Build a User Management App with Flutter
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.
If you get stuck while working through this guide, refer to the full example on GitHub.
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#
- Create a new project in the Supabase Dashboard.
- Enter your project details.
- 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.
- Go to the SQL Editor page in the Dashboard.
- Click User Management Starter.
- Click Run.
You can easily pull the database schema down to your local project by running the following commands:
_10supabase link_10supabase db pull
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.
- Go to the API Settings page in the Dashboard.
- Find your Project
service_rolekeys on this page.
Building the App#
Let's start building the Flutter app from scratch.
Initialize a Flutter app#
We can use
flutter create to initialize
an app called
_10flutter create supabase_quickstart
Then let's install the only additional dependency:
Copy and paste the following line in your pubspec.yaml to install the package:
flutter pub get to install the dependencies.
Setup deep links#
Now that we have the dependencies installed let's setup deep links. Setting up deep links is required to bring back the user to the app when they click on the magic link to sign in. We can setup deep links with just a minor tweak on our Flutter application.
We will use
io.supabase.flutterquickstart as the scheme, and
login-callback as the host for our deep link in this example, but you can change it to whatever you would like.
io.supabase.flutterquickstart://login-callback/ as a new redirect URL in the Dashboard.
That is it on Supabase's end and the rest are platform specific settings:
Add CFBundleURLTypes to enable deep linking:
Now that we have deep links ready let's initialize the Supabase client inside our
main function with the API credentials that you copied earlier.
These variables will be exposed on the app, and that's completely fine since we have
Row Level Security enabled on our Database.
authFlowType parameter indicates that we are using a secure PKCE flow to perform our magic link login.
Set up Splash Screen#
Let's create a splash screen that will be shown to users right after they open the app. This screen retrieves the current session and redirects the user accordingly.
Set up a Login page#
Let's create a Flutter widget to manage logins and sign ups.
We'll use Magic Links, so users can sign in with their email without using passwords.
Notice that this page sets up a listener on the user's auth state using
A new event will fire when the user comes back to the app by clicking their magic link, which this page can catch and redirect the user accordingly.
Set up Account page#
After a user is signed in we can allow them to edit their profile details and manage their account.
Let's create a new widget called
account_page.dart for that.
Now that we have all the components in place, let's update
Once that's done, run this in a terminal window to launch on Android or iOS:
Or for web, run the following command to launch it on
_10flutter run -d web-server --web-hostname localhost --web-port 3000
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.
Making sure we have a public bucket#
We will be storing the image as a publicly sharable image.
Make sure your
avatars bucket is set to public, and if it is not, change the publicity by clicking the dot menu that appears when you hover over the bucket name.
You should see an orange
Public badge next to your bucket name if your bucket is set to public.
Adding image uploading feature to Account page#
We will use
image_picker plugin to select an image from the device.
Add the following line in your pubspec.yaml file to install
Once you are done with all of the above, it is time to dive into coding.
Create an upload widget#
Let's create an avatar for the user so that they can upload a profile photo. We can start by creating a new component:
Add the new widget#
And then we can add the widget to the Account page as well as some logic to update the
avatar_url whenever the user uploads a new avatar.
If you upload additional profile photos, they'll accumulate
avatars bucket because of their random names with only the latest being referenced
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
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:
_34create or replace function delete_storage_object(bucket text, object text, out status int, out content text)_34returns record_34language 'plpgsql'_34security definer_34as $$_34declare_34project_url text := '<YOURPROJECTURL>';_34service_role_key text := '<YOURSERVICEROLEKEY>'; -- full access needed_34url text := project_url||'/storage/v1/object/'||bucket||'/'||object;_34begin_34select_34into status, content_34result.status::int, result.content::text_34FROM extensions.http((_34'DELETE',_34url,_34ARRAY[extensions.http_header('authorization','Bearer '||service_role_key)],_34NULL,_34NULL)::extensions.http_request) as result;_34end;_34$$;_34_34create or replace function delete_avatar(avatar_url text, out status int, out content text)_34returns record_34language 'plpgsql'_34security definer_34as $$_34begin_34select_34into status, content_34result.status, result.content_34from public.delete_storage_object('avatars', avatar_url) as result;_34end;_34$$;
Next, add a trigger that removes any obsolete avatar whenever the profile is updated or deleted:
_32create or replace function delete_old_avatar()_32returns trigger_32language 'plpgsql'_32security definer_32as $$_32declare_32status int;_32content text;_32avatar_name text;_32begin_32if coalesce(old.avatar_url, '') <> ''_32and (tg_op = 'DELETE' or (old.avatar_url <> new.avatar_url)) then_32-- extract avatar name_32avatar_name := old.avatar_url;_32select_32into status, content_32result.status, result.content_32from public.delete_avatar(avatar_name) as result;_32if status <> 200 then_32raise warning 'Could not delete avatar: % %', status, content;_32end if;_32end if;_32if tg_op = 'DELETE' then_32return old;_32end if;_32return new;_32end;_32$$;_32_32create trigger before_profile_changes_32before update of avatar_url or delete on public.profiles_32for 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.
_14create or replace function delete_old_profile()_14returns trigger_14language 'plpgsql'_14security definer_14as $$_14begin_14delete from public.profiles where id = old.id;_14return old;_14end;_14$$;_14_14create trigger before_delete_user_14before delete on auth.users_14for each row execute function public.delete_old_profile();
Congratulations, you've built a fully functional user management app using Flutter and Supabase!