Quickstart: Expo

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.

Dashboard

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

SQL

-- Create a table for public "profiles"
create table profiles (
  id uuid references auth.users not null,
  updated_at timestamp with time zone,
  username text unique,
  avatar_url text,
  website text,

  primary key (id),
  unique(username),
  constraint username_length check (char_length(username) >= 3)
);

alter table profiles enable row level security;

create policy "Public profiles are viewable by everyone."
  on profiles for select
  using ( true );

create policy "Users can insert their own profile."
  on profiles for insert
  with check ( auth.uid() = id );

create policy "Users can update own profile."
  on profiles for update
  using ( auth.uid() = id );

-- Set up Realtime!
begin;
  drop publication if exists supabase_realtime;
  create publication supabase_realtime;
commit;
alter publication supabase_realtime add table profiles;

-- Set up Storage!
insert into storage.buckets (id, name)
values ('avatars', 'avatars');

create policy "Avatar images are publicly accessible."
  on storage.objects for select
  using ( bucket_id = 'avatars' );

create policy "Anyone can upload an avatar."
  on storage.objects for insert
  with check ( bucket_id = 'avatars' );

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 supabaseReactNative:

#select the "Blank (TypeScript)" template when prompted
expo init supabaseReactNative

cd supabaseReactNative

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

yarn add @supabase/supabase-js
yarn add react-native-elements
yarn add react-native-safe-area-context
yarn add @react-native-async-storage/async-storage
yarn add 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, {
  localStorage: 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 { user, error } = await supabase.auth.signIn({
      email: email,
      password: password,
    })

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

  async function signUpWithEmail() {
    setLoading(true)
    const { user, 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 { ApiError, Session } from "@supabase/supabase-js";

export default function Account({ session }: { session: Session }) {
  const [loading, setLoading] = useState(false);
  const [username, setUsername] = useState("");
  const [website, setWebsite] = useState("");
  const [avatar_url, setAvatarUrl] = useState("");

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

  async function getProfile() {
    try {
      setLoading(true);
      const user = supabase.auth.user();
      if (!user) throw new Error("No user on the session!");

      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.alert((error as ApiError).message);
    } finally {
      setLoading(false);
    }
  }

  async function updateProfile({
    username,
    website,
    avatar_url,
  }: {
    username: string;
    website: string;
    avatar_url: string;
  }) {
    try {
      setLoading(true);
      const user = supabase.auth.user();
      if (!user) throw new Error("No user on the session!");

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

      let { error } = await supabase
        .from("profiles")
        .upsert(updates, { returning: "minimal" });

      if (error) {
        throw error;
      }
    } catch (error) {
      Alert.alert((error as ApiError).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 })}
          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(() => {
    setSession(supabase.auth.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:

yarn start

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 for the user so that they can upload a profile photo. We can start by creating a new component:

components/Avatar.js

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

export default function Avatar({ url, size, onUpload }) {
  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.message)
    }
  }

  async function uploadAvatar(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 = `${Math.random()}.${fileExt}`
      const filePath = `${fileName}`

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

      if (uploadError) {
        throw uploadError
      }

      onUpload(filePath)
    } catch (error) {
      alert(error.message)
    } finally {
      setUploading(false)
    }
  }

  return (
    <View>
      {avatarUrl ? (
        <Image src={avatarUrl} alt="Avatar" className="avatar image" />
      ) : (
        <View className="avatar no-image" />
      )}
      <View>
        <Input
          type="file"
          id="single"
          accept="image/*"
          onChange={uploadAvatar}
          disabled={uploading}
        />
      </View>
    </View>
  )
}

Next steps

At this stage you have a fully functional application!

• Got a question? Ask here.
• Sign in: app.supabase.com