Android OMH Auth Client Library

Overview

The Android OMH Auth Client Library simplifies authentication integration for Android developers across devices, supporting both Google Mobile Services (GMS) and non-GMS configurations. With a unified interface, it enables easy incorporation of Google Sign-in and other third-party authentication providers without maintaining separate codebases.

This README serves as a valuable learning resource, providing step-by-step instructions for setting up an Android Studio project and effectively implementing the Android OMH Auth Client Library. Whether you are new to Android development or an experienced programmer, this guide equips you with the knowledge to seamlessly integrate authentication features into your applications. For a broader understanding of OMH's philosophy and comprehensive capabilities, visit the official website at https://openmobilehub.org.

A single codebase, running seamlessly on any device

For instance, the following screenshots showcase multiple devices with Android, both with GMS and Non-GMS. The same app works without changing a single line of code, supporting multiple auth provider implementations.

GMS Device	Non GMS Device

Show more

Facebook login	Microsoft login	Dropbox login

Getting started

This section describes how to setup an Android Studio project to use the Android OMH Auth SDK for Android. For greater ease, a base code will be used within the repository.

Note: To quickly run a full-featured app with all Android OMH Auth functionality, refer to the #sample-app section and follow the provided steps.

Prerequisites

1. Android Studio is required. If you haven't already done so, download and install it.

2. Ensure that you are using the Android Gradle plugin version 7.0 or later in Android Studio.

Clone the repository

The easiest way is cloning the repository from the starter-code branch. Run this CLI command in your terminal:

git clone --branch code-starter https://github.com/openmobilehub/android-omh-auth.git

You can always check what the final result should be in the module sample-app in the main branch.

Note: Before running the starter code application, make sure to follow the starter code app setup instructions.

Provider specific setup

There are different setup requirements based on the provider you will be including into your app. Please find the specific setup instruction for the providers below:

• Google GMS and non-GMS

• Facebook

• Microsoft

• Dropbox

Adding Auth to your app.

First and foremost, the main interface that you'll be interacting with is called OmhAuthClient. It contains all your basic authentication functionalities like login, getting the user profile, sign out, revoking a token, etc.

Initialize client

In order to be able to interact with our OMH Auth client, we need to initialize it first.

The snippet below shows how to initialize the OMH Auth client. The initialize method returns an OmhTask. This is the interface to interact with async functionalities and subscribe to the success or error results. In the MainActivity.kt, add the following code to the onViewCreated() function:

lifecycleScope.launch(Dispatchers.IO) {
    authClientProvider.getClient(requireContext()).initialize()
        .addOnSuccess {
            setupUI()
        }
        .execute()
}

Get user

The snippet below shows how to check if there's a signed in user already in your application. The getUser method returns an OmhTask. This is the interface to interact with async functionalities and subscribe to the success or error results. A successful fetch will return an object of the class OmhUserProfile. In the MainActivity.kt, add the following code to the setupGraph() function:

val navGraph = navController.navInflater.inflate(R.navigation.nav_graph)

lifecycleScope.launch(Dispatchers.IO) {
    omhAuthClient.getUser()
        .addOnSuccess {
            navGraph.setStartDestination(R.id.logged_in_fragment)
            navController.graph = navGraph
        }
        .addOnFailure {
            navGraph.setStartDestination(R.id.login_fragment)
            navController.graph = navGraph
        }
        .execute()
}

Login

If no user is found, then we should request a login intent which will redirect the user to the provider's auth screen, be it the Google SignIn UI or a custom tab that redirects the user to provider specific auth page. In the LoginFragment.kt, add the following code to the startLogin function:

// This will trigger the login flow.
val loginIntent = omhAuthClient.getLoginIntent()
loginLauncher.launch(loginIntent)

This should be used to start an activity for result. In the LoginFragment.kt, add the following code to the handleLoginResult(result: ActivityResult):

if (result.resultCode == Activity.RESULT_OK) {
    navigateToLoggedIn()
} else {
    val errorMessage = result.data?.getStringExtra("errorMessage")
    handleException(Exception(errorMessage))
}

If the returned result contains the account, then you can continue to the logged in activity of your application.

Sign out

To sign-out, the SDK provides a straightforward functionality that returns an OmhTask. in addition to subscribing to the success or error results, the OmhTask also provides a way to cancel it. A cancellable token is provided after the execute() function is called. This can be stored in the CancellableCollector class similar to the CompositeDisposable in RxJava. The sign-out action will remove any and all relevant data of the user from the application storage. In the LoggedInFragment.kt, add the following code to the logout function:

val cancellable = omhAuthClient.signOut()
    .addOnSuccess { navigateToLogin() }
    .addOnFailure(::showErrorDialog)
    .execute()

cancellableCollector.addCancellable(cancellable)

Note: you can cancel all emitted cancellables within the collector running.

cancellableCollector.clear()

Revoke token

The SDK also provides a way to revoke the access token provided to the application. This works similar to the sign-out functionality but on top of clearing all local data, this also makes a request to the auth provider to revoke the token from the server. In the LoggedInFragment.kt, add the following code to the revokeToken function:

val cancellable = omhAuthClient.revokeToken()
    .addOnSuccess { navigateToLogin() }
    .addOnFailure(::showErrorDialog)
    .execute()

cancellableCollector.addCancellable(cancellable)

Some providers like in the case of Microsoft, doesn't provide a way to revoke the authentication token. For this reason, the default behavior for Microsoft when revoking a token is to sign out the user. This is identical to calling the omhAuthClient.signOut() function.

Sample App

This repository includes a /apps/auth-sample that demonstrates the functionality of the OMH Auth Client Library. By cloning the repo and executing the app, you can explore the various features offered by the library. However, if you prefer a step-by-step approach to learn the SDK from scratch, we recommend following the detailed Getting Started guide provided in this repository. The guide will walk you through the implementation process and help you integrate the OMH Auth Client Library into your projects effectively.

Note: Before running the sample application, make sure to follow the #provider-specific-setup instructions for each provider.

Documentation

Full documentation

Reference API

Provider Implementations / Plugins

OMH Auth SDK is open-source, promoting community collaboration and plugin support from other auth providers to enhance capabilities and expand supported auth services. You can find more details in the "creating a custom implementation" section.

Contributing

Please contribute! We will gladly review any pull requests. Make sure to read the /CONTRIBUTING.md page first though.

Troubleshooting

2 files found with path 'META-INF/*'

!CAUTION>2 files found with path 'META-INF/DEPENDENCIES' from inputs:
\- ~/.gradle/caches/transforms-3/974cf06afa1f6a930c75c22e66ec0fcc/transformed/jetified-httpclient-4.5.13.jar
\- ~/.gradle/caches/transforms-3/435f87d6658aae4740f0a56a1a48eac1/transformed/jetified-httpcore-4.4.15.jar

If you see the above error during the android build process, please add the following code snippet to your android/app/build.gradle file:

android {
    // ... other build settings

    packagingOptions {
        resources.excludes.add("META-INF/*")
    }
}

Please also check the related GitHub issue for more context to the problem.

License

Copyright 2023 Open Mobile Hub

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.