How to Authenticate Users with Web3Auth

What is Web3Auth?

info

Visit Web3Auth docs to get more information.

Web3Auth is a pluggable auth infrastructure for Web3 wallets and applications. It streamlines the onboarding of mainstream and crypto-native users in under a minute by providing experiences they're most comfortable with. With support for all social logins, web and mobile-native platforms, wallets, and other key management methods, Web3Auth results in a standard cryptographic key provider specific to the user and application.

Before Starting

You can start this tutorial if you already have a NextJS dapp with MetaMask sign-in functionality.

Installing the Web3Auth Wagmi Connector

Install the @web3auth/web3auth-wagmi-connector dependency:

npm

npm install @web3auth/web3auth-wagmi-connector

Yarn

yarn add @web3auth/web3auth-wagmi-connector

Configuring the Web3Auth Wagmi Connector

1. Open the pages/signin.jsx file and add Web3AuthConnector as a connector to the useConnect() hook:

import { Web3AuthConnector } from '@web3auth/web3auth-wagmi-connector'
import { signIn } from 'next-auth/react'
import { useAccount, useConnect, useSignMessage, useDisconnect } from 'wagmi'
import { useRouter } from 'next/router'
import axios from 'axios'

function SignIn() {
  const { connectAsync } = useConnect({
    connector: new Web3AuthConnector({
      options: {
        enableLogging: true,
        clientId: 'YOUR_CLIENT_ID', // Get your own client id from https://dashboard.web3auth.io
        network: 'testnet', // web3auth network
        chainId: '0x1', // chainId that you want to connect with
      },
    }),
  })
  const { disconnectAsync } = useDisconnect()
  const { isConnected } = useAccount()
  const { signMessageAsync } = useSignMessage()
  const { push } = useRouter()

  const handleAuth = async () => {
    if (isConnected) {
      await disconnectAsync()
    }

    const { account } = await connectAsync()

    const userData = { address: account, chain: '0x1', network: 'evm' }

    const { data } = await axios.post('/api/auth/request-message', userData, {
      headers: {
        'Content-Type': 'application/json',
      },
    })

    const message = data.message

    const signature = await signMessageAsync({ message })

    // redirect user after success authentication to '/user' page
    const { url } = await signIn('credentials', {
      message,
      signature,
      redirect: false,
      callbackUrl: '/user',
    })
    /**
     * instead of using signIn(..., redirect: "/user")
     * we get the url from callback and push it to the router to avoid page refreshing
     */
    push(url)
  }

  return (
    <div>
      <h3>Web3 Authentication</h3>
      <button onClick={() => handleAuth()}>Authenticate via Web3Auth</button>
    </div>
  )
}

export default SignIn

Testing the Web3Auth Connector

Visit http://localhost:3000/signin to test authentication.

1. Click on Authenticate via Web3Auth:

2. Select the preferred sign-in method:

3. After successful authentication, you will be redirected to the /user page:

4. Visit http://localhost:3000/user to test the user session's functionality:

• When a user is authenticated, we show the user's info on the page.
• When a user is not authenticated, we redirect to the /signin page.
• When a user is authenticated, we show the user's info on the page, even refreshing after the page. (Explanation: After Web3 wallet authentication, the next-auth library creates a session cookie with an encrypted JWT [JWE] stored inside. It contains session info [such as an address and signed message] in the user's browser.)