Facebook Login

11 min

Introduction

This section explains how you can create an app with user registration using Facebook Login and Parse Server core features through Back4App.

After following this tutorial, you will be able to do this:

At any time, you can access the complete Ionic Project built with this tutorial at our GItHub repository.

To complete this quickstart, you need:

Visual Studio Code (or any web IDE you like).
Ionic Framework
An app created at Back4App.
- Follow the New Parse App tutorial to learn how to create a Parse app at Back4App.
A Facebook account for creating the app.

1 - Facebook Set up

To start using Facebook functions, you need to:

Go to the Facebook Developer Website and create an account and log in.
Go to My Apps and click on Add a New App:
At the left panel, click on Settings > Basic. In this page:

Take note of your App ID
Add a Privacy Police URL
Select a Category
Scroll down and hit Save changes

4. At the top of the same page, click on the Off button and Confirm to make your app live.

5. Scroll down at the same page and click on Add platform.

For this tutorial, let’s choose Android.
Add your Google Play Package Name which in our case is com.back4app.myapp
Add the Key Hashes of your machine (run keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore | openssl sha1 -binary | openssl base64 to find out yours)
Save changes

6. At the left panel, to back to Dashboard, scroll down and click on Facebook Login.

2 - Link your Facebook App with Back4App

Go to your App dashboard at Back4App Website and click on Server Settings.
Find the “Facebook Login” block and click on Settings. The “Facebook Login” block looks like this:

3. Add the Facebook App ID taken note in the previous step.

3 - Set up

In this tutorial, we will be starting from where we left off in the previous User registration with email verification one.

Let’s first install Facebook cordova plugins:

$ ionic cordova plugin add cordova-plugin-facebook4 --variable APP_ID="XXXXXXXX" --variable APP_NAME="XXXXXXXX" $ npm install --save @ionic-native/facebook

Now, let’s implement the facebookLogin() method:

1     async facebookLogin() {
2       try {
3         // Log in to Facebook and request user data
4         let facebookResponse = await this.facebook.login(['public_profile', 'email']);
5         let facebookAuthData = {
6           id: facebookResponse.authResponse.userID,
7           access_token: facebookResponse.authResponse.accessToken,
8         };
9
10        // Request the user from parse
11        let toLinkUser = new Parse.User();
12        let user = await toLinkUser._linkWith('facebook', {authData: facebookAuthData});
13
14        // If user did not exist, updates its data
15        if (!user.existed()) {
16          let userData = await this.facebook.api('me?fields=id,name,email,first_name,picture.width(720).height(720).as(picture)', []);
17          user.set('username', userData.name);
18          user.set('name', userData.name);
19          user.set('email', userData.email);
20          await user.save();
21        }
22
23        this.navCtrl.setRoot('HomePage');
24      } catch (err) {
25        console.log('Error logging in', err);
26
27        this.toastCtrl.create({
28          message: err.message,
29          duration: 2000
30        }).present();
31      }
32    }

Finally, let’s add a button to our Login page and make it call the method we just created:

1   <div text-center>
2         <button ion-button color="facebook" (click)="facebookLogin()">
3           LOG IN WITH FACEBOOK
4         </button>
5       </div>

5 - Test your app

Since Facebook log in does’t work on a browser, test your app by running ionic cordova run android.
Login at Back4App Website.
Find your app and click on Dashboard > Core > Browser > User to see the user that you’ve created!

It’s done!

At this stage, you can log in, register and log out of your app with Facebook using Parse Server core features through Back4App!