Build a User Management App with NextJS

This tutorial demonstrates how to build a basic user management app. The app authenticates and identifies the user, stores their profile information in the database, and allows the user to log in, update their profile details, and upload a profile photo. The app uses:

• Supabase Database - a Postgres database for storing your user data and Row Level Security so data is protected and users can only access their own information.
• Supabase Auth - users log in through magic links sent to their email (without having to set up passwords).
• Supabase Storage - users can upload a profile photo.

Video Guide#

Project setup#

Before we start building we're going to set up our Database and API. This is as simple as starting a new Project in Supabase and then creating a "schema" inside the database.

Create a project#

1. Create a new project in the Supabase Dashboard.
2. Enter your project details.
3. Wait for the new database to launch.

Set up the database schema#

Now we are going to set up the database schema. We can use the "User Management Starter" quickstart in the SQL Editor, or you can just copy/paste the SQL from below and run it yourself.

Get the API Keys#

Now that you've created some database tables, you are ready to insert data using the auto-generated API. We just need to get the Project URL and anon key from the API settings.

1. Go to the API Settings page in the Dashboard.
2. Find your Project URL, anon, and service_role keys on this page.

Building the App#

Let's start building the Next.js app from scratch.

Initialize a Next.js app#

We can use create-next-app to initialize an app called supabase-nextjs:

1npx create-next-app@latest --use-npm supabase-nextjs
2cd supabase-nextjs

Then install the Supabase client library: supabase-js

1npm install @supabase/supabase-js

And finally we want to save the environment variables in a .env.local. All we need are the API URL and the anon key that you copied earlier.

1NEXT_PUBLIC_SUPABASE_URL=YOUR_SUPABASE_URL
2NEXT_PUBLIC_SUPABASE_ANON_KEY=YOUR_SUPABASE_ANON_KEY

And one optional step is to update the CSS file styles/globals.css to make the app look nice. You can find the full contents of this file here.

Set up a Login component#

Supabase Auth Helpers

Next.js is a highly versatile framework offering pre-rendering at build time (SSG), server-side rendering at request time (SSR), API routes, and middleware edge-functions.

It can be challenging to authenticate your users in all these different environments, that's why we've created the Supabase Auth Helpers to make user management and data fetching within Next.js as easy as possible.

Install the auth helpers for React and Next.js

1npm install @supabase/auth-helpers-react @supabase/auth-helpers-nextjs

import '../styles/globals.css'
import { createBrowserSupabaseClient } from '@supabase/auth-helpers-nextjs'
import { SessionContextProvider } from '@supabase/auth-helpers-react'
import { useState } from 'react'

function MyApp({ Component, pageProps }) {
  const [supabase] = useState(() => createBrowserSupabaseClient())

  return (
    <SessionContextProvider supabaseClient={supabase} initialSession={pageProps.initialSession}>
      <Component {...pageProps} />
    </SessionContextProvider>
  )
}
export default MyApp

Supabase Auth UI

We can use the Supabase Auth UI a pre-built React component for authenticating users via OAuth, email, and magic links.

Install the Supabase Auth UI for React

1npm install @supabase/auth-ui-react

Add the Auth component to your home page

import { Auth } from '@supabase/auth-ui-react'
import { ThemeSupa } from '@supabase/auth-ui-shared'
import { useSession, useSupabaseClient } from '@supabase/auth-helpers-react'

const Home = () => {
  const session = useSession()
  const supabase = useSupabaseClient()

  return (
    <div className="container" style={{ padding: '50px 0 100px 0' }}>
      {!session ? (
        <Auth supabaseClient={supabase} appearance={{ theme: ThemeSupa }} theme="dark" />
      ) : (
        <p>Account page will go here.</p>
      )}
    </div>
  )
}

export default Home

Account page#

After a user is signed in we can allow them to edit their profile details and manage their account.

import { useState, useEffect } from 'react'
import { useUser, useSupabaseClient } from '@supabase/auth-helpers-react'

export default function Account({ session }) {
  const supabase = useSupabaseClient()
  const user = useUser()
  const [loading, setLoading] = useState(true)
  const [username, setUsername] = useState(null)
  const [website, setWebsite] = useState(null)
  const [avatar_url, setAvatarUrl] = useState(null)

  useEffect(() => {
    getProfile()
  }, [session])

  async function getProfile() {
    try {
      setLoading(true)

      let { data, error, status } = await supabase
        .from('profiles')
        .select(`username, website, avatar_url`)
        .eq('id', user.id)
        .single()

      if (error && status !== 406) {
        throw error
      }

      if (data) {
        setUsername(data.username)
        setWebsite(data.website)
        setAvatarUrl(data.avatar_url)
      }
    } catch (error) {
      alert('Error loading user data!')
      console.log(error)
    } finally {
      setLoading(false)
    }
  }

  async function updateProfile({ username, website, avatar_url }) {
    try {
      setLoading(true)

      const updates = {
        id: user.id,
        username,
        website,
        avatar_url,
        updated_at: new Date().toISOString(),
      }

      let { error } = await supabase.from('profiles').upsert(updates)
      if (error) throw error
      alert('Profile updated!')
    } catch (error) {
      alert('Error updating the data!')
      console.log(error)
    } finally {
      setLoading(false)
    }
  }

  return (
    <div className="form-widget">
      <div>
        <label htmlFor="email">Email</label>
        <input id="email" type="text" value={session.user.email} disabled />
      </div>
      <div>
        <label htmlFor="username">Username</label>
        <input
          id="username"
          type="text"
          value={username || ''}
          onChange={(e) => setUsername(e.target.value)}
        />
      </div>
      <div>
        <label htmlFor="website">Website</label>
        <input
          id="website"
          type="url"
          value={website || ''}
          onChange={(e) => setWebsite(e.target.value)}
        />
      </div>

      <div>
        <button
          className="button primary block"
          onClick={() => updateProfile({ username, website, avatar_url })}
          disabled={loading}
        >
          {loading ? 'Loading ...' : 'Update'}
        </button>
      </div>

      <div>
        <button className="button block" onClick={() => supabase.auth.signOut()}>
          Sign Out
        </button>
      </div>
    </div>
  )
}

Launch!#

Now that we have all the components in place, let's update pages/index.js:

import { Auth } from '@supabase/auth-ui-react'
import { ThemeSupa } from '@supabase/auth-ui-shared'
import { useSession, useSupabaseClient } from '@supabase/auth-helpers-react'
import Account from '../components/Account'

const Home = () => {
  const session = useSession()
  const supabase = useSupabaseClient()

  return (
    <div className="container" style={{ padding: '50px 0 100px 0' }}>
      {!session ? (
        <Auth supabaseClient={supabase} appearance={{ theme: ThemeSupa }} theme="dark" />
      ) : (
        <Account session={session} />
      )}
    </div>
  )
}

export default Home

Once that's done, run this in a terminal window:

1npm run dev

And then open the browser to localhost:3000 and you should see the completed app.

Bonus: Profile photos#

Every Supabase project is configured with Storage for managing large files like photos and videos.

Create an upload widget#

Let's create an avatar widget for the user so that they can upload a profile photo. We can start by creating a new component:

import React, { useEffect, useState } from 'react'
import { useSupabaseClient } from '@supabase/auth-helpers-react'

export default function Avatar({ uid, url, size, onUpload }) {
  const supabase = useSupabaseClient()
  const [avatarUrl, setAvatarUrl] = useState(null)
  const [uploading, setUploading] = useState(false)

  useEffect(() => {
    if (url) downloadImage(url)
  }, [url])

  async function downloadImage(path) {
    try {
      const { data, error } = await supabase.storage.from('avatars').download(path)
      if (error) {
        throw error
      }
      const url = URL.createObjectURL(data)
      setAvatarUrl(url)
    } catch (error) {
      console.log('Error downloading image: ', error)
    }
  }

  const uploadAvatar = async (event) => {
    try {
      setUploading(true)

      if (!event.target.files || event.target.files.length === 0) {
        throw new Error('You must select an image to upload.')
      }

      const file = event.target.files[0]
      const fileExt = file.name.split('.').pop()
      const fileName = `${uid}.${fileExt}`
      const filePath = `${fileName}`

      let { error: uploadError } = await supabase.storage
        .from('avatars')
        .upload(filePath, file, { upsert: true })

      if (uploadError) {
        throw uploadError
      }

      onUpload(filePath)
    } catch (error) {
      alert('Error uploading avatar!')
      console.log(error)
    } finally {
      setUploading(false)
    }
  }

  return (
    <div>
      {avatarUrl ? (
        <img
          src={avatarUrl}
          alt="Avatar"
          className="avatar image"
          style={{ height: size, width: size }}
        />
      ) : (
        <div className="avatar no-image" style={{ height: size, width: size }} />
      )}
      <div style={{ width: size }}>
        <label className="button primary block" htmlFor="single">
          {uploading ? 'Uploading ...' : 'Upload'}
        </label>
        <input
          style={{
            visibility: 'hidden',
            position: 'absolute',
          }}
          type="file"
          id="single"
          accept="image/*"
          onChange={uploadAvatar}
          disabled={uploading}
        />
      </div>
    </div>
  )
}

Add the new widget#

And then we can add the widget to the Account page:

// Import the new component
import Avatar from './Avatar'

// ...

return (
  <div className="form-widget">
    {/* Add to the body */}
    <Avatar
      uid={user.id}
      url={avatar_url}
      size={150}
      onUpload={(url) => {
        setAvatarUrl(url)
        updateProfile({ username, website, avatar_url: url })
      }}
    />
    {/* ... */}
  </div>
)

Storage management#

If you upload additional profile photos, they'll accumulate in the avatars bucket because of their random names with only the latest being referenced from public.profiles and the older versions getting orphaned.

To automatically remove obsolete storage objects, extend the database triggers. Note that it is not sufficient to delete the objects from the storage.objects table because that would orphan and leak the actual storage objects in the S3 backend. Instead, invoke the storage API within Postgres via the http extension.

Enable the http extension for the extensions schema in the Dashboard. Then, define the following SQL functions in the SQL Editor to delete storage objects via the API:

create or replace function delete_storage_object(bucket text, object text, out status int, out content text)
returns record
language 'plpgsql'
security definer
as $$
declare
  project_url text := '<YOURPROJECTURL>';
  service_role_key text := '<YOURSERVICEROLEKEY>'; --  full access needed
  url text := project_url||'/storage/v1/object/'||bucket||'/'||object;
begin
  select
      into status, content
           result.status::int, result.content::text
      FROM extensions.http((
    'DELETE',
    url,
    ARRAY[extensions.http_header('authorization','Bearer '||service_role_key)],
    NULL,
    NULL)::extensions.http_request) as result;
end;
$$;

create or replace function delete_avatar(avatar_url text, out status int, out content text)
returns record
language 'plpgsql'
security definer
as $$
begin
  select
      into status, content
           result.status, result.content
      from public.delete_storage_object('avatars', avatar_url) as result;
end;
$$;

Next, add a trigger that removes any obsolete avatar whenever the profile is updated or deleted:

create or replace function delete_old_avatar()
returns trigger
language 'plpgsql'
security definer
as $$
declare
  status int;
  content text;
begin
  if coalesce(old.avatar_url, '') <> ''
      and (tg_op = 'DELETE' or (old.avatar_url <> new.avatar_url)) then
    select
      into status, content
      result.status, result.content
      from public.delete_avatar(old.avatar_url) as result;
    if status <> 200 then
      raise warning 'Could not delete avatar: % %', status, content;
    end if;
  end if;
  if tg_op = 'DELETE' then
    return old;
  end if;
  return new;
end;
$$;

create trigger before_profile_changes
  before update of avatar_url or delete on public.profiles
  for each row execute function public.delete_old_avatar();

Finally, delete the public.profile row before a user is deleted. If this step is omitted, you won't be able to delete users without first manually deleting their avatar image.

create or replace function delete_old_profile()
returns trigger
language 'plpgsql'
security definer
as $$
begin
  delete from public.profiles where id = old.id;
  return old;
end;
$$;

create trigger before_delete_user
  before delete on auth.users
  for each row execute function public.delete_old_profile();

At this stage you have a fully functional application!

See also#

• See the complete example on GitHub and deploy it to Vercel
• Explore the pre-built Auth UI for React
• Explore the Auth Helpers for Next.js
• Explore the Supabase Cache Helpers
• See the Next.js Subscription Payments Starter template on GitHub