OIDC Authorization Code request using HTTP Basic Auth and a Spring RestTemplate

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.jnd.keycloak.web.client.controllers.TokenController;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.*;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.web.client.RestTemplate;
import java.util.Base64;

@RunWith(SpringRunner.class)
@SpringBootTest
public class AuthCodeTests {


	String realm = "psd2";
	String baseUrl = "https://sso.datr.eu:8443";
	String clientId = "Amazon";
	String redirecturl= "http://127.0.0.1:8082/getcode";
	String user = "test_user";
    String password = "123456";


	private Log log = LogFactory.getLog(TokenController.class);

	@Test
	public void getAuthCode()  {
		
		CloseableHttpClient httpClient
				= HttpClients.custom()
                .disableRedirectHandling()
				.setSSLHostnameVerifier(new NoopHostnameVerifier())
				.build();
		HttpComponentsClientHttpRequestFactory requestFactory
				= new HttpComponentsClientHttpRequestFactory();
		requestFactory.setHttpClient(httpClient);

		RestTemplate restTemplate = new RestTemplate(requestFactory);

		log.info("Get Auth code");

		String query_string = "scope=openid&response_type=code&client_id="+clientId+"&redirect_uri="+redirecturl;
		log.info("query_string : "+query_string);

		String uri = baseUrl+"/auth/realms/"+realm+"/protocol/openid-connect/auth";
		log.info("Auth Code URL : "+uri);

		uri = uri+"?"+query_string;

		log.info("Auth Code URL : "+uri);

		HttpHeaders headers = new HttpHeaders();

		String creds = user+":"+password;
		String base64Creds = new String(Base64.getEncoder().encode(creds.getBytes()));
        log.info("base64Creds : "+base64Creds);
        headers.add("Authorization", "Basic "+base64Creds);


		HttpEntity<String> request = new HttpEntity<>(headers);

		ResponseEntity<String> exchange =
				restTemplate.exchange(
						uri,
						HttpMethod.GET,
						request,
						String.class);

        HttpHeaders responseHeaders = exchange.getHeaders();
        log.info("Location : "+responseHeaders.get("Location"));

	}

}

The HTTP Request factory is customised.

1. To Operate against TLS endpoints with self-signed certs. By adding :

.setSSLHostnameVerifier(new NoopHostnameVerifier())

to the HTTPClient configuration.

2. To Allow the 302 Redirect that come backs from Keycloak to be handled within the scope of this code. By Adding :

.disableRedirectHandling()

to the HTTPClient configuration.