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Distribute ERC20 Token

After each round, nodes that effectively executed the task will be rewarded with 10 KTokens allocated to their Ethereum address, along with a KOII token reward.

The distribution process entails interaction with the KToken smart contract to facilitate KToken distribution. Key steps involve formulating a transaction, signing it, and sending it to the Ethereum network. Successful transaction execution results in a transaction hash.

Update Dependency Imports

Navigate to the task/distribution.js file, and update the dependency imports as follows:

const { namespaceWrapper } = require("../_koiiNode/koiiNode");
const { Web3 } = require("web3");
const tokenContractABI = require("../abi/KToken.json");
const { retrieveFromCid } = require("../helper");
const web3 = new Web3(`${process.env.INFURA_ID}`);
const tokenContractAddress = process.env.TOKEN_CONTRACT_ADDRESS;
const privateKey = process.env.PRIVATE_KEY;

Distribution Logic

Still, in the task/distribution.js file, create a new function distributeKToken to handle connecting to the smart contract and distributing the KTokens.

The distributeKToken function accepts two parameters:

  • distributionCandidates: An array containing the public keys of nodes with valid submissions.
  • submissions: All the submissions associated with the current round.
async function distributeKToken(distributionCandidates, submissions) {
// Loop through each candidate in the distributionCandidates array
for (const candidate of distributionCandidates) {
if (candidate in submissions) {
// Retrieve the submission_value(CID) associated with the candidate
const submission_value = submissions[candidate].submission_value;
const output = await retrieveFromCid(submission_value);

// Extract the nodeEthAddress from the retrieved output
const nodeEthAddress = output.nodeEthAddress;

try {
// Create a new instance of the token contract using tokenContractABI and tokenContractAddress
const tokenContract = new web3.eth.Contract(

const gasPrice = await web3.eth.getGasPrice();
const rewardAmount = "10000000000000000000"; // 10 KTOKENS

// Encode the transfer function call data for the token contract
const txData = tokenContract.methods
.transfer(nodeEthAddress, rewardAmount)

// Get the nonce for the transaction from the contract owner's address
const nonce = await web3.eth.getTransactionCount(
const tx = {
nonce: nonce,
gasPrice: gasPrice,
gasLimit: web3.utils.toHex(300000),
to: tokenContractAddress,
data: txData,

// Sign the transaction using the private key
const signedTx = await web3.eth.accounts.signTransaction(

// Send the signed transaction and obtain the transaction receipt
const txReceipt = await web3.eth.sendSignedTransaction(

console.log("TRANSACTION HASH:" + txReceipt.transactionHash);
return txReceipt.transactionHash;
} catch (err) {
console.log("ERROR", err);

Let's break down the code's functionality:

  • Loop through each candidate in the distributionCandidates array and check if the current candidate is present in the submissions object
  • The candidate's submission_value (CID) is retrieved and its data is extracted to get the node's Ethereum address.
  • An instance of the token contract is created using its ABI (Application Binary Interface) and address.
  • The current gas price is fetched from the Ethereum network using web3.eth.getGasPrice().
  • A reward amount of 10 KTokens is defined.
  • Encoded data for the transfer method of the token contract is generated using .encodeABI().
  • The current nonce (transaction count) of the contract owner's address is fetched using web3.eth.getTransactionCount().
  • A transaction object (tx) is created with details like nonce, gas price, gas limit, target address (to), and data.
  • The transaction is signed using the contract owner's private key.
  • The signed transaction is sent to the Ethereum network using web3.eth.sendSignedTransaction().

Finally, call the distributeKToken() function within the generateDistributionList() function, immediately before the return distributionList statement.

// Distribute ERC20 token to nodes on the distributionList
await distributeKToken(distributionCandidates, submissions);
return distributionList;
// ...Existing Code

Note that transaction status might take some time to update on the blockchain, especially during network congestion.

For access to the source code of the Koii Task, refer to the GitHub repository.