How to check if a user is authenticated in Supabase?

 

Step 1: Set up a Supabase Project

 

Before checking if a user is authenticated, you need to set up a Supabase project. If you haven't done so, follow these steps:

• Go to the Supabase website.
• Sign up or log in to your account.
• Create a new project.
• Once the project is created, take note of your API URL and API Key, which you will use to connect your application to Supabase.

 

Step 2: Install Supabase Client Library

 

You need to install the Supabase client library in your application. If you are using Node.js or React, you can do this with npm or yarn.

# Using npm
npm install @supabase/supabase-js

# Using yarn
yarn add @supabase/supabase-js

 

Step 3: Initialize Supabase Client

 

After installing the library, initialize the Supabase client in your application code using the API URL and API Key obtained from your Supabase project.

import { createClient } from '@supabase/supabase-js'

const SUPABASE_URL = 'your_supabase_url' // Replace with your API URL
const SUPABASE_KEY = 'your_supabase_key' // Replace with your API Key

const supabase = createClient(SUPABASE_URL, SUPABASE_KEY)

 

Step 4: Check User Authentication Status

 

To check if a user is authenticated, you can use the auth.getSession() method provided by Supabase. This method retrieves the current session, which contains user information if a user is authenticated.

const checkUserAuthentication = async () => {
  const { data: { session }, error } = await supabase.auth.getSession()

  if (error) {
    console.error('Error retrieving session:', error)
    return null
  }

  if (session) {
    console.log('User is authenticated:', session.user)
    return session.user
  } else {
    console.log('No user is authenticated')
    return null
  }
}

Call this function at the point in your application where you need to verify if a user is logged in.

 

Step 5: Handle User Login

 

If you need to prompt users to log in, you can use the signInWithPassword() method to handle authentication with email and password.

const loginUser = async (email, password) => {
  const { data, error } = await supabase.auth.signInWithPassword({
    email,
    password
  })

  if (error) {
    console.error('Login failed:', error.message)
  } else {
    console.log('Login successful:', data)
  }
}

Call loginUser(email, password) with the user's credentials to log them in.

 

Step 6: Handle User Logout

 

To log the user out, use the signOut() method to end the current user session.

const logoutUser = async () => {
  const { error } = await supabase.auth.signOut()

  if (error) {
    console.error('Logout failed:', error.message)
  } else {
    console.log('Logout successful')
  }
}

Call logoutUser() when you need to log the user out of the application.

 

Conclusion

 

By following these steps, you can effectively check if a user is authenticated in Supabase, handle user logins, and manage user sessions with ease. Ensure to replace the placeholders with your specific project's API URL and API Key to connect successfully with Supabase.