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Step 4 - Integrate Blended Contracts

4.1 Frontend Integration​

Once a blended application is deployed, you can use popular libraries such as ethers.js to integrate your application into user interfaces such as a frontend website.

4.2 Install ethers.js in node.js​

Install ethers.js in node.js

npm i [email protected]

4.3 Test ethers.js script to call Solidity contract​

This script calls the Solidity contract, which then externally calls the Rust contract functions. Update string variable contractAddress with your deployed Solidity contract address

const ethers = require("ethers") // npm i [email protected] https://github.com/smartcontractkit/full-blockchain-solidity-course-js/discussions/5139#discussioncomment-5444517

const rpcURL = "https://rpc.dev.gblend.xyz/" // Your RPC URL goes here

const provider = new ethers.providers.JsonRpcProvider(rpcURL)

const contractAddress = "<INPUT_SOLIDITY_CONTRACT_ADDRESS_HERE>"
const contractABI = [{"inputs":[{"internalType":"address","name":"FluentRustAddress","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"fluentRust","outputs":[{"internalType":"contractIFluentRust","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getRustAddress","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getRustBool","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getRustBytes","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getRustBytes32","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getRustInt256","outputs":[{"internalType":"int256","name":"","type":"int256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getRustString","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getRustUint256","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"}]

const contractDeployed = new ethers.Contract(contractAddress, contractABI, provider);

let fluent_sepolia_chain_id = 20993;

testSolidityContractRead()

async function testSolidityContractRead() {

  const connectedNetworkObject = await provider.getNetwork();
  const chainIdConnected = connectedNetworkObject.chainId;
  console.log("chainIdConnected: " + chainIdConnected)

  if(chainIdConnected != fluent_sepolia_chain_id){
    console.log("RPC endpoint not connected to Fluent Sepolia (chainId: " + fluent_sepolia_chain_id + ").");
    console.log("Switch to Fluent Sepolia then try again.");
    return;
  }

  const fluentRustContractAddress = await contractDeployed.fluentRust()
  console.log("fluentRustContractAddress: " + fluentRustContractAddress)

  const rustString = await contractDeployed.getRustString()
  console.log("rustString: " + rustString)

  const rustUint256 = await contractDeployed.getRustUint256()
  console.log("rustUint256: " + rustUint256)

  const rustInt256 = await contractDeployed.getRustInt256()
  console.log("rustInt256: " + rustInt256)

  const rustAddress = await contractDeployed.getRustAddress()
  console.log("rustAddress: " + rustAddress)

  const rustBytes = await contractDeployed.getRustBytes()
  console.log("rustBytes: " + rustBytes)

  const rustBytes32 = await contractDeployed.getRustBytes32()
  console.log("rustBytes32: " + rustBytes32)

  const rustBool = await contractDeployed.getRustBool()
  console.log("rustBool: " + rustBool)

}

This script should return the expected values the Solidity contract gets from the Rust contract.

4.4 Test ethers.js script to call Rust contract​

This script calls the Rust contract directly with the IFluentRust Solidity interface. Update string variable contractAddress with your deployed Rust contract address

const ethers = require("ethers") // npm i [email protected] https://github.com/smartcontractkit/full-blockchain-solidity-course-js/discussions/5139#discussioncomment-5444517

const rpcURL = "https://rpc.dev.gblend.xyz/" // Your RPC URL goes here

const provider = new ethers.providers.JsonRpcProvider(rpcURL)

const contractAddress = "<INPUT_RUST_CONTRACT_ADDRESS_HERE>"
const contractABI = [{"inputs":[],"name":"rustAddress","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"rustBool","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"rustBytes","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"rustBytes32","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"rustInt256","outputs":[{"internalType":"int256","name":"","type":"int256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"rustString","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"rustUint256","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"}]

const contractDeployed = new ethers.Contract(contractAddress, contractABI, provider);

let fluent_sepolia_chain_id = 20993;

testRustContractRead()

async function testRustContractRead() {

  const connectedNetworkObject = await provider.getNetwork();
  const chainIdConnected = connectedNetworkObject.chainId;
  console.log("chainIdConnected: " + chainIdConnected)

  if(chainIdConnected != fluent_sepolia_chain_id){
    console.log("RPC endpoint not connected to Fluent Sepolia (chainId: " + fluent_sepolia_chain_id + ").");
    console.log("Switch to Fluent Sepolia then try again.");
    return;
  }

  const rustString = await contractDeployed.rustString()
  console.log("rustString: " + rustString)

  const rustUint256 = await contractDeployed.rustUint256()
  console.log("rustUint256: " + rustUint256)

  const rustInt256 = await contractDeployed.rustInt256()
  console.log("rustInt256: " + rustInt256)

  const rustAddress = await contractDeployed.rustAddress()
  console.log("rustAddress: " + rustAddress)

  const rustBytes = await contractDeployed.rustBytes()
  console.log("rustBytes: " + rustBytes)

  const rustBytes32 = await contractDeployed.rustBytes32()
  console.log("rustBytes32: " + rustBytes32)

  const rustBool = await contractDeployed.rustBool()
  console.log("rustBool: " + rustBool)

}

This script should return the expected values directly from the Rust contract.