Google Login for Ionic 4

Google Authentication

There are different ways to integrate Google+ authentication into your Ionic app. However, not all of them use the native approach which uses Google app to perform the login instead of opening a popup requesting users to enter their credentials to login to Google before granting access to your app.

The way it works for hybrid apps to use native API’s and SDK’s is very simple. We need a piece (typically a Cordova plugin) that connects native API’s and SDK’s with the javascript environment where the ionic app runs. For this example ionic app we are going to use a cordova plugin to interact with the native Google SDK.

We will use Google Sign-In Cordova/PhoneGap Plugin to login with Google+ on iOS and Android. This plugin was developed by Eddy Verbruggen and it allows you to log in with your Google account on iOS and Android. Using this plugin you will get email, display name, given name, family name, profile picture url, and user id.

Ionic Google Authentication

For this Ionic example app you will need:

• An Ionic app where you will integrate this login. You can either use a blank app, or an existing one.
• Follow the setup steps for Android (to enable Google login on Android).
• Follow the setup steps for iOS (to enable Google login on iOS).
• The Google Sign-In Cordova/PhoneGap Plugin to interact with the device native API's.

Our Ionic demo app will look like this:

Google API setup

There are some configurations you need to set in order to communicate your app with Google Plus. Please read each step carefully.

Important note!

Open your config.xml and make sure that your package name is what you want it to be (i.e. io.ionic.ionic4GoogleLogin). Use this name when setting up Android and iOS in the following steps. If you don't, you will probably get a 12501, 'user cancelled' error. For example this is the name of this ionic demo app:

<widget id="io.ionic.ionic4GoogleLogin" version="0.0.1" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">

Configuring iOS

You will need to generate a configuration file (GoogleService-Info.plist) in order to get a REVERSED_CLIENT_ID which you will need during the plugin installation process. Let's see how to do it!

The first step is to Create a New Project in the Firebase Console. Wait, why do we need to create a Firebase project if we are on a Google Sign In tutorial with Ionic Framework?. You need to create a Firebase project in order to use Google Cloud features on your mobile app such as google sign in, google maps, google places, and so on.

Now go to the "Project Settings" section of your new Firebase project, scroll down to "Your Apps" and click on "Add App". A modal will open and you need to click on "Add Firebase to your iOS App".

The final step is to register the iOS App using the package name of your Ionic App as the iOS bundle ID. The other fields are optional. Then click "Register App" and now you will be able to download the configuration file: GoogleService-Info.plist. Open this file and you will be able to see the REVERSED_CLIENT_ID.

Some notes about iOS:

• The REVERSED_CLIENT_ID value is only needed for iOS.
• Please note that the REVERSED_CLIENT_ID value is also known as the "iOS URL Scheme" on the Developer's Console.
• Authentication on iOS takes the user to a SafariViewController through the Google SDK.

Configuring Android

For Android, you will also need to generate a configuration file. This file is named google-services.json. Let's see what we need to do.

If you already created a new project on the Firebase Console for iOS, use it, otherwise create a new one.

Now go to the "Project Settings" section of your new Firebase project, scroll down to "Your Apps" and click on "Add App". A modal will open and you need to click on "Add Firebase to your Android App".

The final step is to register the Android App using the package name of your Ionic App as the Android Package Name. The other fields are optional. Then click "Register App" and now you will be able to download the configuration file: google-services.json.

Some notes about Android:

• Once Google Sign-In is enabled, Google will automatically create the necessary credentials in the Developer Console. Please note that there is no need to add the generated google-services.json file into your Ionic project.
• Important! Make sure you execute the keytool steps as explained in Google's documentation to get the Debug signing certificate SHA-1 or the authentication will fail.
• Authentication on Android will use the accounts signed in on the user's device.

Install cordova plugin to interact with Google Plus SDK

Before we start, I want to remember you that you can download for free the code of this ionic project by clicking the GET THE CODE button from the beginning of the page.

After you have done all the above configurations, it’s time to install the plugin into your ionic framework app. Follow these steps to get this done:

• Using your terminal window, go to your Ionic app folder
• Run the following command to install the plugin changing the variable with your own value:

  $ ionic cordova plugin add cordova-plugin-googleplus --save --variable REVERSED_CLIENT_ID=YOUR_REVERSE_CLIENT_ID

  $ npm install --save @ionic-native/google-plus@beta

Notes:

• YOUR_REVERSE_CLIENT_ID is your value of REVERSED_CLIENT_ID and should look like this: com.googleusercontent.apps.uniqueId
• GooglePlus.js library is brought in automatically. There is no need to change or add anything in your Ionic app's html.

To see other ways to install the plugin or if you are using Phonegap Build, please refer to the plugin documentation.

Add Google Auth to your Ionic App

Now we will go straight to the code so open your Ionic app with your preferred code editor. Personally I use and recommend atom.

Ionic Google Login

The best way to show you how to add Login functionality is with a real example of the code, here you can see some Typescript code that handles the google authentication for your app.

The login function walks the user through the Google Auth process. All parameters are optional, however there are a few gotchas.

• To get an idToken on Android, you must pass in your webClientId (a frequent mistake is to supply Android Client ID). On iOS, the idToken is included in the sign in result by default.
• To get a serverAuthCode, you must pass in your webClientId and set offline: true. If offline is true, but no webClientId is provided, the serverAuthCode will NOT be requested.
• Permissions: The default scopes requested are profile and email. To request other scopes, add them as a space-separated list to the scopes parameter.

async doGoogleLogin(){
	const loading = await this.loadingController.create({
		message: 'Please wait...'
	});
	this.presentLoading(loading);

	this.googlePlus.login({
		'scopes': '', // optional, space-separated list of scopes, If not included or empty, defaults to `profile` and `email`.
		'webClientId': 'webClientId.apps.googleusercontent.com', // optional clientId of your Web application from Credentials settings of your project - On Android, this MUST be included to get an idToken. On iOS, it is not required.
		'offline': true // Optional, but requires the webClientId - if set to true the plugin will also return a serverAuthCode, which can be used to grant offline access to a non-Google server
	})
	.then(user =>{
		loading.dismiss();

		this.nativeStorage.setItem('google_user', {
			name: user.displayName,
			email: user.email,
			picture: user.imageUrl
		})
		.then(() =>{
			this.router.navigate(["/user"]);
		}, error =>{
			console.log(error);
		})
		loading.dismiss();
	}, err =>{
		console.log(err)
		loading.dismiss();
	});

	async presentLoading(loading) {
		return await loading.present();
	}
}

You can get your webClientId in https://console.developers.google.com/apis/credentials.

Then in your html you should add a “Sign in with Google” button

<ion-button expand="block" color="danger" (click)="doGoogleLogin()">Google Login<ion-button>

Ionic Google Logout

To perform Google log out we will call the googlePlus.logout() method that will invalidate the token generated at log in. Also, we will remove from the native storage the data from the logged user.

We will use the following code to perform the Google sign out functionality:

doGoogleLogout(){
	this.googlePlus.logout()
	.then(res =>{
		//user logged out so we will remove him from the NativeStorage
		this.nativeStorage.remove('google_user');
		this.router.navigate(["/login"]);
	}, err =>{
		console.log(err);
	})
}

NativeStorage

To install this plugin just run the following command in your ionic project:
$ ionic cordova plugin add cordova-plugin-nativestorage --save
$ npm install --save @ionic-native/native-storage@beta

We added a check inside the platform.ready() in app.component.ts to check if the user is already logged in. In case the user is logged in we navigate to the User page, if not, we navigate to the Log In page.

platform.ready().then(() => {
	//Here we will check if the user is already logged in
	//because we don't want to ask users to log in each time they open the app
	this.nativeStorage.getItem('google_user')
	.then( data =>{
		// user is previously logged and we have his data
		// we will let him access the app
		this.router.navigate(["/user"]);
		this.splashScreen.hide();
	}, error =>{
		this.router.navigate(["/login"]);
		this.splashScreen.hide();
	});
	this.statusBar.styleDefault();
});

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Conclusion

Authentication is an essential part of most applications, and there are different approaches and strategies that you can take. The approach taken for any project depends on its particular application requirements. Let's explore some of these approaches.

In this post we explained how to add Google Sign In to an Ionic Framework application. We built a demo app that you can download and use for free to build your own Ionic application.

To add the log in functionality we used Google Sign In Cordova plugin. It enables a native log in both in iOS and Android apps.

If you have any issues or questions about this tutorial please leave a comment below.

If you want to keep learning Ionic Framework, I suggest you the following tutorials:

• Build a PWA with Ionic and Angular
• Add Facebook Login to your Ionic App
• Add Twitter Login to your Ionic App
• Build a Multi Language Ionic App
• Master Forms and Validations

At IonicThemes we are big fans of Learning by example, that's why all our ionic tutorials include a complete and free ionic code example that you can reuse in your ionic projects.

We strive to create the best content for Ionic Framework, both tutorials and templates to help the Ionic community succeed. We work towards empowering developers to achieve a free life through coding. That's what motivates us at IonicThemes everyday.

Also, you can check out our detailed and professional Ionic Starter App crafted with love and dedication to help you create better apps and supercharge your productivity.