Deploy a Contract Using the Hedera Token Service

Summary

In this example, you will learn how to create a Solidity contract that interacts with the Hedera Token Service (HTS). The initial release of this feature supports token mint, burn, associate, dissociate, and transfer transactions.

The example does not cover the environment setup or creating certain variables that may be seen in the code blocks. The full coding example can be found at the end of the page.

Smart contract entity auto renewal and expiry will be enabled in a future release. Please check out HIP-16 for more information.

Prerequisites

We recommend you complete the following introduction to get a basic understanding of Hedera transactions. This example does not build upon the previous examples.

1. Create Your "HTS" Smart Contract

In this example, you will associate a token to an account and transfer tokens to the associated account by interacting with the HTS contract deployed to Hedera. The HTS contract has three functions that allow you to associate, transfer, and dissociate tokens from a Hedera account.

  • tokenAssociate

  • tokenTransfer

  • tokenDissociate

The HTS.sol will serve as a reference to the contract that was compiled. The HTS.json file contains the data.bytecode.object field that will be used to store the contract bytecode in a file on the Hedera network.

To write a contract using HTS, you will need to add the HTS Solidity support libraries to your project and import them into your contract. Please see the HTS.sol example for reference. The IHederaTokenService.sol will need to be in the same directory as the other two files. An explanation of the functions can be found here.

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.6.12;

import "./HederaTokenService.sol";
import "./HederaResponseCodes.sol";


contract HTS is HederaTokenService {

    function tokenAssociate(address sender, address tokenAddress) external {
        int response = HederaTokenService.associateToken(sender, tokenAddress);

        if (response != HederaResponseCodes.SUCCESS) {
            revert ("Associate Failed");
        }
    }

    function tokenTransfer(address tokenId, address fromAccountId , address toAccountId , int64 tokenAmount) external {
        int response = HederaTokenService.transferToken(tokenId, fromAccountId, toAccountId, tokenAmount);

        if (response != HederaResponseCodes.SUCCESS) {
            revert ("Transfer Failed");
        }
    }

    function tokenDissociate(address sender, address tokenAddress) external {
        int response = HederaTokenService.dissociateToken(sender, tokenAddress);

        if (response != HederaResponseCodes.SUCCESS) {
            revert ("Dissociate Failed");
        }
    }
}

2. Store the Smart Contract Bytecode on Hedera

Create a file using the FileCreateTransaction() API to store the hex-encoded byte code of the "HTS" contract. Once the file is created, you can obtain the file ID from the receipt of the transaction.

Note: The bytecode is required to be hex-encoded. It should not be the actual data the hex represents.

//Import the HTS.json file from the resources folder
ClassLoader cl = HTS.class.getClassLoader();

Gson gson = new Gson();
JsonObject jsonObject;

//Get the json file
InputStream jsonStream = cl.getResourceAsStream("HTS.json");
jsonObject = gson.fromJson(new InputStreamReader(jsonStream, StandardCharsets.UTF_8), JsonObject.class);


//Store the "object" field from the HTS.json file as hex-encoded bytecode
String object = jsonObject.getAsJsonObject("data").getAsJsonObject("bytecode").get("object").getAsString();
byte[] bytecode = object.getBytes(StandardCharsets.UTF_8);

//Create a file on Hedera and store the hex-encoded bytecode
FileCreateTransaction fileCreateTx = new FileCreateTransaction()
        .setKeys(privateKeyTest)
        .setContents(bytecode);

//Submit the file to the Hedera test network
TransactionResponse submitTx = fileCreateTx.execute(client);

//Get the receipt of the file create transaction
TransactionReceipt fileReceipt = submitTx.getReceipt(client);

//Get the file ID
FileId newFileId = fileReceipt.fileId;

//Log the file ID
System.out.println("The smart contract byte code file ID is " + newFileId);

//v2.6.0 Hedera Java SDK

3. Deploy a Hedera Smart Contract

Create the contract and set the file ID to the file that contains the hex-encoded bytecode from the previous step. You will need to set the gas high enough to deploy the contract. The gas should be estimated to be within 25% of the actual gas cost to avoid paying extra gas. You can read more about gas and fees here.

Note: You will need to set the gas value high enough to deploy the contract. If you don't have enough gas, you will receive an INSUFFICIENT_GAS response. If you set the value too high you will be refunded a maximum of 20% of the amount that was set for the transaction.

//Deploy the contract
ContractCreateTransaction contractTx = new ContractCreateTransaction()
        //The contract bytecode file
        .setBytecodeFileId(newFileId)
        //The max gas to reserve for this transaction
        .setGas(2_000_000);

//Submit the transaction to the Hedera test network
TransactionResponse contractResponse = contractTx.execute(client);

//Get the receipt of the file create transaction
TransactionReceipt contractReceipt = contractResponse.getReceipt(client);

//Get the smart contract ID
ContractId newContractId = contractReceipt.contractId;

//Log the smart contract ID
System.out.println("The smart contract ID is " + newContractId);

//v2.6.0 Hedera Java SDK

4. Call the tokenAssociate Contract Function

The tokenAssociate function in the contract was previously used to associate tokens created with the Hedera Token Service (HTS). However, due to a change in the security model, it is no longer possible to associate HTS tokens using this function. Instead, you should use the Hedera SDK to perform token associations. You will pass the token ID and account ID to the function. The parameters must be provided in the order expected by the function to execute successfully.

//Associate the token to an account using the HTS contract
TokenAssociateTransaction transaction = new TokenAssociateTransaction()
        .setAccountId(accountIdTest)
        .setTokenId(Collections.singletonList(tokenId))
        .freezeWith(client);

//Sign with the account key to associate and submit to the Hedera network
TransactionResponse associateTokenResponse = transaction.sign(privateKeyTest).execute(client);

System.out.println("The transaction status: " +associateTokenResponse.getReceipt(client).status);

5. Call the approveTokenAllowance Function

Using the approveTokenAllowance function is a crucial step before initiating a transfer with a smart contract on Hedera. This function grants the necessary permissions from the token owner to authorize the transfer. It serves as a stringent access control measure, ensuring that only approved contracts or accounts can spend the designated tokens. You will pass the owner which is the account that owns the fungible tokens and grants the allowance to the spender, the spender who is the account authorized by the owner to spend fungible tokens from the owner's account. The spender covers the transaction fees for token transfers. And the amount which is the number of tokens the spender is authorized to spend from the owner's account.

// Convert the contract ID to an account ID
AccountId contractIdAsAccountId = AccountId.fromString(newContractId.toString());

//Approve the token allowance
AccountAllowanceApproveTransaction transaction = new AccountAllowanceApproveTransaction()
    .approveHbarAllowance(treasuryAccountId, newContractId, Hbar.from(5));

//Sign the transaction with the owner account key and the transaction fee payer key (client)  
TransactionResponse txResponse = transaction.freezeWith(client).sign(treasuryKey).execute(client);

//Request the receipt of the transaction
TransactionReceipt receipt = txResponse.getReceipt(client);

//Get the transaction consensus status
Status transactionStatus = receipt.status;

System.out.println("The transaction consensus status for the allowance function is " +transactionStatus);

6. Call the tokenTransfer Contract Function

Transfer 100 units of the token to the account that was associated with the token. You will use the ContractExecuteTransaction() API and set the contract function to tokenTransfer. The contract function parameters must be provided in the order of the function expects to receive them.

The transaction must be signed by the account that is sending the tokens. In this case, it is the treasury account.

You can verify the transfer was successful by checking the account token balance!

//Transfer the new token to the account
//Contract function params need to be in the order of the paramters provided in the tokenTransfer contract function
ContractExecuteTransaction tokenTransfer = new ContractExecuteTransaction()
     .setContractId(newContractId)
     .setGas(2_000_000)
     .setFunction("tokenTransfer", new ContractFunctionParameters()
          //The ID of the token
          .addAddress(tokenId.toSolidityAddress())
          //The account to transfer the tokens from
          .addAddress(treasuryAccountId.toSolidityAddress())
          //The account to transfer the tokens to
          .addAddress(accountIdTest.toSolidityAddress())
          //The number of tokens to transfer
         .addInt64(5));

//Sign the token transfer transaction with the treasury account to authorize the transfer and submit
ContractExecuteTransaction signTokenTransfer = tokenTransfer.freezeWith(client).sign(treasuryKey);

//Submit transfer transaction
TransactionResponse submitTransfer = signTokenTransfer.execute(client);

//Get transaction status
Status txStatus = submitTransfer.getReceipt(client).status;

//Verify your account received the 5 tokens
 AccountBalance newAccountBalance = new AccountBalanceQuery()
      .setAccountId(accountIdTest)
      .execute(client);

System.out.println("My new account balance is " +newAccountBalance.tokens);

Note: Check out our smart contract mirror node rest APIs that return information about a contract like contract results and logs!

Congratulations 🎉! You have learned how to deploy a contract using the Hedera Token Service and completed the following:

  • Associated an HTS token by using the SDK

  • Approved the token allowance so that the contract can transfer tokens

  • Transferred tokens using the deployed contract

Code Check ✅

Java
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import com.hedera.hashgraph.sdk.*;

import io.github.cdimascio.dotenv.Dotenv;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;


public class HTS {

    public static void main(String[] args) throws TimeoutException, PrecheckStatusException, ReceiptStatusException, InterruptedException, IOException {

        AccountId accountIdTest = AccountId.fromString(Dotenv.load().get("MY_ACCOUNT_ID"));
        PrivateKey privateKeyTest = PrivateKey.fromString(Dotenv.load().get(MY_PRIVATE_KEY"));

        Client client = Client.forTestnet();
        client.setOperator(accountIdTest, privateKeyTest);

        //Import the HTS.json file from the resources folder
        ClassLoader cl = HTS.class.getClassLoader();

        Gson gson = new Gson();
        JsonObject jsonObject;

        //Get the json file
        InputStream jsonStream = cl.getResourceAsStream("HTS.json");
        jsonObject = gson.fromJson(new InputStreamReader(jsonStream, StandardCharsets.UTF_8), JsonObject.class);


        //Store the "object" field from the HTS.json file as hex-encoded bytecode
        String object = jsonObject.getAsJsonObject("data").getAsJsonObject("bytecode").get("object").getAsString();
        byte[] bytecode = object.getBytes(StandardCharsets.UTF_8);

        //Create a treasury Key
        PrivateKey treasuryKey = PrivateKey.generateED25519();

        //Create a treasury account
        AccountCreateTransaction treasuryAccount = new AccountCreateTransaction()
                .setKey(treasuryKey)
                .setInitialBalance(new Hbar(10))
                .setAccountMemo("treasury account");

        //Submit the account create transaction
        TransactionResponse submitAccountCreateTx = treasuryAccount.execute(client);

        //Get the receipt of the transaction
        TransactionReceipt newAccountReceipt = submitAccountCreateTx.getReceipt(client);

        //Get the treasury account ID
        AccountId treasuryAccountId = newAccountReceipt.accountId;
        System.out.println("The new account ID is " +treasuryAccountId);

        //Create a token to interact with
        TokenCreateTransaction createToken = new TokenCreateTransaction()
                .setTokenName("HSCS demo")
                .setTokenSymbol("H")
                .setTokenType(TokenType.FUNGIBLE_COMMON)
                .setTreasuryAccountId(treasuryAccountId)
                .setInitialSupply(500);

        //Submit the token create transaction
        TransactionResponse submitTokenTx = createToken.freezeWith(client).sign(treasuryKey).execute(client);

        //Get the token ID
        TokenId tokenId = submitTokenTx.getReceipt(client).tokenId;
        System.out.println("The new token ID is " +tokenId);


        //Create a file on Hedera and store the hex-encoded bytecode
        FileCreateTransaction fileCreateTx = new FileCreateTransaction()
                .setKeys(privateKeyTest)
                .setContents(bytecode);

        //Submit the file to the Hedera test network
        TransactionResponse submitTx = fileCreateTx.execute(client);

        //Get the receipt of the file create transaction
        TransactionReceipt fileReceipt = submitTx.getReceipt(client);

        //Get the file ID
        FileId newFileId = fileReceipt.fileId;

        //Log the file ID
        System.out.println("The smart contract byte code file ID is " + newFileId);


        //Deploy the contract
        ContractCreateTransaction contractTx = new ContractCreateTransaction()
                //The contract bytecode file
                .setBytecodeFileId(newFileId)
                //The max gas to reserve for this transaction
                .setGas(2_000_000);

        //Submit the transaction to the Hedera test network
        TransactionResponse contractResponse = contractTx.execute(client);

        //Get the receipt of the file create transaction
        TransactionReceipt contractReceipt = contractResponse.getReceipt(client);

        //Get the smart contract ID
        ContractId newContractId = contractReceipt.contractId;

        //Log the smart contract ID
        System.out.println("The smart contract ID is " + newContractId);

        //Associate the token to an account using the SDK
        TokenAssociateTransaction transaction = new TokenAssociateTransaction()
                .setAccountId(accountIdTest)
                .setTokenId(Collections.singletonList(tokenId))
                .freezeWith(client)


        //Sign with the account key to associate and submit to the Hedera network
        TransactionResponse associateTokenResponse = transaction.sign(privateKeyTest).execute(client);

        System.out.println("The transaction status: " +associateTokenResponse.getReceipt(client).status);

        // Convert the contract ID to an account ID
        AccountId contractIdAsAccountId = AccountId.fromString(newContractId.toString());
        
        //Approve the token allowance so that the contract can transfer tokens from the treasury account
        AccountAllowanceApproveTransaction transaction = new AccountAllowanceApproveTransaction()
                .approveTokenAllowance(tokenId, treasuryAccountId, contractIdAsAccountId, 10);

        //Sign the transaction with the owner account key and the transaction fee payer key (client)  
        TransactionResponse txResponse = transaction.freezeWith(client).sign(treasuryKey).execute(client);

        //Request the receipt of the transaction
        TransactionReceipt receipt = txResponse.getReceipt(client);

        //Get the transaction consensus status
        Status transactionStatus = receipt.status;

        System.out.println("The transaction consensus status is " +transactionStatus);

        //Transfer the new token to the account
        //Contract function params need to be in the order of the paramters provided in the tokenTransfer contract function
        ContractExecuteTransaction tokenTransfer = new ContractExecuteTransaction()
                .setContractId(newContractId)
                .setGas(2_000_000)
                .setFunction("tokenTransfer", new ContractFunctionParameters()
                        //The ID of the token
                        .addAddress(tokenId.toSolidityAddress())
                        //The account to transfer the tokens from
                        .addAddress(treasuryAccountId.toSolidityAddress())
                        //The account to transfer the tokens to
                        .addAddress(accountIdTest.toSolidityAddress())
                        //The number of tokens to transfer
                        .addInt64(5);

        //Sign the token transfer transaction with the treasury account to authorize the transfer and submit
        ContractExecuteTransaction signTokenTransfer = tokenTransfer.freezeWith(client).sign(treasuryKey);

        //Submit transfer transaction
        TransactionResponse submitTransfer = signTokenTransfer.execute(client);

        //Get transaction status
        Status txStatus = submitTransfer.getReceipt(client).status;

        //Get the transaction status
        System.out.println("The transfer transaction status " +txStatus);

        //Verify your account received the 5 tokens
        AccountBalance newAccountBalance = new AccountBalanceQuery()
                .setAccountId(accountIdTest)
                .execute(client);

        System.out.println("My new account balance is " +newAccountBalance.tokens);
    }
}
JavaScript
require("dotenv").config();

const {
  Hbar,
  Client,
  AccountId,
  TokenType,
  PrivateKey,
  AccountBalanceQuery,
  FileCreateTransaction,
  TokenCreateTransaction,
  ContractCreateTransaction,
  ContractExecuteTransaction,
  ContractFunctionParameters,
  AccountCreateTransaction,
  AccountAllowanceApproveTransaction,
  TokenAssociateTransaction,
} = require("@hashgraph/sdk");

// Import the compiled contract
const htsContract = require("./HTS.json");

async function htsContractFunction() {
  //Grab your Hedera testnet account ID and private key from your .env file
  const accountIdTest = AccountId.fromString(process.env.MY_ACCOUNT_ID);
  const accountKeyTest = PrivateKey.fromStringED25519(
    process.env.MY_PRIVATE_KEY
  );

  // If we weren't able to grab it, we should throw a new error
  if (accountIdTest == null || accountKeyTest == null) {
    throw new Error(
      "Environment variables myAccountId and myPrivateKey must be present"
    );
  }

  const client = Client.forTestnet();
  client.setOperator(accountIdTest, accountKeyTest);

  //Get the contract bytecode
  const bytecode = htsContract.data.bytecode.object;

  //Treasury Key
  const treasuryKey = PrivateKey.generateED25519();

  //Create token treasury account
  const treasuryAccount = new AccountCreateTransaction()
    .setKey(treasuryKey)
    .setInitialBalance(new Hbar(5))
    .setAccountMemo("treasury account");

  //Submit the transaction to a Hedera network
  const submitAccountCreateTx = await treasuryAccount.execute(client);

  //Get the receipt of the transaction
  const newAccountReceipt = await submitAccountCreateTx.getReceipt(client);

  //Get the account ID from the receipt
  const treasuryAccountId = newAccountReceipt.accountId;

  console.log("The new account ID is " + treasuryAccountId);

  //Create a token to interact with
  const createToken = new TokenCreateTransaction()
    .setTokenName("HTS demo")
    .setTokenSymbol("H")
    .setTokenType(TokenType.FungibleCommon)
    .setTreasuryAccountId(treasuryAccountId)
    .setInitialSupply(500);

  //Sign with the treasury key
  const signTokenTx = await createToken.freezeWith(client).sign(treasuryKey);

  //Submit the transaction to a Hedera network
  const submitTokenTx = await signTokenTx.execute(client);

  //Get the token ID from the receipt
  const tokenId = await (await submitTokenTx.getReceipt(client)).tokenId;

  //Log the token ID
  console.log("The new token ID is " + tokenId);

  //Create a file on Hedera and store the hex-encoded bytecode
  const fileCreateTx = new FileCreateTransaction().setContents(bytecode);

  //Submit the file to the Hedera test network signing with the transaction fee payer key specified with the client
  const submitTx = await fileCreateTx.execute(client);

  //Get the receipt of the file create transaction
  const fileReceipt = await submitTx.getReceipt(client);

  //Get the file ID from the receipt
  const bytecodeFileId = fileReceipt.fileId;

  //Log the file ID
  console.log("The smart contract byte code file ID is " + bytecodeFileId);

  //Deploy the contract instance
  const contractTx = await new ContractCreateTransaction()
    //The bytecode file ID
    .setBytecodeFileId(bytecodeFileId)
    //The max gas to reserve
    .setGas(2000000);

  //Submit the transaction to the Hedera test network
  const contractResponse = await contractTx.execute(client);

  //Get the receipt of the file create transaction
  const contractReceipt = await contractResponse.getReceipt(client);

  //Get the smart contract ID
  const newContractId = contractReceipt.contractId;

  //Log the smart contract ID
  console.log("The smart contract ID is " + newContractId);

  //Associate the token to an account using the SDK
  const transaction = new TokenAssociateTransaction()
    .setAccountId(accountIdTest)
    .setTokenIds([tokenId])
    .freezeWith(client);

  //Sign the transaction with the client
  const signTx = await transaction.sign(accountKeyTest);

  //Submit the transaction
  const submitAssociateTx = await signTx.execute(client);

  //Get the receipt
  const txReceipt = await submitAssociateTx.getReceipt(client);

  //Get transaction status
  const txStatus = txReceipt.status;

  console.log("The associate transaction was " + txStatus.toString());

  //Approve the token allowance
  const transactionAllowance = new AccountAllowanceApproveTransaction()
    .approveTokenAllowance(tokenId, treasuryAccountId, newContractId, 5)
    .freezeWith(client);

  //Sign the transaction with the owner account key
  const signTxAllowance = await transactionAllowance.sign(treasuryKey);

  //Sign the transaction with the client operator private key and submit to a Hedera network
  const txResponseAllowance = await signTxAllowance.execute(client);

  //Request the receipt of the transaction
  const receiptAllowance = await txResponseAllowance.getReceipt(client);

  //Get the transaction consensus status
  const transactionStatusAllowance = receiptAllowance.status;

  console.log(
    "The transaction consensus status for the allowance function is " +
      transactionStatusAllowance.toString()
  );

  //Transfer the new token to the account
  //Contract function params need to be in the order of the parameters provided in the tokenTransfer contract function
  const tokenTransfer = new ContractExecuteTransaction()
    .setContractId(newContractId)
    .setGas(2000000)
    .setFunction(
      "tokenTransfer",
      new ContractFunctionParameters()
        //The ID of the token
        .addAddress(tokenId.toSolidityAddress())
        //The account to transfer the tokens from
        .addAddress(treasuryAccountId.toSolidityAddress())
        //The account to transfer the tokens to
        .addAddress(accountIdTest.toSolidityAddress())
        //The number of tokens to transfer
        .addInt64(5)
    );

  //Sign the token transfer transaction with the treasury account to authorize the transfer and submit
  const signTokenTransfer = await tokenTransfer
    .freezeWith(client)
    .sign(treasuryKey);

  //Submit transfer transaction
  const submitTransfer = await signTokenTransfer.execute(client);

  //Get transaction status
  const transferTxStatus = await (
    await submitTransfer.getReceipt(client)
  ).status;

  //Get the transaction status
  console.log("The transfer transaction status " + transferTxStatus.toString());

  //Verify your account received the 10 tokens
  const newAccountBalance = new AccountBalanceQuery()
    .setAccountId(accountIdTest)
    .execute(client);

  console.log(
    "My new account balance is " + (await newAccountBalance).tokens.toString()
  );
}

void htsContractFunction();
Go
package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"

	"github.com/hashgraph/hedera-sdk-go/v2"
	"github.com/joho/godotenv"
)

type contract struct {
	// ignore the link references since it is empty
	Object    string `json:"object"`
	OpCodes   string `json:"opcodes"`
	SourceMap string `json:"sourceMap"`
}

func main() {

	//Loads the .env file and throws an error if it cannot load the variables from that file corectly
	err := godotenv.Load(".env")
	if err != nil {
		panic(fmt.Errorf("Unable to load enviroment variables from .env file. Error:\n%v\n", err))
	}

	//Grab your testnet account ID and private key from the .env file
	accountIdTest, err := hedera.AccountIDFromString(os.Getenv("MY_ACCOUNT_ID"))
	if err != nil {
		panic(err)
	}

	privateKeyTest, err := hedera.PrivateKeyFromString(os.Getenv("MY_PRIVATE_KEY"))
	if err != nil {
		panic(err)
	}

	//Create your testnet client
	client := hedera.ClientForTestnet()
	client.SetOperator(accountIdTest, privateKeyTest)

	//Treasury Key
	treasuryKey, err := hedera.PrivateKeyGenerateEd25519()

	//Create token treasury account
	treasuryAccount := hedera.NewAccountCreateTransaction().
		SetKey(treasuryKey).
		SetInitialBalance(hedera.NewHbar(5).
		SetAccountMemo("treasury account")

	//Submit the transaction to a Hedera network
	submitAccountCreateTx, err := treasuryAccount.Execute(client)

	//Get the receipt of the transaction
	newAccountReceipt, err := submitAccountCreateTx.GetReceipt(client)

	//Get the account ID from the receipt
	treasuryAccountId := *newAccountReceipt.AccountID

	fmt.Printf("The treasury account ID: %v\n", treasuryAccountId)

	//Create a token to interact with
	createToken := hedera.NewTokenCreateTransaction().
		SetTokenName("HTS demo").
		SetTokenSymbol("H").
		SetTokenType(hedera.TokenTypeFungibleCommon).
		SetTreasuryAccountID(treasuryAccountId).
		SetInitialSupply(500)

	//Freeze the transaction for signing
	freezeTokenTx, err := createToken.FreezeWith(client)

	//Sign with the treasury key to authorize the transaction
	signTokenTx := freezeTokenTx.Sign(treasuryKey)

	//Submit the transaction
	submitTokenTx, err := signTokenTx.Execute(client)

	//Get the receipt of the transaction
	getTokenReceipt, err := submitTokenTx.GetReceipt(client)

	//Get the token ID
	tokenId := *getTokenReceipt.TokenID

	//Log the token ID
	fmt.Printf("The token ID: %v\n", tokenId)

	//Get the HTS contract bytecode
	rawSmartContract, err := ioutil.ReadFile("./hts.json")
	if err != nil {
		println(err.Error(), ": error reading hts.json")
		return
	}

	var contract contract = contract{}

	err = json.Unmarshal([]byte(rawSmartContract), &contract)
	if err != nil {
		println(err.Error(), ": error unmarshaling the json file")
		return
	}

	smartContractByteCode := []byte(contract.Object)

	// Upload a file containing the byte code
	fileCreateTx, err := hedera.NewFileCreateTransaction().
		SetContents([]byte(smartContractByteCode)).
		Execute(client)

	if err != nil {
		println(err.Error(), ": error creating file")
		return
	}

	//Get the receipt of the transaction
	fileTxReceipt, err := fileCreateTx.GetReceipt(client)
	if err != nil {
		println(err.Error(), ": error getting file create transaction receipt")
		return
	}

	//Get the bytecode file ID
	byteCodeFileID := *fileTxReceipt.FileID

	fmt.Printf("The contract bytecode file ID: %v\n", byteCodeFileID)

	// Deploy the contract instance
	contractTransactionID, err := hedera.NewContractCreateTransaction().
		//The max gas for the transaction
		SetGas(2000000).
		//The contract bytecode file ID
		SetBytecodeFileID(byteCodeFileID).
		Execute(client)

	if err != nil {
		println(err.Error(), ": error creating contract")
		return
	}

	//Get the contract receipt
	contractReceipt, err := contractTransactionID.GetReceipt(client)

	//Get the contract contract ID
	contractId := *contractReceipt.ContractID

	//Log the contract ID
	fmt.Printf("The contract ID %v\n", contractId)

	//Associate an account with a token
	associateTx, err := hedera.NewTokenAssociateTransaction().
    	SetAccountID(accountIdTest).
    	SetTokenIDs(tokenId).
    	FreezeWith(client)

	if err != nil {
	  panic(err)
	}

	//Sign with the private key of the account that is being associated to a token, submit the transaction to a Hedera network
	associateTxResponse, err := associateTx.Sign(privateKeyTest).Execute(client)

	if err != nil {
	  panic(err)
	}

	//Get the receipt
	associateTxReceipt, err := associateTxResponse.GetReceipt(client)

	if err != nil {
	  panic(err)
	}

	//Get transaction status
	txStatus := associateTxReceipt.Status

	fmt.Printf("The associate transaction status %v\n", txStatus)

	//Create the transaction
	transaction := hedera.NewAccountAllowanceApproveTransaction().
     	ApproveHbarAllowance(ownerAccount, spenderAccountId, Hbar.fromTinybars(500))
        	FreezeWith(client)

	if err != nil {
    		panic(err)
	}

	//Sign the transaction with the owner account private key   
	txResponse, err := transaction.Sign(ownerAccountKey).Execute(client)

	//Request the receipt of the transaction
	receipt, err := txResponse.GetReceipt(client)
	if err != nil {
    		panic(err)
	}

	//Get the transaction consensus status
	transactionStatus := receipt.Status

	println("The transaction consensus status is ", transactionStatus)
	
	//Transfer the token
	transferTx := hedera.NewContractExecuteTransaction().
		//The contract ID
		SetContractID(contractId).
		//The max gas
		SetGas(2000000).
		//The contract function to call and parameters
		SetFunction("tokenTransfer", contractParamsAmount)

	//Sign with treasury key to authorize the transfer from the treasury account
	signTx, err := transferTx.Sign(treasuryKey).Execute(client)

	if err != nil {
		println(err.Error(), ": error executing contract")
		return
	}
	//Get the receipt
	transferTxReceipt, err := signTx.GetReceipt(client)

	if err != nil {
		println(err.Error(), ": error getting receipt")
		return
	}

	//Get transaction status
	transferTxStatus := transferTxReceipt.Status

	fmt.Printf("The transfer transaction status %v\n", transferTxStatus)

	//Verify the transfer by checking the balance
	transferAccountBalance, err := hedera.NewAccountBalanceQuery().
		SetAccountID(accountIdTest).
		Execute(client)

	if err != nil {
		println(err.Error(), ": error getting balance")
		return
	}

	//Log the account token balance
	fmt.Printf("The account token balance %v\n", transferAccountBalance.Tokens)

}

Additional Resources

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Writer: Simi, Sr. Software Manager

GitHub | LinkedIn

Editor: Krystal, Technical Writer

GitHub | Twitter

Editor: Lucía, Developer

(Hashgraph Association)

GitHub | Twitter

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