How to retrieve the wallet of a user authenticated via AWS Cognito?

Help - Plug n Play PnP Web SDKs
1

Hello, I’ve setup web3auth + aws cognito by using the “Web3Auth & ReactJS Example using AWS Cognito” example code on my NextJS app. Everything works fine and I’m able to login/authenticate a user.

On the frontend code, I’m able to retrieve the user wallet.

Now, I want to retrieve the user wallet on my backend code, which probably means I need to use the “@web3auth/node-sdk”. I’m not able to retrieve the user wallet on my backend, I get error 403 Unauthorized. Can you please help?

  • SDK Version:
    “@web3auth/base”: “^8.4.0”,
    “@web3auth/ethereum-provider”: “^8.4.0”,
    “@web3auth/no-modal”: “^8.4.0”,
    “@web3auth/openlogin-adapter”: “^8.4.0”,
    “@web3auth/node-sdk”: “^3.3.0”,

  • Platform: NextJS/NodeJS

Code:

import { Web3Auth } from "@web3auth/node-sdk";
import { CHAIN_NAMESPACES } from "@web3auth/base";
import jwt, { JwtHeader, SigningKeyCallback } from "jsonwebtoken";
import jwksClient, { SigningKey } from "jwks-rsa";
import { EthereumPrivateKeyProvider } from "@web3auth/ethereum-provider";

const web3authClientId = "<web3auth_client_id>";
const awsCognitoClientId = "<aws_cognito_client_id>";
const w3aVerifier = "<w3a_verifier>";
const cognitoDomain = "<cognito_domain_url>";

const web3auth = new Web3Auth({
	clientId: web3authClientId,
	web3AuthNetwork: "mainnet",
	usePnPKey: false, // Setting this to true returns the same key as PnP Web SDK.
	// By default, this SDK returns CoreKitKey.
});

const chainConfig = {
	chainNamespace: CHAIN_NAMESPACES.EIP155,
	displayName: "ETH Mainnet",
	blockExplorer: "https://etherscan.io",
	ticker: "ETH",
	tickerName: "Ethereum",
	chainId: "0x1",
	rpcTarget: "https://rpc.ankr.com/eth", // needed for non-other chains
};

const provider = new EthereumPrivateKeyProvider({ config: { chainConfig } });

web3auth.init({ provider });

const client = jwksClient({
	jwksUri:
		"https://cognito-idp.eu-central-1.amazonaws.com/eu-central-1_gkn7r52OP/.well-known/jwks.json",
});

function getKey(header: JwtHeader, callback: SigningKeyCallback): void {
	client.getSigningKey(
		header.kid as string,
		(err: Error | null, key: SigningKey | undefined) => {
			const signingKey = key?.getPublicKey();
			callback(null, signingKey);
		}
	);
}

const verifyJWT = (token: string): Promise<any> => {
	return new Promise((resolve, reject) => {
		jwt.verify(token, getKey, { algorithms: ["RS256"] }, (err, decoded) => {
			if (err) {
				return reject("Invalid token");
			}
			resolve(decoded);
		});
	});
};

const getToken = async (idToken: string): Promise<void> => {
	try {
		// Fetch wallet address using Web3Auth
		const walletProvider = await web3auth.connect({
			verifier: w3aVerifier,
			verifierId: "1314b8b2-20a1-7034-68fc-dab6ee931e03",
			idToken,
		});

		// Proceed with the logic to create a checkout session using the wallet address
		console.log("Wallet Address:");
		// ...
	} catch (error) {
		console.error("Error getting token:", error);
	}
};

// Example usage
const exampleUsage = async () => {
	const idToken =
		"eyJraWQiOiJTckp3cWtWT1R1Y29qQzlZWG9rRmY4NG5mN3BGbnp0V1NieGpIWHF2SGlvPSIsImFsZyI6IlJTMjU2In0.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.GHCWGZ1U88W5h7ztPzUUIgYa19_v8SeSAxQ8BYFRt7MtxrIfei9pqgHZZKmpZH8p_JJWTMbsqBANsB7IRBKOqW4FIJ7VOH5iOyQ4dQC1lcjvx8zoP0EGMP26GZXWW1mWgN9p5OJPTrzrilD90aCTw4pBKAsvTFS9oZ6l1DFtsyKn9_xE1wS8lPjUDRXUfynVt5yfmhx3-qkTT4poixDWyJA1gs1Pyki5l7mFiC93Z1BL1DZREs4SurhVSghuzKPwwbHWQ-2utRmnYMZFyq_pADY7De7l60HcqCkqdtMk1iZPhmbXlLgnDChALH9ei9Kx3PEXN9Z2XmKXhcGai8iUcw";
	try {
		const decodedToken = await verifyJWT(idToken);
		console.log("Decoded Token:", decodedToken);
		await getToken(idToken);
	} catch (error) {
		console.error("Error:", error);
	}
};

exampleUsage();
2

hi @luca,

Please check this example: web3auth-core-kit-examples/single-factor-auth-node/sfa-node-quick-start/index.js at 4f5756aefaf6765a9c8db9cb984f3d29d9ad9a27 · Web3Auth/web3auth-core-kit-examples · GitHub

const provider = await web3auth.connect({
    verifier: "w3a-node-demo", // replace with your verifier name
    verifierId: sub, // replace with your verifier id's value, for example, sub value of JWT Token, or email address.
    idToken: token, 
  });
  const eth_private_key = await provider.request({ method: "eth_private_key" });
3

Hi @TomTom when I run this code, I get the error “Duplicate token found”.
I’ve used a fresh new user to test this, so I’m sure there is not more than 1 token for that user.
Any suggestion on how to fix this error?

Also, in the example code you provided, do I need to modify it to include information about AWS cognito?

4

Hi Luca,

I’ve shared this problem with the team so they can assist us in solving it.

thanks for your patience

5

Hey @luca,

I noticed that you are hardcoding the idToken. Could you try obtaining a fresh one using Cognito and testing it again? Sometimes, when we hardcode tokens, we might forget to use a new one, which often leads to errors.