😱 Crazy new Supabase feature: Understand and learn about anonymous users

Summary

This tutorial covers how to implement anonymous user functionality in a Superbase-powered e-commerce app, allowing users to add items to their shopping cart without signing in. It explains how to create anonymous users, convert them to real users at checkout, and merge their cart data. The video also highlights potential issues such as database clutter from anonymous users, security concerns, and the need for regular cleanup. It provides practical solutions, such as using a custom function to merge anonymous user data, while emphasizing the importance of handling these features carefully for optimal user experience and security.

Takeaways

• 😀 Enabling anonymous users in Superbase simplifies the development of public-facing applications by allowing users to add items to a shopping cart without signing in.
• 😀 Anonymous users can be converted to real users in Superbase by simply linking them to an email, making the transition smooth without disrupting the cart functionality.
• 😀 The Superbase feature for anonymous sign-ins can be activated through the project's authentication settings, simplifying the process for users who aren't signed in.
• 😀 There are two main tables in the example project: 'products' (with product names, image paths, and costs) and 'cart items' (which links products with user IDs).
• 😀 The main issue with anonymous users is avoiding confusion by properly differentiating between signed-in and anonymous users in the user interface.
• 😀 To merge anonymous users' cart data with a signed-in user's cart, an RPC function can be created to copy cart items between user IDs, with admin privileges for the operation.
• 😀 When enabling anonymous sign-ins, developers should expect to manage many anonymous users in the database, which may require cleanup over time.
• 😀 A pitfall when enabling anonymous sign-ins is that security policies (such as access control for certain tables) can be inadvertently weakened if not handled carefully.
• 😀 Developers can link an anonymous user to external OAuth providers (like Google) to seamlessly convert them into a real user while preserving their cart data.
• 😀 Users can face issues where the cart items added anonymously are lost when they sign in. To address this, cart items must be merged between the anonymous and signed-in user accounts.
• 😀 It's important to regularly clean up old anonymous users from the database based on conditions like user inactivity to maintain performance and data hygiene.

Q & A

What is the primary benefit of enabling anonymous users in an e-commerce application?

The primary benefit is allowing users to add items to their shopping cart without needing to sign in, simplifying the user experience and reducing friction during the shopping process.

How does the Superbase setup handle anonymous sign-ins?

To enable anonymous sign-ins in Superbase, you need to set the 'Enable Anonymous Sign-ins' option to true in the Superbase project configuration. This allows users to be automatically signed in anonymously if they are not logged in.

What happens when an anonymous user decides to check out?

When an anonymous user decides to check out, they are prompted to provide their email address. This converts the anonymous user to a real user, and they can proceed with the order once their account is confirmed.

What problem arises when using anonymous users in the shopping cart system, and how is it solved?

The problem is that the shopping cart is tied to the anonymous user's session, and if they sign out or close the browser, their cart is lost. The solution is to enable anonymous sign-ins and allow users to add items to the cart even without being signed in.

How does the React code handle user authentication state changes?

The React code listens for authentication state changes using a custom hook that subscribes to Superbase's authentication events. It updates the UI based on whether the user is signed in or anonymous, reflecting the correct state in the app.

What happens if an anonymous user logs in after adding items to their cart?

If an anonymous user logs in, their items in the cart are not lost. Instead, they are merged with the items of their new signed-in user account. This ensures the user's cart persists across sessions.

What is the role of the `useRef` hook in the anonymous user flow?

The `useRef` hook is used to track if an anonymous user has already been created. It prevents the system from creating multiple anonymous users during a session, especially during multiple re-renders in development mode when React's strict mode is enabled.

What potential issue should developers be aware of when enabling anonymous users for their app?

A key issue is that enabling anonymous users can lead to a large number of unverified accounts filling the database. Developers need to manage these anonymous users properly, including implementing cleanup procedures to remove old accounts.

How can you clean up old anonymous users in the Superbase database?

You can clean up old anonymous users by running a query to delete users whose `is_anonymous` field is true and who have not been updated in a specified time period, such as users who haven't been active for more than 10 days.

What security risk is associated with using anonymous users, and how can it be mitigated?

A security risk is that enabling anonymous users can inadvertently bypass role-based access control policies, especially for tables like blog posts where access should be restricted to authenticated users. This can be mitigated by ensuring that access policies check whether the user is truly authenticated before granting access.