Smart Contract Execution
TxTypeSmartContractExecution executes a smart contract with the given data. TxTypeSmartContractExecution is accepted only if "to" is a smart contract account.
Import necessary classes from the Web3j and kaia libraries(web3j-ext
).
Connect to the kaia blockchain using Web3j and specify the URL
Creating sender and fee payer credentials using private keys.
Define gas price and gas limit for the transaction
Get the sender's address from credentials.getAddress()
Getting the nonce for the sender's address
Define smart contract data
Get the chain ID from the Kaia network
Initialize variables for transaction parameters
Create a raw transaction
Signing the transaction as sender using KlayTransactionEncoder.signMessage
.
Signing the transaction as fee payer using KlayTransactionEncoder.signMessageAsFeePayer
.
Sending the signed transaction to kaia network
Getting the transaction receipt
Shutting down the Web3j instance
Decoding the raw transaction to get the transaction type
package org.web3j.example.transactions;import org.web3j.tx.response.PollingTransactionReceiptProcessor;import org.web3j.tx.response.TransactionReceiptProcessor;import org.web3j.example.keySample;import java.io.IOException;import java.math.BigInteger;import org.web3j.crypto.KlayCredentials;import org.web3j.crypto.KlayRawTransaction;import org.web3j.crypto.KlayTransactionEncoder;import org.web3j.crypto.transaction.type.TxType;import org.web3j.crypto.transaction.type.TxTypeFeeDelegatedSmartContractExecution;import org.web3j.crypto.transaction.type.TxType.Type;import org.web3j.protocol.core.DefaultBlockParameterName;import org.web3j.protocol.core.methods.response.EthChainId;import org.web3j.protocol.core.methods.response.EthSendTransaction;import org.web3j.protocol.http.HttpService;import org.web3j.protocol.kaia.Web3j;import org.web3j.utils.Numeric;import org.web3j.protocol.kaia.core.method.response.TransactionReceipt;/** * */public class FeeDelegatedSmartContractExecutionExample implements keySample { /** * */ public static void run() throws Exception { Web3j web3j = Web3j.build(new HttpService(keySample.BAOBAB_URL)); KlayCredentials credentials = KlayCredentials.create(keySample.LEGACY_KEY_privkey); KlayCredentials credentials_feepayer = KlayCredentials.create(keySample.LEGACY_KEY_FEEPAYER_privkey); BigInteger GAS_PRICE = BigInteger.valueOf(50000000000L); BigInteger GAS_LIMIT = BigInteger.valueOf(6721950); String from = credentials.getAddress(); BigInteger nonce = web3j.ethGetTransactionCount(from, DefaultBlockParameterName.LATEST).send() .getTransactionCount(); String data = "0xcfae3217"; EthChainId EthchainId = web3j.ethChainId().send(); long chainId = EthchainId.getChainId().longValue(); String to = "0xc58294ecde8fdb288fd845e7a43a56564b597bdb"; byte[] payload = Numeric.hexStringToByteArray(data); BigInteger value = BigInteger.ZERO; TxType.Type type = Type.FEE_DELEGATED_SMART_CONTRACT_EXECUTION; KlayRawTransaction raw = KlayRawTransaction.createTransaction( type, nonce, GAS_PRICE, GAS_LIMIT, to, value, from, payload); // Sign as sender byte[] signedMessage = KlayTransactionEncoder.signMessage(raw, chainId, credentials); // Sign same message as Fee payer signedMessage = KlayTransactionEncoder.signMessageAsFeePayer(raw, chainId, credentials_feepayer); String hexValue = Numeric.toHexString(signedMessage); EthSendTransaction transactionResponse = web3j.ethSendRawTransaction(hexValue).send(); System.out.println("TxHash : \n " + transactionResponse.getResult()); String txHash = transactionResponse.getResult(); int DEFAULT_POLLING_ATTEMPTS_PER_TX_HASH = 40; int DEFAULT_BLOCK_TIME = 1 * 1000; long DEFAULT_POLLING_FREQUENCY = DEFAULT_BLOCK_TIME; TransactionReceiptProcessor transactionReceiptProcessor = new PollingTransactionReceiptProcessor(web3j, DEFAULT_POLLING_FREQUENCY, DEFAULT_POLLING_ATTEMPTS_PER_TX_HASH); org.web3j.protocol.core.methods.response.TransactionReceipt ethReceipt = transactionReceiptProcessor .waitForTransactionReceipt(txHash); System.out.println("Receipt from eth_getTransactionReceipt : \n" + ethReceipt); TransactionReceipt receipt = web3j.klayGetTransactionReceipt(txHash).send().getResult(); System.out.println("Receipt from klay_getTransactionReceipt : \n" + receipt); web3j.shutdown(); TxTypeFeeDelegatedSmartContractExecution rawTransaction = TxTypeFeeDelegatedSmartContractExecution .decodeFromRawTransaction(signedMessage); System.out.println("TxType : " + rawTransaction.getKlayType()); }}
❯ java FeeDelegatedSmartContractExecutionExample.javaTxHash : 0x43419d6dd268fd246f82f69174b46e4b599e030feca5de4542a1b524559c0879receipt :class TransactionReceipt { blockHash: 0x33376f94093970fcf54d9c87669a04046b245c59c68431afef3b3444ceada0d3 blockNumber: 0x8def1f0 codeFormat: null contractAddress: null feePayer: 0xcb0eb737dfda52756495a5e08a9b37aab3b271da feePayerSignatures: [class TransactionReceiptFeePayerSignaturesInner { V: 0x7f5 R: 0x934223d90aa3ca87b17ad1b8b9914512a58e54e337bdd28e746321b35da43b91 S: 0x2cf45437c26f6a849c142d69e5382ce142d8c1bf3115203d482e8d22eb83c164 }] feeRatio: null from: 0xa2a8854b1802d8cd5de631e690817c253d6a9153 gas: 0x66919e effectiveGasPrice: 0x5d21dba00 gasPrice: 0xba43b7400 gasUsed: 0x86f3 humanReadable: null key: null input: 0xcfae3217 logs: [] logsBloom: 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 nonce: 0x3cb senderTxHash: 0x7c67092dcae6ba99682d0cac6ece60388099c198c0481c3f1cc03a6294303b61 signature: [] status: 0x1 txError: null to: 0xc58294ecde8fdb288fd845e7a43a56564b597bdb transactionHash: 0x43419d6dd268fd246f82f69174b46e4b599e030feca5de4542a1b524559c0879 transactionIndex: 0x0 type: TxTypeFeeDelegatedSmartContractExecution typeInt: 49 value: 0x0}TxType : FEE_DELEGATED_SMART_CONTRACT_EXECUTION