Build a User Management App with Expo React Native

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.

Supabase User Management example

note

If you get stuck while working through this guide, refer to the full example on GitHub.

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#

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.

note

You can easily pull the database schema down to your local project by running the db pull command. Read the local development docs for detailed instructions.


_10supabase link --project-ref <project-id>
_10# You can get <project-id> from your project's dashboard URL: https://supabase.com/dashboard/project/<project-id>
_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 URL, anon, and service_role keys on this page.

Building the App#

Let's start building the React Native app from scratch.

Initialize a React Native app#

We can use expo to initialize an app called expo-user-management:


_10npx create-expo-app -t expo-template-blank-typescript expo-user-management
_10
_10cd expo-user-management

Then let's install the additional dependencies: supabase-js


_10npx expo install @supabase/supabase-js @react-native-async-storage/async-storage react-native-elements react-native-url-polyfill

Now let's create a helper file to initialize the Supabase client. We need the API URL and the anon key that you copied earlier. These variables are safe to expose in your Expo app since Supabase has Row Level Security enabled on your Database.

lib/supabase.ts


_15import 'react-native-url-polyfill/auto'
_15import AsyncStorage from '@react-native-async-storage/async-storage'
_15import { createClient } from '@supabase/supabase-js'
_15
_15const supabaseUrl = YOUR_REACT_NATIVE_SUPABASE_URL
_15const supabaseAnonKey = YOUR_REACT_NATIVE_SUPABASE_ANON_KEY
_15
_15export const supabase = createClient(supabaseUrl, supabaseAnonKey, {
_15  auth: {
_15    storage: AsyncStorage,
_15    autoRefreshToken: true,
_15    persistSession: true,
_15    detectSessionInUrl: false,
_15  },
_15})

Let's set up a React Native component to manage logins and sign ups. Users would be able to sign in with their email and password.

components/Auth.tsx


_83import React, { useState } from 'react'
_83import { Alert, StyleSheet, View } from 'react-native'
_83import { supabase } from '../lib/supabase'
_83import { Button, Input } from 'react-native-elements'
_83
_83export default function Auth() {
_83  const [email, setEmail] = useState('')
_83  const [password, setPassword] = useState('')
_83  const [loading, setLoading] = useState(false)
_83
_83  async function signInWithEmail() {
_83    setLoading(true)
_83    const { error } = await supabase.auth.signInWithPassword({
_83      email: email,
_83      password: password,
_83    })
_83
_83    if (error) Alert.alert(error.message)
_83    setLoading(false)
_83  }
_83
_83  async function signUpWithEmail() {
_83    setLoading(true)
_83    const {
_83      data: { session },
_83      error,
_83    } = await supabase.auth.signUp({
_83      email: email,
_83      password: password,
_83    })
_83
_83    if (error) Alert.alert(error.message)
_83    if (!session) Alert.alert('Please check your inbox for email verification!')
_83    setLoading(false)
_83  }
_83
_83  return (
_83    <View style={styles.container}>
_83      <View style={[styles.verticallySpaced, styles.mt20]}>
_83        <Input
_83          label="Email"
_83          leftIcon={{ type: 'font-awesome', name: 'envelope' }}
_83          onChangeText={(text) => setEmail(text)}
_83          value={email}
_83          placeholder="email@address.com"
_83          autoCapitalize={'none'}
_83        />
_83      </View>
_83      <View style={styles.verticallySpaced}>
_83        <Input
_83          label="Password"
_83          leftIcon={{ type: 'font-awesome', name: 'lock' }}
_83          onChangeText={(text) => setPassword(text)}
_83          value={password}
_83          secureTextEntry={true}
_83          placeholder="Password"
_83          autoCapitalize={'none'}
_83        />
_83      </View>
_83      <View style={[styles.verticallySpaced, styles.mt20]}>
_83        <Button title="Sign in" disabled={loading} onPress={() => signInWithEmail()} />
_83      </View>
_83      <View style={styles.verticallySpaced}>
_83        <Button title="Sign up" disabled={loading} onPress={() => signUpWithEmail()} />
_83      </View>
_83    </View>
_83  )
_83}
_83
_83const styles = StyleSheet.create({
_83  container: {
_83    marginTop: 40,
_83    padding: 12,
_83  },
_83  verticallySpaced: {
_83    paddingTop: 4,
_83    paddingBottom: 4,
_83    alignSelf: 'stretch',
_83  },
_83  mt20: {
_83    marginTop: 20,
_83  },
_83})

note

By default Supabase Auth requires email verification before a session is created for the users. To support email verification you need to implement deep link handling!

While testing, you can disable email confirmation in your project's email auth provider settings.

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 component for that called Account.tsx.

components/Account.tsx


_120import { useState, useEffect } from 'react'
_120import { supabase } from '../lib/supabase'
_120import { StyleSheet, View, Alert } from 'react-native'
_120import { Button, Input } from 'react-native-elements'
_120import { Session } from '@supabase/supabase-js'
_120
_120export default function Account({ session }: { session: Session }) {
_120  const [loading, setLoading] = useState(true)
_120  const [username, setUsername] = useState('')
_120  const [website, setWebsite] = useState('')
_120  const [avatarUrl, setAvatarUrl] = useState('')
_120
_120  useEffect(() => {
_120    if (session) getProfile()
_120  }, [session])
_120
_120  async function getProfile() {
_120    try {
_120      setLoading(true)
_120      if (!session?.user) throw new Error('No user on the session!')
_120
_120      const { data, error, status } = await supabase
_120        .from('profiles')
_120        .select(`username, website, avatar_url`)
_120        .eq('id', session?.user.id)
_120        .single()
_120      if (error && status !== 406) {
_120        throw error
_120      }
_120
_120      if (data) {
_120        setUsername(data.username)
_120        setWebsite(data.website)
_120        setAvatarUrl(data.avatar_url)
_120      }
_120    } catch (error) {
_120      if (error instanceof Error) {
_120        Alert.alert(error.message)
_120      }
_120    } finally {
_120      setLoading(false)
_120    }
_120  }
_120
_120  async function updateProfile({
_120    username,
_120    website,
_120    avatar_url,
_120  }: {
_120    username: string
_120    website: string
_120    avatar_url: string
_120  }) {
_120    try {
_120      setLoading(true)
_120      if (!session?.user) throw new Error('No user on the session!')
_120
_120      const updates = {
_120        id: session?.user.id,
_120        username,
_120        website,
_120        avatar_url,
_120        updated_at: new Date(),
_120      }
_120
_120      const { error } = await supabase.from('profiles').upsert(updates)
_120
_120      if (error) {
_120        throw error
_120      }
_120    } catch (error) {
_120      if (error instanceof Error) {
_120        Alert.alert(error.message)
_120      }
_120    } finally {
_120      setLoading(false)
_120    }
_120  }
_120
_120  return (
_120    <View style={styles.container}>
_120      <View style={[styles.verticallySpaced, styles.mt20]}>
_120        <Input label="Email" value={session?.user?.email} disabled />
_120      </View>
_120      <View style={styles.verticallySpaced}>
_120        <Input label="Username" value={username || ''} onChangeText={(text) => setUsername(text)} />
_120      </View>
_120      <View style={styles.verticallySpaced}>
_120        <Input label="Website" value={website || ''} onChangeText={(text) => setWebsite(text)} />
_120      </View>
_120
_120      <View style={[styles.verticallySpaced, styles.mt20]}>
_120        <Button
_120          title={loading ? 'Loading ...' : 'Update'}
_120          onPress={() => updateProfile({ username, website, avatar_url: avatarUrl })}
_120          disabled={loading}
_120        />
_120      </View>
_120
_120      <View style={styles.verticallySpaced}>
_120        <Button title="Sign Out" onPress={() => supabase.auth.signOut()} />
_120      </View>
_120    </View>
_120  )
_120}
_120
_120const styles = StyleSheet.create({
_120  container: {
_120    marginTop: 40,
_120    padding: 12,
_120  },
_120  verticallySpaced: {
_120    paddingTop: 4,
_120    paddingBottom: 4,
_120    alignSelf: 'stretch',
_120  },
_120  mt20: {
_120    marginTop: 20,
_120  },
_120})

Launch!#

Now that we have all the components in place, let's update App.tsx:

App.tsx


_27import 'react-native-url-polyfill/auto'
_27import { useState, useEffect } from 'react'
_27import { supabase } from './lib/supabase'
_27import Auth from './components/Auth'
_27import Account from './components/Account'
_27import { View } from 'react-native'
_27import { Session } from '@supabase/supabase-js'
_27
_27export default function App() {
_27  const [session, setSession] = useState<Session | null>(null)
_27
_27  useEffect(() => {
_27    supabase.auth.getSession().then(({ data: { session } }) => {
_27      setSession(session)
_27    })
_27
_27    supabase.auth.onAuthStateChange((_event, session) => {
_27      setSession(session)
_27    })
_27  }, [])
_27
_27  return (
_27    <View>
_27      {session && session.user ? <Account key={session.user.id} session={session} /> : <Auth />}
_27    </View>
_27  )
_27}

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


_10npm start

And then press the appropriate key for the environment you want to test the app in 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.

Additional dependency installation#

You will need a file picker that works on the environment you will build the project for, we will use react-native-document-picker in this example.


_10expo install react-native-document-picker

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

components/Avatar.tsx


_124import { useState, useEffect } from 'react'
_124import { supabase } from '../lib/supabase'
_124import { StyleSheet, View, Alert, Image, Button } from 'react-native'
_124import DocumentPicker, { isCancel, isInProgress, types } from 'react-native-document-picker'
_124
_124interface Props {
_124  size: number
_124  url: string | null
_124  onUpload: (filePath: string) => void
_124}
_124
_124export default function Avatar({ url, size = 150, onUpload }: Props) {
_124  const [uploading, setUploading] = useState(false)
_124  const [avatarUrl, setAvatarUrl] = useState<string | null>(null)
_124  const avatarSize = { height: size, width: size }
_124
_124  useEffect(() => {
_124    if (url) downloadImage(url)
_124  }, [url])
_124
_124  async function downloadImage(path: string) {
_124    try {
_124      const { data, error } = await supabase.storage.from('avatars').download(path)
_124
_124      if (error) {
_124        throw error
_124      }
_124
_124      const fr = new FileReader()
_124      fr.readAsDataURL(data)
_124      fr.onload = () => {
_124        setAvatarUrl(fr.result as string)
_124      }
_124    } catch (error) {
_124      if (error instanceof Error) {
_124        console.log('Error downloading image: ', error.message)
_124      }
_124    }
_124  }
_124
_124  async function uploadAvatar() {
_124    try {
_124      setUploading(true)
_124
_124      const file = await DocumentPicker.pickSingle({
_124        presentationStyle: 'fullScreen',
_124        copyTo: 'cachesDirectory',
_124        type: types.images,
_124        mode: 'open',
_124      })
_124
_124      const photo = {
_124        uri: file.fileCopyUri,
_124        type: file.type,
_124        name: file.name,
_124      }
_124
_124      const formData = new FormData()
_124      formData.append('file', photo)
_124
_124      const fileExt = file.name.split('.').pop()
_124      const filePath = `${Math.random()}.${fileExt}`
_124
_124      const { error } = await supabase.storage.from('avatars').upload(filePath, formData)
_124
_124      if (error) {
_124        throw error
_124      }
_124
_124      onUpload(filePath)
_124    } catch (error) {
_124      if (isCancel(error)) {
_124        console.warn('cancelled')
_124        // User cancelled the picker, exit any dialogs or menus and move on
_124      } else if (isInProgress(error)) {
_124        console.warn('multiple pickers were opened, only the last will be considered')
_124      } else if (error instanceof Error) {
_124        Alert.alert(error.message)
_124      } else {
_124        throw error
_124      }
_124    } finally {
_124      setUploading(false)
_124    }
_124  }
_124
_124  return (
_124    <View>
_124      {avatarUrl ? (
_124        <Image
_124          source={{ uri: avatarUrl }}
_124          accessibilityLabel="Avatar"
_124          style={[avatarSize, styles.avatar, styles.image]}
_124        />
_124      ) : (
_124        <View style={[avatarSize, styles.avatar, styles.noImage]} />
_124      )}
_124      <View>
_124        <Button
_124          title={uploading ? 'Uploading ...' : 'Upload'}
_124          onPress={uploadAvatar}
_124          disabled={uploading}
_124        />
_124      </View>
_124    </View>
_124  )
_124}
_124
_124const styles = StyleSheet.create({
_124  avatar: {
_124    borderRadius: 5,
_124    overflow: 'hidden',
_124    maxWidth: '100%',
_124  },
_124  image: {
_124    objectFit: 'cover',
_124    paddingTop: 0,
_124  },
_124  noImage: {
_124    backgroundColor: '#333',
_124    border: '1px solid rgb(200, 200, 200)',
_124    borderRadius: 5,
_124  },
_124})

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

components/Account.tsx


_22// Import the new component
_22import Avatar from './Avatar'
_22
_22// ...
_22  return (
_22    <View>
_22      {/* Add to the body */}
_22      <View>
_22        <Avatar
_22          size={200}
_22          url={avatarUrl}
_22          onUpload={(url: string) => {
_22            setAvatarUrl(url)
_22            updateProfile({ username, website, avatar_url: url })
_22          }}
_22        />
_22      </View>
_22      {/* ... */}
_22    </View>
_22  )
_22}
_22// ...

Now you will need to run the prebuild command to get the application working on your chosen platform.


_10expo prebuild

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:


_34create or replace function delete_storage_object(bucket text, object text, out status int, out content text)
_34returns record
_34language 'plpgsql'
_34security definer
_34as $$
_34declare
_34  project_url text := '<YOURPROJECTURL>';
_34  service_role_key text := '<YOURSERVICEROLEKEY>'; --  full access needed
_34  url text := project_url||'/storage/v1/object/'||bucket||'/'||object;
_34begin
_34  select
_34      into status, content
_34           result.status::int, result.content::text
_34      FROM extensions.http((
_34    'DELETE',
_34    url,
_34    ARRAY[extensions.http_header('authorization','Bearer '||service_role_key)],
_34    NULL,
_34    NULL)::extensions.http_request) as result;
_34end;
_34$$;
_34
_34create or replace function delete_avatar(avatar_url text, out status int, out content text)
_34returns record
_34language 'plpgsql'
_34security definer
_34as $$
_34begin
_34  select
_34      into status, content
_34           result.status, result.content
_34      from public.delete_storage_object('avatars', avatar_url) as result;
_34end;
_34$$;

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 $$
_32declare
_32  status int;
_32  content text;
_32  avatar_name text;
_32begin
_32  if coalesce(old.avatar_url, '') <> ''
_32      and (tg_op = 'DELETE' or (old.avatar_url <> coalesce(new.avatar_url, ''))) then
_32    -- extract avatar name
_32    avatar_name := old.avatar_url;
_32    select
_32      into status, content
_32      result.status, result.content
_32      from public.delete_avatar(avatar_name) as result;
_32    if status <> 200 then
_32      raise warning 'Could not delete avatar: % %', status, content;
_32    end if;
_32  end if;
_32  if tg_op = 'DELETE' then
_32    return old;
_32  end if;
_32  return new;
_32end;
_32$$;
_32
_32create trigger before_profile_changes
_32  before update of avatar_url or delete on public.profiles
_32  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.


_14create or replace function delete_old_profile()
_14returns trigger
_14language 'plpgsql'
_14security definer
_14as $$
_14begin
_14  delete from public.profiles where id = old.id;
_14  return old;
_14end;
_14$$;
_14
_14create trigger before_delete_user
_14  before delete on auth.users
_14  for each row execute function public.delete_old_profile();

At this stage you have a fully functional application!

Edit this page on GitHub

Build a User Management App with Expo React Native

note

Project setup#

Create a project#

Set up the database schema#

note

Get the API Keys#

Building the App#

Initialize a React Native app#

note

Account page#

Launch!#

Bonus: Profile photos#

Additional dependency installation#

Create an upload widget#

Add the new widget#

Storage management#

Build a User Management App with Expo React Native

note

Project setup#

Create a project#

Set up the database schema#

note

Get the API Keys#

Building the App#

Initialize a React Native app#

Set up a Login component#

note

Account page#

Launch!#

Bonus: Profile photos#

Additional dependency installation#

Create an upload widget#

Add the new widget#

Storage management#