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Protect a service application by using OpenID Connect (OIDC) Bearer token authentication

Use the Quarkus OpenID Connect (OIDC) extension to secure a Jakarta REST application with Bearer token authentication. The bearer tokens are issued by OIDC and OAuth 2.0 compliant authorization servers, such as Keycloak.

For more information about OIDC Bearer token authentication, see the Quarkus OpenID Connect (OIDC) Bearer token authentication guide.

If you want to protect web applications by using OIDC Authorization Code Flow authentication, see the OpenID Connect authorization code flow mechanism for protecting web applications guide.

Prerequisites

To complete this guide, you need:

Roughly 15 minutes
An IDE
JDK 11+ installed with JAVA_HOME configured appropriately
Apache Maven 3.9.5
A working container runtime (Docker or Podman)
Optionally the Quarkus CLI if you want to use it
Optionally Mandrel or GraalVM installed and configured appropriately if you want to build a native executable (or Docker if you use a native container build)
The jq command-line processor tool

Architecture

This example shows how you can build a simple microservice that offers two endpoints:

/api/users/me
/api/admin

These endpoints are protected and can only be accessed if a client sends a bearer token along with the request, which must be valid (for example, signature, expiration, and audience) and trusted by the microservice.

The bearer token is issued by a Keycloak server and represents the subject for which the token was issued. Because it is an OAuth 2.0 Authorization server, the token also references the client acting on the user’s behalf.

Any user with a valid token can access the /api/users/me endpoint. As a response, it returns a JSON document with user details obtained from the information in the token.

The /api/admin endpoint is protected with RBAC (Role-Based Access Control), which only users with the admin role can access. At this endpoint, the @RolesAllowed annotation is used to enforce the access constraint declaratively.

Solution

Follow the instructions in the next sections and create the application step by step. You can also go straight to the completed example.

You can clone the Git repository by running the command git clone https://github.com/quarkusio/quarkus-quickstarts.git, or you can download an archive.

The solution is located in the security-openid-connect-quickstart directory.

Procedure

.1. Create the Maven project

You can either create a new Maven project with the oidc extension or you can add the extension to an existing Maven project. Complete one of the following commands:

To create a new Maven project, use the following command:
CLI

quarkus create app org.acme:security-openid-connect-quickstart \ --no-code cd security-openid-connect-quickstart

To create a Gradle project, add the --gradle or --gradle-kotlin-dsl option.

For more information about how to install and use the Quarkus CLI, see the Quarkus CLI guide.
Maven

mvn io.quarkus.platform:quarkus-maven-plugin:3.6.0:create \ -DprojectGroupId=org.acme \ -DprojectArtifactId=security-openid-connect-quickstart \ -DnoCode cd security-openid-connect-quickstart

To create a Gradle project, add the -DbuildTool=gradle or -DbuildTool=gradle-kotlin-dsl option.
For Windows users:
- If using cmd, (don’t use backward slash \ and put everything on the same line)
- If using Powershell, wrap -D parameters in double quotes e.g. "-DprojectArtifactId=security-openid-connect-quickstart"
This command generates a Maven project, importing the oidc extension which is an implementation of OIDC for Quarkus.
If you already have your Quarkus project configured, you can add the oidc extension to your project by running the following command in your project base directory:
CLI
quarkus extension add oidc
Maven
./mvnw quarkus:add-extension -Dextensions='oidc'
Gradle
./gradlew addExtension --extensions='oidc'
The following configuration gets added to your build file:

Using Maven (pom.xml):

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-oidc</artifactId>
</dependency>

Using Gradle (build.gradle):

implementation("io.quarkus:quarkus-oidc")

.2. Write the application

Implement the /api/users/me endpoint as shown in the following example, which is a regular Jakarta REST resource:

package org.acme.security.openid.connect;

import jakarta.annotation.security.RolesAllowed;
import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import org.jboss.resteasy.reactive.NoCache;
import io.quarkus.security.identity.SecurityIdentity;

@Path("/api/users")
public class UsersResource {

    @Inject
    SecurityIdentity securityIdentity;

    @GET
    @Path("/me")
    @RolesAllowed("user")
    @NoCache
    public User me() {
        return new User(securityIdentity);
    }

    public static class User {

        private final String userName;

        User(SecurityIdentity securityIdentity) {
            this.userName = securityIdentity.getPrincipal().getName();
        }

        public String getUserName() {
            return userName;
        }
    }
}

Implement the /api/admin endpoint as shown in the following simple example:

package org.acme.security.openid.connect;

import jakarta.annotation.security.RolesAllowed;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

@Path("/api/admin")
public class AdminResource {

    @GET
    @RolesAllowed("admin")
    @Produces(MediaType.TEXT_PLAIN)
    public String admin() {
        return "granted";
    }
}

The main difference in this example is that the @RolesAllowed annotation is used to verify that only users granted the admin role can access the endpoint.

Injection of the SecurityIdentity is supported in both @RequestScoped and @ApplicationScoped contexts.

.3. Configure the application

Configure the Quarkus OpenID Connect (OIDC) extension by setting the following configuration properties in the src/main/resources/application.properties file.

%prod.quarkus.oidc.auth-server-url=http://localhost:8180/realms/quarkus
quarkus.oidc.client-id=backend-service
quarkus.oidc.credentials.secret=secret

# Tell Dev Services for Keycloak to import the realm file
# This property is not effective when running the application in JVM or Native modes

quarkus.keycloak.devservices.realm-path=quarkus-realm.json

Where:

%prod.quarkus.oidc.auth-server-url sets the base URL of the OpenID Connect (OIDC) server. The %prod. profile prefix ensures that Dev Services for Keycloak launches a container when you run the application in development (dev) mode. For more information, see the Run the application in dev mode section.
quarkus.oidc.client-id sets a client-ID that identifies the application.
quarkus.oidc.credentials.secret sets the client secret, which is used by the client_secret_basic authentication method.

For more information, see the Quarkus OpenID Connect (OIDC) configuration properties guide.

.4. Start and configure the Keycloak server

Put the realm configuration file on the classpath (target/classes directory) so that it gets imported automatically when running in dev mode. You do not need to do this if you have already built a complete solution, in which case, this realm file is added to the classpath during the build.

Do not start the Keycloak server when you run the application in dev mode; Dev Services for Keycloak will start a container. For more information, see the Run the application in dev mode section.

To start a Keycloak server, you can use Docker to run the following command:

docker run --name keycloak -e KEYCLOAK_ADMIN=admin -e KEYCLOAK_ADMIN_PASSWORD=admin -p 8180:8080 quay.io/keycloak/keycloak:{keycloak.version} start-dev

Where the keycloak.version is set to version 17.0.0 or later.

You can access your Keycloak Server at localhost:8180.
To access the Keycloak Administration Console, log in as the admin user by using the following login credentials:
- Username: admin
- Password: admin
Import the realm configuration file from the upstream community repository to create a new realm.

For more information, see the Keycloak documentation about creating a new realm.

If you want to use the Keycloak Admin Client to configure your server from your application, you need to include either the quarkus-keycloak-admin-client or the quarkus-keycloak-admin-client-reactive (if the application uses quarkus-rest-client-reactive) extension. For more information, see the Quarkus Keycloak Admin Client guide.

.5. Run the application in dev mode

To run the application in dev mode, run the following commands:
CLI
quarkus dev
Maven
./mvnw quarkus:dev
Gradle
./gradlew --console=plain quarkusDev
- Dev Services for Keycloak will start a Keycloak container and import a quarkus-realm.json.
Open a Dev UI, which you can find at /q/dev-v1, then click a Provider: Keycloak link in an OpenID Connect Dev UI card.
When prompted to log in to a Single Page Application provided by OpenID Connect Dev UI, do the following steps:
- Log in as alice (password: alice), who has a user role.
  - Accessing /api/admin returns 403.
  - Accessing /api/users/me returns 200.
- Log out and log in as admin (password: admin), who has both admin and user roles.
  - Accessing /api/admin returns 200.
  - Accessing /api/users/me returns 200.

.6. Run the Application in JVM mode

When you are done with dev mode, you can run the application as a standard Java application.

Compile the application:

CLI

quarkus build

Maven

./mvnw install

Gradle

./gradlew build

Run the application:

java -jar target/quarkus-app/quarkus-run.jar

.7. Run the application in native mode

You can compile this same demo as-is into native mode without needing any modifications. This implies that you no longer need to install a JVM on your production environment. The runtime technology is included in the produced binary and optimized to run with minimal resources required.

Compilation takes a bit longer, so this step is disabled by default.

Build your application again by enabling the native profile:

CLI

quarkus build --native

Maven

./mvnw install -Dnative

Gradle

./gradlew build -Dquarkus.package.type=native

After waiting a little while, you run the following binary directly:
./target/security-openid-connect-quickstart-1.0.0-SNAPSHOT-runner

.8. Test the application

For information about testing your application in dev mode, see the preceding Run the application in dev mode section.

You can test the application launched in JVM or Native modes with curl.

Because the application uses Bearer token authentication, you first need to obtain an access token from the Keycloak server to access the application resources:

export access_token=$(\
    curl --insecure -X POST http://localhost:8180/realms/quarkus/protocol/openid-connect/token \
    --user backend-service:secret \
    -H 'content-type: application/x-www-form-urlencoded' \
    -d 'username=alice&password=alice&grant_type=password' | jq --raw-output '.access_token' \
 )

The preceding example obtains an access token for the user alice.

Any user can access the http://localhost:8080/api/users/me endpoint, which returns a JSON payload with details about the user.

curl -v -X GET \
  http://localhost:8080/api/users/me \
  -H "Authorization: Bearer "$access_token

Only users with the admin role can access the http://localhost:8080/api/admin endpoint. If you try to access this endpoint with the previously-issued access token, you get a 403 response from the server.

curl -v -X GET \
   http://localhost:8080/api/admin \
   -H "Authorization: Bearer "$access_token

To access the admin endpoint, obtain a token for the admin user:

export access_token=$(\
    curl --insecure -X POST http://localhost:8180/realms/quarkus/protocol/openid-connect/token \
    --user backend-service:secret \
    -H 'content-type: application/x-www-form-urlencoded' \
    -d 'username=admin&password=admin&grant_type=password' | jq --raw-output '.access_token' \
 )

For information about writing integration tests that depend on Dev Services for Keycloak, see the Dev Services for Keycloak section of the "OpenID Connect (OIDC) Bearer token authentication" guide.

References

Prerequisites
Architecture
Solution
Procedure
References