Supabase Auth: Create A Login Page

by Alex Braham 35 views

Hey guys! Let's dive into setting up a login page using Supabase auth. Supabase is an awesome open-source Firebase alternative that provides a suite of tools to help you build scalable and secure applications. Authentication is a critical aspect of any web application, and Supabase makes it incredibly easy to implement. In this guide, we'll walk through the steps to create a simple yet effective login page using Supabase.

Setting Up Your Supabase Project

Before we get our hands dirty with code, we need to set up a Supabase project. This is where you'll manage your database, authentication, and other backend services. Follow these steps to get started:

  1. Create a Supabase Account:

    • Head over to the Supabase website and sign up for a free account. Supabase offers a generous free tier that's perfect for learning and small projects.

  2. Create a New Project:

    • Once you're logged in, click on the "New Project" button. You'll be prompted to enter a name for your project, choose a region, and set a database password. Make sure to choose a strong password and keep it safe!

  3. Wait for Project to Initialize:

    • Supabase will take a few minutes to set up your project. Once it's ready, you'll be redirected to the project dashboard.

  4. Get Your API Keys:

    • In the project dashboard, navigate to the "Settings" section and then click on "API." Here, you'll find your project's API URL and API key. You'll need these to connect your login page to Supabase.

    • Important Note: There are two types of keys: anon and service_role. For client-side applications like our login page, you should use the anon (anonymous) key. The service_role key has higher privileges and should be kept secure on your server.

With your Supabase project set up and your API keys in hand, we're ready to start building the login page.

Building the Login Page

Let's create a basic HTML form for our login page. This form will contain fields for email and password, as well as a button to submit the form. Here's the HTML structure:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Supabase Login</title>
</head>
<body>
    
        <h1>Login</h1>
        <form id="loginForm">
            
                <label for="email">Email:</label>
                <input type="email" id="email" name="email" required>
            
            
                <label for="password">Password:</label>
                <input type="password" id="password" name="password" required>
            
            <button type="submit">Login</button>
        </form>
        <div id="message"></div>
    

    <script src="script.js"></script>
</body>
</html>

This HTML code sets up a simple login form with fields for email and password. When the form is submitted, the login function in script.js will be called.

Adding JavaScript for Authentication

Now, let's add some JavaScript to handle the authentication logic. We'll use the Supabase client library to interact with the Supabase API. Make sure you have included the Supabase client library in your HTML file. You can add it via CDN:

<script src="https://cdn.jsdelivr.net/npm/@supabase/supabase-js@2"></script>

Here's the JavaScript code to handle the login functionality:

const SUPABASE_URL = 'YOUR_SUPABASE_URL';
const SUPABASE_ANON_KEY = 'YOUR_SUPABASE_ANON_KEY';

const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);

const loginForm = document.getElementById('loginForm');
const messageDiv = document.getElementById('message');

loginForm.addEventListener('submit', async (event) => {
    event.preventDefault();

    const email = document.getElementById('email').value;
    const password = document.getElementById('password').value;

    const { data, error } = await supabase.auth.signInWithPassword({
        email: email,
        password: password,
    });

    if (error) {
        messageDiv.textContent = `Error: ${error.message}`;
    } else {
        messageDiv.textContent = 'Login successful!';
        console.log('User logged in:', data);
        // Redirect to dashboard or another page
        window.location.href = '/dashboard'; // Example redirect
    }
});

Explanation:

  • Initialize Supabase Client: We start by initializing the Supabase client with your project's URL and anonymous key. Replace 'YOUR_SUPABASE_URL' and 'YOUR_SUPABASE_ANON_KEY' with your actual Supabase URL and key.
  • Get Form Elements: We grab references to the login form and the message div to display feedback to the user.
  • Handle Form Submission: We add an event listener to the form that triggers when the user submits it. Inside the event listener, we prevent the default form submission behavior, get the email and password from the form fields, and then call the supabase.auth.signInWithPassword method to authenticate the user.
  • Handle Response: We check the response for errors. If there's an error, we display it in the message div. If the login is successful, we display a success message and redirect the user to the dashboard or another page.

Enhancing the User Experience

While the above code provides the basic functionality for a login page, there are several ways to enhance the user experience.

Adding Real-time Error Handling

Rather than waiting for the form to be submitted to display errors, you can add real-time error handling to provide immediate feedback to the user as they type. This can help prevent frustration and improve the overall user experience.

Implementing Password Reset

It's crucial to provide users with a way to reset their passwords if they forget them. Supabase provides built-in support for password resets, which you can easily integrate into your login page.

Adding Social Login

Social login allows users to sign up and log in using their existing accounts from providers like Google, Facebook, and GitHub. Supabase supports social login out of the box, making it easy to add this feature to your application.

Adding Input Validation

Validating user input on the client-side can help prevent errors and improve the security of your application. For example, you can use JavaScript to check if the email address is in a valid format or if the password meets certain complexity requirements.

Implementing Remember Me

The "Remember Me" feature allows users to stay logged in even after they close their browser. This can be implemented using cookies or local storage.

Customizing the UI

Don't be afraid to customize the UI of your login page to match your brand. You can use CSS to style the form elements, add your logo, and create a unique look and feel.

Securing Your Login Page

Security is paramount when dealing with user authentication. Here are some best practices to keep your login page secure:

Use HTTPS

Always serve your login page over HTTPS to encrypt the communication between the client and the server. This prevents eavesdropping and man-in-the-middle attacks.

Protect Against Brute-Force Attacks

Implement rate limiting to prevent attackers from trying to guess passwords by making a large number of login attempts. Supabase provides built-in rate limiting features that you can use.

Sanitize User Input

Always sanitize user input to prevent cross-site scripting (XSS) attacks. This involves escaping any HTML or JavaScript code that users enter into the form fields.

Use Strong Passwords

Encourage users to choose strong passwords that are difficult to guess. You can enforce password complexity requirements, such as requiring a minimum length and including a mix of uppercase letters, lowercase letters, numbers, and symbols.

Store Passwords Securely

Never store passwords in plain text. Always hash passwords using a strong hashing algorithm like bcrypt or Argon2. Supabase handles password hashing automatically, so you don't have to worry about this.

Conclusion

Setting up a login page with Supabase auth is straightforward, thanks to Supabase's simple API and client libraries. By following the steps outlined in this guide, you can quickly create a secure and functional login page for your application. Remember to enhance the user experience and implement security best practices to ensure the safety of your users' data.

So there you have it! You've successfully created a login page using Supabase. This is just the beginning, though. Supabase offers a ton of other features, like social login, password resets, and real-time database updates. Feel free to explore the Supabase documentation to learn more and build even more awesome features into your application. Happy coding!