12. OAuth2

12.1 OAuth 2.0 Login

The OAuth 2.0 Login feature provides an application with the capability to have users log in to the application by using their existing account at an OAuth 2.0 Provider (e.g. GitHub) or OpenID Connect 1.0 Provider (such as Google). OAuth 2.0 Login implements the use cases: "Login with Google" or "Login with GitHub".

[Note]Note

OAuth 2.0 Login is implemented by using the Authorization Code Grant, as specified in the OAuth 2.0 Authorization Framework and OpenID Connect Core 1.0.

12.1.1 Spring Boot 2.x Sample

Spring Boot 2.x brings full auto-configuration capabilities for OAuth 2.0 Login.

This section shows how to configure the OAuth 2.0 Login sample using Google as the Authentication Provider and covers the following topics:

Initial setup

To use Google’s OAuth 2.0 authentication system for login, you must set up a project in the Google API Console to obtain OAuth 2.0 credentials.

[Note]Note

Google’s OAuth 2.0 implementation for authentication conforms to the OpenID Connect 1.0 specification and is OpenID Certified.

Follow the instructions on the OpenID Connect page, starting in the section, "Setting up OAuth 2.0".

After completing the "Obtain OAuth 2.0 credentials" instructions, you should have a new OAuth Client with credentials consisting of a Client ID and a Client Secret.

Setting the redirect URI

The redirect URI is the path in the application that the end-user’s user-agent is redirected back to after they have authenticated with Google and have granted access to the OAuth Client (created in the previous step) on the Consent page.

In the "Set a redirect URI" sub-section, ensure that the Authorized redirect URIs field is set to http://localhost:8080/login/oauth2/code/google.

[Tip]Tip

The default redirect URI template is {baseUrl}/login/oauth2/code/{registrationId}. The registrationId is a unique identifier for the ClientRegistration.

[Important]Important

If the OAuth Client is running behind a proxy server, it is recommended to check Proxy Server Configuration to ensure the application is correctly configured. Also, see the supported URI template variables for redirect-uri.

Configure application.yml

Now that you have a new OAuth Client with Google, you need to configure the application to use the OAuth Client for the authentication flow. To do so:

  1. Go to application.yml and set the following configuration:

    spring:
      security:
        oauth2:
          client:
            registration:   1
              google:   2
                client-id: google-client-id
                client-secret: google-client-secret

    Example 12.1. OAuth Client properties

    1

    spring.security.oauth2.client.registration is the base property prefix for OAuth Client properties.

    2

    Following the base property prefix is the ID for the ClientRegistration, such as google.


  2. Replace the values in the client-id and client-secret property with the OAuth 2.0 credentials you created earlier.

Boot up the application

Launch the Spring Boot 2.x sample and go to http://localhost:8080. You are then redirected to the default auto-generated login page, which displays a link for Google.

Click on the Google link, and you are then redirected to Google for authentication.

After authenticating with your Google account credentials, the next page presented to you is the Consent screen. The Consent screen asks you to either allow or deny access to the OAuth Client you created earlier. Click Allow to authorize the OAuth Client to access your email address and basic profile information.

At this point, the OAuth Client retrieves your email address and basic profile information from the UserInfo Endpoint and establishes an authenticated session.

12.1.2 Spring Boot 2.x Property Mappings

The following table outlines the mapping of the Spring Boot 2.x OAuth Client properties to the ClientRegistration properties.

Spring Boot 2.xClientRegistration

spring.security.oauth2.client.registration.[registrationId]

registrationId

spring.security.oauth2.client.registration.[registrationId].client-id

clientId

spring.security.oauth2.client.registration.[registrationId].client-secret

clientSecret

spring.security.oauth2.client.registration.[registrationId].client-authentication-method

clientAuthenticationMethod

spring.security.oauth2.client.registration.[registrationId].authorization-grant-type

authorizationGrantType

spring.security.oauth2.client.registration.[registrationId].redirect-uri

redirectUriTemplate

spring.security.oauth2.client.registration.[registrationId].scope

scopes

spring.security.oauth2.client.registration.[registrationId].client-name

clientName

spring.security.oauth2.client.provider.[providerId].authorization-uri

providerDetails.authorizationUri

spring.security.oauth2.client.provider.[providerId].token-uri

providerDetails.tokenUri

spring.security.oauth2.client.provider.[providerId].jwk-set-uri

providerDetails.jwkSetUri

spring.security.oauth2.client.provider.[providerId].user-info-uri

providerDetails.userInfoEndpoint.uri

spring.security.oauth2.client.provider.[providerId].user-info-authentication-method

providerDetails.userInfoEndpoint.authenticationMethod

spring.security.oauth2.client.provider.[providerId].userNameAttribute

providerDetails.userInfoEndpoint.userNameAttributeName

[Tip]Tip

A ClientRegistration can be initially configured using discovery of an OpenID Connect Provider’s Configuration endpoint or an Authorization Server’s Metadata endpoint, by specifying the spring.security.oauth2.client.provider.[providerId].issuer-uri property.

12.1.3 CommonOAuth2Provider

CommonOAuth2Provider pre-defines a set of default client properties for a number of well known providers: Google, GitHub, Facebook, and Okta.

For example, the authorization-uri, token-uri, and user-info-uri do not change often for a Provider. Therefore, it makes sense to provide default values in order to reduce the required configuration.

As demonstrated previously, when we configured a Google client, only the client-id and client-secret properties are required.

The following listing shows an example:

spring:
  security:
    oauth2:
      client:
        registration:
          google:
            client-id: google-client-id
            client-secret: google-client-secret
[Tip]Tip

The auto-defaulting of client properties works seamlessly here because the registrationId (google) matches the GOOGLE enum (case-insensitive) in CommonOAuth2Provider.

For cases where you may want to specify a different registrationId, such as google-login, you can still leverage auto-defaulting of client properties by configuring the provider property.

The following listing shows an example:

spring:
  security:
    oauth2:
      client:
        registration:
          google-login: 1
            provider: google    2
            client-id: google-client-id
            client-secret: google-client-secret

1

The registrationId is set to google-login.

2

The provider property is set to google, which will leverage the auto-defaulting of client properties set in CommonOAuth2Provider.GOOGLE.getBuilder().

12.1.4 Configuring Custom Provider Properties

There are some OAuth 2.0 Providers that support multi-tenancy, which results in different protocol endpoints for each tenant (or sub-domain).

For example, an OAuth Client registered with Okta is assigned to a specific sub-domain and have their own protocol endpoints.

For these cases, Spring Boot 2.x provides the following base property for configuring custom provider properties: spring.security.oauth2.client.provider.[providerId].

The following listing shows an example:

spring:
  security:
    oauth2:
      client:
        registration:
          okta:
            client-id: okta-client-id
            client-secret: okta-client-secret
        provider:
          okta: 1
            authorization-uri: https://your-subdomain.oktapreview.com/oauth2/v1/authorize
            token-uri: https://your-subdomain.oktapreview.com/oauth2/v1/token
            user-info-uri: https://your-subdomain.oktapreview.com/oauth2/v1/userinfo
            user-name-attribute: sub
            jwk-set-uri: https://your-subdomain.oktapreview.com/oauth2/v1/keys

1

The base property (spring.security.oauth2.client.provider.okta) allows for custom configuration of protocol endpoint locations.

12.1.5 Overriding Spring Boot 2.x Auto-configuration

The Spring Boot 2.x auto-configuration class for OAuth Client support is OAuth2ClientAutoConfiguration.

It performs the following tasks:

  • Registers a ClientRegistrationRepository @Bean composed of ClientRegistration(s) from the configured OAuth Client properties.
  • Provides a WebSecurityConfigurerAdapter @Configuration and enables OAuth 2.0 Login through httpSecurity.oauth2Login().

If you need to override the auto-configuration based on your specific requirements, you may do so in the following ways:

Register a ClientRegistrationRepository @Bean

The following example shows how to register a ClientRegistrationRepository @Bean:

@Configuration
public class OAuth2LoginConfig {

    @Bean
    public ClientRegistrationRepository clientRegistrationRepository() {
        return new InMemoryClientRegistrationRepository(this.googleClientRegistration());
    }

    private ClientRegistration googleClientRegistration() {
        return ClientRegistration.withRegistrationId("google")
            .clientId("google-client-id")
            .clientSecret("google-client-secret")
            .clientAuthenticationMethod(ClientAuthenticationMethod.BASIC)
            .authorizationGrantType(AuthorizationGrantType.AUTHORIZATION_CODE)
            .redirectUriTemplate("{baseUrl}/login/oauth2/code/{registrationId}")
            .scope("openid", "profile", "email", "address", "phone")
            .authorizationUri("https://accounts.google.com/o/oauth2/v2/auth")
            .tokenUri("https://www.googleapis.com/oauth2/v4/token")
            .userInfoUri("https://www.googleapis.com/oauth2/v3/userinfo")
            .userNameAttributeName(IdTokenClaimNames.SUB)
            .jwkSetUri("https://www.googleapis.com/oauth2/v3/certs")
            .clientName("Google")
            .build();
    }
}

Provide a WebSecurityConfigurerAdapter

The following example shows how to provide a WebSecurityConfigurerAdapter with @EnableWebSecurity and enable OAuth 2.0 login through httpSecurity.oauth2Login():

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests(authorizeRequests ->
                authorizeRequests
                    .anyRequest().authenticated()
            )
            .oauth2Login(withDefaults());
    }
}

Completely Override the Auto-configuration

The following example shows how to completely override the auto-configuration by registering a ClientRegistrationRepository @Bean and providing a WebSecurityConfigurerAdapter.

@Configuration
public class OAuth2LoginConfig {

    @EnableWebSecurity
    public static class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http
                .authorizeRequests(authorizeRequests ->
                    authorizeRequests
                        .anyRequest().authenticated()
                )
                .oauth2Login(withDefaults());
        }
    }

    @Bean
    public ClientRegistrationRepository clientRegistrationRepository() {
        return new InMemoryClientRegistrationRepository(this.googleClientRegistration());
    }

    private ClientRegistration googleClientRegistration() {
        return ClientRegistration.withRegistrationId("google")
            .clientId("google-client-id")
            .clientSecret("google-client-secret")
            .clientAuthenticationMethod(ClientAuthenticationMethod.BASIC)
            .authorizationGrantType(AuthorizationGrantType.AUTHORIZATION_CODE)
            .redirectUriTemplate("{baseUrl}/login/oauth2/code/{registrationId}")
            .scope("openid", "profile", "email", "address", "phone")
            .authorizationUri("https://accounts.google.com/o/oauth2/v2/auth")
            .tokenUri("https://www.googleapis.com/oauth2/v4/token")
            .userInfoUri("https://www.googleapis.com/oauth2/v3/userinfo")
            .userNameAttributeName(IdTokenClaimNames.SUB)
            .jwkSetUri("https://www.googleapis.com/oauth2/v3/certs")
            .clientName("Google")
            .build();
    }
}

12.1.6 Java Configuration without Spring Boot 2.x

If you are not able to use Spring Boot 2.x and would like to configure one of the pre-defined providers in CommonOAuth2Provider (for example, Google), apply the following configuration:

@Configuration
public class OAuth2LoginConfig {

    @EnableWebSecurity
    public static class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http
                .authorizeRequests(authorizeRequests ->
                    authorizeRequests
                        .anyRequest().authenticated()
                )
                .oauth2Login(withDefaults());
        }
    }

    @Bean
    public ClientRegistrationRepository clientRegistrationRepository() {
        return new InMemoryClientRegistrationRepository(this.googleClientRegistration());
    }

    @Bean
    public OAuth2AuthorizedClientService authorizedClientService(
            ClientRegistrationRepository clientRegistrationRepository) {
        return new InMemoryOAuth2AuthorizedClientService(clientRegistrationRepository);
    }

    @Bean
    public OAuth2AuthorizedClientRepository authorizedClientRepository(
            OAuth2AuthorizedClientService authorizedClientService) {
        return new AuthenticatedPrincipalOAuth2AuthorizedClientRepository(authorizedClientService);
    }

    private ClientRegistration googleClientRegistration() {
        return CommonOAuth2Provider.GOOGLE.getBuilder("google")
            .clientId("google-client-id")
            .clientSecret("google-client-secret")
            .build();
    }
}

12.1.7 Advanced Configuration

HttpSecurity.oauth2Login() provides a number of configuration options for customizing OAuth 2.0 Login. The main configuration options are grouped into their protocol endpoint counterparts.

For example, oauth2Login().authorizationEndpoint() allows configuring the Authorization Endpoint, whereas oauth2Login().tokenEndpoint() allows configuring the Token Endpoint.

The following code shows an example:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .authorizationEndpoint(authorizationEndpoint ->
                        authorizationEndpoint
                            ...
                    )
                    .redirectionEndpoint(redirectionEndpoint ->
                        redirectionEndpoint
                            ...
                    )
                    .tokenEndpoint(tokenEndpoint ->
                        tokenEndpoint
                            ...
                    )
                    .userInfoEndpoint(userInfoEndpoint ->
                        userInfoEndpoint
                            ...
                    )
            );
    }
}

The main goal of the oauth2Login() DSL was to closely align with the naming, as defined in the specifications.

The OAuth 2.0 Authorization Framework defines the Protocol Endpoints as follows:

The authorization process utilizes two authorization server endpoints (HTTP resources):

  • Authorization Endpoint: Used by the client to obtain authorization from the resource owner via user-agent redirection.
  • Token Endpoint: Used by the client to exchange an authorization grant for an access token, typically with client authentication.

As well as one client endpoint:

  • Redirection Endpoint: Used by the authorization server to return responses containing authorization credentials to the client via the resource owner user-agent.

The OpenID Connect Core 1.0 specification defines the UserInfo Endpoint as follows:

The UserInfo Endpoint is an OAuth 2.0 Protected Resource that returns claims about the authenticated end-user. To obtain the requested claims about the end-user, the client makes a request to the UserInfo Endpoint by using an access token obtained through OpenID Connect Authentication. These claims are normally represented by a JSON object that contains a collection of name-value pairs for the claims.

The following code shows the complete configuration options available for the oauth2Login() DSL:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .clientRegistrationRepository(this.clientRegistrationRepository())
                    .authorizedClientRepository(this.authorizedClientRepository())
                    .authorizedClientService(this.authorizedClientService())
                    .loginPage("/login")
                    .authorizationEndpoint(authorizationEndpoint ->
                        authorizationEndpoint
                            .baseUri(this.authorizationRequestBaseUri())
                            .authorizationRequestRepository(this.authorizationRequestRepository())
                            .authorizationRequestResolver(this.authorizationRequestResolver())
                    )
                    .redirectionEndpoint(redirectionEndpoint ->
                         redirectionEndpoint
                            .baseUri(this.authorizationResponseBaseUri())
                    )
                    .tokenEndpoint(tokenEndpoint ->
                        tokenEndpoint
                            .accessTokenResponseClient(this.accessTokenResponseClient())
                    )
                    .userInfoEndpoint(userInfoEndpoint ->
                        userInfoEndpoint
                            .userAuthoritiesMapper(this.userAuthoritiesMapper())
                            .userService(this.oauth2UserService())
                            .oidcUserService(this.oidcUserService())
                            .customUserType(GitHubOAuth2User.class, "github")
                    )
            );
    }
}

The following sections go into more detail on each of the configuration options available:

OAuth 2.0 Login Page

By default, the OAuth 2.0 Login Page is auto-generated by the DefaultLoginPageGeneratingFilter. The default login page shows each configured OAuth Client with its ClientRegistration.clientName as a link, which is capable of initiating the Authorization Request (or OAuth 2.0 Login).

[Note]Note

In order for DefaultLoginPageGeneratingFilter to show links for configured OAuth Clients, the registered ClientRegistrationRepository needs to also implement Iterable<ClientRegistration>. See InMemoryClientRegistrationRepository for reference.

The link’s destination for each OAuth Client defaults to the following:

OAuth2AuthorizationRequestRedirectFilter.DEFAULT_AUTHORIZATION_REQUEST_BASE_URI + "/{registrationId}"

The following line shows an example:

<a href="/oauth2/authorization/google">Google</a>

To override the default login page, configure oauth2Login().loginPage() and (optionally) oauth2Login().authorizationEndpoint().baseUri().

The following listing shows an example:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .loginPage("/login/oauth2")
                    ...
                    .authorizationEndpoint(authorizationEndpoint ->
                        authorizationEndpoint
                            .baseUri("/login/oauth2/authorization")
                            ...
                    )
            );
    }
}
[Important]Important

You need to provide a @Controller with a @RequestMapping("/login/oauth2") that is capable of rendering the custom login page.

[Tip]Tip

As noted earlier, configuring oauth2Login().authorizationEndpoint().baseUri() is optional. However, if you choose to customize it, ensure the link to each OAuth Client matches the authorizationEndpoint().baseUri().

The following line shows an example:

<a href="/login/oauth2/authorization/google">Google</a>

Redirection Endpoint

The Redirection Endpoint is used by the Authorization Server for returning the Authorization Response (which contains the authorization credentials) to the client via the Resource Owner user-agent.

[Tip]Tip

OAuth 2.0 Login leverages the Authorization Code Grant. Therefore, the authorization credential is the authorization code.

The default Authorization Response baseUri (redirection endpoint) is /login/oauth2/code/*, which is defined in OAuth2LoginAuthenticationFilter.DEFAULT_FILTER_PROCESSES_URI.

If you would like to customize the Authorization Response baseUri, configure it as shown in the following example:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .redirectionEndpoint(redirectionEndpoint ->
                        redirectionEndpoint
                            .baseUri("/login/oauth2/callback/*")
                            ...
                    )
            );
    }
}
[Important]Important

You also need to ensure the ClientRegistration.redirectUriTemplate matches the custom Authorization Response baseUri.

The following listing shows an example:

return CommonOAuth2Provider.GOOGLE.getBuilder("google")
    .clientId("google-client-id")
    .clientSecret("google-client-secret")
    .redirectUriTemplate("{baseUrl}/login/oauth2/callback/{registrationId}")
    .build();

UserInfo Endpoint

The UserInfo Endpoint includes a number of configuration options, as described in the following sub-sections:

Mapping User Authorities

After the user successfully authenticates with the OAuth 2.0 Provider, the OAuth2User.getAuthorities() (or OidcUser.getAuthorities()) may be mapped to a new set of GrantedAuthority instances, which will be supplied to OAuth2AuthenticationToken when completing the authentication.

[Tip]Tip

OAuth2AuthenticationToken.getAuthorities() is used for authorizing requests, such as in hasRole('USER') or hasRole('ADMIN').

There are a couple of options to choose from when mapping user authorities:

Using a GrantedAuthoritiesMapper

Provide an implementation of GrantedAuthoritiesMapper and configure it as shown in the following example:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .userInfoEndpoint(userInfoEndpoint ->
                        userInfoEndpoint
                            .userAuthoritiesMapper(this.userAuthoritiesMapper())
                            ...
                    )
            );
    }

    private GrantedAuthoritiesMapper userAuthoritiesMapper() {
        return (authorities) -> {
            Set<GrantedAuthority> mappedAuthorities = new HashSet<>();

            authorities.forEach(authority -> {
                if (OidcUserAuthority.class.isInstance(authority)) {
                    OidcUserAuthority oidcUserAuthority = (OidcUserAuthority)authority;

                    OidcIdToken idToken = oidcUserAuthority.getIdToken();
                    OidcUserInfo userInfo = oidcUserAuthority.getUserInfo();

                    // Map the claims found in idToken and/or userInfo
                    // to one or more GrantedAuthority's and add it to mappedAuthorities

                } else if (OAuth2UserAuthority.class.isInstance(authority)) {
                    OAuth2UserAuthority oauth2UserAuthority = (OAuth2UserAuthority)authority;

                    Map<String, Object> userAttributes = oauth2UserAuthority.getAttributes();

                    // Map the attributes found in userAttributes
                    // to one or more GrantedAuthority's and add it to mappedAuthorities

                }
            });

            return mappedAuthorities;
        };
    }
}

Alternatively, you may register a GrantedAuthoritiesMapper @Bean to have it automatically applied to the configuration, as shown in the following example:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(withDefaults());
    }

    @Bean
    public GrantedAuthoritiesMapper userAuthoritiesMapper() {
        ...
    }
}
Delegation-based strategy with OAuth2UserService

This strategy is advanced compared to using a GrantedAuthoritiesMapper, however, it’s also more flexible as it gives you access to the OAuth2UserRequest and OAuth2User (when using an OAuth 2.0 UserService) or OidcUserRequest and OidcUser (when using an OpenID Connect 1.0 UserService).

The OAuth2UserRequest (and OidcUserRequest) provides you access to the associated OAuth2AccessToken, which is very useful in the cases where the delegator needs to fetch authority information from a protected resource before it can map the custom authorities for the user.

The following example shows how to implement and configure a delegation-based strategy using an OpenID Connect 1.0 UserService:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .userInfoEndpoint(userInfoEndpoint ->
                        userInfoEndpoint
                            .oidcUserService(this.oidcUserService())
                            ...
                    )
            );
    }

    private OAuth2UserService<OidcUserRequest, OidcUser> oidcUserService() {
        final OidcUserService delegate = new OidcUserService();

        return (userRequest) -> {
            // Delegate to the default implementation for loading a user
            OidcUser oidcUser = delegate.loadUser(userRequest);

            OAuth2AccessToken accessToken = userRequest.getAccessToken();
            Set<GrantedAuthority> mappedAuthorities = new HashSet<>();

            // TODO
            // 1) Fetch the authority information from the protected resource using accessToken
            // 2) Map the authority information to one or more GrantedAuthority's and add it to mappedAuthorities

            // 3) Create a copy of oidcUser but use the mappedAuthorities instead
            oidcUser = new DefaultOidcUser(mappedAuthorities, oidcUser.getIdToken(), oidcUser.getUserInfo());

            return oidcUser;
        };
    }
}
Configuring a Custom OAuth2User

CustomUserTypesOAuth2UserService is an implementation of an OAuth2UserService that provides support for custom OAuth2User types.

If the default implementation (DefaultOAuth2User) does not suit your needs, you can define your own implementation of OAuth2User.

The following code demonstrates how you would register a custom OAuth2User type for GitHub:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .userInfoEndpoint(userInfoEndpoint ->
                        userInfoEndpoint
                            .customUserType(GitHubOAuth2User.class, "github")
                            ...
                    )
            );
    }
}

The following code shows an example of a custom OAuth2User type for GitHub:

public class GitHubOAuth2User implements OAuth2User {
    private List<GrantedAuthority> authorities =
        AuthorityUtils.createAuthorityList("ROLE_USER");
    private Map<String, Object> attributes;
    private String id;
    private String name;
    private String login;
    private String email;

    @Override
    public Collection<? extends GrantedAuthority> getAuthorities() {
        return this.authorities;
    }

    @Override
    public Map<String, Object> getAttributes() {
        if (this.attributes == null) {
            this.attributes = new HashMap<>();
            this.attributes.put("id", this.getId());
            this.attributes.put("name", this.getName());
            this.attributes.put("login", this.getLogin());
            this.attributes.put("email", this.getEmail());
        }
        return attributes;
    }

    public String getId() {
        return this.id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @Override
    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getLogin() {
        return this.login;
    }

    public void setLogin(String login) {
        this.login = login;
    }

    public String getEmail() {
        return this.email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}
[Tip]Tip

id, name, login, and email are attributes returned in GitHub’s UserInfo Response. For detailed information returned from the UserInfo Endpoint, see the API documentation for "Get the authenticated user".

OAuth 2.0 UserService

DefaultOAuth2UserService is an implementation of an OAuth2UserService that supports standard OAuth 2.0 Provider’s.

[Note]Note

OAuth2UserService obtains the user attributes of the end-user (the resource owner) from the UserInfo Endpoint (by using the access token granted to the client during the authorization flow) and returns an AuthenticatedPrincipal in the form of an OAuth2User.

DefaultOAuth2UserService uses a RestOperations when requesting the user attributes at the UserInfo Endpoint.

If you need to customize the pre-processing of the UserInfo Request, you can provide DefaultOAuth2UserService.setRequestEntityConverter() with a custom Converter<OAuth2UserRequest, RequestEntity<?>>. The default implementation OAuth2UserRequestEntityConverter builds a RequestEntity representation of a UserInfo Request that sets the OAuth2AccessToken in the Authorization header by default.

On the other end, if you need to customize the post-handling of the UserInfo Response, you will need to provide DefaultOAuth2UserService.setRestOperations() with a custom configured RestOperations. The default RestOperations is configured as follows:

RestTemplate restTemplate = new RestTemplate();
restTemplate.setErrorHandler(new OAuth2ErrorResponseErrorHandler());

OAuth2ErrorResponseErrorHandler is a ResponseErrorHandler that can handle an OAuth 2.0 Error (400 Bad Request). It uses an OAuth2ErrorHttpMessageConverter for converting the OAuth 2.0 Error parameters to an OAuth2Error.

Whether you customize DefaultOAuth2UserService or provide your own implementation of OAuth2UserService, you’ll need to configure it as shown in the following example:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .userInfoEndpoint(userInfoEndpoint ->
                        userInfoEndpoint
                            .userService(this.oauth2UserService())
                            ...
                    )
            );
    }

    private OAuth2UserService<OAuth2UserRequest, OAuth2User> oauth2UserService() {
        ...
    }
}
OpenID Connect 1.0 UserService

OidcUserService is an implementation of an OAuth2UserService that supports OpenID Connect 1.0 Provider’s.

The OidcUserService leverages the DefaultOAuth2UserService when requesting the user attributes at the UserInfo Endpoint.

If you need to customize the pre-processing of the UserInfo Request and/or the post-handling of the UserInfo Response, you will need to provide OidcUserService.setOauth2UserService() with a custom configured DefaultOAuth2UserService.

Whether you customize OidcUserService or provide your own implementation of OAuth2UserService for OpenID Connect 1.0 Provider’s, you’ll need to configure it as shown in the following example:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .userInfoEndpoint(userInfoEndpoint ->
                        userInfoEndpoint
                            .oidcUserService(this.oidcUserService())
                            ...
                    )
            );
    }

    private OAuth2UserService<OidcUserRequest, OidcUser> oidcUserService() {
        ...
    }
}

ID Token Signature Verification

OpenID Connect 1.0 Authentication introduces the ID Token, which is a security token that contains Claims about the Authentication of an End-User by an Authorization Server when used by a Client.

The ID Token is represented as a JSON Web Token (JWT) and MUST be signed using JSON Web Signature (JWS).

The OidcIdTokenDecoderFactory provides a JwtDecoder used for OidcIdToken signature verification. The default algorithm is RS256 but may be different when assigned during client registration. For these cases, a resolver may be configured to return the expected JWS algorithm assigned for a specific client.

The JWS algorithm resolver is a Function that accepts a ClientRegistration and returns the expected JwsAlgorithm for the client, eg. SignatureAlgorithm.RS256 or MacAlgorithm.HS256

The following code shows how to configure the OidcIdTokenDecoderFactory @Bean to default to MacAlgorithm.HS256 for all ClientRegistration:

@Bean
public JwtDecoderFactory<ClientRegistration> idTokenDecoderFactory() {
    OidcIdTokenDecoderFactory idTokenDecoderFactory = new OidcIdTokenDecoderFactory();
    idTokenDecoderFactory.setJwsAlgorithmResolver(clientRegistration -> MacAlgorithm.HS256);
    return idTokenDecoderFactory;
}
[Note]Note

For MAC based algorithms such as HS256, HS384 or HS512, the client-secret corresponding to the client-id is used as the symmetric key for signature verification.

[Tip]Tip

If more than one ClientRegistration is configured for OpenID Connect 1.0 Authentication, the JWS algorithm resolver may evaluate the provided ClientRegistration to determine which algorithm to return.

OpenID Connect 1.0 Logout

OpenID Connect Session Management 1.0 allows the ability to log out the End-User at the Provider using the Client. One of the strategies available is RP-Initiated Logout.

If the OpenID Provider supports both Session Management and Discovery, the client may obtain the end_session_endpoint URL from the OpenID Provider’s Discovery Metadata. This can be achieved by configuring the ClientRegistration with the issuer-uri, as in the following example:

spring:
  security:
    oauth2:
      client:
        registration:
          okta:
            client-id: okta-client-id
            client-secret: okta-client-secret
            ...
        provider:
          okta:
            issuer-uri: https://dev-1234.oktapreview.com

…​and the OidcClientInitiatedLogoutSuccessHandler, which implements RP-Initiated Logout, may be configured as follows:

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private ClientRegistrationRepository clientRegistrationRepository;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests(authorizeRequests ->
                authorizeRequests
                    .anyRequest().authenticated()
            )
            .oauth2Login(withDefaults())
            .logout(logout ->
                logout
                    .logoutSuccessHandler(oidcLogoutSuccessHandler())
            );
    }

    private LogoutSuccessHandler oidcLogoutSuccessHandler() {
        OidcClientInitiatedLogoutSuccessHandler oidcLogoutSuccessHandler =
                new OidcClientInitiatedLogoutSuccessHandler(this.clientRegistrationRepository);

        // Sets the `URI` that the End-User's User Agent will be redirected to
        // after the logout has been performed at the Provider
        oidcLogoutSuccessHandler.setPostLogoutRedirectUri(URI.create("https://localhost:8080"));

        return oidcLogoutSuccessHandler;
    }
}

12.2 OAuth 2.0 Client

The OAuth 2.0 Client features provide support for the Client role as defined in the OAuth 2.0 Authorization Framework.

At a high-level, the core features available are:

HTTP Client support

The HttpSecurity.oauth2Client() DSL provides a number of configuration options for customizing the core components used by OAuth 2.0 Client. In addition, HttpSecurity.oauth2Client().authorizationCodeGrant() enables the customization of the Authorization Code grant.

The following code shows the complete configuration options provided by the HttpSecurity.oauth2Client() DSL:

@EnableWebSecurity
public class OAuth2ClientSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Client(oauth2Client ->
                oauth2Client
                    .clientRegistrationRepository(this.clientRegistrationRepository())
                    .authorizedClientRepository(this.authorizedClientRepository())
                    .authorizedClientService(this.authorizedClientService())
                    .authorizationCodeGrant(authorizationCodeGrant ->
                        authorizationCodeGrant
                            .authorizationRequestRepository(this.authorizationRequestRepository())
                            .authorizationRequestResolver(this.authorizationRequestResolver())
                            .accessTokenResponseClient(this.accessTokenResponseClient())
                    )
            );
    }
}

The OAuth2AuthorizedClientManager is responsible for managing the authorization (or re-authorization) of an OAuth 2.0 Client, in collaboration with one or more OAuth2AuthorizedClientProvider(s).

The following code shows an example of how to register an OAuth2AuthorizedClientManager @Bean and associate it with an OAuth2AuthorizedClientProvider composite that provides support for the authorization_code, refresh_token, client_credentials and password authorization grant types:

@Bean
public OAuth2AuthorizedClientManager authorizedClientManager(
        ClientRegistrationRepository clientRegistrationRepository,
        OAuth2AuthorizedClientRepository authorizedClientRepository) {

    OAuth2AuthorizedClientProvider authorizedClientProvider =
            OAuth2AuthorizedClientProviderBuilder.builder()
                    .authorizationCode()
                    .refreshToken()
                    .clientCredentials()
                    .password()
                    .build();

    DefaultOAuth2AuthorizedClientManager authorizedClientManager =
            new DefaultOAuth2AuthorizedClientManager(
                    clientRegistrationRepository, authorizedClientRepository);
    authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);

    return authorizedClientManager;
}

The following sections will go into more detail on the core components used by OAuth 2.0 Client and the configuration options available:

12.2.1 Core Interfaces / Classes

ClientRegistration

ClientRegistration is a representation of a client registered with an OAuth 2.0 or OpenID Connect 1.0 Provider.

A client registration holds information, such as client id, client secret, authorization grant type, redirect URI, scope(s), authorization URI, token URI, and other details.

ClientRegistration and its properties are defined as follows:

public final class ClientRegistration {
    private String registrationId;  1
    private String clientId;    2
    private String clientSecret;    3
    private ClientAuthenticationMethod clientAuthenticationMethod;  4
    private AuthorizationGrantType authorizationGrantType;  5
    private String redirectUriTemplate; 6
    private Set<String> scopes; 7
    private ProviderDetails providerDetails;
    private String clientName;  8

    public class ProviderDetails {
        private String authorizationUri;    9
        private String tokenUri;    10
        private UserInfoEndpoint userInfoEndpoint;
        private String jwkSetUri;   11
        private Map<String, Object> configurationMetadata;  12

        public class UserInfoEndpoint {
            private String uri; 13
            private AuthenticationMethod authenticationMethod;  14
            private String userNameAttributeName;   15

        }
    }
}

1

registrationId: The ID that uniquely identifies the ClientRegistration.

2

clientId: The client identifier.

3

clientSecret: The client secret.

4

clientAuthenticationMethod: The method used to authenticate the Client with the Provider. The supported values are basic, post and none (public clients).

5

authorizationGrantType: The OAuth 2.0 Authorization Framework defines four Authorization Grant types. The supported values are authorization_code, client_credentials, password and implicit.

6

redirectUriTemplate: The client’s registered redirect URI that the Authorization Server redirects the end-user’s user-agent to after the end-user has authenticated and authorized access to the client.

7

scopes: The scope(s) requested by the client during the Authorization Request flow, such as openid, email, or profile.

8

clientName: A descriptive name used for the client. The name may be used in certain scenarios, such as when displaying the name of the client in the auto-generated login page.

9

authorizationUri: The Authorization Endpoint URI for the Authorization Server.

10

tokenUri: The Token Endpoint URI for the Authorization Server.

11

jwkSetUri: The URI used to retrieve the JSON Web Key (JWK) Set from the Authorization Server, which contains the cryptographic key(s) used to verify the JSON Web Signature (JWS) of the ID Token and optionally the UserInfo Response.

12

configurationMetadata: The OpenID Provider Configuration Information. This information will only be available if the Spring Boot 2.x property spring.security.oauth2.client.provider.[providerId].issuerUri is configured.

13

(userInfoEndpoint)uri: The UserInfo Endpoint URI used to access the claims/attributes of the authenticated end-user.

14

(userInfoEndpoint)authenticationMethod: The authentication method used when sending the access token to the UserInfo Endpoint. The supported values are header, form and query.

15

userNameAttributeName: The name of the attribute returned in the UserInfo Response that references the Name or Identifier of the end-user.

A ClientRegistration can be initially configured using discovery of an OpenID Connect Provider’s Configuration endpoint or an Authorization Server’s Metadata endpoint.

ClientRegistrations provides convenience methods for configuring a ClientRegistration in this way, as can be seen in the following example:

ClientRegistration clientRegistration =
    ClientRegistrations.fromIssuerLocation("https://idp.example.com/issuer").build();

The above code will query in series https://idp.example.com/issuer/.well-known/openid-configuration, and then https://idp.example.com/.well-known/openid-configuration/issuer, and finally https://idp.example.com/.well-known/oauth-authorization-server/issuer, stopping at the first to return a 200 response.

As an alternative, you can use ClientRegistrations.fromOidcIssuerLocation() to only query the OpenID Connect Provider’s Configuration endpoint.

ClientRegistrationRepository

The ClientRegistrationRepository serves as a repository for OAuth 2.0 / OpenID Connect 1.0 ClientRegistration(s).

[Note]Note

Client registration information is ultimately stored and owned by the associated Authorization Server. This repository provides the ability to retrieve a sub-set of the primary client registration information, which is stored with the Authorization Server.

Spring Boot 2.x auto-configuration binds each of the properties under spring.security.oauth2.client.registration.[registrationId] to an instance of ClientRegistration and then composes each of the ClientRegistration instance(s) within a ClientRegistrationRepository.

[Note]Note

The default implementation of ClientRegistrationRepository is InMemoryClientRegistrationRepository.

The auto-configuration also registers the ClientRegistrationRepository as a @Bean in the ApplicationContext so that it is available for dependency-injection, if needed by the application.

The following listing shows an example:

@Controller
public class OAuth2ClientController {

    @Autowired
    private ClientRegistrationRepository clientRegistrationRepository;

    @GetMapping("/")
    public String index() {
        ClientRegistration oktaRegistration =
            this.clientRegistrationRepository.findByRegistrationId("okta");

        ...

        return "index";
    }
}

OAuth2AuthorizedClient

OAuth2AuthorizedClient is a representation of an Authorized Client. A client is considered to be authorized when the end-user (Resource Owner) has granted authorization to the client to access its protected resources.

OAuth2AuthorizedClient serves the purpose of associating an OAuth2AccessToken (and optional OAuth2RefreshToken) to a ClientRegistration (client) and resource owner, who is the Principal end-user that granted the authorization.

OAuth2AuthorizedClientRepository / OAuth2AuthorizedClientService

OAuth2AuthorizedClientRepository is responsible for persisting OAuth2AuthorizedClient(s) between web requests. Whereas, the primary role of OAuth2AuthorizedClientService is to manage OAuth2AuthorizedClient(s) at the application-level.

From a developer perspective, the OAuth2AuthorizedClientRepository or OAuth2AuthorizedClientService provides the capability to lookup an OAuth2AccessToken associated with a client so that it may be used to initiate a protected resource request.

The following listing shows an example:

@Controller
public class OAuth2ClientController {

    @Autowired
    private OAuth2AuthorizedClientService authorizedClientService;

    @GetMapping("/")
    public String index(Authentication authentication) {
        OAuth2AuthorizedClient authorizedClient =
            this.authorizedClientService.loadAuthorizedClient("okta", authentication.getName());

        OAuth2AccessToken accessToken = authorizedClient.getAccessToken();

        ...

        return "index";
    }
}
[Note]Note

Spring Boot 2.x auto-configuration registers an OAuth2AuthorizedClientRepository and/or OAuth2AuthorizedClientService @Bean in the ApplicationContext. However, the application may choose to override and register a custom OAuth2AuthorizedClientRepository or OAuth2AuthorizedClientService @Bean.

OAuth2AuthorizedClientManager / OAuth2AuthorizedClientProvider

The OAuth2AuthorizedClientManager is responsible for the overall management of OAuth2AuthorizedClient(s).

The primary responsibilities include:

  • Authorizing (or re-authorizing) an OAuth 2.0 Client, using an OAuth2AuthorizedClientProvider.
  • Delegating the persistence of an OAuth2AuthorizedClient, typically using an OAuth2AuthorizedClientService or OAuth2AuthorizedClientRepository.

An OAuth2AuthorizedClientProvider implements a strategy for authorizing (or re-authorizing) an OAuth 2.0 Client. Implementations will typically implement an authorization grant type, eg. authorization_code, client_credentials, etc.

The default implementation of OAuth2AuthorizedClientManager is DefaultOAuth2AuthorizedClientManager, which is associated with an OAuth2AuthorizedClientProvider that may support multiple authorization grant types using a delegation-based composite. The OAuth2AuthorizedClientProviderBuilder may be used to configure and build the delegation-based composite.

The following code shows an example of how to configure and build an OAuth2AuthorizedClientProvider composite that provides support for the authorization_code, refresh_token, client_credentials and password authorization grant types:

@Bean
public OAuth2AuthorizedClientManager authorizedClientManager(
        ClientRegistrationRepository clientRegistrationRepository,
        OAuth2AuthorizedClientRepository authorizedClientRepository) {

    OAuth2AuthorizedClientProvider authorizedClientProvider =
            OAuth2AuthorizedClientProviderBuilder.builder()
                    .authorizationCode()
                    .refreshToken()
                    .clientCredentials()
                    .password()
                    .build();

    DefaultOAuth2AuthorizedClientManager authorizedClientManager =
            new DefaultOAuth2AuthorizedClientManager(
                    clientRegistrationRepository, authorizedClientRepository);
    authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);

    return authorizedClientManager;
}

The DefaultOAuth2AuthorizedClientManager is also associated with a contextAttributesMapper of type Function<OAuth2AuthorizeRequest, Map<String, Object>>, which is responsible for mapping attribute(s) from the OAuth2AuthorizeRequest to a Map of attributes to be associated to the OAuth2AuthorizationContext. This can be useful when you need to supply an OAuth2AuthorizedClientProvider with required (supported) attribute(s), eg. the PasswordOAuth2AuthorizedClientProvider requires the resource owner’s username and password to be available in OAuth2AuthorizationContext.getAttributes().

The following code shows an example of the contextAttributesMapper:

@Bean
public OAuth2AuthorizedClientManager authorizedClientManager(
        ClientRegistrationRepository clientRegistrationRepository,
        OAuth2AuthorizedClientRepository authorizedClientRepository) {

    OAuth2AuthorizedClientProvider authorizedClientProvider =
            OAuth2AuthorizedClientProviderBuilder.builder()
                    .password()
                    .refreshToken()
                    .build();

    DefaultOAuth2AuthorizedClientManager authorizedClientManager =
            new DefaultOAuth2AuthorizedClientManager(
                    clientRegistrationRepository, authorizedClientRepository);
    authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);

    // Assuming the `username` and `password` are supplied as `HttpServletRequest` parameters,
    // map the `HttpServletRequest` parameters to `OAuth2AuthorizationContext.getAttributes()`
    authorizedClientManager.setContextAttributesMapper(contextAttributesMapper());

    return authorizedClientManager;
}

private Function<OAuth2AuthorizeRequest, Map<String, Object>> contextAttributesMapper() {
    return authorizeRequest -> {
        Map<String, Object> contextAttributes = Collections.emptyMap();
        HttpServletRequest servletRequest = authorizeRequest.getAttribute(HttpServletRequest.class.getName());
        String username = servletRequest.getParameter(OAuth2ParameterNames.USERNAME);
        String password = servletRequest.getParameter(OAuth2ParameterNames.PASSWORD);
        if (StringUtils.hasText(username) && StringUtils.hasText(password)) {
            contextAttributes = new HashMap<>();

            // `PasswordOAuth2AuthorizedClientProvider` requires both attributes
            contextAttributes.put(OAuth2AuthorizationContext.USERNAME_ATTRIBUTE_NAME, username);
            contextAttributes.put(OAuth2AuthorizationContext.PASSWORD_ATTRIBUTE_NAME, password);
        }
        return contextAttributes;
    };
}

The DefaultOAuth2AuthorizedClientManager is designed to be used within the context of a HttpServletRequest. When operating outside of a HttpServletRequest context, use AuthorizedClientServiceOAuth2AuthorizedClientManager instead.

A service application is a common use case for when to use an AuthorizedClientServiceOAuth2AuthorizedClientManager. Service applications often run in the background, without any user interaction, and typically run under a system-level account instead of a user account. An OAuth 2.0 Client configured with the client_credentials grant type can be considered a type of service application.

The following code shows an example of how to configure an AuthorizedClientServiceOAuth2AuthorizedClientManager that provides support for the client_credentials grant type:

@Bean
public OAuth2AuthorizedClientManager authorizedClientManager(
        ClientRegistrationRepository clientRegistrationRepository,
        OAuth2AuthorizedClientService authorizedClientService) {

    OAuth2AuthorizedClientProvider authorizedClientProvider =
            OAuth2AuthorizedClientProviderBuilder.builder()
                    .clientCredentials()
                    .build();

    AuthorizedClientServiceOAuth2AuthorizedClientManager authorizedClientManager =
            new AuthorizedClientServiceOAuth2AuthorizedClientManager(
                    clientRegistrationRepository, authorizedClientService);
    authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);

    return authorizedClientManager;
}

12.2.2 Authorization Grant Support

Authorization Code

[Note]Note

Please refer to the OAuth 2.0 Authorization Framework for further details on the Authorization Code grant.

Obtaining Authorization
[Note]Note

Please refer to the Authorization Request/Response protocol flow for the Authorization Code grant.

Initiating the Authorization Request

The OAuth2AuthorizationRequestRedirectFilter uses an OAuth2AuthorizationRequestResolver to resolve an OAuth2AuthorizationRequest and initiate the Authorization Code grant flow by redirecting the end-user’s user-agent to the Authorization Server’s Authorization Endpoint.

The primary role of the OAuth2AuthorizationRequestResolver is to resolve an OAuth2AuthorizationRequest from the provided web request. The default implementation DefaultOAuth2AuthorizationRequestResolver matches on the (default) path /oauth2/authorization/{registrationId} extracting the registrationId and using it to build the OAuth2AuthorizationRequest for the associated ClientRegistration.

Given the following Spring Boot 2.x properties for an OAuth 2.0 Client registration:

spring:
  security:
    oauth2:
      client:
        registration:
          okta:
            client-id: okta-client-id
            client-secret: okta-client-secret
            authorization-grant-type: authorization_code
            redirect-uri: "{baseUrl}/authorized/okta"
            scope: read, write
        provider:
          okta:
            authorization-uri: https://dev-1234.oktapreview.com/oauth2/v1/authorize
            token-uri: https://dev-1234.oktapreview.com/oauth2/v1/token

A request with the base path /oauth2/authorization/okta will initiate the Authorization Request redirect by the OAuth2AuthorizationRequestRedirectFilter and ultimately start the Authorization Code grant flow.

[Note]Note

The AuthorizationCodeOAuth2AuthorizedClientProvider is an implementation of OAuth2AuthorizedClientProvider for the Authorization Code grant, which also initiates the Authorization Request redirect by the OAuth2AuthorizationRequestRedirectFilter.

If the OAuth 2.0 Client is a Public Client, then configure the OAuth 2.0 Client registration as follows:

spring:
  security:
    oauth2:
      client:
        registration:
          okta:
            client-id: okta-client-id
            client-authentication-method: none
            authorization-grant-type: authorization_code
            redirect-uri: "{baseUrl}/authorized/okta"
            ...

Public Clients are supported using Proof Key for Code Exchange (PKCE). If the client is running in an untrusted environment (eg. native application or web browser-based application) and therefore incapable of maintaining the confidentiality of it’s credentials, PKCE will automatically be used when the following conditions are true:

  1. client-secret is omitted (or empty)
  2. client-authentication-method is set to "none" (ClientAuthenticationMethod.NONE)

The DefaultOAuth2AuthorizationRequestResolver also supports URI template variables for the redirect-uri using UriComponentsBuilder.

The following configuration uses all the supported URI template variables:

spring:
  security:
    oauth2:
      client:
        registration:
          okta:
            ...
            redirect-uri: "{baseScheme}://{baseHost}{basePort}{basePath}/authorized/{registrationId}"
            ...
[Note]Note

{baseUrl} resolves to {baseScheme}://{baseHost}{basePort}{basePath}

Configuring the redirect-uri with URI template variables is especially useful when the OAuth 2.0 Client is running behind a Proxy Server. This ensures that the X-Forwarded-* headers are used when expanding the redirect-uri.

Customizing the Authorization Request

One of the primary use cases an OAuth2AuthorizationRequestResolver can realize is the ability to customize the Authorization Request with additional parameters above the standard parameters defined in the OAuth 2.0 Authorization Framework.

For example, OpenID Connect defines additional OAuth 2.0 request parameters for the Authorization Code Flow extending from the standard parameters defined in the OAuth 2.0 Authorization Framework. One of those extended parameters is the prompt parameter.

[Note]Note

OPTIONAL. Space delimited, case sensitive list of ASCII string values that specifies whether the Authorization Server prompts the End-User for reauthentication and consent. The defined values are: none, login, consent, select_account

The following example shows how to implement an OAuth2AuthorizationRequestResolver that customizes the Authorization Request for oauth2Login(), by including the request parameter prompt=consent.

@EnableWebSecurity
public class OAuth2LoginSecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private ClientRegistrationRepository clientRegistrationRepository;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests(authorizeRequests ->
                authorizeRequests
                    .anyRequest().authenticated()
            )
            .oauth2Login(oauth2Login ->
                oauth2Login
                    .authorizationEndpoint(authorizationEndpoint ->
                        authorizationEndpoint
                            .authorizationRequestResolver(
                                new CustomAuthorizationRequestResolver(
                                        this.clientRegistrationRepository))    1
                    )
            );
    }
}

public class CustomAuthorizationRequestResolver implements OAuth2AuthorizationRequestResolver {
    private final OAuth2AuthorizationRequestResolver defaultAuthorizationRequestResolver;

    public CustomAuthorizationRequestResolver(
            ClientRegistrationRepository clientRegistrationRepository) {

        this.defaultAuthorizationRequestResolver =
                new DefaultOAuth2AuthorizationRequestResolver(
                        clientRegistrationRepository, "/oauth2/authorization");
    }

    @Override
    public OAuth2AuthorizationRequest resolve(HttpServletRequest request) {
        OAuth2AuthorizationRequest authorizationRequest =
                this.defaultAuthorizationRequestResolver.resolve(request);  2

        return authorizationRequest != null ?   3
                customAuthorizationRequest(authorizationRequest) :
                null;
    }

    @Override
    public OAuth2AuthorizationRequest resolve(
            HttpServletRequest request, String clientRegistrationId) {

        OAuth2AuthorizationRequest authorizationRequest =
                this.defaultAuthorizationRequestResolver.resolve(
                    request, clientRegistrationId);    4

        return authorizationRequest != null ?   5
                customAuthorizationRequest(authorizationRequest) :
                null;
    }

    private OAuth2AuthorizationRequest customAuthorizationRequest(
            OAuth2AuthorizationRequest authorizationRequest) {

        Map<String, Object> additionalParameters =
                new LinkedHashMap<>(authorizationRequest.getAdditionalParameters());
        additionalParameters.put("prompt", "consent");  6

        return OAuth2AuthorizationRequest.from(authorizationRequest)    7
                .additionalParameters(additionalParameters) 8
                .build();
    }
}

1

Configure the custom OAuth2AuthorizationRequestResolver

2 4

Attempt to resolve the OAuth2AuthorizationRequest using the DefaultOAuth2AuthorizationRequestResolver

3 5

If an OAuth2AuthorizationRequest was resolved than return a customized version else return null

6

Add custom parameters to the existing OAuth2AuthorizationRequest.additionalParameters

7

Create a copy of the default OAuth2AuthorizationRequest which returns an OAuth2AuthorizationRequest.Builder for further modifications

8

Override the default additionalParameters

[Tip]Tip

OAuth2AuthorizationRequest.Builder.build() constructs the OAuth2AuthorizationRequest.authorizationRequestUri, which represents the complete Authorization Request URI including all query parameters using the application/x-www-form-urlencoded format.

For the simple use case, where the additional request parameter is always the same for a specific provider, it can be added directly in the authorization-uri.

For example, if the value for the request parameter prompt is always consent for the provider okta, than simply configure as follows:

spring:
  security:
    oauth2:
      client:
        provider:
          okta:
            authorization-uri: https://dev-1234.oktapreview.com/oauth2/v1/authorize?prompt=consent

The preceding example shows the common use case of adding a custom parameter on top of the standard parameters. Alternatively, if your requirements are more advanced, than you can take full control in building the Authorization Request URI by simply overriding the OAuth2AuthorizationRequest.authorizationRequestUri property.

The following example shows a variation of the customAuthorizationRequest() method from the preceding example, and instead overrides the OAuth2AuthorizationRequest.authorizationRequestUri property.

private OAuth2AuthorizationRequest customAuthorizationRequest(
        OAuth2AuthorizationRequest authorizationRequest) {

    String customAuthorizationRequestUri = UriComponentsBuilder
            .fromUriString(authorizationRequest.getAuthorizationRequestUri())
            .queryParam("prompt", "consent")
            .build(true)
            .toUriString();

    return OAuth2AuthorizationRequest.from(authorizationRequest)
            .authorizationRequestUri(customAuthorizationRequestUri)
            .build();
}
Storing the Authorization Request

The AuthorizationRequestRepository is responsible for the persistence of the OAuth2AuthorizationRequest from the time the Authorization Request is initiated to the time the Authorization Response is received (the callback).

[Tip]Tip

The OAuth2AuthorizationRequest is used to correlate and validate the Authorization Response.

The default implementation of AuthorizationRequestRepository is HttpSessionOAuth2AuthorizationRequestRepository, which stores the OAuth2AuthorizationRequest in the HttpSession.

If you have a custom implementation of AuthorizationRequestRepository, you may configure it as shown in the following example:

@EnableWebSecurity
public class OAuth2ClientSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Client(oauth2Client ->
                oauth2Client
                    .authorizationCodeGrant(authorizationCodeGrant ->
                        authorizationCodeGrant
                            .authorizationRequestRepository(this.authorizationRequestRepository())
                            ...
                    )
            );
    }
}
Requesting an Access Token
[Note]Note

Please refer to the Access Token Request/Response protocol flow for the Authorization Code grant.

The default implementation of OAuth2AccessTokenResponseClient for the Authorization Code grant is DefaultAuthorizationCodeTokenResponseClient, which uses a RestOperations for exchanging an authorization code for an access token at the Authorization Server’s Token Endpoint.

The DefaultAuthorizationCodeTokenResponseClient is quite flexible as it allows you to customize the pre-processing of the Token Request and/or post-handling of the Token Response.

Customizing the Access Token Request

If you need to customize the pre-processing of the Token Request, you can provide DefaultAuthorizationCodeTokenResponseClient.setRequestEntityConverter() with a custom Converter<OAuth2AuthorizationCodeGrantRequest, RequestEntity<?>>. The default implementation OAuth2AuthorizationCodeGrantRequestEntityConverter builds a RequestEntity representation of a standard OAuth 2.0 Access Token Request. However, providing a custom Converter, would allow you to extend the standard Token Request and add custom parameter(s).

[Important]Important

The custom Converter must return a valid RequestEntity representation of an OAuth 2.0 Access Token Request that is understood by the intended OAuth 2.0 Provider.

Customizing the Access Token Response

On the other end, if you need to customize the post-handling of the Token Response, you will need to provide DefaultAuthorizationCodeTokenResponseClient.setRestOperations() with a custom configured RestOperations. The default RestOperations is configured as follows:

RestTemplate restTemplate = new RestTemplate(Arrays.asList(
        new FormHttpMessageConverter(),
        new OAuth2AccessTokenResponseHttpMessageConverter()));

restTemplate.setErrorHandler(new OAuth2ErrorResponseErrorHandler());
[Tip]Tip

Spring MVC FormHttpMessageConverter is required as it’s used when sending the OAuth 2.0 Access Token Request.

OAuth2AccessTokenResponseHttpMessageConverter is a HttpMessageConverter for an OAuth 2.0 Access Token Response. You can provide OAuth2AccessTokenResponseHttpMessageConverter.setTokenResponseConverter() with a custom Converter<Map<String, String>, OAuth2AccessTokenResponse> that is used for converting the OAuth 2.0 Access Token Response parameters to an OAuth2AccessTokenResponse.

OAuth2ErrorResponseErrorHandler is a ResponseErrorHandler that can handle an OAuth 2.0 Error, eg. 400 Bad Request. It uses an OAuth2ErrorHttpMessageConverter for converting the OAuth 2.0 Error parameters to an OAuth2Error.

Whether you customize DefaultAuthorizationCodeTokenResponseClient or provide your own implementation of OAuth2AccessTokenResponseClient, you’ll need to configure it as shown in the following example:

@EnableWebSecurity
public class OAuth2ClientSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .oauth2Client(oauth2Client ->
                oauth2Client
                    .authorizationCodeGrant(authorizationCodeGrant ->
                        authorizationCodeGrant
                            .accessTokenResponseClient(this.accessTokenResponseClient())
                            ...
                     )
            );
    }
}

Refresh Token

[Note]Note

Please refer to the OAuth 2.0 Authorization Framework for further details on the Refresh Token.

Refreshing an Access Token
[Note]Note

Please refer to the Access Token Request/Response protocol flow for the Refresh Token grant.

The default implementation of OAuth2AccessTokenResponseClient for the Refresh Token grant is DefaultRefreshTokenTokenResponseClient, which uses a RestOperations when refreshing an access token at the Authorization Server’s Token Endpoint.

The DefaultRefreshTokenTokenResponseClient is quite flexible as it allows you to customize the pre-processing of the Token Request and/or post-handling of the Token Response.

Customizing the Access Token Request

If you need to customize the pre-processing of the Token Request, you can provide DefaultRefreshTokenTokenResponseClient.setRequestEntityConverter() with a custom Converter<OAuth2RefreshTokenGrantRequest, RequestEntity<?>>. The default implementation OAuth2RefreshTokenGrantRequestEntityConverter builds a RequestEntity representation of a standard OAuth 2.0 Access Token Request. However, providing a custom Converter, would allow you to extend the standard Token Request and add custom parameter(s).

[Important]Important

The custom Converter must return a valid RequestEntity representation of an OAuth 2.0 Access Token Request that is understood by the intended OAuth 2.0 Provider.

Customizing the Access Token Response

On the other end, if you need to customize the post-handling of the Token Response, you will need to provide DefaultRefreshTokenTokenResponseClient.setRestOperations() with a custom configured RestOperations. The default RestOperations is configured as follows:

RestTemplate restTemplate = new RestTemplate(Arrays.asList(
        new FormHttpMessageConverter(),
        new OAuth2AccessTokenResponseHttpMessageConverter()));

restTemplate.setErrorHandler(new OAuth2ErrorResponseErrorHandler());
[Tip]Tip

Spring MVC FormHttpMessageConverter is required as it’s used when sending the OAuth 2.0 Access Token Request.

OAuth2AccessTokenResponseHttpMessageConverter is a HttpMessageConverter for an OAuth 2.0 Access Token Response. You can provide OAuth2AccessTokenResponseHttpMessageConverter.setTokenResponseConverter() with a custom Converter<Map<String, String>, OAuth2AccessTokenResponse> that is used for converting the OAuth 2.0 Access Token Response parameters to an OAuth2AccessTokenResponse.

OAuth2ErrorResponseErrorHandler is a ResponseErrorHandler that can handle an OAuth 2.0 Error, eg. 400 Bad Request. It uses an OAuth2ErrorHttpMessageConverter for converting the OAuth 2.0 Error parameters to an OAuth2Error.

Whether you customize DefaultRefreshTokenTokenResponseClient or provide your own implementation of OAuth2AccessTokenResponseClient, you’ll need to configure it as shown in the following example:

// Customize
OAuth2AccessTokenResponseClient<OAuth2RefreshTokenGrantRequest> refreshTokenTokenResponseClient = ...

OAuth2AuthorizedClientProvider authorizedClientProvider =
        OAuth2AuthorizedClientProviderBuilder.builder()
                .authorizationCode()
                .refreshToken(configurer -> configurer.accessTokenResponseClient(refreshTokenTokenResponseClient))
                .build();

...

authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);
[Note]Note

OAuth2AuthorizedClientProviderBuilder.builder().refreshToken() configures a RefreshTokenOAuth2AuthorizedClientProvider, which is an implementation of an OAuth2AuthorizedClientProvider for the Refresh Token grant.

The OAuth2RefreshToken may optionally be returned in the Access Token Response for the authorization_code and password grant types. If the OAuth2AuthorizedClient.getRefreshToken() is available and the OAuth2AuthorizedClient.getAccessToken() is expired, it will automatically be refreshed by the RefreshTokenOAuth2AuthorizedClientProvider.

Client Credentials

[Note]Note

Please refer to the OAuth 2.0 Authorization Framework for further details on the Client Credentials grant.

Requesting an Access Token
[Note]Note

Please refer to the Access Token Request/Response protocol flow for the Client Credentials grant.

The default implementation of OAuth2AccessTokenResponseClient for the Client Credentials grant is DefaultClientCredentialsTokenResponseClient, which uses a RestOperations when requesting an access token at the Authorization Server’s Token Endpoint.

The DefaultClientCredentialsTokenResponseClient is quite flexible as it allows you to customize the pre-processing of the Token Request and/or post-handling of the Token Response.

Customizing the Access Token Request

If you need to customize the pre-processing of the Token Request, you can provide DefaultClientCredentialsTokenResponseClient.setRequestEntityConverter() with a custom Converter<OAuth2ClientCredentialsGrantRequest, RequestEntity<?>>. The default implementation OAuth2ClientCredentialsGrantRequestEntityConverter builds a RequestEntity representation of a standard OAuth 2.0 Access Token Request. However, providing a custom Converter, would allow you to extend the standard Token Request and add custom parameter(s).

[Important]Important

The custom Converter must return a valid RequestEntity representation of an OAuth 2.0 Access Token Request that is understood by the intended OAuth 2.0 Provider.

Customizing the Access Token Response

On the other end, if you need to customize the post-handling of the Token Response, you will need to provide DefaultClientCredentialsTokenResponseClient.setRestOperations() with a custom configured RestOperations. The default RestOperations is configured as follows:

RestTemplate restTemplate = new RestTemplate(Arrays.asList(
        new FormHttpMessageConverter(),
        new OAuth2AccessTokenResponseHttpMessageConverter()));

restTemplate.setErrorHandler(new OAuth2ErrorResponseErrorHandler());
[Tip]Tip

Spring MVC FormHttpMessageConverter is required as it’s used when sending the OAuth 2.0 Access Token Request.

OAuth2AccessTokenResponseHttpMessageConverter is a HttpMessageConverter for an OAuth 2.0 Access Token Response. You can provide OAuth2AccessTokenResponseHttpMessageConverter.setTokenResponseConverter() with a custom Converter<Map<String, String>, OAuth2AccessTokenResponse> that is used for converting the OAuth 2.0 Access Token Response parameters to an OAuth2AccessTokenResponse.

OAuth2ErrorResponseErrorHandler is a ResponseErrorHandler that can handle an OAuth 2.0 Error, eg. 400 Bad Request. It uses an OAuth2ErrorHttpMessageConverter for converting the OAuth 2.0 Error parameters to an OAuth2Error.

Whether you customize DefaultClientCredentialsTokenResponseClient or provide your own implementation of OAuth2AccessTokenResponseClient, you’ll need to configure it as shown in the following example:

// Customize
OAuth2AccessTokenResponseClient<OAuth2ClientCredentialsGrantRequest> clientCredentialsTokenResponseClient = ...

OAuth2AuthorizedClientProvider authorizedClientProvider =
        OAuth2AuthorizedClientProviderBuilder.builder()
                .clientCredentials(configurer -> configurer.accessTokenResponseClient(clientCredentialsTokenResponseClient))
                .build();

...

authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);
[Note]Note

OAuth2AuthorizedClientProviderBuilder.builder().clientCredentials() configures a ClientCredentialsOAuth2AuthorizedClientProvider, which is an implementation of an OAuth2AuthorizedClientProvider for the Client Credentials grant.

Using the Access Token

Given the following Spring Boot 2.x properties for an OAuth 2.0 Client registration:

spring:
  security:
    oauth2:
      client:
        registration:
          okta:
            client-id: okta-client-id
            client-secret: okta-client-secret
            authorization-grant-type: client_credentials
            scope: read, write
        provider:
          okta:
            token-uri: https://dev-1234.oktapreview.com/oauth2/v1/token

…​and the OAuth2AuthorizedClientManager @Bean:

@Bean
public OAuth2AuthorizedClientManager authorizedClientManager(
        ClientRegistrationRepository clientRegistrationRepository,
        OAuth2AuthorizedClientRepository authorizedClientRepository) {

    OAuth2AuthorizedClientProvider authorizedClientProvider =
            OAuth2AuthorizedClientProviderBuilder.builder()
                    .clientCredentials()
                    .build();

    DefaultOAuth2AuthorizedClientManager authorizedClientManager =
            new DefaultOAuth2AuthorizedClientManager(
                    clientRegistrationRepository, authorizedClientRepository);
    authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);

    return authorizedClientManager;
}

You may obtain the OAuth2AccessToken as follows:

@Controller
public class OAuth2ClientController {

    @Autowired
    private OAuth2AuthorizedClientManager authorizedClientManager;

    @GetMapping("/")
    public String index(Authentication authentication,
                        HttpServletRequest servletRequest,
                        HttpServletResponse servletResponse) {

        OAuth2AuthorizeRequest authorizeRequest = OAuth2AuthorizeRequest.withClientRegistrationId("okta")
                .principal(authentication)
                .attributes(attrs -> {
                    attrs.put(HttpServletRequest.class.getName(), servletRequest);
                    attrs.put(HttpServletResponse.class.getName(), servletResponse);
                })
                .build();
        OAuth2AuthorizedClient authorizedClient = this.authorizedClientManager.authorize(authorizeRequest);

        OAuth2AccessToken accessToken = authorizedClient.getAccessToken();

        ...

        return "index";
    }
}
[Note]Note

HttpServletRequest and HttpServletResponse are both OPTIONAL attributes. If not provided, it will default to ServletRequestAttributes using RequestContextHolder.getRequestAttributes().

Resource Owner Password Credentials

[Note]Note

Please refer to the OAuth 2.0 Authorization Framework for further details on the Resource Owner Password Credentials grant.

Requesting an Access Token
[Note]Note

Please refer to the Access Token Request/Response protocol flow for the Resource Owner Password Credentials grant.

The default implementation of OAuth2AccessTokenResponseClient for the Resource Owner Password Credentials grant is DefaultPasswordTokenResponseClient, which uses a RestOperations when requesting an access token at the Authorization Server’s Token Endpoint.

The DefaultPasswordTokenResponseClient is quite flexible as it allows you to customize the pre-processing of the Token Request and/or post-handling of the Token Response.

Customizing the Access Token Request

If you need to customize the pre-processing of the Token Request, you can provide DefaultPasswordTokenResponseClient.setRequestEntityConverter() with a custom Converter<OAuth2PasswordGrantRequest, RequestEntity<?>>. The default implementation OAuth2PasswordGrantRequestEntityConverter builds a RequestEntity representation of a standard OAuth 2.0 Access Token Request. However, providing a custom Converter, would allow you to extend the standard Token Request and add custom parameter(s).

[Important]Important

The custom Converter must return a valid RequestEntity representation of an OAuth 2.0 Access Token Request that is understood by the intended OAuth 2.0 Provider.

Customizing the Access Token Response

On the other end, if you need to customize the post-handling of the Token Response, you will need to provide DefaultPasswordTokenResponseClient.setRestOperations() with a custom configured RestOperations. The default RestOperations is configured as follows:

RestTemplate restTemplate = new RestTemplate(Arrays.asList(
        new FormHttpMessageConverter(),
        new OAuth2AccessTokenResponseHttpMessageConverter()));

restTemplate.setErrorHandler(new OAuth2ErrorResponseErrorHandler());
[Tip]Tip

Spring MVC FormHttpMessageConverter is required as it’s used when sending the OAuth 2.0 Access Token Request.

OAuth2AccessTokenResponseHttpMessageConverter is a HttpMessageConverter for an OAuth 2.0 Access Token Response. You can provide OAuth2AccessTokenResponseHttpMessageConverter.setTokenResponseConverter() with a custom Converter<Map<String, String>, OAuth2AccessTokenResponse> that is used for converting the OAuth 2.0 Access Token Response parameters to an OAuth2AccessTokenResponse.

OAuth2ErrorResponseErrorHandler is a ResponseErrorHandler that can handle an OAuth 2.0 Error, eg. 400 Bad Request. It uses an OAuth2ErrorHttpMessageConverter for converting the OAuth 2.0 Error parameters to an OAuth2Error.

Whether you customize DefaultPasswordTokenResponseClient or provide your own implementation of OAuth2AccessTokenResponseClient, you’ll need to configure it as shown in the following example:

// Customize
OAuth2AccessTokenResponseClient<OAuth2PasswordGrantRequest> passwordTokenResponseClient = ...

OAuth2AuthorizedClientProvider authorizedClientProvider =
        OAuth2AuthorizedClientProviderBuilder.builder()
                .password(configurer -> configurer.accessTokenResponseClient(passwordTokenResponseClient))
                .refreshToken()
                .build();

...

authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);
[Note]Note

OAuth2AuthorizedClientProviderBuilder.builder().password() configures a PasswordOAuth2AuthorizedClientProvider, which is an implementation of an OAuth2AuthorizedClientProvider for the Resource Owner Password Credentials grant.

Using the Access Token

Given the following Spring Boot 2.x properties for an OAuth 2.0 Client registration:

spring:
  security:
    oauth2:
      client:
        registration:
          okta:
            client-id: okta-client-id
            client-secret: okta-client-secret
            authorization-grant-type: password
            scope: read, write
        provider:
          okta:
            token-uri: https://dev-1234.oktapreview.com/oauth2/v1/token

…​and the OAuth2AuthorizedClientManager @Bean:

@Bean
public OAuth2AuthorizedClientManager authorizedClientManager(
        ClientRegistrationRepository clientRegistrationRepository,
        OAuth2AuthorizedClientRepository authorizedClientRepository) {

    OAuth2AuthorizedClientProvider authorizedClientProvider =
            OAuth2AuthorizedClientProviderBuilder.builder()
                    .password()
                    .refreshToken()
                    .build();

    DefaultOAuth2AuthorizedClientManager authorizedClientManager =
            new DefaultOAuth2AuthorizedClientManager(
                    clientRegistrationRepository, authorizedClientRepository);
    authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);

    // Assuming the `username` and `password` are supplied as `HttpServletRequest` parameters,
    // map the `HttpServletRequest` parameters to `OAuth2AuthorizationContext.getAttributes()`
    authorizedClientManager.setContextAttributesMapper(contextAttributesMapper());

    return authorizedClientManager;
}

private Function<OAuth2AuthorizeRequest, Map<String, Object>> contextAttributesMapper() {
    return authorizeRequest -> {
        Map<String, Object> contextAttributes = Collections.emptyMap();
        HttpServletRequest servletRequest = authorizeRequest.getAttribute(HttpServletRequest.class.getName());
        String username = servletRequest.getParameter(OAuth2ParameterNames.USERNAME);
        String password = servletRequest.getParameter(OAuth2ParameterNames.PASSWORD);
        if (StringUtils.hasText(username) && StringUtils.hasText(password)) {
            contextAttributes = new HashMap<>();

            // `PasswordOAuth2AuthorizedClientProvider` requires both attributes
            contextAttributes.put(OAuth2AuthorizationContext.USERNAME_ATTRIBUTE_NAME, username);
            contextAttributes.put(OAuth2AuthorizationContext.PASSWORD_ATTRIBUTE_NAME, password);
        }
        return contextAttributes;
    };
}

You may obtain the OAuth2AccessToken as follows:

@Controller
public class OAuth2ClientController {

    @Autowired
    private OAuth2AuthorizedClientManager authorizedClientManager;

    @GetMapping("/")
    public String index(Authentication authentication,
                        HttpServletRequest servletRequest,
                        HttpServletResponse servletResponse) {

        OAuth2AuthorizeRequest authorizeRequest = OAuth2AuthorizeRequest.withClientRegistrationId("okta")
                .principal(authentication)
                .attributes(attrs -> {
                    attrs.put(HttpServletRequest.class.getName(), servletRequest);
                    attrs.put(HttpServletResponse.class.getName(), servletResponse);
                })
                .build();
        OAuth2AuthorizedClient authorizedClient = this.authorizedClientManager.authorize(authorizeRequest);

        OAuth2AccessToken accessToken = authorizedClient.getAccessToken();

        ...

        return "index";
    }
}
[Note]Note

HttpServletRequest and HttpServletResponse are both OPTIONAL attributes. If not provided, it will default to ServletRequestAttributes using RequestContextHolder.getRequestAttributes().

12.2.3 Additional Features

Resolving an Authorized Client

The @RegisteredOAuth2AuthorizedClient annotation provides the capability of resolving a method parameter to an argument value of type OAuth2AuthorizedClient. This is a convenient alternative compared to accessing the OAuth2AuthorizedClient using the OAuth2AuthorizedClientManager or OAuth2AuthorizedClientService.

@Controller
public class OAuth2ClientController {

    @GetMapping("/")
    public String index(@RegisteredOAuth2AuthorizedClient("okta") OAuth2AuthorizedClient authorizedClient) {
        OAuth2AccessToken accessToken = authorizedClient.getAccessToken();

        ...

        return "index";
    }
}

The @RegisteredOAuth2AuthorizedClient annotation is handled by OAuth2AuthorizedClientArgumentResolver, which directly uses an OAuth2AuthorizedClientManager and therefore inherits it’s capabilities.

12.2.4 WebClient integration for Servlet Environments

The OAuth 2.0 Client support integrates with WebClient using an ExchangeFilterFunction.

The ServletOAuth2AuthorizedClientExchangeFilterFunction provides a simple mechanism for requesting protected resources by using an OAuth2AuthorizedClient and including the associated OAuth2AccessToken as a Bearer Token. It directly uses an OAuth2AuthorizedClientManager and therefore inherits the following capabilities:

  • An OAuth2AccessToken will be requested if the client has not yet been authorized.

    • authorization_code - triggers the Authorization Request redirect to initiate the flow
    • client_credentials - the access token is obtained directly from the Token Endpoint
    • password - the access token is obtained directly from the Token Endpoint
  • If the OAuth2AccessToken is expired, it will be refreshed (or renewed) if an OAuth2AuthorizedClientProvider is available to perform the authorization

The following code shows an example of how to configure WebClient with OAuth 2.0 Client support:

@Bean
WebClient webClient(OAuth2AuthorizedClientManager authorizedClientManager) {
    ServletOAuth2AuthorizedClientExchangeFilterFunction oauth2Client =
            new ServletOAuth2AuthorizedClientExchangeFilterFunction(authorizedClientManager);
    return WebClient.builder()
            .apply(oauth2Client.oauth2Configuration())
            .build();
}

Providing the Authorized Client

The ServletOAuth2AuthorizedClientExchangeFilterFunction determines the client to use (for a request) by resolving the OAuth2AuthorizedClient from the ClientRequest.attributes() (request attributes).

The following code shows how to set an OAuth2AuthorizedClient as a request attribute:

@GetMapping("/")
public String index(@RegisteredOAuth2AuthorizedClient("okta") OAuth2AuthorizedClient authorizedClient) {
    String resourceUri = ...

    String body = webClient
            .get()
            .uri(resourceUri)
            .attributes(oauth2AuthorizedClient(authorizedClient))   1
            .retrieve()
            .bodyToMono(String.class)
            .block();

    ...

    return "index";
}

1

oauth2AuthorizedClient() is a static method in ServletOAuth2AuthorizedClientExchangeFilterFunction.

The following code shows how to set the ClientRegistration.getRegistrationId() as a request attribute:

@GetMapping("/")
public String index() {
    String resourceUri = ...

    String body = webClient
            .get()
            .uri(resourceUri)
            .attributes(clientRegistrationId("okta"))   1
            .retrieve()
            .bodyToMono(String.class)
            .block();

    ...

    return "index";
}

1

clientRegistrationId() is a static method in ServletOAuth2AuthorizedClientExchangeFilterFunction.

Defaulting the Authorized Client

If neither OAuth2AuthorizedClient or ClientRegistration.getRegistrationId() is provided as a request attribute, the ServletOAuth2AuthorizedClientExchangeFilterFunction can determine the default client to use depending on it’s configuration.

If setDefaultOAuth2AuthorizedClient(true) is configured and the user has authenticated using HttpSecurity.oauth2Login(), the OAuth2AccessToken associated with the current OAuth2AuthenticationToken is used.

The following code shows the specific configuration:

@Bean
WebClient webClient(OAuth2AuthorizedClientManager authorizedClientManager) {
    ServletOAuth2AuthorizedClientExchangeFilterFunction oauth2Client =
            new ServletOAuth2AuthorizedClientExchangeFilterFunction(authorizedClientManager);
    oauth2Client.setDefaultOAuth2AuthorizedClient(true);
    return WebClient.builder()
            .apply(oauth2Client.oauth2Configuration())
            .build();
}
[Warning]Warning

It is recommended to be cautious with this feature since all HTTP requests will receive the access token.

Alternatively, if setDefaultClientRegistrationId("okta") is configured with a valid ClientRegistration, the OAuth2AccessToken associated with the OAuth2AuthorizedClient is used.

The following code shows the specific configuration:

@Bean
WebClient webClient(OAuth2AuthorizedClientManager authorizedClientManager) {
    ServletOAuth2AuthorizedClientExchangeFilterFunction oauth2Client =
            new ServletOAuth2AuthorizedClientExchangeFilterFunction(authorizedClientManager);
    oauth2Client.setDefaultClientRegistrationId("okta");
    return WebClient.builder()
            .apply(oauth2Client.oauth2Configuration())
            .build();
}
[Warning]Warning

It is recommended to be cautious with this feature since all HTTP requests will receive the access token.

12.3 OAuth 2.0 Resource Server

Spring Security supports protecting endpoints using two forms of OAuth 2.0 Bearer Tokens:

  • JWT
  • Opaque Tokens

This is handy in circumstances where an application has delegated its authority management to an authorization server (for example, Okta or Ping Identity). This authorization server can be consulted by resource servers to authorize requests.

[Note]Note

Working samples for both JWTs and Opaque Tokens are available in the Spring Security repository.

12.3.1 Dependencies

Most Resource Server support is collected into spring-security-oauth2-resource-server. However, the support for decoding and verifying JWTs is in spring-security-oauth2-jose, meaning that both are necessary in order to have a working resource server that supports JWT-encoded Bearer Tokens.

12.3.2 Minimal Configuration for JWTs

When using Spring Boot, configuring an application as a resource server consists of two basic steps. First, include the needed dependencies and second, indicate the location of the authorization server.

Specifying the Authorization Server

In a Spring Boot application, to specify which authorization server to use, simply do:

spring:
  security:
    oauth2:
      resourceserver:
        jwt:
          issuer-uri: https://idp.example.com/issuer

Where https://idp.example.com/issuer is the value contained in the iss claim for JWT tokens that the authorization server will issue. Resource Server will use this property to further self-configure, discover the authorization server’s public keys, and subsequently validate incoming JWTs.

[Note]Note

To use the issuer-uri property, it must also be true that one of https://idp.example.com/issuer/.well-known/openid-configuration, https://idp.example.com/.well-known/openid-configuration/issuer, or https://idp.example.com/.well-known/oauth-authorization-server/issuer is a supported endpoint for the authorization server. This endpoint is referred to as a Provider Configuration endpoint or a Authorization Server Metadata endpoint.

And that’s it!

Startup Expectations

When this property and these dependencies are used, Resource Server will automatically configure itself to validate JWT-encoded Bearer Tokens.

It achieves this through a deterministic startup process:

  1. Hit the Provider Configuration or Authorization Server Metadata endpoint, processing the response for the jwks_url property
  2. Configure the validation strategy to query jwks_url for valid public keys
  3. Configure the validation strategy to validate each JWTs iss claim against https://idp.example.com.

A consequence of this process is that the authorization server must be up and receiving requests in order for Resource Server to successfully start up.

[Note]Note

If the authorization server is down when Resource Server queries it (given appropriate timeouts), then startup will fail.

Runtime Expectations

Once the application is started up, Resource Server will attempt to process any request containing an Authorization: Bearer header:

GET / HTTP/1.1
Authorization: Bearer some-token-value # Resource Server will process this

So long as this scheme is indicated, Resource Server will attempt to process the request according to the Bearer Token specification.

Given a well-formed JWT, Resource Server will:

  1. Validate its signature against a public key obtained from the jwks_url endpoint during startup and matched against the JWT
  2. Validate the JWT’s exp and nbf timestamps and the JWT’s iss claim, and
  3. Map each scope to an authority with the prefix SCOPE_.
[Note]Note

As the authorization server makes available new keys, Spring Security will automatically rotate the keys used to validate JWTs.

The resulting Authentication#getPrincipal, by default, is a Spring Security Jwt object, and Authentication#getName maps to the JWT’s sub property, if one is present.

From here, consider jumping to:

How to Configure without Tying Resource Server startup to an authorization server’s availability

How to Configure without Spring Boot

12.3.3 Specifying the Authorization Server JWK Set Uri Directly

If the authorization server doesn’t support any configuration endpoints, or if Resource Server must be able to start up independently from the authorization server, then the jwk-set-uri can be supplied as well:

spring:
  security:
    oauth2:
      resourceserver:
        jwt:
          issuer-uri: https://idp.example.com
          jwk-set-uri: https://idp.example.com/.well-known/jwks.json
[Note]Note

The JWK Set uri is not standardized, but can typically be found in the authorization server’s documentation

Consequently, Resource Server will not ping the authorization server at startup. We still specify the issuer-uri so that Resource Server still validates the iss claim on incoming JWTs.

[Note]Note

This property can also be supplied directly on the DSL.

12.3.4 Overriding or Replacing Boot Auto Configuration

There are two @Bean s that Spring Boot generates on Resource Server’s behalf.

The first is a WebSecurityConfigurerAdapter that configures the app as a resource server. When including spring-security-oauth2-jose, this WebSecurityConfigurerAdapter looks like:

protected void configure(HttpSecurity http) {
    http
        .authorizeRequests()
            .anyRequest().authenticated()
            .and()
        .oauth2ResourceServer(OAuth2ResourceServerConfigurer::jwt)
}

If the application doesn’t expose a WebSecurityConfigurerAdapter bean, then Spring Boot will expose the above default one.

Replacing this is as simple as exposing the bean within the application:

@EnableWebSecurity
public class MyCustomSecurityConfiguration extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests()
                .mvcMatchers("/messages/**").hasAuthority("SCOPE_message:read")
                .anyRequest().authenticated()
                .and()
            .oauth2ResourceServer()
                .jwt()
                    .jwtAuthenticationConverter(myConverter());
    }
}

The above requires the scope of message:read for any URL that starts with /messages/.

Methods on the oauth2ResourceServer DSL will also override or replace auto configuration.

For example, the second @Bean Spring Boot creates is a JwtDecoder, which decodes String tokens into validated instances of Jwt:

@Bean
public JwtDecoder jwtDecoder() {
    return JwtDecoders.fromIssuerLocation(issuerUri);
}
[Note]Note

Calling JwtDecoders#fromIssuerLocation is what invokes the Provider Configuration or Authorization Server Metadata endpoint in order to derive the JWK Set Uri.

If the application doesn’t expose a JwtDecoder bean, then Spring Boot will expose the above default one.

And its configuration can be overridden using jwkSetUri() or replaced using decoder().

Using jwkSetUri()

An authorization server’s JWK Set Uri can be configured as a configuration property or it can be supplied in the DSL:

@EnableWebSecurity
public class DirectlyConfiguredJwkSetUri extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests()
                .anyRequest().authenticated()
                .and()
            .oauth2ResourceServer()
                .jwt()
                    .jwkSetUri("https://idp.example.com/.well-known/jwks.json");
    }
}

Using jwkSetUri() takes precedence over any configuration property.

Using decoder()

More powerful than jwkSetUri() is decoder(), which will completely replace any Boot auto configuration of JwtDecoder:

@EnableWebSecurity
public class DirectlyConfiguredJwtDecoder extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests()
                .anyRequest().authenticated()
                .and()
            .oauth2ResourceServer()
                .jwt()
                    .decoder(myCustomDecoder());
    }
}

This is handy when deeper configuration, like validation, mapping, or request timeouts, is necessary.

Exposing a JwtDecoder @Bean

Or, exposing a JwtDecoder @Bean has the same effect as decoder():

@Bean
public JwtDecoder jwtDecoder() {
    return NimbusJwtDecoder.withJwkSetUri(jwkSetUri).build();
}

12.3.5 Configuring Trusted Algorithms

By default, NimbusJwtDecoder, and hence Resource Server, will only trust and verify tokens using RS256.

You can customize this via Spring Boot, the NimbusJwtDecoder builder, or from the JWK Set response.

Via Spring Boot

The simplest way to set the algorithm is as a property:

spring:
  security:
    oauth2:
      resourceserver:
        jwt:
          jws-algorithm: RS512
          jwk-set-uri: https://idp.example.org/.well-known/jwks.json

Using a Builder

For greater power, though, we can use a builder that ships with NimbusJwtDecoder:

@Bean
JwtDecoder jwtDecoder() {
    return NimbusJwtDecoder.fromJwkSetUri(this.jwkSetUri)
            .jwsAlgorithm(RS512).build();
}

Calling jwsAlgorithm more than once will configure NimbusJwtDecoder to trust more than one algorithm, like so:

@Bean
JwtDecoder jwtDecoder() {
    return NimbusJwtDecoder.fromJwkSetUri(this.jwkSetUri)
            .jwsAlgorithm(RS512).jwsAlgorithm(EC512).build();
}

Or, you can call jwsAlgorithms:

@Bean
JwtDecoder jwtDecoder() {
    return NimbusJwtDecoder.fromJwkSetUri(this.jwkSetUri)
            .jwsAlgorithms(algorithms -> {
                    algorithms.add(RS512);
                    algorithms.add(EC512);
            }).build();
}

From JWK Set response

Since Spring Security’s JWT support is based off of Nimbus, you can use all it’s great features as well.

For example, Nimbus has a JWSKeySelector implementation that will select the set of algorithms based on the JWK Set URI response. You can use it to generate a NimbusJwtDecoder like so:

@Bean
public JwtDecoder jwtDecoder() {
    // makes a request to the JWK Set endpoint
    JWSKeySelector<SecurityContext> jwsKeySelector =
            JWSAlgorithmFamilyJWSKeySelector.fromJWKSetURL(this.jwkSetUrl);

    DefaultJWTProcessor<SecurityContext> jwtProcessor =
            new DefaultJWTProcessor<>();
    jwtProcessor.setJWSKeySelector(jwsKeySelector);

    return new NimbusJwtDecoder(jwtProcessor);
}

12.3.6 Trusting a Single Asymmetric Key

Simpler than backing a Resource Server with a JWK Set endpoint is to hard-code an RSA public key. The public key can be provided via Spring Boot or by Using a Builder.

Via Spring Boot

Specifying a key via Spring Boot is quite simple. The key’s location can be specified like so:

spring:
  security:
    oauth2:
      resourceserver:
        jwt:
          public-key-location: classpath:my-key.pub

Or, to allow for a more sophisticated lookup, you can post-process the RsaKeyConversionServicePostProcessor:

@Bean
BeanFactoryPostProcessor conversionServiceCustomizer() {
    return beanFactory ->
        beanFactory.getBean(RsaKeyConversionServicePostProcessor.class)
                .setResourceLoader(new CustomResourceLoader());
}

Specify your key’s location:

key.location: hfds://my-key.pub

And then autowire the value:

@Value("${key.location}")
RSAPublicKey key;

Using a Builder

To wire an RSAPublicKey directly, you can simply use the appropriate NimbusJwtDecoder builder, like so:

@Bean
public JwtDecoder jwtDecoder() {
    return NimbusJwtDecoder.withPublicKey(this.key).build();
}

12.3.7 Trusting a Single Symmetric Key

Using a single symmetric key is also simple. You can simply load in your SecretKey and use the appropriate NimbusJwtDecoder builder, like so:

@Bean
public JwtDecoder jwtDecoder() {
    return NimbusJwtDecoder.withSecretKey(this.key).build();
}

12.3.8 Configuring Authorization

A JWT that is issued from an OAuth 2.0 Authorization Server will typically either have a scope or scp attribute, indicating the scopes (or authorities) it’s been granted, for example:

{ …​, "scope" : "messages contacts"}

When this is the case, Resource Server will attempt to coerce these scopes into a list of granted authorities, prefixing each scope with the string "SCOPE_".

This means that to protect an endpoint or method with a scope derived from a JWT, the corresponding expressions should include this prefix:

@EnableWebSecurity
public class DirectlyConfiguredJwkSetUri extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests(authorizeRequests -> authorizeRequests
                .mvcMatchers("/contacts/**").hasAuthority("SCOPE_contacts")
                .mvcMatchers("/messages/**").hasAuthority("SCOPE_messages")
                .anyRequest().authenticated()
            )
            .oauth2ResourceServer(OAuth2ResourceServerConfigurer::jwt);
    }
}

Or similarly with method security:

@PreAuthorize("hasAuthority('SCOPE_messages')")
public List<Message> getMessages(...) {}

Extracting Authorities Manually

However, there are a number of circumstances where this default is insufficient. For example, some authorization servers don’t use the scope attribute, but instead have their own custom attribute. Or, at other times, the resource server may need to adapt the attribute or a composition of attributes into internalized authorities.

To this end, the DSL exposes jwtAuthenticationConverter():

@EnableWebSecurity
public class DirectlyConfiguredJwkSetUri extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests()
                .anyRequest().authenticated()
                .and()
            .oauth2ResourceServer()
                .jwt()
                    .jwtAuthenticationConverter(grantedAuthoritiesExtractor());
    }
}

Converter<Jwt, AbstractAuthenticationToken> grantedAuthoritiesExtractor() {
    JwtAuthenticationConverter jwtAuthenticationConverter =
            new JwtAuthenticationConverter();

    jwtAuthenticationConverter.setJwtGrantedAuthoritiesConverter
            (new GrantedAuthoritiesExtractor());

    return jwtAuthenticationConverter;
}

which is responsible for converting a Jwt into an Authentication. As part of its configuration, we can supply a subsidiary converter to go from Jwt to a Collection of granted authorities.

That final converter might be something like GrantedAuthoritiesExtractor below:

static class GrantedAuthoritiesExtractor
        implements Converter<Jwt, Collection<GrantedAuthority>> {

    public Collection<GrantedAuthority> convert(Jwt jwt) {
        Collection<String> authorities = (Collection<String>)
                jwt.getClaims().get("mycustomclaim");

        return authorities.stream()
                .map(SimpleGrantedAuthority::new)
                .collect(Collectors.toList());
    }
}

For more flexibility, the DSL supports entirely replacing the converter with any class that implements Converter<Jwt, AbstractAuthenticationToken>:

static class CustomAuthenticationConverter implements Converter<Jwt, AbstractAuthenticationToken> {
    public AbstractAuthenticationToken convert(Jwt jwt) {
        return new CustomAuthenticationToken(jwt);
    }
}

12.3.9 Configuring Validation

Using minimal Spring Boot configuration, indicating the authorization server’s issuer uri, Resource Server will default to verifying the iss claim as well as the exp and nbf timestamp claims.

In circumstances where validation needs to be customized, Resource Server ships with two standard validators and also accepts custom OAuth2TokenValidator instances.

Customizing Timestamp Validation

JWT’s typically have a window of validity, with the start of the window indicated in the nbf claim and the end indicated in the exp claim.

However, every server can experience clock drift, which can cause tokens to appear expired to one server, but not to another. This can cause some implementation heartburn as the number of collaborating servers increases in a distributed system.

Resource Server uses JwtTimestampValidator to verify a token’s validity window, and it can be configured with a clockSkew to alleviate the above problem:

@Bean
JwtDecoder jwtDecoder() {
     NimbusJwtDecoder jwtDecoder = (NimbusJwtDecoder)
             JwtDecoders.fromIssuerLocation(issuerUri);

     OAuth2TokenValidator<Jwt> withClockSkew = new DelegatingOAuth2TokenValidator<>(
            new JwtTimestampValidator(Duration.ofSeconds(60)),
            new IssuerValidator(issuerUri));

     jwtDecoder.setJwtValidator(withClockSkew);

     return jwtDecoder;
}
[Note]Note

By default, Resource Server configures a clock skew of 60 seconds.

Configuring a Custom Validator

Adding a check for the aud claim is simple with the OAuth2TokenValidator API:

public class AudienceValidator implements OAuth2TokenValidator<Jwt> {
    OAuth2Error error = new OAuth2Error("invalid_token", "The required audience is missing", null);

    public OAuth2TokenValidatorResult validate(Jwt jwt) {
        if (jwt.getAudience().contains("messaging")) {
            return OAuth2TokenValidatorResult.success();
        } else {
            return OAuth2TokenValidatorResult.failure(error);
        }
    }
}

Then, to add into a resource server, it’s a matter of specifying the JwtDecoder instance:

@Bean
JwtDecoder jwtDecoder() {
    NimbusJwtDecoder jwtDecoder = (NimbusJwtDecoder)
        JwtDecoders.fromIssuerLocation(issuerUri);

    OAuth2TokenValidator<Jwt> audienceValidator = new AudienceValidator();
    OAuth2TokenValidator<Jwt> withIssuer = JwtValidators.createDefaultWithIssuer(issuerUri);
    OAuth2TokenValidator<Jwt> withAudience = new DelegatingOAuth2TokenValidator<>(withIssuer, audienceValidator);

    jwtDecoder.setJwtValidator(withAudience);

    return jwtDecoder;
}

12.3.10 Configuring Claim Set Mapping

Spring Security uses the Nimbus library for parsing JWTs and validating their signatures. Consequently, Spring Security is subject to Nimbus’s interpretation of each field value and how to coerce each into a Java type.

For example, because Nimbus remains Java 7 compatible, it doesn’t use Instant to represent timestamp fields.

And it’s entirely possible to use a different library or for JWT processing, which may make its own coercion decisions that need adjustment.

Or, quite simply, a resource server may want to add or remove claims from a JWT for domain-specific reasons.

For these purposes, Resource Server supports mapping the JWT claim set with MappedJwtClaimSetConverter.

Customizing the Conversion of a Single Claim

By default, MappedJwtClaimSetConverter will attempt to coerce claims into the following types:

Claim

Java Type

aud

Collection<String>

exp

Instant

iat

Instant

iss

String

jti

String

nbf

Instant

sub

String

An individual claim’s conversion strategy can be configured using MappedJwtClaimSetConverter.withDefaults:

@Bean
JwtDecoder jwtDecoder() {
    NimbusJwtDecoder jwtDecoder = NimbusJwtDecoder.withJwkSetUri(jwkSetUri).build();

    MappedJwtClaimSetConverter converter = MappedJwtClaimSetConverter
            .withDefaults(Collections.singletonMap("sub", this::lookupUserIdBySub));
    jwtDecoder.setClaimSetConverter(converter);

    return jwtDecoder;
}

This will keep all the defaults, except it will override the default claim converter for sub.

Adding a Claim

MappedJwtClaimSetConverter can also be used to add a custom claim, for example, to adapt to an existing system:

MappedJwtClaimSetConverter.withDefaults(Collections.singletonMap("custom", custom -> "value"));

Removing a Claim

And removing a claim is also simple, using the same API:

MappedJwtClaimSetConverter.withDefaults(Collections.singletonMap("legacyclaim", legacy -> null));

Renaming a Claim

In more sophisticated scenarios, like consulting multiple claims at once or renaming a claim, Resource Server accepts any class that implements Converter<Map<String, Object>, Map<String,Object>>:

public class UsernameSubClaimAdapter implements Converter<Map<String, Object>, Map<String, Object>> {
    private final MappedJwtClaimSetConverter delegate =
            MappedJwtClaimSetConverter.withDefaults(Collections.emptyMap());

    public Map<String, Object> convert(Map<String, Object> claims) {
        Map<String, Object> convertedClaims = this.delegate.convert(claims);

        String username = (String) convertedClaims.get("user_name");
        convertedClaims.put("sub", username);

        return convertedClaims;
    }
}

And then, the instance can be supplied like normal:

@Bean
JwtDecoder jwtDecoder() {
    NimbusJwtDecoder jwtDecoder = NimbusJwtDecoder.withJwkSetUri(jwkSetUri).build();
    jwtDecoder.setClaimSetConverter(new UsernameSubClaimAdapter());
    return jwtDecoder;
}

12.3.11 Configuring Timeouts

By default, Resource Server uses connection and socket timeouts of 30 seconds each for coordinating with the authorization server.

This may be too short in some scenarios. Further, it doesn’t take into account more sophisticated patterns like back-off and discovery.

To adjust the way in which Resource Server connects to the authorization server, NimbusJwtDecoder accepts an instance of RestOperations:

@Bean
public JwtDecoder jwtDecoder(RestTemplateBuilder builder) {
    RestOperations rest = builder
            .setConnectionTimeout(60000)
            .setReadTimeout(60000)
            .build();

    NimbusJwtDecoder jwtDecoder = NimbusJwtDecoder.withJwkSetUri(jwkSetUri).restOperations(rest).build();
    return jwtDecoder;
}

12.3.12 Minimal Configuration for Introspection

Typically, an opaque token can be verified via an OAuth 2.0 Introspection Endpoint, hosted by the authorization server. This can be handy when revocation is a requirement.

When using Spring Boot, configuring an application as a resource server that uses introspection consists of two basic steps. First, include the needed dependencies and second, indicate the introspection endpoint details.

Specifying the Authorization Server

To specify where the introspection endpoint is, simply do:

security:
  oauth2:
    resourceserver:
      opaque-token:
        introspection-uri: https://idp.example.com/introspect
        client-id: client
        client-secret: secret

Where https://idp.example.com/introspect is the introspection endpoint hosted by your authorization server and client-id and client-secret are the credentials needed to hit that endpoint.

Resource Server will use these properties to further self-configure and subsequently validate incoming JWTs.

[Note]Note

When using introspection, the authorization server’s word is the law. If the authorization server responses that the token is valid, then it is.

And that’s it!

Startup Expectations

When this property and these dependencies are used, Resource Server will automatically configure itself to validate Opaque Bearer Tokens.

This startup process is quite a bit simpler than for JWTs since no endpoints need to be discovered and no additional validation rules get added.

Runtime Expectations

Once the application is started up, Resource Server will attempt to process any request containing an Authorization: Bearer header:

GET / HTTP/1.1
Authorization: Bearer some-token-value # Resource Server will process this

So long as this scheme is indicated, Resource Server will attempt to process the request according to the Bearer Token specification.

Given an Opaque Token, Resource Server will

  1. Query the provided introspection endpoint using the provided credentials and the token
  2. Inspect the response for an { 'active' : true } attribute
  3. Map each scope to an authority with the prefix SCOPE_

The resulting Authentication#getPrincipal, by default, is a Spring Security OAuth2AuthenticatedPrincipal object, and Authentication#getName maps to the token’s sub property, if one is present.

From here, you may want to jump to:

12.3.13 Looking Up Attributes Post-Authentication

Once a token is authenticated, an instance of BearerTokenAuthentication is set in the SecurityContext.

This means that it’s available in @Controller methods when using @EnableWebMvc in your configuration:

@GetMapping("/foo")
public String foo(BearerTokenAuthentication authentication) {
    return authentication.getTokenAttributes().get("sub") + " is the subject";
}

Since BearerTokenAuthentication holds an OAuth2AuthenticatedPrincipal, that also means that it’s available to controller methods, too:

@GetMapping("/foo")
public String foo(@AuthenticationPrincipal OAuth2AuthenticatedPrincipal principal) {
    return principal.getAttribute("sub") + " is the subject";
}

Looking Up Attributes Via SpEL

Of course, this also means that attributes can be accessed via SpEL.

For example, if using @EnableGlobalMethodSecurity so that you can use @PreAuthorize annotations, you can do:

@PreAuthorize("principal?.attributes['sub'] == 'foo'")
public String forFoosEyesOnly() {
    return "foo";
}

12.3.14 Overriding or Replacing Boot Auto Configuration

There are two @Bean s that Spring Boot generates on Resource Server’s behalf.

The first is a WebSecurityConfigurerAdapter that configures the app as a resource server. When use Opaque Token, this WebSecurityConfigurerAdapter looks like:

protected void configure(HttpSecurity http) {
    http
        .authorizeRequests()
            .anyRequest().authenticated()
            .and()
        .oauth2ResourceServer(OAuth2ResourceServerConfigurer::opaqueToken)
}

If the application doesn’t expose a WebSecurityConfigurerAdapter bean, then Spring Boot will expose the above default one.

Replacing this is as simple as exposing the bean within the application:

@EnableWebSecurity
public class MyCustomSecurityConfiguration extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests()
                .mvcMatchers("/messages/**").hasAuthority("SCOPE_message:read")
                .anyRequest().authenticated()
                .and()
            .oauth2ResourceServer()
                .opaqueToken()
                    .introspector(myIntrospector());
    }
}

The above requires the scope of message:read for any URL that starts with /messages/.

Methods on the oauth2ResourceServer DSL will also override or replace auto configuration.

For example, the second @Bean Spring Boot creates is an OpaqueTokenIntrospector, which decodes String tokens into validated instances of OAuth2AuthenticatedPrincipal:

@Bean
public OpaqueTokenIntrospector introspector() {
    return new NimbusOpaqueTokenIntrospector(introspectionUri, clientId, clientSecret);
}

If the application doesn’t expose a OpaqueTokenIntrospector bean, then Spring Boot will expose the above default one.

And its configuration can be overridden using introspectionUri() and introspectionClientCredentials() or replaced using introspector().

Using introspectionUri()

An authorization server’s Introspection Uri can be configured as a configuration property or it can be supplied in the DSL:

@EnableWebSecurity
public class DirectlyConfiguredIntrospectionUri extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests()
                .anyRequest().authenticated()
                .and()
            .oauth2ResourceServer()
                .opaqueToken()
                    .introspectionUri("https://idp.example.com/introspect")
                    .introspectionClientCredentials("client", "secret");
    }
}

Using introspectionUri() takes precedence over any configuration property.

Using introspector()

More powerful than introspectionUri() is introspector(), which will completely replace any Boot auto configuration of OpaqueTokenIntrospector:

@EnableWebSecurity
public class DirectlyConfiguredIntrospector extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests()
                .anyRequest().authenticated()
                .and()
            .oauth2ResourceServer()
                .opaqueToken()
                    .introspector(myCustomIntrospector());
    }
}

This is handy when deeper configuration, like authority mapping, JWT revocation, or request timeouts, is necessary.

Exposing a OpaqueTokenIntrospector @Bean

Or, exposing a OpaqueTokenIntrospector @Bean has the same effect as introspector():

@Bean
public OpaqueTokenIntrospector introspector() {
    return new NimbusOpaqueTokenIntrospector(introspectionUri, clientId, clientSecret);
}

12.3.15 Configuring Authorization

An OAuth 2.0 Introspection endpoint will typically return a scope attribute, indicating the scopes (or authorities) it’s been granted, for example:

{ …​, "scope" : "messages contacts"}

When this is the case, Resource Server will attempt to coerce these scopes into a list of granted authorities, prefixing each scope with the string "SCOPE_".

This means that to protect an endpoint or method with a scope derived from an Opaque Token, the corresponding expressions should include this prefix:

@EnableWebSecurity
public class MappedAuthorities extends WebSecurityConfigurerAdapter {
    protected void configure(HttpSecurity http) {
        http
            .authorizeRequests(authorizeRequests -> authorizeRequests
                .mvcMatchers("/contacts/**").hasAuthority("SCOPE_contacts")
                .mvcMatchers("/messages/**").hasAuthority("SCOPE_messages")
                .anyRequest().authenticated()
            )
            .oauth2ResourceServer(OAuth2ResourceServerConfigurer::opaqueToken);
    }
}

Or similarly with method security:

@PreAuthorize("hasAuthority('SCOPE_messages')")
public List<Message> getMessages(...) {}

Extracting Authorities Manually

By default, Opaque Token support will extract the scope claim from an introspection response and parse it into individual GrantedAuthority instances.

For example, if the introspection response were:

{
    "active" : true,
    "scope" : "message:read message:write"
}

Then Resource Server would generate an Authentication with two authorities, one for message:read and the other for message:write.

This can, of course, be customized using a custom OpaqueTokenIntrospector that takes a look at the attribute set and converts in its own way:

public class CustomAuthoritiesOpaqueTokenIntrospector implements OpaqueTokenIntrospector {
    private OpaqueTokenIntrospector delegate =
            new NimbusOpaqueTokenIntrospector("https://idp.example.org/introspect", "client", "secret");

    public OAuth2AuthenticatedPrincipal introspect(String token) {
        OAuth2AuthenticatedPrincipal principal = this.delegate.introspect(token);
        return new DefaultOAuth2AuthenticatedPrincipal(
                principal.getName(), principal.getAttributes(), extractAuthorities(principal));
    }

    private Collection<GrantedAuthority> extractAuthorities(OAuth2AuthenticatedPrincipal principal) {
        List<String> scopes = principal.getAttribute(OAuth2IntrospectionClaimNames.SCOPE);
        return scopes.stream()
                .map(SimpleGrantedAuthority::new)
                .collect(Collectors.toList());
    }
}

Thereafter, this custom introspector can be configured simply by exposing it as a @Bean:

@Bean
public OpaqueTokenIntrospector introspector() {
    return new CustomAuthoritiesOpaqueTokenIntrospector();
}

12.3.16 Configuring Timeouts

By default, Resource Server uses connection and socket timeouts of 30 seconds each for coordinating with the authorization server.

This may be too short in some scenarios. Further, it doesn’t take into account more sophisticated patterns like back-off and discovery.

To adjust the way in which Resource Server connects to the authorization server, NimbusOpaqueTokenIntrospector accepts an instance of RestOperations:

@Bean
public OpaqueTokenIntrospector introspector(RestTemplateBuilder builder) {
    RestOperations rest = builder
            .basicAuthentication(clientId, clientSecret)
            .setConnectionTimeout(60000)
            .setReadTimeout(60000)
            .build();

    return new NimbusOpaqueTokenIntrospector(introspectionUri, rest);
}

12.3.17 Using Introspection with JWTs

A common question is whether or not introspection is compatible with JWTs. Spring Security’s Opaque Token support has been designed to not care about the format of the token — it will gladly pass any token to the introspection endpoint provided.

So, let’s say that you’ve got a requirement that requires you to check with the authorization server on each request, in case the JWT has been revoked.

Even though you are using the JWT format for the token, your validation method is introspection, meaning you’d want to do:

spring:
  security:
    oauth2:
      resourceserver:
        opaque-token:
          introspection-uri: https://idp.example.org/introspection
          client-id: client
          client-secret: secret

In this case, the resulting Authentication would be BearerTokenAuthentication. Any attributes in the corresponding OAuth2AuthenticatedPrincipal would be whatever was returned by the introspection endpoint.

But, let’s say that, oddly enough, the introspection endpoint only returns whether or not the token is active. Now what?

In this case, you can create a custom OpaqueTokenIntrospector that still hits the endpoint, but then updates the returned principal to have the JWTs claims as the attributes:

public class JwtOpaqueTokenIntrospector implements OpaqueTokenIntrospector {
    private OpaqueTokenIntrospector delegate =
            new NimbusOpaqueTokenIntrospector("https://idp.example.org/introspect", "client", "secret");
    private JwtDecoder jwtDecoder = new NimbusJwtDecoder(new ParseOnlyJWTProcessor());

    public OAuth2AuthenticatedPrincipal introspect(String token) {
        OAuth2AuthenticatedPrincipal principal = this.delegate.introspect(token);
        try {
            Jwt jwt = this.jwtDecoder.decode(token);
            return new DefaultOAuth2AuthenticatedPrincipal(jwt.getClaims(), NO_AUTHORITIES);
        } catch (JwtException e) {
            throw new OAuth2IntrospectionException(e);
        }
    }

    private static class ParseOnlyJWTProcessor extends DefaultJWTProcessor<SecurityContext> {
        JWTClaimsSet process(SignedJWT jwt, SecurityContext context)
                throws JOSEException {
            return jwt.getJWTClaimSet();
        }
    }
}

Thereafter, this custom introspector can be configured simply by exposing it as a @Bean:

@Bean
public OpaqueTokenIntrospector introspector() {
    return new JwtOpaqueTokenIntropsector();
}

12.3.18 Calling a /userinfo Endpoint

Generally speaking, a Resource Server doesn’t care about the underlying user, but instead about the authorities that have been granted.

That said, at times it can be valuable to tie the authorization statement back to a user.

If an application is also using spring-security-oauth2-client, having set up the appropriate ClientRegistrationRepository, then this is quite simple with a custom OpaqueTokenIntrospector. This implementation below does three things:

  • Delegates to the introspection endpoint, to affirm the token’s validity
  • Looks up the appropriate client registration associated with the /userinfo endpoint
  • Invokes and returns the response from the /userinfo endpoint
public class UserInfoOpaqueTokenIntrospector implements OpaqueTokenIntrospector {
    private final OpaqueTokenIntrospector delegate =
            new NimbusOpaqueTokenIntrospector("https://idp.example.org/introspect", "client", "secret");
    private final OAuth2UserService oauth2UserService = new DefaultOAuth2UserService();

    private final ClientRegistrationRepository repository;

    // ... constructor

    @Override
    public OAuth2AuthenticatedPrincipal introspect(String token) {
        OAuth2AuthenticatedPrincipal authorized = this.delegate.introspect(token);
        Instant issuedAt = authorized.getAttribute(ISSUED_AT);
        Instant expiresAt = authorized.getAttribute(EXPIRES_AT);
        ClientRegistration clientRegistration = this.repository.findByRegistrationId("registration-id");
        OAuth2AccessToken token = new OAuth2AccessToken(BEARER, token, issuedAt, expiresAt);
        OAuth2UserRequest oauth2UserRequest = new OAuth2UserRequest(clientRegistration, token);
        return this.oauth2UserService.loadUser(oauth2UserRequest);
    }
}

If you aren’t using spring-security-oauth2-client, it’s still quite simple. You will simply need to invoke the /userinfo with your own instance of WebClient:

public class UserInfoOpaqueTokenIntrospector implements OpaqueTokenIntrospector {
    private final OpaqueTokenIntrospector delegate =
            new NimbusOpaqueTokenIntrospector("https://idp.example.org/introspect", "client", "secret");
    private final WebClient rest = WebClient.create();

    @Override
    public OAuth2AuthenticatedPrincipal introspect(String token) {
        OAuth2AuthenticatedPrincipal authorized = this.delegate.introspect(token);
        return makeUserInfoRequest(authorized);
    }
}

Either way, having created your OpaqueTokenIntrospector, you should publish it as a @Bean to override the defaults:

@Bean
OpaqueTokenIntrospector introspector() {
    return new UserInfoOpaqueTokenIntrospector(...);
}

12.3.19 Supporting both JWT and Opaque Token

In some cases, you may have a need to access both kinds of tokens. For example, you may support more than one tenant where one tenant issues JWTs and the other issues opaque tokens.

If this decision must be made at request-time, then you can use an AuthenticationManagerResolver to achieve it, like so:

@Bean
AuthenticationManagerResolver<HttpServletRequest> tokenAuthenticationManagerResolver() {
    BearerTokenResolver bearerToken = new DefaultBearerTokenResolver();
    JwtAuthenticationProvider jwt = jwt();
    OpaqueTokenAuthenticationProvider opaqueToken = opaqueToken();

    return request -> {
        String token = bearerToken.resolve(request);
        if (isAJwt(token)) {
            return jwt::authenticate;
        } else {
            return opaqueToken::authenticate;
        }
    }
}

And then specify this AuthenticationManagerResolver in the DSL:

http
    .authorizeRequests()
        .anyRequest().authenticated()
        .and()
    .oauth2ResourceServer()
        .authenticationManagerResolver(this.tokenAuthenticationManagerResolver);

12.3.20 Multi-tenancy

A resource server is considered multi-tenant when there are multiple strategies for verifying a bearer token, keyed by some tenant identifier.

For example, your resource server may accept bearer tokens from two different authorization servers. Or, your authorization server may represent a multiplicity of issuers.

In each case, there are two things that need to be done and trade-offs associated with how you choose to do them:

  1. Resolve the tenant
  2. Propagate the tenant

Resolving the Tenant By Request Material

Resolving the tenant by request material can be done my implementing an AuthenticationManagerResolver, which determines the AuthenticationManager at runtime, like so:

@Component
public class TenantAuthenticationManagerResolver
        implements AuthenticationManagerResolver<HttpServletRequest> {
    private final BearerTokenResolver resolver = new DefaultBearerTokenResolver();
    private final TenantRepository tenants; 1

    private final Map<String, AuthenticationManager> authenticationManagers = new ConcurrentHashMap<>(); 2

    public TenantAuthenticationManagerResolver(TenantRepository tenants) {
        this.tenants = tenants;
    }

    @Override
    public AuthenticationManager resolve(HttpServletRequest request) {
        return this.authenticationManagers.computeIfAbsent(toTenant(request), this::fromTenant);
    }

    private String toTenant(HttpServletRequest request) {
        String[] pathParts = request.getRequestURI().split("/");
        return pathParts.length > 0 ? pathParts[1] : null;
    }

    private AuthenticationManager fromTenant(String tenant) {
        return Optional.ofNullable(this.tenants.get(tenant)) 3
                .map(JwtDecoders::fromIssuerLocation) 4
                .map(JwtAuthenticationProvider::new)
                .orElseThrow(() -> new IllegalArgumentException("unknown tenant"))::authenticate;
    }
}

1

A hypothetical source for tenant information

2

A cache for `AuthenticationManager`s, keyed by tenant identifier

3

Looking up the tenant is more secure than simply computing the issuer location on the fly - the lookup acts as a tenant whitelist

4

Create a JwtDecoder via the discovery endpoint - the lazy lookup here means that you don’t need to configure all tenants at startup

And then specify this AuthenticationManagerResolver in the DSL:

http
    .authorizeRequests()
        .anyRequest().authenticated()
        .and()
    .oauth2ResourceServer()
        .authenticationManagerResolver(this.tenantAuthenticationManagerResolver);

Resolving the Tenant By Claim

Resolving the tenant by claim is similar to doing so by request material. The only real difference is the toTenant method implementation:

@Component
public class TenantAuthenticationManagerResolver implements AuthenticationManagerResolver<HttpServletRequest> {
    private final BearerTokenResolver resolver = new DefaultBearerTokenResolver();
    private final TenantRepository tenants; 1

    private final Map<String, AuthenticationManager> authenticationManagers = new ConcurrentHashMap<>(); 2

    public TenantAuthenticationManagerResolver(TenantRepository tenants) {
        this.tenants = tenants;
    }

    @Override
    public AuthenticationManager resolve(HttpServletRequest request) {
        return this.authenticationManagers.computeIfAbsent(toTenant(request), this::fromTenant); 3
    }

    private String toTenant(HttpServletRequest request) {
        try {
            String token = this.resolver.resolve(request);
            return (String) JWTParser.parse(token).getJWTClaimsSet().getIssuer();
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }

    private AuthenticationManager fromTenant(String tenant) {
        return Optional.ofNullable(this.tenants.get(tenant)) 4
                .map(JwtDecoders::fromIssuerLocation) 5
                .map(JwtAuthenticationProvider::new)
                .orElseThrow(() -> new IllegalArgumentException("unknown tenant"))::authenticate;
    }
}

1

A hypothetical source for tenant information

2

A cache for `AuthenticationManager`s, keyed by tenant identifier

3 4

Looking up the tenant is more secure than simply computing the issuer location on the fly - the lookup acts as a tenant whitelist

5

Create a JwtDecoder via the discovery endpoint - the lazy lookup here means that you don’t need to configure all tenants at startup

http
    .authorizeRequests()
        .anyRequest().authenticated()
        .and()
    .oauth2ResourceServer()
        .authenticationManagerResolver(this.tenantAuthenticationManagerResolver);

Parsing the Claim Only Once

You may have observed that this strategy, while simple, comes with the trade-off that the JWT is parsed once by the AuthenticationManagerResolver and then again by the JwtDecoder.

This extra parsing can be alleviated by configuring the JwtDecoder directly with a JWTClaimSetAwareJWSKeySelector from Nimbus:

@Component
public class TenantJWSKeySelector
    implements JWTClaimSetAwareJWSKeySelector<SecurityContext> {

    private final TenantRepository tenants; 1
    private final Map<String, JWSKeySelector<SecurityContext>> selectors = new ConcurrentHashMap<>(); 2

    public TenantJWSKeySelector(TenantRepository tenants) {
        this.tenants = tenants;
    }

    @Override
    public List<? extends Key> selectKeys(JWSHeader jwsHeader, JWTClaimsSet jwtClaimsSet, SecurityContext securityContext)
            throws KeySourceException {
        return this.selectors.computeIfAbsent(toTenant(jwtClaimsSet), this::fromTenant)
                .selectJWSKeys(jwsHeader, securityContext);
    }

    private String toTenant(JWTClaimsSet claimSet) {
        return (String) claimSet.getClaim("iss");
    }

    private JWSKeySelector<SecurityContext> fromTenant(String tenant) {
        return Optional.ofNullable(this.tenantRepository.findById(tenant)) 3
                .map(t -> t.getAttrbute("jwks_uri"))
                .map(this::fromUri)
                .orElseThrow(() -> new IllegalArgumentException("unknown tenant"));
    }

    private JWSKeySelector<SecurityContext> fromUri(String uri) {
        try {
            return JWSAlgorithmFamilyJWSKeySelector.fromJWKSetURL(new URL(uri)); 4
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }
}

1

A hypothetical source for tenant information

2

A cache for `JWKKeySelector`s, keyed by tenant identifier

3

Looking up the tenant is more secure than simply calculating the JWK Set endpoint on the fly - the lookup acts as a tenant whitelist

4

Create a JWSKeySelector via the types of keys that come back from the JWK Set endpoint - the lazy lookup here means that you don’t need to configure all tenants at startup

The above key selector is a composition of many key selectors. It chooses which key selector to use based on the iss claim in the JWT.

[Note]Note

To use this approach, make sure that the authorization server is configured to include the claim set as part of the token’s signature. Without this, you have no guarantee that the issuer hasn’t been altered by a bad actor.

Next, we can construct a JWTProcessor:

@Bean
JWTProcessor jwtProcessor(JWTClaimSetJWSKeySelector keySelector) {
    ConfigurableJWTProcessor<SecurityContext> jwtProcessor =
            new DefaultJWTProcessor();
    jwtProcessor.setJWTClaimsSetAwareJWSKeySelector(keySelector);
    return jwtProcessor;
}

As you are already seeing, the trade-off for moving tenant-awareness down to this level is more configuration. We have just a bit more.

Next, we still want to make sure you are validating the issuer. But, since the issuer may be different per JWT, then you’ll need a tenant-aware validator, too:

@Component
public class TenantJwtIssuerValidator implements OAuth2TokenValidator<Jwt> {
    private final TenantRepository tenants;
    private final Map<String, JwtIssuerValidator> validators = new ConcurrentHashMap<>();

    public TenantJwtIssuerValidator(TenantRepository tenants) {
        this.tenants = tenants;
    }

    @Override
    public OAuth2TokenValidatorResult validate(Jwt token) {
        return this.validators.computeIfAbsent(toTenant(token), this::fromTenant)
                .validate(token);
    }

    private String toTenant(Jwt jwt) {
        return jwt.getIssuer();
    }

    private JwtIssuerValidator fromTenant(String tenant) {
        return Optional.ofNullable(this.tenants.findById(tenant))
                .map(t -> t.getAttribute("issuer"))
                .map(JwtIssuerValidator::new)
                .orElseThrow(() -> new IllegalArgumentException("unknown tenant"));
    }
}

Now that we have a tenant-aware processor and a tenant-aware validator, we can proceed with creating our JwtDecoder:

@Bean
JwtDecoder jwtDecoder(JWTProcessor jwtProcessor, OAuth2TokenValidator<Jwt> jwtValidator) {
    NimbusJwtDecoder decoder = new NimbusJwtDecoder(jwtProcessor);
    OAuth2TokenValidator<Jwt> validator = new DelegatingOAuth2TokenValidator<>
            (JwtValidators.createDefault(), jwtValidator);
    decoder.setJwtValidator(validator);
    return decoder;
}

We’ve finished talking about resolving the tenant.

If you’ve chosen to resolve the tenant by request material, then you’ll need to make sure you address your downstream resource servers in the same way. For example, if you are resolving it by subdomain, you’ll need to address the downstream resource server using the same subdomain.

However, if you resolve it by a claim in the bearer token, read on to learn about Spring Security’s support for bearer token propagation.

12.3.21 Bearer Token Resolution

By default, Resource Server looks for a bearer token in the Authorization header. This, however, can be customized in a couple of ways.

Reading the Bearer Token from a Custom Header

For example, you may have a need to read the bearer token from a custom header. To achieve this, you can wire a HeaderBearerTokenResolver instance into the DSL, as you can see in the following example:

http
    .oauth2ResourceServer()
        .bearerTokenResolver(new HeaderBearerTokenResolver("x-goog-iap-jwt-assertion"));

Reading the Bearer Token from a Form Parameter

Or, you may wish to read the token from a form parameter, which you can do by configuring the DefaultBearerTokenResolver, as you can see below:

DefaultBearerTokenResolver resolver = new DefaultBearerTokenResolver();
resolver.setAllowFormEncodedBodyParameter(true);
http
    .oauth2ResourceServer()
        .bearerTokenResolver(resolver);

12.3.22 Bearer Token Propagation

Now that you’re in possession of a bearer token, it might be handy to pass that to downstream services. This is quite simple with ServletBearerExchangeFilterFunction, which you can see in the following example:

@Bean
public WebClient rest() {
    return WebClient.builder()
            .filter(new ServletBearerExchangeFilterFunction())
            .build();
}

When the above WebClient is used to perform requests, Spring Security will look up the current Authentication and extract any AbstractOAuth2Token credential. Then, it will propagate that token in the Authorization header.

For example:

this.rest.get()
        .uri("https://other-service.example.com/endpoint")
        .retrieve()
        .bodyToMono(String.class)
        .block()

Will invoke the https://other-service.example.com/endpoint, adding the bearer token Authorization header for you.

In places where you need to override this behavior, it’s a simple matter of supplying the header yourself, like so:

this.rest.get()
        .uri("https://other-service.example.com/endpoint")
        .headers(headers -> headers.setBearerAuth(overridingToken))
        .retrieve()
        .bodyToMono(String.class)
        .block()

In this case, the filter will fall back and simply forward the request onto the rest of the web filter chain.

[Note]Note

Unlike the OAuth 2.0 Client filter function, this filter function makes no attempt to renew the token, should it be expired. To obtain this level of support, please use the OAuth 2.0 Client filter.

RestTemplate support

There is no dedicated support for RestTemplate at the moment, but you can achieve propagation quite simply with your own interceptor:

@Bean
RestTemplate rest() {
    RestTemplate rest = new RestTemplate();
    rest.getInterceptors().add((request, body, execution) -> {
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
        if (authentication == null) {
            return execution.execute(request, body);
        }

        if (!(authentication.getCredentials() instanceof AbstractOAuth2Token)) {
            return execution.execute(request, body);
        }

        AbstractOAuth2Token token = (AbstractOAuth2Token) authentication.getCredentials();
        request.getHeaders().setBearerAuth(token.getTokenValue());
        return execution.execute(request, body);
    });
    return rest;
}