Consume OAuth2 secured REST API using swagger generated ApiClient

Question

I am trying to use an ApiClient generated by swagger-codegen-maven-plugin (Version 3.0.0), to consume an OAuth2 secured REST API from within my spring boot application. The auth server (keycloak) provides a JWT and refresh token, but I cannot figure out how to best handle tokens in my bean. At the moment my bean looks like this:

@Configuration
public class SomeApiClientConfiguration {

    @Bean
    public SomeApi someApi() {
        return new SomeApi(apiClient());
    }

    @Bean
    public ApiClient apiClient() {
        ApiClient apiClient = new ApiClient();

        OAuth oAuth = (OAuth) apiClient.getAuthentication("auth");
        oAuth.setAccessToken("");

        return apiClient;
    }
}

Question is: What is the best approach for getting the token and handling the refresh token?

EDIT: In order to get the token I want to use client ID, username, and password. Grant type: Password Credentials.

Best,

Marc

Answer 1

I was able to solve this problem and want to share the solution for future reference:

This is my SomeApiClientConfiguration:

@Configuration
public class SomeApiClientConfiguration{

    @Value("${app.api.url}")
    private String apiURL;

    @Bean
    public SomeApi someApi(OAuth2RestTemplate restTemplate) {
        return new SomeApi(apiClient(restTemplate));
    }

    @Bean
    public ApiClient apiClient(OAuth2RestTemplate restTemplate) {
        var apiClient = new ApiClient(restTemplate);
        apiClient.setBasePath(apiURL);
        return apiClient;
    }
}

Additionally I needed a SomeApiOAuth2Config class, which look as follows:

@Configuration
@EnableOAuth2Client
public class SomeApiOAuth2Config {

    @Value("${app.api.client-id}")
    private String clientId;

    @Value("${app.api.token-endpoint}")
    private String accessTokenUri;

    @Value("${app.api.name}")
    private String username;

    @Value("${app.api.password}")
    private String password;

    @Bean
    public ClientHttpRequestFactory httpRequestFactory() {
        return new HttpComponentsClientHttpRequestFactory(httpClient());
    }

    @Bean
    public HttpClient httpClient() {
        var connectionManager = new PoolingHttpClientConnectionManager();
        var maxPoolSize = 1;
        connectionManager.setMaxTotal(maxPoolSize);
        // This client is for internal connections so only one route is expected
        connectionManager.setDefaultMaxPerRoute(maxPoolSize);
        return HttpClientBuilder.create().setConnectionManager(connectionManager).build();
    }

    @Bean
    public OAuth2ProtectedResourceDetails oauth2ProtectedResourceDetails() {
        var details = new ResourceOwnerPasswordResourceDetails();
        var resourceId = "";
        details.setId(resourceId);
        details.setClientId(clientId);
        var clientSecret = "";
        details.setClientSecret(clientSecret);
        details.setAccessTokenUri(accessTokenUri);
        details.setClientAuthenticationScheme(AuthenticationScheme.form);
        return details;
    }

    @Bean
    public AccessTokenProvider accessTokenProvider() {
        var tokenProvider = new ResourceOwnerPasswordAccessTokenProvider();
        tokenProvider.setRequestFactory(httpRequestFactory());
        return new AccessTokenProviderChain(
            Collections.<AccessTokenProvider>singletonList(tokenProvider)
        );
    }

    @Bean
    @Scope(value = "session", proxyMode = ScopedProxyMode.TARGET_CLASS)
    public OAuth2RestTemplate restTemplate(@Qualifier("oauth2ClientContext") OAuth2ClientContext oauth2ClientContext) {
    var template = new OAuth2RestTemplate(oauth2ProtectedResourceDetails(),     oauth2ClientContext);
        template.setRequestFactory(httpRequestFactory());
        template.setAccessTokenProvider(accessTokenProvider());
        template.getOAuth2ClientContext().getAccessTokenRequest().set("username", username);
        template.getOAuth2ClientContext().getAccessTokenRequest().set("password", password);
        return template;
    }
}