How to use Google with Web3Auth Plug and Play No Modal SDK

This guide will cover the basics of how to set up your Web3Auth Plug and Play No Modal SDK and Google Login for custom authentication and provide you the steps on how to develop a basic web application on the Ethereum blockchain.

Live Demo: https://web3auth-core-google-demo.vercel.app

Quick Start​

npx degit Web3Auth/web3auth-pnp-examples/web-no-modal-sdk/custom-authentication/single-verifier-examples/google-no-modal-example w3a-google-demo && cd w3a-google-demo && npm install && npm run start

How it works?​

When integrating Web3Auth Plug and Play No Modal SDK with Google Login the flow looks something like this:

• When a user logs in with Google, Google sends a JWT id_token to the app. This JWT token is sent to the Web3Auth SDK's login function.

• Finally, on successful validation of the JWT token, Web3Auth SDK will generate a private key for the user, in a self-custodial way, resulting in easy onboarding for your user to the application.

Prerequisites​

• For Web Apps: A basic knowledge of JavaScript is required to use Web3Auth SDK.

• For Mobile Apps: For the Web3Auth Mobile SDKs, you have a choice between iOS, Android, React Native & Flutter. Please refer to the Web3Auth SDK Reference for more information.

• Create a Web3Auth account on the Web3Auth Dashboard

• A Google Developer account to be used as Login provider for Web3Auth Custom Authentication.

Setup​

Setup your Google App​

1. Follow Google’s instructions to set up an OAuth 2.0 app.

2. Paste the following as a Redirect URI into the "Authorized redirect URIs" field.

   • https://auth.web3auth.io/auth

   

3. Obtain the OAuth Client ID from your App on the Google Developer dashboard

Setup your Web3Auth Dashboard​

• Create a Project from the Project Section of the Web3Auth Developer Dashboard.

  

  • Enter your desired Project name.

  • Select the Product you want to use. For this guide, we'll be using the Plug n Play product.

  • Select the Platform type you want to use. For this guide, we'll be using the Web Application as the platform.

  • Select the Web3Auth Network as Sapphire Devnet. We recommend creating a project in the sapphire_devnet network during development. While moving to a production environment, make sure to convert your project to sapphire_mainnet or any of the legacy mainnet network mainnet, aqua, or cyan network. Otherwise, you'll end up losing users and keys.

  • Select the blockchain(s) you'll be building this project on. For interoperability with Torus Wallets, you have the option of allowing the user's private key to be used in other applications using Torus Wallets (EVM, Solana, XRPL & Casper).

  • Finally, once you create the project, you have the option to whitelist your URLs for the project. Please whitelist the domains where your project will be hosted.

    

• Create a Verifier from the Custom Auth Section of the Web3Auth Developer Dashboard with following configuration:

  • Choose a name of your choice for the verifier identifier. eg. google-core-verifier
  • Select environment: Sapphire Devnet or Sapphire Mainnet as per your requirement.
  • Select Google from the Login Provider.
  • Paste the Client ID from the Google App(above) to the Client ID field.
  • Click on the Create button to create your verifier. It may take up to 10 minutes to deploy the verifier on Sapphire Devnet. You'll receive an email once it's complete.

• You will require the verifierName of the newly created verifier and the clientId of the project.

Using the Web3Auth SDK​

To use the Web3Auth SDK, you need to add the dependency of the respective platform SDK of Web3Auth to your project. To know more about the available SDKs, please have a look at this documentation page.

For this guide, we will be talking through the Web3Auth Plug and Play No Modal SDK and using the Auth Adapter alongside it to enable Custom Authentication through Google Login.

Setting up your base project for using Web3 libraries:​

If you are starting from scratch, to set up this project locally, you will need to create a base Web application, where you can install the required dependencies. However, while working with Web3, there are a few base libraries, which need additional configuration. This is because certain packages are not available in the browser environment, and we need to polyfill them manually. You can follow this documentation where we have mentioned the configuration changes for some popular frameworks for your reference.

Installation​

For this project, you need to add the following Web3Auth dependencies to your package.json

npm install --save @web3auth/no-modal @web3auth/auth-adapter @web3auth/ethereum-provider @web3auth/base web3

Understanding the Dependencies​

npm install --save @web3auth/no-modal

npm install --save @web3auth/auth-adapter

npm install --save @web3auth/ethereum-provider

npm install --save @web3auth/base

npm install --save web3

Initialization​

Once installed, your Web3Auth application needs to be initialized. Initialization is a 4 step process where we add all the config details for Web3Auth:

1. Instantiation
2. Configuration of Adapters
3. Configuration of Plugins
4. Initialization of the Web3Auth

Please make sure all of this is happening in your application constructor. This makes sure that Web3Auth is initialized when your application starts up.

For this guide, we're only focusing on the Instantiation, Configuration for the Auth Adapter (the default adapter that enables social logins) and Initialization of the Web3Auth SDK. To know more about the other things you can do with Web3Auth, check out our SDK Reference.

Instantiating Web3Auth​

Importing the packages​

import { WALLET_ADAPTERS, CHAIN_NAMESPACES, IProvider } from "@web3auth/base";
import { Web3AuthNoModal } from "@web3auth/no-modal";
import { AuthAdapter } from "@web3auth/auth-adapter";
import { EthereumPrivateKeyProvider } from "@web3auth/ethereum-provider";

Alongside the Web3Auth and AuthAdapter you need the above-mentioned packages from @web3auth/base for different initializations mentioned further in this guide.

Instantiate the Web3Auth SDK​

import { Web3AuthNoModal } from "@web3auth/no-modal";
import { CHAIN_NAMESPACES } from "@web3auth/base";

const chainConfig = {
  chainNamespace: CHAIN_NAMESPACES.EIP155,
  chainId: "0x1",
  rpcTarget: "https://rpc.ankr.com/eth",
  displayName: "Ethereum Mainnet",
  blockExplorerUrl: "https://etherscan.io",
  ticker: "ETH",
  tickerName: "Ethereum",
};

const web3auth = new Web3AuthNoModal({
  clientId:
    "BPi5PB_UiIZ-cPz1GtV5i1I2iOSOHuimiXBI0e-Oe_u6X3oVAbCiAZOTEBtTXw4tsluTITPqA8zMsfxIKMjiqNQ",
  web3AuthNetwork: "sapphire_mainnet",
  chainConfig,
});

Here, we're using the chainConfig property to set the chainId and chainNamespace. The chainId and chainNamespace are the id and the namespace respectively of the chain you're connecting to. We've initialized them for EVM for this guide. You can find the list of available providers here to select from.

Additionally, sometimes you might face clogging in the network because the test network is a bit clogged at that point. To avoid this, we can use the property rpcTarget and pass over the URL of the node you want to connect to.

Initializing the Auth Adapter​

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

const authAdapter = new AuthAdapter({
  adapterSettings: {
    clientId: "YOUR-WEB3AUTH-CLIENT-ID", //Optional - Provide only if you haven't provided it in the Web3Auth Instantiation Code
    uxMode: "popup",
    loginConfig: {
      google: {
        name: "Name of your choice",
        verifier: "YOUR-VERIFIER-NAME-ON-WEB3AUTH-DASHBOARD",
        typeOfLogin: "google",
        clientId: "YOUR-CLIENTID-FROM-GOOGLE",
      },
    },
  },
  privateKeyProvider,
});

web3auth.configureAdapter(authAdapter);

Here, you need to pass over your Web3Auth clientId in the adapterSettings object and your Custom Auth verifierName and AWS Cognito clientId in the loginConfig object. This makes sure that the Auth Adapter can connect to the correct verifier and AWS Cognito server.

Initializing the Web3Auth SDK​

await web3auth.init();

Initializing on Mobile Platforms​

• For Mobile, depending on the platform, there will be different steps to initialize the SDK. Refer to the respective Mobile SDKs,
  • Android
  • iOS
  • Flutter
  • React Native

Authentication​

Logging in​

Once initialized, you can use the connectTo() function to authenticate the user when they click the login button.

import { WALLET_ADAPTERS, CHAIN_NAMESPACES } from "@web3auth/base";

await web3auth.connectTo(WALLET_ADAPTERS.AUTH, {
  loginProvider: "google",
});

When connecting, your connectTo function takes the arguments for the adapter you want to connect to and the loginProvider for the login.

Get the User Profile​

const user = await web3auth.getUserInfo();
console.log("User info", user);

Using the getUserInfo function, you can get the details of the logged-in user. Please note that these details are not stored anywhere in Web3Auth network, but are fetched from the id_token you received from AWS Cognito and live in the frontend context.

Logout​

await web3auth.logout();

Logging out your user is as simple as calling the logout function.

Interacting with Blockchain​

So if you have completed this far, it means that you have successfully authenticated your user. Now, you can use the provider returned by Web3Auth as web3auth.provider to interact with your blockchain. You can use the Provider SDKs to perform RPC Calls to your blockchain.

Web3Auth is chain agnostic, ie. depending on whatever blockchain or layer-2 you use, Web3Auth can easily support that. Web3Auth has native providers for EVM and Solana blockchains and for others, you can get the private key in the user scope and make RPC calls. For standardising the type of provider, Web3Auth Base provides a IProvider from which you can create your own provider.

• Ethereum Provider gives you the capability of making RPC calls to the EVM compatible blockchains.
• Solana Provider gives you the capability of making RPC calls to the Solana blockchain.
• XRPL Provider gives you the capability of making RPC calls to the XRPL blockchain.
• If you want to use any other chain except Solana or EVM chains, for ex: Starknet, you can specify the value of chainNamespace field as other in the Web3Auth SDK Constructor. Refer to: Using other blockchains

Get User Accounts​

const getAccounts = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  const web3 = new Web3(provider as any);
  const userAccounts = await web3.eth.getAccounts();
  console.log(userAccounts);
};

const getAccounts = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  // For ethers v5
  // const ethersProvider = new ethers.providers.Web3Provider(this.provider);
  const ethersProvider = new ethers.BrowserProvider(this.provider);

  // For ethers v5
  // const signer = ethersProvider.getSigner();
  const signer = await ethersProvider.getSigner();

  // Get the user's Ethereum public address
  const address = signer.getAddress();
  console.log(address);
};

View User Balance​

const getBalance = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  const web3 = new Web3(provider as any);
  const accounts = await web3.eth.getAccounts();
  const balance = await web3.eth.getBalance(accounts[0]);
  console.log(web3.utils.fromWei(balance));
};

const getBalance = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  // For ethers v5
  // const ethersProvider = new ethers.providers.Web3Provider(this.provider);
  const ethersProvider = new ethers.BrowserProvider(this.provider);

  // For ethers v5
  // const signer = ethersProvider.getSigner();
  const signer = await ethersProvider.getSigner();

  // Get the user's Ethereum public address
  const address = signer.getAddress();

  // Get the user's balance in ether
  // For ethers v5
  // const balance = ethers.utils.formatEther(
  // await ethersProvider.getBalance(address) // Balance is in wei
  // );
  const balance = ethers.formatEther(
    await ethersProvider.getBalance(address), // Balance is in wei
  );
  console.log(balance);
};

Sign Message​

const signMessage = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  const web3 = new Web3(provider as any);
  // Get user's Ethereum public address
  const account = (await web3.eth.getAccounts())[0];

  // Message
  const message = "Hello MPC, Bye Bye SeedPhrase";

  const typedMessage = [
    {
      type: "string",
      name: "message",
      value: message,
    },
  ];
  const params = [JSON.stringify(typedMessage), account];
  const method = "eth_signTypedData";

  const signedMessage = await this.provider.request({
    method,
    params,
  });
  console.log(signedMessage);
};

const signMessage = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  // For ethers v5
  // const ethersProvider = new ethers.providers.Web3Provider(this.provider);
  const ethersProvider = new ethers.BrowserProvider(this.provider);

  // For ethers v5
  // const signer = ethersProvider.getSigner();
  const signer = await ethersProvider.getSigner();
  const originalMessage = "YOUR_MESSAGE";

  // Sign the message
  const signedMessage = await signer.signMessage(originalMessage);

  console.log(signedMessage);
};

Sign Transaction​

const signTransaction = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  const web3 = new Web3(provider as any);
  const accounts = await web3.eth.getAccounts();

  const txRes = await web3.eth.signTransaction({
    from: accounts[0],
    to: accounts[0],
    value: web3.utils.toWei("0.0001"),
    chainId: 1, // change it to your specific chain id.
  });
  console.log(txRes.transactionHash);
};

Send Transaction​

const sendTransaction = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  const web3 = new Web3(provider as any);
  const accounts = await web3.eth.getAccounts();

  const txRes = await web3.eth.sendTransaction({
    from: accounts[0],
    to: accounts[0],
    value: web3.utils.toWei("0.0001"),
    chainId: 1, // change it to your specific chain id.
  });
  console.log(txRes.transactionHash);
};

const sendTransaction = async () => {
  if (!provider) {
    console.log("provider not initialized yet");
    return;
  }
  // For ethers v5
  // const ethersProvider = new ethers.providers.Web3Provider(this.provider);
  const ethersProvider = new ethers.BrowserProvider(this.provider);

  // For ethers v5
  // const signer = ethersProvider.getSigner();
  const signer = await ethersProvider.getSigner();

  const destination = "0x40e1c367Eca34250cAF1bc8330E9EddfD403fC56";

  // Convert 1 ether to wei
  // For ethers v5
  // const amount = ethers.utils.parseEther("0.001");
  const amount = ethers.parseEther("0.001");

  // Submit transaction to the blockchain
  const tx = await signer.sendTransaction({
    to: destination,
    value: amount,
    maxPriorityFeePerGas: "5000000000", // Max priority fee per gas
    maxFeePerGas: "6000000000000", // Max fee per gas
  });

  // Wait for the transaction to be mined
  const receipt = await tx.wait();

  console.log(receipt.transactionHash);
};

Example code​

The code for the application we developed in this guide can be found in the Web3Auth Core Google Login Example. Check it out and try running it locally yourself!

Questions?​

Ask us on Web3Auth's Community Support Portal