The cryptocurrency wallet is the main touchpoint connecting prospects and customers in the Web3 app. Furthermore, it’s a trending fashionable approach to appeal to new signups and convert more sales.
In this article, I would briefly walk through how to let new users sign up for an account on your web app using Metamask API. By the end of this article, your visitors can sign up using the MetaMask wallet and you can identify the users using the wallet public key.
Table of Contents: Web App New User Sign-up, Login Using Metamask API, Javascript
- MetaMask Javascript Code in Frontend
- Flask Route Code in Backend to Store the Public Key
- Full Javascript and Python Script of User Sign-up and Login System
- FAQ
MetaMask Javascript Code in Frontend
First thing first, it requires developers to add the Ethereum provider detector script between the header
<script src="https://cdn.jsdelivr.net/npm/@metamask/detect-provider"></script>Then, we need to write a Javascript to trigger the Metamask account access request when the user clicks the signup or login button.
<section> <form action="/login" method="GET" onsubmit="return false;"> <button id="connect-button" type="button">Connect with MetaMask</button> </form> </section> <script> const connectButton = document.querySelector('#connect-button');In this case, there are two scenarios. M. etaMask extension has been installed or not on the browser. Therefore, we need to add an if condition in this click event.
connectButton.addEventListener('click', async () => { // Check if MetaMask is installed if (typeof window.ethereum === 'undefined') { alert('Please install MetaMask to continue.'); Return; }The next step requires us to call the MetaMask and grab the account address for creating a new User ID in a database or identify whom when the user logins in.
const accounts = await window.ethereum.request({ method: 'eth_requestAccounts' }); const metamaskAddress = accounts[0];Last but not least, we will send the account public key to the web app database. As MetaMask uses the args.get parameter. So here is the code sample as follows:
window.location.href = '/login?metamask_address=' + metamaskAddress; } catch (error) { console.error(error);Flask Route Code in Backend to Store the Public Key
Once the user confirms to connect with your Web App, her or his wallet public key would respond to your app server. Here is the code sample to capture the key for user authentication from now on.
@app.route('/login', methods=['GET', 'POST'])def login(): metamask_address = request.args.get('metamask_address') return render_template('masklogin.html', metamask_address=metamask_address)Regarding the new user database setup, here are two articles in which one elaborates on using SQL and the other explains MongoDB. For more details, please check out.
https://www.easy2digital.com/automation/data/python-tutorial-66-flask-application-database-using-mongodb-atlas-and-python-to-better-big-data-management/
Full Javascript and Python Script of User Sign-up and Login System
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