feature/Add DecodeRawTx utility for decoding Ethereum raw transactions to JSON format and include web3j dependency

obp-api/pom.xml

@@ -329,6 +329,12 @@
       <artifactId>flexmark-util-options</artifactId>
       <version>0.64.0</version>
     </dependency>
+      <!-- https://mvnrepository.com/artifact/org.web3j/core -->
+      <dependency>
+          <groupId>org.web3j</groupId>
+          <artifactId>core</artifactId>
+          <version>4.9.8</version>
+      </dependency>
     <dependency>
       <groupId>com.zaxxer</groupId>
       <artifactId>HikariCP</artifactId>

obp-api/src/main/scala/code/bankconnectors/ethereum/DecodeRawTx.scala

@@ -0,0 +1,119 @@
+package code.bankconnectors.ethereum
+
+import java.math.BigInteger
+import org.web3j.crypto.{Hash, RawTransaction, TransactionDecoder, Sign, SignedRawTransaction}
+import org.web3j.utils.{Numeric => W3Numeric}
+import net.liftweb.json._
+
+object DecodeRawTx {
+
+  private def fatal(msg: String): Nothing = {
+    Console.err.println(msg)
+    sys.exit(1)
+  }
+
+  // File/stdin helpers removed; input is provided as a function parameter now.
+
+  private def normalizeHex(hex: String): String = {
+    val h = Option(hex).getOrElse("").trim
+    if (!h.startsWith("0x")) fatal("Input must start with 0x")
+    val body = h.drop(2)
+    if (!body.matches("[0-9a-fA-F]+")) fatal("Invalid hex characters in input")
+    if (body.length % 2 != 0) fatal("Hex string length must be even")
+    "0x" + body.toLowerCase
+  }
+
+  private def detectType(hex: String): Int = {
+    val body = hex.stripPrefix("0x")
+    if (body.startsWith("02")) 2
+    else if (body.startsWith("01")) 1
+    else 0
+  }
+
+  // Build EIP-155 v when chainId is available; parity from v-byte (27/28 -> 0/1, otherwise lowest bit)
+  private def vToHex(sig: Sign.SignatureData, chainIdOpt: Option[BigInteger]): String = {
+    val vb: Int = {
+      val arr = sig.getV
+      if (arr != null && arr.length > 0) java.lang.Byte.toUnsignedInt(arr(0)) else 0
+    }
+    chainIdOpt match {
+      case Some(cid) if cid.signum() > 0 =>
+        val parity = if (vb == 27 || vb == 28) vb - 27 else (vb & 1)
+        val v = cid.multiply(BigInteger.valueOf(2)).add(BigInteger.valueOf(35L + parity))
+        "0x" + v.toString(16)
+      case _ =>
+        "0x" + Integer.toHexString(vb)
+    }
+  }
+
+  private def jStrOrNull(v: String): JValue = if (v == null) JNull else JString(v)
+  private def jOptStrOrNull(v: Option[String]): JValue = v.map(JString).getOrElse(JNull)
+
+  /**
+    * Decode raw Ethereum transaction hex and return a JSON string summarizing the fields.
+    * The input must be a 0x-prefixed hex string; no file or stdin reading is performed.
+    */
+  def decodeRawTxToJson(rawIn: String): String = {
+    val rawHex  = normalizeHex(rawIn)
+    val txType  = detectType(rawHex)
+
+    val decoded: RawTransaction =
+      try TransactionDecoder.decode(rawHex)
+      catch { case e: Throwable => fatal(s"decode failed: ${e.getMessage}") }
+
+    val (fromOpt, chainIdOpt, vHexOpt, rHexOpt, sHexOpt):
+      (Option[String], Option[BigInteger], Option[String], Option[String], Option[String]) = decoded match {
+      case srt: SignedRawTransaction =>
+        val from = Option(srt.getFrom)
+        val cid: Option[BigInteger] = try {
+          val c = srt.getChainId // long in web3j 4.x; -1 if absent
+          if (c > 0L) Some(BigInteger.valueOf(c)) else None
+        } catch { case _: Throwable => None }
+        val sig  = srt.getSignatureData
+        val vH   = vToHex(sig, cid)
+    val rH   = W3Numeric.toHexString(sig.getR)
+    val sH   = W3Numeric.toHexString(sig.getS)
+        (from, cid, Some(vH), Some(rH), Some(sH))
+      case _ =>
+        (None, None, None, None, None)
+    }
+
+    val hash        = Hash.sha3(rawHex)
+    val gasPriceHex = Option(decoded.getGasPrice).map(W3Numeric.toHexStringWithPrefix).getOrElse(null)
+    val gasLimitHex = Option(decoded.getGasLimit).map(W3Numeric.toHexStringWithPrefix).getOrElse(null)
+    val valueHex    = Option(decoded.getValue).map(W3Numeric.toHexStringWithPrefix).getOrElse(null)
+    val nonceHex    = Option(decoded.getNonce).map(W3Numeric.toHexStringWithPrefix).getOrElse(null)
+    val toAddr      = decoded.getTo
+    val inputData   = Option(decoded.getData).getOrElse("0x")
+
+    val estimatedFeeHex =
+      (for {
+        gp <- Option(decoded.getGasPrice)
+        gl <- Option(decoded.getGasLimit)
+      } yield W3Numeric.toHexStringWithPrefix(gp.multiply(gl))).getOrElse(null)
+
+    val j = JObject(List(
+      JField("hash", JString(hash)),
+      JField("type", JString(txType.toString)),
+      JField("chainId", chainIdOpt.map(cid => JString(cid.toString)).getOrElse(JNull)),
+      JField("nonce", jStrOrNull(nonceHex)),
+      JField("gasPrice", jStrOrNull(gasPriceHex)),
+      JField("gas", jStrOrNull(gasLimitHex)),
+      JField("to", jStrOrNull(toAddr)),
+      JField("value", jStrOrNull(valueHex)),
+      JField("input", jStrOrNull(inputData)),
+      JField("from", jOptStrOrNull(fromOpt)),
+      JField("v", jOptStrOrNull(vHexOpt)),
+      JField("r", jOptStrOrNull(rHexOpt)),
+      JField("s", jOptStrOrNull(sHexOpt)),
+      JField("estimatedFee", jStrOrNull(estimatedFeeHex))
+    ))
+    compactRender(j)
+  }
+
+  def main(args: Array[String]): Unit = {
+    val raxHex = "0xf86b178203e882520894627306090abab3a6e1400e9345bc60c78a8bef57880de0b6b3a764000080820ff6a016878a008fb817df6d771749336fa0c905ec5b7fafcd043f0d9e609a2b5e41e0a0611dbe0f2ee2428360c72f4287a2996cb0d45cb8995cc23eb6ba525cb9580e02"
+    val out = decodeRawTxToJson(raxHex)
+    print(out)
+  }
+}