Start enable Authentication for Android App

Overview

This android library currently supports:

OAuth 2.0 Authorization Code Flow using the PKCE extension

Register Application

Access WSO2 Identity Server Developer Portal .
Go to Applications and click New Application.
Click Show More
Open Mobile Application template.
Enter Name and Description and click Next.
Enter Callback URL.

The Callback URL is the exact location in the service provider's application where an access token would be sent. This URL should be the redirect scheme of the application that the user is redirected to after successful authentication.
Click Next
View the application details and Click Finish
Click on Access tab and Note the the Client ID that appears.

Field	Value
Service Provider Name	your-application-name
Description	This is a mobile application
CallBack Url	your-application-uri

Eg:

Field	Value
Service Provider Name	sample-app
Description	This is a mobile application
CallBack Url	wso2sample://oauth2

Installation

Add the dependency

Add latest released SDK in your app's build.gradle file.

dependencies {
   dependencies {
        implementation 'io.asgardio.android.oidc.sdk:io.asgardio.android.oidc.sdk:0.1.0-SNAPSHOT'
   }
}

Build the SDK locally.

If you want to build the SDK in your local machine,

Clone the SDK repo
- git clone https://github.com/wso2-extensions/identity-sdks-android
Add mavenLocal() under repositories in the build.gradle file (This build.gradle file is the top-level build file where you can add configuration options common to all sub-projects/modules).
```
repositories {
    google()
    jcenter()
    mavenLocal()           
 }
```
Run the following commands.
- ./gradlew clean assembleRelease
- ./gradlew publishToMavenLocal
Now the library will be available in your local .m2 cache.

Add a URI Scheme

You need to add a redirect scheme in the application. You need to add the appAuthRedirectScheme in your app's build.gradle file.

android.defaultConfig.manifestPlaceholders = [
       'appAuthRedirectScheme': 'your-application'
]

Eg:

android.defaultConfig.manifestPlaceholders = [
       'appAuthRedirectScheme': 'wso2sample'
]

Verify that this should be consistent with the CallBack Url of the application that you configured in the developer-portal and in the oidc_config.json file. Refer the configuration section for further information.

For example, if you have configured the callBackUrl as wso2sample://oauth2, then the appAuthRedirectScheme should be wso2sample

Configuration

Create the oidc_config.json file inside the res/raw folder.

Copy the following configurations into the oidc_config.json file.
Change the client_id and redirect_uri configs. These should be taken from application.
Update the {HOST_NAME}:{PORT} with the IS server's hostname and port respectively in the discovery_uri config.

{
 "client_id": "{client-id}",
 "redirect_uri": "{your-application-url}",
 "authorization_scope": "openid",
 "discovery_uri": "https://{HOST_NAME}:{PORT}/oauth2/oidcdiscovery/.well-known/openid-configuration"
}

Example:

{
"client_id": "rs5ww91iychg9JN0DJGLMaxG2gha",
 "redirect_uri": "wso2sample://oauth2",
 "authorization_scope": "openid",
 "discovery_uri": "https://stgcloud.kubesb.com/t/example/oauth2/oidcdiscovery/.well-known/openid-configuration"
}

Login

First, you need to initialize the SDK object in an Activity that you are using to log users into your app.
In this example, we will call it LoginActivity. After successful authentication, the user will be redirected to another Activity. Let's name it as UserInfoActivity.

    LoginService mLoginService = new DefaultLoginService(this);

Have a login button inside LoginActivity. Here the button id is referred as login.
Call thedoLogin() method when the login button is clicked to initiate authentication with WSO2 Identity Server.

-You need to create completionIntent and cancelIntent while calling the authorize method of LoginService.

You can pass either true or false for the callUserInfo parameter. If callUserInfo value is true , then userinfo request will be made to the IdentityServer after successful token exchange. Else, if callUserInfo value is false, SDK will not make any request to UserInfo Endpoint after token flow.

    findViewById(R.id.login).setOnClickListener(v ->
                   doLogin()
    );

private void doLogin() {
   
      Intent completionIntent = new Intent(this, UserInfoActivity.class);
      Intent cancelIntent = new Intent(this, LoginActivity.class);
      cancelIntent.putExtra("failed", true);
      cancelIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
      PendingIntent successIntent = PendingIntent.getActivity(this, 0, completionIntent, 0);
      PendingIntent failureIntent = PendingIntent.getActivity(this, 0, cancelIntent, 0);

      mLoginService.authorize(successIntent, failureIntent, true);
   }

Now you will be able to authenticate the user with Identity Server.

Authentication Context.

After successful authentication, AuthenticationContext object will be returned in the Intent . This AuthenticationContext Object is used to store all the context related to that authentication flow.
From the oncreate() method of the UserInfoActivity, get the AuthenticationContext object.
Authentication context object has User, OidcDiscovery response, TokenResponse, and UserInfoResponse.

@Override
    protected void create() {  
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_info);
        mLoginService = new DefaultLoginService(this);
        mAuthenticationContext = (AuthenticationContext) getIntent().getSerializableExtra("context");
    }

Get User Details.

In order to get user-related information,

String userName = mAuthenticationContext.getUser().getUserName();

Map<String, Object> userAttributes = mAuthenticationContext.getUser().getAttributes();

Authentication Context Information

Get information related to token response

To get information related to token response, first you need to get OAuth2TokenResponse from AuthenticationContext. You can use the following code blocks.

OAuth2TokenResponse oAuth2TokenResponse = mAuthenticationContext.getOAuth2TokenResponse();

To get AccessToken and IDToken from OAuth2TokenResponse

String idToken = oAuth2TokenResponse.getIdToken();
String accessToken = oAuth2TokenResponse.getAccessToken();
Long accessTokenExpTime = oAuth2TokenResponse.getAccessTokenExpirationTime();
String tokenType = oAuth2TokenResponse.getTokenType();
String refreshToken = oAuth2TokenResponse.getRefreshToken();

Get claims from IDToken

To get information from idToken , first you need to get IDTokenResponse from OAuth2TokenResponse. You can use the following code blocks.

OAuth2TokenResponse.IDTokenResponse idTokenResponse = mAuthenticationContext
                .getOAuth2TokenResponse().getIdTokenResponse();

To get server specific claims from idToken:

String iss = idTokenResponse.getIssuer();
String sub = idTokenResponse.getSubject();
String iat = idTokenResponse.getIssueTime();
String exp = idTokenResponse.getExpiryTime();
List<String> audience = idTokenResponse.getAudience()

To get the map of all claims

Map<String, Object> claims = idTokenResponse.getClaims();

To get a specific String claim

String claimValue = idTokenResponse.getClaim(claimName)

Get userinfo response

Get userinfo response from authentication context

If you called LoginService.authorize(PendingIntent successIntent, PendingIntent failureIntent , Boolean callUserInfo) with callUserInfo parameter as true, then UserInfoResponse will be stored in the AuthenticationContext object.

To get UserInfoResponse from AuthenticationContext,

UserInfoResponse userInfoResponse = mAuthenticationContext.getUserInfoResponse();

To get the subject,

String subject = userInfoResponse.getSubject();
To get some specific claim,

String email = userInfoResponse.getUserInfoProperty("email");
To get all claims,

JSONObject userClaims = userInfoResponse.getUserInfoProperties();

Call UserInfo explicitly.

You can get userclaims by calling getUserInfo(..) method in the LoginService.

private void getUserInfo(){
   mLoginService.getUserInfo(mAuthenticationContext,
                  new UserInfoRequestHandler.UserInfoResponseCallback() {
               @Override
               public void onUserInfoRequestCompleted(UserInfoResponse userInfoResponse,
                       ServerException e) {
                   if (userInfoResponse != null) {
                       mSubject = userInfoResponse.getSubject();
                       mEmail = userInfoResponse.getUserInfoProperty("email");
                       JSONObject userInfoProperties = userInfoResponse.getUserInfoProperties();
                   }
    }

Logout

Have a button with id logout.
Call the logout method when logout button is clicked.

findViewById(R.id.logout).setOnClickListener(v -> logout());

Call the logout method of LoginService instance.

private void logout() {

        mLoginService.logout(this, mAuthenticationContext);
        finish();
    }

Sample app

Refer this repository for a sample.

gayashanbc/identity-sdks-android