Demo Authorization Server using Nimbus and Spring Security

Before using, make sure to modify your /etc/hosts file so that you don't have problems with session cookies from a client app fighting with the authorization server.

127.0.0.1   idp

This is a Spring Boot application, so to start it, you can do:

gw :bootRun

To check that it is up, you can hit the OIDC discovery endpoint:

http :8081/.well-known/openid-configuration

The server has one client whose client id and secret are client/secret.

It has one user whose username and password are user/password.

It has three scopes, profile, message:read, and message:write.

Now, configure a client application to point at this authorization server:

http --from https://start.spring.io/starter.tgz \
  dependencies=web,oauth2-client baseDir=client | tar -xzvf -

Modifying the application.yml like so:

spring:
  security:
    oauth2:
      client:
        provider:
          keycloak:
            issuer-uri: http://idp:8081
        registration:
          keycloak:
            client-id: client
            client-secret: secret

Make sure to add some kind of endpoint:

@RestController
public class ClientController {

	@GetMapping("/")
	public String index(Model model,
						@RegisteredOAuth2AuthorizedClient OAuth2AuthorizedClient authorizedClient,
						@AuthenticationPrincipal OAuth2User oauth2User) {
		return oauth2User.getName();
	}
}

And you should see the name of the user: user.