Open Authorization, popularly known as OAuth 2.0, is a secure and fast security mechanism that enables users to access websites and applications. Beyond the safety and ease of use, it gives users total control of the information shared with the requesting websites/applications.
In this post, we will learn how to set up OAuth 2.0 social login in a Flutter application using Facebook as the provider. The project repository can be found here.
Prerequisites
To fully grasp the concepts presented in this tutorial, the following are required:
- Basic understanding of Dart and Flutter
- Flutter SDK installed
- Xcode with a developer account
- Appwrite account; sign-up is completely free
- Facebook developer account; sign-up is completely free
Getting started
To get started, we need to clone the project by navigating to the desired directory and running the command below:
git clone https://github.com/Mr-Malomz/flutter_auth
Running the project
First, we need to install the project dependencies by running the command below:
flutter pub get
Then, run the project using the following command:
flutter run
The command above will run the application on the selected device.
Set up a project on Appwrite
To get started, we need to log into our Appwrite console, click the Create project button, input flutter_auth as the name, and then click Create.
Add platform support
To add support for our Flutter app, navigate to the Home menu and click the Flutter App button.
Next, we must modify the Flutter application as detailed below.
To obtain our Bundle ID, navigate to the path below:
ios > Runner.xcodeproj > project.pbxproj
Open the project.pbxproj file and search for PRODUCT_BUNDLE_IDENTIFIER.
Finally, open the project directory on Xcode, open the Runner.xcworkspace folder in the app's iOS folder, select the Runner project in the Xcode project navigator, select the Runner target in the primary menu sidebar, and then select iOS 11 in the deployment info’s target.
Enable Facebook as the preferred OAuth 2.0 provider
To do this, we need to navigate to the Auth menu, click the Settings tab, and enable Facebook as a provider.
We will fill in the required details later, however, we must copy and keep the redirect URI; it will come in handy when setting up our application on Facebook.
Set up Facebook OAuth 2.0
With our project partly configured on Appwrite, we also need to set up our project on the Facebook developer portal. To do this, log into the portal, navigate to the My Apps section, click the Create App button, select the Set up Facebook Login option and click Next.
Next, we need to input our application name, contact email, and then select Create app.
Finally, we navigate to the Products menu, select Settings under Facebook Login, input the redirect URI we copied from Appwrite earlier, and Save changes.
Lastly, we need to click on the Products menu again, select the QuickStart option, and select iOS as the preferred platform.
Configuring the iOS
After selecting the iOS option, click the Next button, input the Bundle ID, Save, and Continue.
Click Next on the Enable Single Sign On for Your App step.
Next, we need to copy and configure our Application using the provided XML snippet.
To do this, we need to modify the info.plist file in our source code and paste the copied snippet below the <dict> body tag.
We can find the file using the path below:
ios > Runner > info.plist
We must also update the snippet with our Application ID, Client Token, and App name.
We can get the required parameter as shown below:
Sample of a properly filled snippet below:
<key>CFBundleURLTypes</key>
<array>
<dict>
<key>1232334554343456</key>
<array>
<string>1232334554343456</string>
</array>
</dict>
</array>
<key>FacebookAppID</key>
<string>APP-ID</string>
<key></key>
<string>1ac7fd263ettr6yeta1b807ad589rt</string>
<key>flutter_auth</key>
<string>APP-NAME</string>
Putting it together on Appwrite
With our application configured on Facebook, we need to create a link to it on Appwrite. To do this, we need to first navigate to the Basic tab under Settings menu and copy the App ID and App secret.
Lastly, we need to update the Facebook provider details on Appwrite with the copied parameters and Update.
Integrating Facebook OAuth 2.0 with Flutter using Appwrite
With all that done, let’s build the social login into our application.
First, we need to create a class for storing our Appwrite credentials. To do this, we need to create a utils.dart file in the lib folder and add the snippet below:
class AppConstant {
final String projectId = "REPLACE WITH PROJECT ID";
final String endpoint = "https://cloud.appwrite.io/v1";
}
PS: We can get our Project ID from the Appwrite console.
Second, we need to create a service file to separate the application core logic from the UI. To do this, we need to create an auth_service.dart file in the same lib folder and add the snippet below:
import 'package:appwrite/appwrite.dart';
import 'package:flutter_auth/utils.dart';
class AuthService {
Client _client = Client();
late Account _account;
AuthService() {
_init();
}
//initialize the application
_init() async {
_client
.setEndpoint(AppConstant().endpoint)
.setProject(AppConstant().projectId);
_account = Account(_client);
}
Future loginWithFacebook() async {
try {
return await _account.createOAuth2Session(provider: 'facebook');
} catch (e) {
throw Exception('Error login into Facebook!');
}
}
}
The snippet above does the following:
- Imports the required dependencies
- Creates an
AuthServiceclass with_clientand_accountproperties to connect to the Appwrite instance - Creates an
_initmethod that configures Appwrite using the properties - Creates a
loginWithFacebookmethod that uses the_accountproperty to login with OAuth 2.0 usingfacebookas the provider
Lastly, we need to modify the login.dart file inside the screens folder to use the service.
import 'package:flutter/material.dart';
import 'package:flutter_auth/auth_service.dart';
class Login extends StatefulWidget {
const Login({super.key});
@override
State<Login> createState() => _LoginState();
}
class _LoginState extends State<Login> {
bool _isLoading = false;
_loginWithFacebook() {
setState(() {
_isLoading = true;
});
AuthService()
.loginWithFacebook()
.then((value) => {
setState(() {
_isLoading = false;
})
})
.catchError((e) {
setState(() {
_isLoading = false;
});
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(content: Text('Error login into facebook!')),
);
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Image.asset('images/lock.png'),
const SizedBox(height: 40.0),
Padding(
padding: const EdgeInsets.symmetric(horizontal: 10.0),
child: Container(
width: double.infinity,
height: 45.0,
child: TextButton(
onPressed: _isLoading
? null
: () {
_loginWithFacebook();
},
child: Text(
'Login with Facebook',
style: TextStyle(
fontSize: 12.0,
fontWeight: FontWeight.bold,
color: Colors.white),
),
style: ButtonStyle(
backgroundColor:
MaterialStateProperty.all(Color(0xff3b5998)),
padding: MaterialStateProperty.all<EdgeInsets>(
const EdgeInsets.symmetric(horizontal: 15.0),
)),
),
),
)
],
),
),
);
}
}
The snippet above does the following:
- Lines 1-2: Import the required dependencies
- Line 12: Creates an
_isLoading, property to manage the application state - Lines 14-33: Create a
_loginWithFacebookmethod to log in users using theAuthService().loginWithFacebookservice and set state accordingly - Lines 52-56: Update the button to use the method created
With that done, we restart the application using the code editor or run the command below:
flutter run
Facebook update on business verification
Facebook recently updated its permission system for applications using OAuth 2.0. It requires the developer to do a Business Verification to gain full access. If we decide to log in using our credentials, we will get an error about permissions, as shown below:
Conclusion
This post detailed a step-by-step guide to implementing Facebook OAuth 2.0 social login in a Flutter application using Appwrite. Beyond Facebook, Appwrite supports up to 35 other providers.
These resources may also be helpful:
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