For our new friends

Every app needs authentication and authorization. Logto is an Auth0 alternative designed for modern apps and SaaS products.

In this article, we will go through the steps to quickly build the Facebook sign-in experience (user authentication) with PHP and  Logto.

Prerequisites

• A running Logto instance. Check out the get started page if you don't have one.
• Basic knowledge of PHP.
• A usable Facebook account.

Create an application in Logto

In you browser, open a new tab and enter the link of Logto Admin Console.

Once the page is loaded, in the "Get Started" section click the View all link to open the application framework list page.

Choose your application type

In the opening modal, scroll to the "Traditional web" section or filter all the available " Traditional web" frameworks using the quick filter checkboxes on the left.

Click the "Laravel" framework card to start creating your application.

Enter application name

Enter the application name, e.g., "Bookstore," and click "Create application."

🎉 Ta-da! You just created your first application in Logto. You'll see a congrats page which includes a detailed integration guide. Follow the guide to see what the experience will be in your application.

Integrate Logto SDK

This guide will show you how to integrate Logto into your PHP web application.

tip

• The example uses Laravel, but the concepts are the same for other frameworks.

Installation

composer require logto/sdk

Init LogtoClient

First, create a Logto config:

index.php

use Logto\Sdk\LogtoClient;
use Logto\Sdk\LogtoConfig;

$client = new LogtoClient(
  new LogtoConfig(
    endpoint: "https://you-logto-endpoint.app",
    appId: "replace-with-your-app-id",
    appSecret: "replace-with-your-app-secret",
  ),
);

tip

You can find and copy "App Secret" from application details page in Admin Console:

By default, the SDK uses the built-in PHP session to store the Logto data. If you want to use other storage, you can pass a custom storage object as the second parameter:

index.php

$client = new LogtoClient(
  new LogtoConfig(
    // ...
  ),
  new YourCustomStorage(),
);

See Storage for more details.

Configure redirect URIs

Before we dive into the details, here's a quick overview of the end-user experience. The sign-in process can be simplified as follows:

1. Your app invokes the sign-in method.
2. The user is redirected to the Logto sign-in page. For native apps, the system browser is opened.
3. The user signs in and is redirected back to your app (configured as the redirect URI).

Regarding redirect-based sign-in:

1. This authentication process follows the OpenID Connect (OIDC) protocol, and Logto enforces strict security measures to protect user sign-in.
2. If you have multiple apps, you can use the same identity provider (Logto). Once the user signs in to one app, Logto will automatically complete the sign-in process when the user accesses another app.

To learn more about the rationale and benefits of redirect-based sign-in, see Logto sign-in experience explained.

---

note

In the following code snippets, we assume your app is running on http://localhost:3000.

Configure redirect URIs

Switch to the application details page of Logto Console. Add a Redirect URI http://localhost:3000/callback.

Just like signing in, users should be redirected to Logto for signing out of the shared session. Once finished, it would be great to redirect the user back to your website. For example, add http://localhost:3000/ as the post sign-out redirect URI section.

Then click "Save" to save the changes.

Handle callback

After the user signs in, Logto will redirect the user to the callback URL you set in the Logto Console. In this example, we use /callback as the callback URL:

Route::get('/callback', function () {
  try {
    $client->handleSignInCallback(); // Handle a lot of stuff
  } catch (\Throwable $exception) {
    return $exception; // Change this to your error handling logic
  }
  return redirect('/'); // Redirect the user to the home page after a successful sign-in
});

Implement sign-in route

In your web application, add a route to properly handle the sign-in request from users. For example:

Route::get('/sign-in', function () {
  return redirect($client->signIn('http://localhost:3000/callback'));
});

Replace http://localhost:3000/callback with the callback URL you set in your Logto Console for this application.

If you want to show the sign-up page on the first screen, you can set interactionMode to signUp:

Route::get('/sign-in', function () {
  return redirect($client->signIn('http://localhost:3000/callback', InteractionMode::signUp));
});

Now, whenever your users visit http://localhost:3000/sign-in, it will start a new sign-in attempt and redirect the user to the Logto sign-in page.

Note Creating a sign-in route isn't the only way to start a sign-in attempt. You can always use the signIn method to get the sign-in URL and redirect the user to it.

Implement sign-out route

After the user makes a signing-out request, Logto will clear all user authentication information in the session.

To clean up the PHP session and Logto session, a sign-out route can be implemented as follows:

Route::get('/sign-out', function () {
  return redirect(
    // Redirect the user to the home page after a successful sign-out
    $client->signOut('http://localhost:3000/')
  );
});

postLogoutRedirectUri is optional, and if not provided, the user will be redirected to a Logto default page after a successful sign-out (without redirecting back to your application).

Note The name postLogoutRedirectUri is from the OpenID Connect RP-Initiated Logout specification. Although Logto uses "sign-out" instead of "logout", the concept is the same.

Handle authentication status

In Logto SDK, we can use $client->isAuthenticated() to check the authentication status, if the user is signed in, the value will be true, otherwise, the value will be false.

We also need to implement a home page for demonstration:

• If the user is not signed in, show a sign-in button;
• If the user is signed in, show a sign-out button.

Route::get('/', function () {
  if ($client->isAuthenticated() === false) {
    return "Not authenticated <a href='/sign-in'>Sign in</a>";
  }

  return "<a href='/sign-out'>Sign out</a>";
});

Test your integration

Open your PHP app to test if the integration works. When you click the "Sign In" button, the page should be redirected to a Logto sign-in page, and you should be able to create a new account by entering username and password and complete the sign-in process.

Add Facebook connector

To add a social connector, go to the "Connector" tab in the Admin Console, then click on "Social connectors". From there, click "Add social connector".

In the openning modal, select "Facebook" and click "Next".

On the next page, you will see a two-column layout with the README content on the left and configuration on the right.

Feel free to follow the README file in place or read the following section to complete the configuration process. If you follow the in-place guide, you can skip the next section.

Set up Facebook login

Register a Facebook developer account

Register as a Facebook Developer if you don't have one.

Set up a Facebook app

1. Visit the Apps page.
2. Click your existing app or create a new one if needed.
   • The selected app type is up to you, but it should have the product Facebook Login.
3. On the app dashboard page, scroll to the "Add a product" section and click the "Set up" button on the "Facebook Login" card.
4. Skip the Facebook Login Quickstart page, and click the sidebar -> "Products" -> "Facebook Login" -> "Settings".
5. In the Facebook Login Settings page, fill ${your_logto_origin}/callback/${connector_id} in the "Valid OAuth Redirect URIs" field. The connector_id can be found on the top bar of the Logto Admin Console connector details page. E.g.:
   • https://your-logto-domain.com/callback/${connector_id} for production
   • https://localhost:3001/callback/${connector_id} for testing in the local environment
6. Click the "Save changes" button at the bottom right corner.
7. In the Facebook app dashboard page, click the sidebar -> "Settings" -> "Basic" and then you will get the App ID and App secret. The App ID is the clientId in your Logto connector conifg and the App secret is the clientSecret.

Test sign-in with Facebook's test users

You can use the accounts of the test, developer, and admin users to test sign-in with the related app under both development and live app modes.

You can also set the app to "live mode" by switching modes so that any Facebook user can sign in with the app.

• In the app dashboard page, click the sidebar -> "Roles" -> "Test Users".
• Click the "Create test users" button to create a testing user.
• Click the "Options" button of the existing test user, and you will see more operations, e.g., "Change name and password".

Publish Facebook sign-in settings

Usually, only the test, admin, and developer users can sign in with the related app under development mode.

To enable normal Facebook users sign-in with the app in the production environment, you may need to switch your Facebook app to live mode, depending on the app type. E.g., the pure business type app doesn't have the "live" switch button, but it won't block you from using it.

1. In the Facebook app dashboard page, click the sidebar -> "Settings" -> "Basic".
2. Fill out the "Privacy Policy URL" and "User data deletion" fields on the panel if required.
3. Click the "Save changes" button at the bottom right corner.
4. Click the "Live" switch button on the app top bar.

References

Config types

Name	Type
clientId	string
clientSecret	string

Facebook developer docs

• Facebook Login - Documentation - Facebook for Developers
• Manually Build a Login Flow
• Permissions Guide

Save your configuration

Double check you have filled out necessary values in the Logto connector configuration area. Click "Save and Done" (or "Save changes") and the Facebook connector should be available now.

Enable Facebook connector in Sign-in Experience

Switch to the "Sign-in experience" tab, then click the "Sign-up and sign-in" tab.

note

If it's the first time you enter the tab, you will see a quick introduction about Sign-in Experience and its basic configuration.

Select "None" for the "Sign-up identifier" to provide minimum sign-up effort for Facebook sign-in, which may increase your conversion rate.

In the "Social sign-in" section, add "Add Social Connector" and choose "Facebook". Then you should be able to see a button with text "Continue with Facebook" in the preview section.

Finally, click "Save changes" on the bottom right corner.

Testing and Validation

Return to your PHP app. You should now be able to sign in with Facebook. Enjoy!

Further readings

⚔️ Protect your API For native and single page apps, you'll need to call one or more API endpoints to retrieve and update data.
Learn more about identifying who's who and keeping your API secure.

🧑‍🚀 Manage users We know you care about user management and activities, as we also do.
Learn more about how to know your users and see the figures like DAU and MAU graphically.

🌐 Localization From one regional business to a global corporate, the willingness to offer the best user experience won't change.
You can change current language phrases or add a new language without friction.

🧑‍🎓 Customer IAM series Our serial blog posts about Customer (or Consumer) Identity and Access Management, from 101 to advanced topics and beyond.