Auth

Login with Slack

To enable Slack Auth for your project, you need to set up a Slack OAuth application and add the application credentials to your Supabase Dashboard.

Overview

Setting up Slack logins for your application consists of 3 parts:

Access your Slack Developer account

  • Go to api.slack.com.
  • Click on Your Apps at the top right to log in.

Slack Developer Portal.

Find your callback URL

The next step requires a callback URL, which looks like this: https://<project-ref>.supabase.co/auth/v1/callback

  • Go to your Supabase Project Dashboard
  • Click on the Authentication icon in the left sidebar
  • Click on Providers under the Configuration section
  • Click on Slack from the accordion list to expand and you'll find your Callback URL, you can click Copy to copy it to the clipboard

Create a Slack OAuth app

Under Create an app...:

  • Click From scratch
  • Type the name of your app
  • Select your Slack Workspace
  • Click Create App

Under App Credentials:

  • Copy and save your newly-generated Client ID
  • Copy and save your newly-generated Client Secret

Under the sidebar, select OAuth & Permissions and look for Redirect URLs:

  • Click Add New Redirect URL
  • Paste your Callback URL then click Add
  • Click Save URLs

Under Scopes:

Enter your Slack credentials into your Supabase project

  • Go to your Supabase Project Dashboard
  • In the left sidebar, click the Authentication icon (near the top)
  • Click on Providers under the Configuration section
  • Click on Slack from the accordion list to expand and turn Slack Enabled to ON
  • Enter your Slack Client ID and Slack Client Secret saved in the previous step
  • Click Save

Add login code to your client app

When your user signs in, call signInWithOAuth() with slack_oidc as the provider:


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async function signInWithSlack() {
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const { data, error } = await supabase.auth.signInWithOAuth({
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provider: 'slack_oidc',
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})
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}

For a PKCE flow, for example in Server-Side Auth, you need an extra step to handle the code exchange. When calling signInWithOAuth, provide a redirectTo URL which points to a callback route. This redirect URL should be added to your redirect allow list.

In the browser, signInWithOAuth automatically redirects to the OAuth provider's authentication endpoint, which then redirects to your endpoint.


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await supabase.auth.signInWithOAuth({
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provider,
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options: {
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redirectTo: `http://example.com/auth/callback`,
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},
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})

At the callback endpoint, handle the code exchange to save the user session.

Create a new file at app/auth/callback/route.ts and populate with the following:

app/auth/callback/route.ts

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import { NextResponse } from 'next/server'
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// The client you created from the Server-Side Auth instructions
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import { createClient } from '@/utils/supabase/server'
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export async function GET(request: Request) {
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const { searchParams, origin } = new URL(request.url)
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const code = searchParams.get('code')
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// if "next" is in param, use it as the redirect URL
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const next = searchParams.get('next') ?? '/'
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if (code) {
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const supabase = await createClient()
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const { error } = await supabase.auth.exchangeCodeForSession(code)
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if (!error) {
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const forwardedHost = request.headers.get('x-forwarded-host') // original origin before load balancer
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const isLocalEnv = process.env.NODE_ENV === 'development'
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if (isLocalEnv) {
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// we can be sure that there is no load balancer in between, so no need to watch for X-Forwarded-Host
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return NextResponse.redirect(`${origin}${next}`)
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} else if (forwardedHost) {
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return NextResponse.redirect(`https://${forwardedHost}${next}`)
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} else {
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return NextResponse.redirect(`${origin}${next}`)
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}
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}
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}
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// return the user to an error page with instructions
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return NextResponse.redirect(`${origin}/auth/auth-code-error`)
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}

When your user signs out, call signOut() to remove them from the browser session and any objects from localStorage:


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async function signOut() {
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const { error } = await supabase.auth.signOut()
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}

Resources