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Quickstart: Expo

note

This guide uses supabase-js v2.0.0 Release Candidate (RC).

Intro

This example provides the steps to build a simple user management app (from scratch!) using Supabase and React Native. It includes:

  • Supabase Database: a Postgres database for storing your user data.
  • Supabase Auth: users can sign in with magic links (no passwords, only email).
  • Supabase Storage: users can upload a photo.
  • Row Level Security: data is protected so that individuals can only access their own data.
  • Instant APIs: APIs will be automatically generated when you create your database tables.

By the end of this guide you'll have an app which allows users to login and update some basic profile details:

Project set up

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. Go to app.supabase.com.
  2. Click on "New Project".
  3. Enter your project details.
  4. 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.

  1. Go to the SQL Editor page in the Dashboard.
  2. Click User Management Starter.
  3. Click Run.

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 URL and anon key from the API settings.

  1. Go to the Settings page in the Dashboard.
  2. Click API in the sidebar.
  3. Find your API 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:

npx create-expo-app -t expo-template-blank-typescript expo-user-management

cd expo-user-management

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

npm install @supabase/supabase-js@rc
npm install react-native-elements @react-native-async-storage/async-storage 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 will be exposed on the browser, and that's completely fine since we have Row Level Security enabled on our Database.

lib/supabase.ts
import AsyncStorage from '@react-native-async-storage/async-storage'
import { createClient } from '@supabase/supabase-js'

const supabaseUrl = YOUR_REACT_NATIVE_SUPABASE_URL
const supabaseAnonKey = YOUR_REACT_NATIVE_SUPABASE_ANON_KEY

export const supabase = createClient(supabaseUrl, supabaseAnonKey, {
auth: {
storage: AsyncStorage as any,
autoRefreshToken: true,
persistSession: true,
detectSessionInUrl: false,
},
})

Set up a Login component

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
import React, { useState } from 'react'
import { Alert, StyleSheet, View } from 'react-native'
import { supabase } from '../lib/supabase'
import { Button, Input } from 'react-native-elements'

export default function Auth() {
const [email, setEmail] = useState('')
const [password, setPassword] = useState('')
const [loading, setLoading] = useState(false)

async function signInWithEmail() {
setLoading(true)
const { error } = await supabase.auth.signInWithPassword({
email: email,
password: password,
})

if (error) Alert.alert(error.message)
setLoading(false)
}

async function signUpWithEmail() {
setLoading(true)
const { error } = await supabase.auth.signUp({
email: email,
password: password,
})

if (error) Alert.alert(error.message)
setLoading(false)
}

return (
<View>
<View style={[styles.verticallySpaced, styles.mt20]}>
<Input
label="Email"
leftIcon={{ type: 'font-awesome', name: 'envelope' }}
onChangeText={(text) => setEmail(text)}
value={email}
placeholder="email@address.com"
autoCapitalize={'none'}
/>
</View>
<View style={styles.verticallySpaced}>
<Input
label="Password"
leftIcon={{ type: 'font-awesome', name: 'lock' }}
onChangeText={(text) => setPassword(text)}
value={password}
secureTextEntry={true}
placeholder="Password"
autoCapitalize={'none'}
/>
</View>
<View style={[styles.verticallySpaced, styles.mt20]}>
<Button
title="Sign in"
disabled={loading}
onPress={() => signInWithEmail()}
/>
</View>
<View style={styles.verticallySpaced}>
<Button
title="Sign up"
disabled={loading}
onPress={() => signUpWithEmail()}
/>
</View>
</View>
)
}

const styles = StyleSheet.create({
container: {
marginTop: 40,
padding: 12,
},
verticallySpaced: {
paddingTop: 4,
paddingBottom: 4,
alignSelf: 'stretch',
},
mt20: {
marginTop: 20,
},
})

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
import { useState, useEffect } from 'react'
import { supabase } from '../lib/supabase'
import { StyleSheet, View, Alert } from 'react-native'
import { Button, Input } from 'react-native-elements'
import { Session } from '@supabase/supabase-js'

export default function Account({ session }: { session: Session }) {
const [loading, setLoading] = useState(true)
const [username, setUsername] = useState('')
const [website, setWebsite] = useState('')
const [avatarUrl, setAvatarUrl] = useState('')

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

async function getProfile() {
try {
setLoading(true)
if (!session?.user) throw new Error('No user on the session!')

let { data, error, status } = await supabase
.from('profiles')
.select(`username, website, avatar_url`)
.eq('id', session?.user.id)
.single()
if (error && status !== 406) {
throw error
}

if (data) {
setUsername(data.username)
setWebsite(data.website)
setAvatarUrl(data.avatar_url)
}
} catch (error) {
if (error instanceof Error) {
Alert.alert(error.message)
}
} finally {
setLoading(false)
}
}

async function updateProfile({
username,
website,
avatar_url,
}: {
username: string
website: string
avatar_url: string
}) {
try {
setLoading(true)
if (!session?.user) throw new Error('No user on the session!')

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

let { error } = await supabase.from('profiles').upsert(updates)

if (error) {
throw error
}
} catch (error) {
if (error instanceof Error) {
Alert.alert(error.message)
}
} finally {
setLoading(false)
}
}

return (
<View>
<View style={[styles.verticallySpaced, styles.mt20]}>
<Input label="Email" value={session?.user?.email} disabled />
</View>
<View style={styles.verticallySpaced}>
<Input
label="Username"
value={username || ''}
onChangeText={(text) => setUsername(text)}
/>
</View>
<View style={styles.verticallySpaced}>
<Input
label="Website"
value={website || ''}
onChangeText={(text) => setWebsite(text)}
/>
</View>

<View style={[styles.verticallySpaced, styles.mt20]}>
<Button
title={loading ? 'Loading ...' : 'Update'}
onPress={() =>
updateProfile({ username, website, avatar_url: avatarUrl })
}
disabled={loading}
/>
</View>

<View style={styles.verticallySpaced}>
<Button title="Sign Out" onPress={() => supabase.auth.signOut()} />
</View>
</View>
)
}

const styles = StyleSheet.create({
container: {
marginTop: 40,
padding: 12,
},
verticallySpaced: {
paddingTop: 4,
paddingBottom: 4,
alignSelf: 'stretch',
},
mt20: {
marginTop: 20,
},
})

Launch!

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

App.tsx
import 'react-native-url-polyfill/auto'
import { useState, useEffect } from 'react'
import { supabase } from './lib/supabase'
import Auth from './components/Auth'
import Account from './components/Account'
import { View } from 'react-native'
import { Session } from '@supabase/supabase-js'

export default function App() {
const [session, setSession] = useState<Session | null>(null)

useEffect(() => {
supabase.auth.getSession().then(({ data: { session } }) => {
setSession(session)
})

supabase.auth.onAuthStateChange((_event, session) => {
setSession(session)
})
}, [])

return (
<View>
{session && session.user ? (
<Account key={session.user.id} session={session} />
) : (
<Auth />
)}
</View>
)
}

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

npm 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.

expo install react-native-document-picker

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:

components/Avatar.tsx
import { useState, useEffect } from 'react'
import { supabase } from '../lib/supabase'
import { StyleSheet, View, Alert, Image, Button } from 'react-native'
import DocumentPicker, {
isCancel,
isInProgress,
types,
} from 'react-native-document-picker'

interface Props {
size: number
url: string | null
onUpload: (filePath: string) => void
}

export default function Avatar({ url, size = 150, onUpload }: Props) {
const [uploading, setUploading] = useState(false)
const [avatarUrl, setAvatarUrl] = useState<string | null>(null)
const avatarSize = { height: size, width: size }

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

async function downloadImage(path: string) {
try {
const { data, error } = await supabase.storage
.from('avatars')
.download(path)

if (error) {
throw error
}

const fr = new FileReader()
fr.readAsDataURL(data)
fr.onload = () => {
setAvatarUrl(fr.result as string)
}
} catch (error) {
if (error instanceof Error) {
console.log('Error downloading image: ', error.message)
}
}
}

async function uploadAvatar() {
try {
setUploading(true)

const file = await DocumentPicker.pickSingle({
presentationStyle: 'fullScreen',
copyTo: 'cachesDirectory',
type: types.images,
mode: 'open',
})

const photo = {
uri: file.fileCopyUri,
type: file.type,
name: file.name,
}

const formData = new FormData()
formData.append('file', photo)

const fileExt = file.name.split('.').pop()
const filePath = `${Math.random()}.${fileExt}`

let { error } = await supabase.storage
.from('avatars')
.upload(filePath, formData)

if (error) {
throw error
}

onUpload(filePath)
} catch (error) {
if (isCancel(error)) {
console.warn('cancelled')
// User cancelled the picker, exit any dialogs or menus and move on
} else if (isInProgress(error)) {
console.warn(
'multiple pickers were opened, only the last will be considered'
)
} else if (error instanceof Error) {
Alert.alert(error.message)
} else {
throw error
}
} finally {
setUploading(false)
}
}

return (
<View>
{avatarUrl ? (
<Image
source={{ uri: avatarUrl }}
accessibilityLabel="Avatar"
style={[avatarSize, styles.avatar, styles.image]}
/>
) : (
<View style={[avatarSize, styles.avatar, styles.noImage]} />
)}
<View>
<Button
title={uploading ? 'Uploading ...' : 'Upload'}
onPress={uploadAvatar}
disabled={uploading}
/>
</View>
</View>
)
}

const styles = StyleSheet.create({
avatar: {
borderRadius: 5,
overflow: 'hidden',
maxWidth: '100%',
},
image: {
objectFit: 'cover',
paddingTop: 0,
},
noImage: {
backgroundColor: '#333',
border: '1px solid rgb(200, 200, 200)',
borderRadius: 5,
},
})

Add the new widget

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

components/Account.tsx
// Import the new component
import Avatar from './Avatar'

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

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

expo prebuild

Next steps

At this stage you have a fully functional application!