String safeGetTxHash(byte[] txBodyBytes) {
+        return HexUtil.encodeHexString(Blake2bUtil.blake2bHash256(txBodyBytes));
     }
+
 }