How to Use Ionic 4 for JHipster 6 to Build a Mobile App

For all those who know me, you know how much I love Java, Spring Boot, JHipster, and Ionic.

JHipster is the best thing ever. It’s a popular, fully open-source app generator and platform where you can quickly build Java apps with JavaScript front-ends.

Ionic is also a complete open-source framework where you can build cross-platform apps (hybrid) with web technology. Hybrid mobile apps, similar to native mobile apps, can be listed on app stores and installed on your mobile devices. Ionic supports PWA, which means you can ship the same app for the web to an app store.

Spring Boot is the only back-end framework currently supported, with .NET and Node.js implementations currently in development. On the front-end, Angular, React, Vue, React Native, and Ionic are all supported.

In this brief tutorial, I’ll show you to use Ionic for JHipster v4 with Spring Boot and JHipster 6.

To complete this tutorial, you’ll need to have Java 8+, Node.js 10+, and Docker installed. You’ll also need to create an Okta developer account.

Create a Spring Boot + Angular App With JHipster

You can install JHipster via Homebrew (brew install jhipster) or with npm.

npm i -g generator-jhipster@6.1.2

Once you have JHipster installed, you have two choices. There’s the quick way to generate an app (which I recommend), and there’s the tedious way of picking all your options. I don’t care which one you use, but you must select OAuth 2.0 / OIDC authentication to complete this tutorial successfully.

Here’s the easy way:

mkdir app && cd app

echo "application { config { baseName oauth2, authenticationType oauth2, \
  buildTool gradle, testFrameworks [protractor] }}" >> app.jh

jhipster import-jdl app.jh

The hard way is you run jhipster and answer a number of questions. There are so many choices when you run this option that you might question your sanity. At last count, I remember reading that JHipster allows 26K+ combinations!

The project generation process will take a couple of minutes to complete if you’re on fast Internet and have a bad-ass laptop. When it’s finished, you should see output like the following.

OIDC With Keycloak and Spring Security

JHipster has several authentication options: JWT, OAuth 2.0 / OIDC, and UAA. With JWT (the default), you store the access token on the client (in local storage); this works but isn’t the most secure. UAA involves using your own OAuth 2.0 authorization server (powered by Spring Security), and OAuth 2.0/OIDC allows you to use Keycloak or Okta.

Spring Security makes Keycloak and Okta integration so incredibly easy it’s silly. Keycloak and Okta are called "identity providers," and if you have a similar solution that is OIDC-compliant, I’m confident it’ll work with Spring Security and JHipster.

Having Keycloak set by default is nice because you can use it without having an internet connection.

To log into the JHipster app you just created, you’ll need to have Keycloak up and running. When you create a JHipster project with OIDC for authentication, it creates a Docker container definition that has the default users and roles. Start Keycloak using the following command.

docker-compose -f src/main/docker/keycloak.yml up -d

Start your application with ./gradlew (or ./mvnw if you chose Maven) and you should be able to log in using "admin/admin" for your credentials.

Open another terminal and prove all the end-to-end tests pass:

npm run e2e

If your environment is set up correctly, you’ll see output like the following:

> oauth-2@0.0.0 e2e /Users/mraible/app
> protractor src/test/javascript/protractor.conf.js

[16:02:18] W/configParser - pattern ./e2e/entities/**/*.spec.ts did not match any files.
[16:02:18] I/launcher - Running 1 instances of WebDriver
[16:02:18] I/direct - Using ChromeDriver directly...


  account
    ✓ should fail to login with bad password
    ✓ should login successfully with admin account (1754ms)

  administration
    ✓ should load metrics
    ✓ should load health
    ✓ should load configuration
    ✓ should load audits
    ✓ should load logs


  7 passing (15s)

[16:02:36] I/launcher - 0 instance(s) of WebDriver still running
[16:02:36] I/launcher - chrome #01 passed
Execution time: 19 s.

OIDC With Okta and Spring Security

To switch to Okta, you’ll first need to create an OIDC app. If you don’t have an Okta Developer account, now is the time!

Why Okta instead of Keycloak?

Keycloak works great in development, and Okta has free multi-factor authentication, email support, and excellent performance for production. A developer account gets you 1000 monthly active users for free! You can see other free features and our transparent pricing at developer.okta.com/pricing.

Log in to your Okta Developer account.

• In the top menu, click on Applications
• Click on Add Application
• Select Web and click Next
• Enter JHipster FTW! for the Name (this value doesn’t matter, so feel free to change it)
• Change the Login redirect URI to be http://localhost:8080/login/oauth2/code/oidc
• Click Done, then Edit and add http://localhost:8080 as a Logout redirect URI
• Click Save

These are the steps you’ll need to complete for JHipster. Start your JHipster app using a command like the following:

SPRING_SECURITY_OAUTH2_CLIENT_PROVIDER_OIDC_ISSUER_URI=https://{yourOktaDomain}/oauth2/default \
  SPRING_SECURITY_OAUTH2_CLIENT_REGISTRATION_OIDC_CLIENT_ID=$clientId \
  SPRING_SECURITY_OAUTH2_CLIENT_REGISTRATION_OIDC_CLIENT_SECRET=$clientSecret ./gradlew

The above command can be painful to type, so I encourage you to copy/paste or set the values as environment variables. You can also configure them in a properties/YAML file in Spring Boot, but you should never store secrets in source control.

Create a Native App for Ionic

You’ll also need to create a Native app for Ionic. The reason for this is because Ionic for JHipster is configured to use PKCE (Proof Key for Code Exchange). The current Spring Security OIDC support in JHipster still requires a client secret. PKCE does not.

Go back to the Okta developer console and follow the steps below:

• In the top menu, click on Applications
• Click on Add Application
• Select Native and click Next
• Enter Ionic FTW! for the Name
• Add Login redirect URIs: http://localhost:8100/implicit/callback and dev.localhost.ionic:/callback
• Click Done, then Edit and add Logout redirect URIs: http://localhost:8100/implicit/logout and dev.localhost.ionic:/logout
• Click Save

You’ll need the client ID from your Native app, so keep your browser tab open or copy/paste it somewhere.

Create Groups and Add Them as Claims to the ID Token

In order to login to your JHipster app, you’ll need to adjust your Okta authorization server to include a groupsclaim.

On Okta, navigate to Users > Groups. Create ROLE_ADMIN and ROLE_USER groups and add your account to them.

Navigate to API > Authorization Servers, click the Authorization Servers tab and edit the default one. Click the Claims tab and Add Claim. Name it "groups" or "roles" and include it in the ID Token. Set the value type to "Groups" and set the filter to be a Regex of .*. Click Create.

Navigate to http://localhost:8080, click sign in, and you’ll be redirected to Okta to log in.

Enter the credentials you used to sign up for your account, and you should be redirected back to your JHipster app.

Generate Entities for a Photo Gallery

Let’s enhance this example a bit and create a photo gallery that you can upload pictures to. Kinda like Flickr, but waaayyyy more primitive.

JHipster has a JDL (JHipster Domain Language) feature that allows you to model the data in your app, and generate entities from it. You can use its JDL Studio feature to do this online and save it locally once you’ve finished.

I created a data model for this app that has an Album, Photo, and Tag entities and set up relationships between them. Below is a screenshot of what it looks like in JDL Studio.

CCopy the JDL below and save it in a photos.jdl file in the root directory of your project.

entity Album {
  title String required,
  description TextBlob,
  created Instant
}

entity Photo {
  title String required,
  description TextBlob,
  image ImageBlob required,
  taken Instant
}

entity Tag {
  name String required minlength(2)
}

relationship ManyToOne {
  Album{user(login)} to User,
  Photo{album(title)} to Album
}

relationship ManyToMany {
  Photo{tag(name)} to Tag{photo}
}

paginate Album with pagination
paginate Photo, Tag with infinite-scroll

You can generate entities and CRUD code (Java for Spring Boot; TypeScript, and HTML for Angular) using the following command:

jhipster import-jdl photos.jdl

When prompted, type a to update existing files.

This process will create Liquibase changelog files (to create your database tables), entities, repositories, Spring MVC controllers, and all the Angular code that’s necessary to create, read, update, and delete your data objects. It’ll even generate Jest unit tests and Protractor end-to-end tests!

When the process completes, restart your app, and confirm that all your entities exist (and work) under the Entities menu.

You might notice that the entity list screen is pre-loaded with data. This is done by faker.js. To turn it off, edit src/main/resources/config/application-dev.yml, search for liquibase, and set its contexts value to dev. I made this change in this example’s code and ran ./gradlew clean to clear the database.

liquibase:
  # Add 'faker' if you want the sample data to be loaded automatically
  contexts: dev

Develop a Mobile App With Ionic and Angular

Getting started with Ionic for JHipster is similar to JHipster. You simply have to install the Ionic CLI, Yeoman, the module itself, and run a command to create the app.

npm i -g generator-jhipster-ionic@4.0.0 ionic@5.1.0 yo
yo jhipster-ionic

If you have your app application at ~/app, you should run this command from your home directory (~). Ionic for JHipster will prompt you for the location of your backend application. Use mobile for your app’s name and app for the JHipster app’s location.

Type a when prompted to overwrite mobile/src/app/app.component.ts.

Open mobile/src/app/auth/auth.service.ts in an editor, search for data.clientId, and replace it with the client ID from your Native app on Okta.

// try to get the oauth settings from the server
this.requestor.xhr({method: 'GET', url: AUTH_CONFIG_URI}).then(async (data: any) => {
  this.authConfig = {
    identity_client: '{yourClientId}',
    identity_server: data.issuer,
    redirect_url: redirectUri,
    end_session_redirect_url: logoutRedirectUri,
    scopes,
    usePkce: true
  };
  ...
}

When using Keycloak, this change is not necessary.

Add Claims to Access Token

In order to set-up authentication successfully with your Ionic app, you have to do a bit more configuration in Okta. Since the Ionic client will only send an access token to JHipster, you need to 1) add a groups claim to the access token and 2) add a couple more claims so the user’s name will be available in JHipster.

Navigate to API > Authorization Servers, click the Authorization Servers tab, and edit the default one. Click the Claims tab and Add Claim. Name it "groups" and include it in the Access Token. Set the value type to "Groups" and set the filter to be a Regex of .*. Click Create.

Add another claim, name it given_name, include it in the access token, use Expression in the value type, and set the value to user.firstName. Optionally, include it in the profile scope. Perform the same actions to create a family_name claim and use the expression user.lastName.

When you are finished, your claims should look as follows.

Run the following commands to start your Ionic app.

cd mobile
ionic serve

You’ll see a screen with a sign-in button. Click on it, and you’ll be redirected to Okta to authenticate.

Now that you having log in working, you can use the entity generator to generate Ionic pages for your data model. Run the following commands (in your ~/mobile directory) to generate screens for your entities.

yo jhipster-ionic:entity album

When prompted to generate this entity from an existing one, type Y. Enter ../app as the path to your existing application. When prompted to regenerate entities and overwrite files, type Y. Enter a when asked about conflicting files.

Go back to your browser where your Ionic app is running (or restart it if you stopped it). Click on Entities on the bottom, then Albums. Click the blue + icon in the bottom corner, and add a new album.

Click the checkmark in the top right corner to save your album. You’ll see a success message and it listed on the next screen.

Refresh your JHipster app’s album list, and you’ll see it there too!

Generate code for the other entities using the following commands and the same answers as above.

yo jhipster-ionic:entity photo
yo jhipster-ionic:entity tag

Run Your Ionic App on iOS

To generate an iOS project for your Ionic application, run the following command:

ionic cordova prepare ios

When prompted to install the ios platform, type Y. When the process completes, open your project in Xcode:

open platforms/ios/MyApp.xcworkspace

If you don’t have Xcode installed, you can download it from Apple.

You’ll need to configure code signing in the General tab, then you should be able to run your app in Simulator.

Log in to your Ionic app, tap Entities and view the list of photos.

Add a photo in the JHipster app at http://localhost:8080.

To see this new album in your Ionic app, pull down with your mouse to simulate the pull-to-refresh gesture on a phone. Looky there — it works!

There are some gestures you should know about on this screen. Clicking on the row will take you to a view screen where you can see the photo’s details. You can also swipe left to expose edit and delete buttons.

Run Your Ionic App on Android

Deploying your app on Android is very similar to iOS. In short:

1. Make sure you’re using Java 8
2. Run ionic cordova prepare android
3. Open platforms/android in Android Studio, upgrade Gradle if prompted
4. Set launchMode to singleTask in AndroidManifest.xml
5. Start your app using Android Studio
6. While your app is starting, run adb reverse tcp:8080 tcp:8080 so the emulator can talk to JHipster

For more thorough instructions, see my Ionic 4 tutorial’s Android section.

Learn More About Ionic 4 and JHipster 6

Ionic is a nice way to leverage your web development skills to build mobile apps. You can do most of your development in the browser, and deploy to your device when you’re ready to test it. You can also just deploy your app as a PWA and not both to deploy it to an app store.

JHipster supports PWAs too, but I think Ionic apps look like native apps, which is a nice effect. There’s a lot more I could cover about JHipster and Ionic, but this should be enough to get you started.

You can find the source code for the application developed in this post on GitHub.

I’ve written a few other posts on Ionic, JHipster, and Angular. Check them out if you have a moment.

• Tutorial: User Login and Registration in Ionic 4
• Java Microservices with Spring Cloud Config and JHipster
• Angular 8 + Spring Boot 2.2: Build a CRUD App Today!
• Better, Faster, Lighter Java with Java 12 and JHipster 6
• Build a Mobile App with React Native and Spring Boot

Give @oktadev a follow on Twitter if you liked this tutorial. If you have any questions, please leave a comment or post your question to Stack Overflow with a jhipster tag.

Build Mobile Apps with Angular, Ionic 4, and Spring Boot was originally posted on the Okta Developer Blog on June 24, 2019.