OAuth2

Spring Security provides comprehensive OAuth 2.0 support. This section discusses how to integrate OAuth 2.0 into your servlet based application.

Overview

Spring Security’s OAuth 2.0 support consists of two primary feature sets:

OAuth2 Resource Server
OAuth2 Client

OAuth2 Login is a very powerful OAuth2 Client feature that deserves its own section in the reference documentation. However, it does not exist as a standalone feature and requires OAuth2 Client in order to function.

These feature sets cover the resource server and client roles defined in the OAuth 2.0 Authorization Framework, while the authorization server role is covered by Spring Authorization Server, which is a separate project built on Spring Security.

The resource server and client roles in OAuth2 are typically represented by one or more server-side applications. Additionally, the authorization server role can be represented by one or more third parties (as is the case when centralizing identity management and/or authentication within an organization) -or- it can be represented by an application (as is the case with Spring Authorization Server).

For example, a typical OAuth2-based microservices architecture might consist of a single user-facing client application, several backend resource servers providing REST APIs and a third party authorization server for managing users and authentication concerns. It is also common to have a single application representing only one of these roles with the need to integrate with one or more third parties that are providing the other roles.

Spring Security handles these scenarios and more. The following sections cover the roles provided by Spring Security and contain examples for common scenarios.

OAuth2 Resource Server

This section contains a summary of OAuth2 Resource Server features with examples. See OAuth 2.0 Resource Server for complete reference documentation.

To get started, add the spring-security-oauth2-resource-server dependency to your project. When using Spring Boot, add the following starter:

OAuth2 Client with Spring Boot

Gradle
Maven

implementation 'org.springframework.boot:spring-boot-starter-oauth2-resource-server'

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-oauth2-resource-server</artifactId>
</dependency>

See Getting Spring Security for additional options when not using Spring Boot.

Consider the following use cases for OAuth2 Resource Server:

I want to protect access to the API using OAuth2 (authorization server provides JWT or opaque access token)
I want to protect access to the API using a JWT (custom token)

Protect Access with an OAuth2 Access Token

It is very common to protect access to an API using OAuth2 access tokens. In most cases, Spring Security requires only minimal configuration to secure an application with OAuth2.

There are two types of Bearer tokens supported by Spring Security which each use a different component for validation:

JWT support uses a JwtDecoder bean to validate signatures and decode tokens
Opaque token support uses an OpaqueTokenIntrospector bean to introspect tokens

JWT Support

The following example configures a JwtDecoder bean using Spring Boot configuration properties:

spring:
  security:
    oauth2:
      resourceserver:
        jwt:
          issuer-uri: https://my-auth-server.com

When using Spring Boot, this is all that is required. The default arrangement provided by Spring Boot is equivalent to the following:

Configure Resource Server with JWTs

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http
			.authorizeHttpRequests((authorize) -> authorize
				.anyRequest().authenticated()
			)
			.oauth2ResourceServer((oauth2) -> oauth2
				.jwt(Customizer.withDefaults())
			);
		return http.build();
	}

	@Bean
	public JwtDecoder jwtDecoder() {
		return JwtDecoders.fromIssuerLocation("https://my-auth-server.com");
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		http {
			authorizeHttpRequests {
				authorize(anyRequest, authenticated)
			}
			oauth2ResourceServer {
				jwt { }
			}
		}

		return http.build()
	}

	@Bean
	fun jwtDecoder(): JwtDecoder {
		return JwtDecoders.fromIssuerLocation("https://my-auth-server.com")
	}

}

Opaque Token Support

The following example configures an OpaqueTokenIntrospector bean using Spring Boot configuration properties:

spring:
  security:
    oauth2:
      resourceserver:
        opaquetoken:
          introspection-uri: https://my-auth-server.com/oauth2/introspect
          client-id: my-client-id
          client-secret: my-client-secret

When using Spring Boot, this is all that is required. The default arrangement provided by Spring Boot is equivalent to the following:

Configure Resource Server with Opaque Tokens

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http
			.authorizeHttpRequests((authorize) -> authorize
				.anyRequest().authenticated()
			)
			.oauth2ResourceServer((oauth2) -> oauth2
				.opaqueToken(Customizer.withDefaults())
			);
		return http.build();
	}

	@Bean
	public OpaqueTokenIntrospector opaqueTokenIntrospector() {
		return new SpringOpaqueTokenIntrospector(
			"https://my-auth-server.com/oauth2/introspect", "my-client-id", "my-client-secret");
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		http {
			authorizeHttpRequests {
				authorize(anyRequest, authenticated)
			}
			oauth2ResourceServer {
				opaqueToken { }
			}
		}

		return http.build()
	}

	@Bean
	fun opaqueTokenIntrospector(): OpaqueTokenIntrospector {
		return SpringOpaqueTokenIntrospector(
			"https://my-auth-server.com/oauth2/introspect", "my-client-id", "my-client-secret"
		)
	}

}

Protect Access with a custom JWT

It is a fairly common goal to protect access to an API using JWTs, particularly when the frontend is developed as a single-page application. The OAuth2 Resource Server support in Spring Security can be used for any type of Bearer token, including a custom JWT.

All that is required to protect an API using JWTs is a JwtDecoder bean, which is used to validate signatures and decode tokens. Spring Security will automatically use the provided bean to configure protection within the SecurityFilterChain.

The following example configures a JwtDecoder bean using Spring Boot configuration properties:

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

You can provide the public key as a classpath resource (called my-public-key.pub in this example).

When using Spring Boot, this is all that is required. The default arrangement provided by Spring Boot is equivalent to the following:

Configure Resource Server with Custom JWTs

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http
			.authorizeHttpRequests((authorize) -> authorize
				.anyRequest().authenticated()
			)
			.oauth2ResourceServer((oauth2) -> oauth2
				.jwt(Customizer.withDefaults())
			);
		return http.build();
	}

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

	private RSAPublicKey publicKey() {
		// ...
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		http {
			authorizeHttpRequests {
				authorize(anyRequest, authenticated)
			}
			oauth2ResourceServer {
				jwt { }
			}
		}

		return http.build()
	}

	@Bean
	fun jwtDecoder(): JwtDecoder {
		return NimbusJwtDecoder.withPublicKey(publicKey()).build()
	}

	private fun publicKey(): RSAPublicKey {
		// ...
	}

}

Spring Security does not provide an endpoint for minting tokens. However, Spring Security does provide the JwtEncoder interface along with one implementation, which is NimbusJwtEncoder.

OAuth2 Client

This section contains a summary of OAuth2 Client features with examples. See OAuth 2.0 Client and OAuth 2.0 Login for complete reference documentation.

To get started, add the spring-security-oauth2-client dependency to your project. When using Spring Boot, add the following starter:

OAuth2 Client with Spring Boot

Gradle
Maven

implementation 'org.springframework.boot:spring-boot-starter-oauth2-client'

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-oauth2-client</artifactId>
</dependency>

See Getting Spring Security for additional options when not using Spring Boot.

Consider the following use cases for OAuth2 Client:

I want to log users in using OAuth 2.0 or OpenID Connect 1.0
I want to use RestClient to obtain an access token for users in order to access a third-party API
I want to use WebClient to obtain an access token for users in order to access a third-party API
I want to do both (log users in and access a third-party API)
I want to use the client_credentials grant type to obtain a single token per application
I want to enable an extension grant type
I want to customize an existing grant type
I want to customize token request parameters
I want to customize the RestOperations used by OAuth2 Client components

Log Users In with OAuth2

It is very common to require users to log in via OAuth2. OpenID Connect 1.0 provides a special token called the id_token which is designed to provide an OAuth2 Client with the ability to perform user identity verification and log users in. In certain cases, OAuth2 can be used directly to log users in (as is the case with popular social login providers that do not implement OpenID Connect such as GitHub and Facebook).

The following example configures the application to act as an OAuth2 Client capable of logging users in with OAuth2 or OpenID Connect:

Configure OAuth2 Login

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http
			// ...
			.oauth2Login(Customizer.withDefaults());
		return http.build();
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		http {
			// ...
			oauth2Login { }
		}

		return http.build()
	}

}

In addition to the above configuration, the application requires at least one ClientRegistration to be configured through the use of a ClientRegistrationRepository bean. The following example configures an InMemoryClientRegistrationRepository bean using Spring Boot configuration properties:

spring:
  security:
    oauth2:
      client:
        registration:
          my-oidc-client:
            provider: my-oidc-provider
            client-id: my-client-id
            client-secret: my-client-secret
            authorization-grant-type: authorization_code
            scope: openid,profile
        provider:
          my-oidc-provider:
            issuer-uri: https://my-oidc-provider.com

With the above configuration, the application now supports two additional endpoints:

The login endpoint (e.g. /oauth2/authorization/my-oidc-client) is used to initiate login and perform a redirect to the third party authorization server.
The redirection endpoint (e.g. /login/oauth2/code/my-oidc-client) is used by the authorization server to redirect back to the client application, and will contain a code parameter used to obtain an id_token and/or access_token via the access token request.

The presence of the openid scope in the above configuration indicates that OpenID Connect 1.0 should be used. This instructs Spring Security to use OIDC-specific components (such as OidcUserService) during request processing. Without this scope, Spring Security will use OAuth2-specific components (such as DefaultOAuth2UserService) instead.

Access Protected Resources

Making requests to a third party API that is protected by OAuth2 is a core use case of OAuth2 Client. This is accomplished by authorizing a client (represented by the OAuth2AuthorizedClient class in Spring Security) and accessing protected resources by placing a Bearer token in the Authorization header of an outbound request.

The following example configures the application to act as an OAuth2 Client capable of requesting protected resources from a third party API:

Configure OAuth2 Client

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http
			// ...
			.oauth2Client(Customizer.withDefaults());
		return http.build();
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		http {
			// ...
			oauth2Client { }
		}

		return http.build()
	}

}

The above example does not provide a way to log users in. You can use any other login mechanism (such as formLogin()). See the next section for an example combining oauth2Client() with oauth2Login().

spring:
  security:
    oauth2:
      client:
        registration:
          my-oauth2-client:
            provider: my-auth-server
            client-id: my-client-id
            client-secret: my-client-secret
            authorization-grant-type: authorization_code
            scope: message.read,message.write
        provider:
          my-auth-server:
            issuer-uri: https://my-auth-server.com

In addition to configuring Spring Security to support OAuth2 Client features, you will also need to decide how you will be accessing protected resources and configure your application accordingly. Spring Security provides implementations of OAuth2AuthorizedClientManager for obtaining access tokens that can be used to access protected resources.

Spring Security registers a default OAuth2AuthorizedClientManager bean for you when one does not exist.

The easiest way to use an OAuth2AuthorizedClientManager is via a ClientHttpRequestInterceptor that intercepts requests through a RestClient, which is already available when spring-web is on the classpath.

The following example uses the default OAuth2AuthorizedClientManager to configure a RestClient capable of accessing protected resources by placing Bearer tokens in the Authorization header of each request:

Configure RestClient with ClientHttpRequestInterceptor

Java
Kotlin

@Configuration
public class RestClientConfig {

	@Bean
	public RestClient restClient(OAuth2AuthorizedClientManager authorizedClientManager) {
		OAuth2ClientHttpRequestInterceptor requestInterceptor =
				new OAuth2ClientHttpRequestInterceptor(authorizedClientManager);
		return RestClient.builder()
				.requestInterceptor(requestInterceptor)
				.build();
	}

}

@Configuration
class RestClientConfig {

	@Bean
	fun restClient(authorizedClientManager: OAuth2AuthorizedClientManager): RestClient {
		val requestInterceptor = OAuth2ClientHttpRequestInterceptor(authorizedClientManager)
		return RestClient.builder()
			.requestInterceptor(requestInterceptor)
			.build()
	}

}

This configured RestClient can be used as in the following example:

Use RestClient to Access Protected Resources

Java
Kotlin

import static org.springframework.security.oauth2.client.web.client.RequestAttributeClientRegistrationIdResolver.clientRegistrationId;

@RestController
public class MessagesController {

	private final RestClient restClient;

	public MessagesController(RestClient restClient) {
		this.restClient = restClient;
	}

	@GetMapping("/messages")
	public ResponseEntity<List<Message>> messages() {
		Message[] messages = this.restClient.get()
				.uri("http://localhost:8090/messages")
				.attributes(clientRegistrationId("my-oauth2-client"))
				.retrieve()
				.body(Message[].class);
		return ResponseEntity.ok(Arrays.asList(messages));
	}

	public record Message(String message) {
	}

}

import org.springframework.security.oauth2.client.web.client.RequestAttributeClientRegistrationIdResolver.clientRegistrationId
import org.springframework.web.client.body

@RestController
class MessagesController(private val restClient: RestClient) {

	@GetMapping("/messages")
	fun messages(): ResponseEntity<List<Message>> {
		val messages = restClient.get()
			.uri("http://localhost:8090/messages")
			.attributes(clientRegistrationId("my-oauth2-client"))
			.retrieve()
			.body<Array<Message>>()!!
			.toList()
		return ResponseEntity.ok(messages)
	}

	data class Message(val message: String)

}

Access Protected Resources with `WebClient`

The following example configures the application to act as an OAuth2 Client capable of requesting protected resources from a third party API:

Configure OAuth2 Client

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http
			// ...
			.oauth2Client(Customizer.withDefaults());
		return http.build();
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		http {
			// ...
			oauth2Client { }
		}

		return http.build()
	}

}

The above example does not provide a way to log users in. You can use any other login mechanism (such as formLogin()). See the previous section for an example combining oauth2Client() with oauth2Login().

spring:
  security:
    oauth2:
      client:
        registration:
          my-oauth2-client:
            provider: my-auth-server
            client-id: my-client-id
            client-secret: my-client-secret
            authorization-grant-type: authorization_code
            scope: message.read,message.write
        provider:
          my-auth-server:
            issuer-uri: https://my-auth-server.com

Spring Security registers a default OAuth2AuthorizedClientManager bean for you when one does not exist.

Instead of configuring a RestClient, another way to use an OAuth2AuthorizedClientManager is via an ExchangeFilterFunction that intercepts requests through a WebClient. To use WebClient, you will need to add the spring-webflux dependency along with a reactive client implementation:

Add Spring WebFlux Dependency

Gradle
Maven

implementation 'org.springframework:spring-webflux'
implementation 'io.projectreactor.netty:reactor-netty'

<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-webflux</artifactId>
</dependency>
<dependency>
	<groupId>io.projectreactor.netty</groupId>
	<artifactId>reactor-netty</artifactId>
</dependency>

The following example uses the default OAuth2AuthorizedClientManager to configure a WebClient capable of accessing protected resources by placing Bearer tokens in the Authorization header of each request:

Configure WebClient with ExchangeFilterFunction

Java
Kotlin

@Configuration
public class WebClientConfig {

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

}

@Configuration
class WebClientConfig {

	@Bean
	fun webClient(authorizedClientManager: OAuth2AuthorizedClientManager): WebClient {
		val filter = ServletOAuth2AuthorizedClientExchangeFilterFunction(authorizedClientManager)
		return WebClient.builder()
			.apply(filter.oauth2Configuration())
			.build()
	}

}

This configured WebClient can be used as in the following example:

Use WebClient to Access Protected Resources

Java
Kotlin

import static org.springframework.security.oauth2.client.web.reactive.function.client.ServletOAuth2AuthorizedClientExchangeFilterFunction.clientRegistrationId;

@RestController
public class MessagesController {

	private final WebClient webClient;

	public MessagesController(WebClient webClient) {
		this.webClient = webClient;
	}

	@GetMapping("/messages")
	public ResponseEntity<List<Message>> messages() {
		return this.webClient.get()
				.uri("http://localhost:8090/messages")
				.attributes(clientRegistrationId("my-oauth2-client"))
				.retrieve()
				.toEntityList(Message.class)
				.block();
	}

	public record Message(String message) {
	}

}

import org.springframework.security.oauth2.client.web.reactive.function.client.ServletOAuth2AuthorizedClientExchangeFilterFunction.clientRegistrationId

@RestController
class MessagesController(private val webClient: WebClient) {

	@GetMapping("/messages")
	fun messages(): ResponseEntity<List<Message>> {
		return webClient.get()
			.uri("http://localhost:8090/messages")
			.attributes(clientRegistrationId("my-oauth2-client"))
			.retrieve()
			.toEntityList<Message>()
			.block()!!
	}

	data class Message(val message: String)

}

Access Protected Resources for the Current User

When a user is logged in via OAuth2 or OpenID Connect, the authorization server may provide an access token that can be used directly to access protected resources. This is convenient because it only requires a single ClientRegistration to be configured for both use cases simultaneously.

This section combines Log Users In with OAuth2 and Access Protected Resources into a single configuration. Other advanced scenarios exist, such as configuring one ClientRegistration for login and another for accessing protected resources. All such scenarios would use the same basic configuration.

The following example configures the application to act as an OAuth2 Client capable of logging the user in and requesting protected resources from a third party API:

Configure OAuth2 Login and OAuth2 Client

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http
			// ...
			.oauth2Login(Customizer.withDefaults())
			.oauth2Client(Customizer.withDefaults());
		return http.build();
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		http {
			// ...
			oauth2Login { }
			oauth2Client { }
		}

		return http.build()
	}

}

spring:
  security:
    oauth2:
      client:
        registration:
          my-combined-client:
            provider: my-auth-server
            client-id: my-client-id
            client-secret: my-client-secret
            authorization-grant-type: authorization_code
            scope: openid,profile,message.read,message.write
        provider:
          my-auth-server:
            issuer-uri: https://my-auth-server.com

The main difference between the previous examples (Log Users In with OAuth2, Access Protected Resources) and this one is what is configured via the scope property, which combines the standard scopes openid and profile with the custom scopes message.read and message.write.

Spring Security registers a default OAuth2AuthorizedClientManager bean for you when one does not exist.

Configure RestClient with ClientHttpRequestInterceptor

Java
Kotlin

@Configuration
public class RestClientConfig {

	@Bean
	public RestClient restClient(OAuth2AuthorizedClientManager authorizedClientManager) {
		OAuth2ClientHttpRequestInterceptor requestInterceptor =
				new OAuth2ClientHttpRequestInterceptor(authorizedClientManager, clientRegistrationIdResolver());
		return RestClient.builder()
				.requestInterceptor(requestInterceptor)
				.build();
	}

	private static ClientRegistrationIdResolver clientRegistrationIdResolver() {
		return (request) -> {
			Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
			return (authentication instanceof OAuth2AuthenticationToken principal)
				? principal.getAuthorizedClientRegistrationId()
				: null;
		};
	}

}

@Configuration
class RestClientConfig {

	@Bean
	fun restClient(authorizedClientManager: OAuth2AuthorizedClientManager): RestClient {
		val requestInterceptor = OAuth2ClientHttpRequestInterceptor(authorizedClientManager, clientRegistrationIdResolver())
		return RestClient.builder()
			.requestInterceptor(requestInterceptor)
			.build()
	}

	private fun clientRegistrationIdResolver(): OAuth2ClientHttpRequestInterceptor.ClientRegistrationIdResolver {
		return OAuth2ClientHttpRequestInterceptor.ClientRegistrationIdResolver { request ->
			val authentication = SecurityContextHolder.getContext().authentication
			if (authentication is OAuth2AuthenticationToken) {
				authentication.authorizedClientRegistrationId
			} else {
				null
			}
		}
	}

}

This configured RestClient can be used as in the following example:

Use RestClient to Access Protected Resources (Current User)

Java
Kotlin

@RestController
public class MessagesController {

	private final RestClient restClient;

	public MessagesController(RestClient restClient) {
		this.restClient = restClient;
	}

	@GetMapping("/messages")
	public ResponseEntity<List<Message>> messages() {
		Message[] messages = this.restClient.get()
				.uri("http://localhost:8090/messages")
				.retrieve()
				.body(Message[].class);
		return ResponseEntity.ok(Arrays.asList(messages));
	}

	public record Message(String message) {
	}

}

import org.springframework.web.client.body

@RestController
class MessagesController(private val restClient: RestClient) {

	@GetMapping("/messages")
	fun messages(): ResponseEntity<List<Message>> {
		val messages = restClient.get()
			.uri("http://localhost:8090/messages")
			.retrieve()
			.body<Array<Message>>()!!
			.toList()
		return ResponseEntity.ok(messages)
	}

	data class Message(val message: String)

}

Unlike the previous example, notice that we do not need to tell Spring Security about the clientRegistrationId we’d like to use. This is because it can be derived from the currently logged in user.

Use the Client Credentials Grant

This section focuses on additional considerations for the client credentials grant type. See Access Protected Resources for general setup and usage with all grant types.

The client credentials grant allows a client to obtain an access_token on behalf of itself. The client credentials grant is a simple flow that does not involve a resource owner (i.e. a user).

It is important to note that typical use of the client credentials grant implies that any request (or user) can potentially obtain an access token and make protected resources requests to a resource server. Exercise caution when designing applications to ensure that users cannot make unauthorized requests since every request will be able to obtain an access token.

When obtaining access tokens within a web application where users can log in, the default behavior of Spring Security is to obtain an access token per user.

By default, access tokens are scoped to the principal name of the current user which means every user will receive a unique access token.

Clients using the client credentials grant typically require access tokens to be scoped to the application instead of to individual users so there is only one access token per application. In order to scope access tokens to the application, you will need to set a strategy for resolving a custom principal name. The following example does this by configuring a RestClient with the RequestAttributePrincipalResolver:

Configure RestClient for client_credentials

Java
Kotlin

@Configuration
public class RestClientConfig {

	@Bean
	public RestClient restClient(OAuth2AuthorizedClientManager authorizedClientManager) {
		OAuth2ClientHttpRequestInterceptor requestInterceptor =
				new OAuth2ClientHttpRequestInterceptor(authorizedClientManager);
		requestInterceptor.setPrincipalResolver(new RequestAttributePrincipalResolver());
		return RestClient.builder()
				.requestInterceptor(requestInterceptor)
				.build();
	}

}

@Configuration
class RestClientConfig {

	@Bean
	fun restClient(authorizedClientManager: OAuth2AuthorizedClientManager): RestClient {
		val requestInterceptor = OAuth2ClientHttpRequestInterceptor(authorizedClientManager)
		requestInterceptor.setPrincipalResolver(RequestAttributePrincipalResolver())
		return RestClient.builder()
			.requestInterceptor(requestInterceptor)
			.build()
	}

}

With the above configuration in place, a principal name can be specified for each request. The following example demonstrates how to scope access tokens to the application by specifying a principal name:

Scope Access Tokens to the Application

Java
Kotlin

import static org.springframework.security.oauth2.client.web.client.RequestAttributeClientRegistrationIdResolver.clientRegistrationId;
import static org.springframework.security.oauth2.client.web.client.RequestAttributePrincipalResolver.principal;

@RestController
public class MessagesController {

	private final RestClient restClient;

	public MessagesController(RestClient restClient) {
		this.restClient = restClient;
	}

	@GetMapping("/messages")
	public ResponseEntity<List<Message>> messages() {
		Message[] messages = this.restClient.get()
				.uri("http://localhost:8090/messages")
				.attributes(clientRegistrationId("my-oauth2-client"))
				.attributes(principal("my-application"))
				.retrieve()
				.body(Message[].class);
		return ResponseEntity.ok(Arrays.asList(messages));
	}

	public record Message(String message) {
	}

}

import org.springframework.security.oauth2.client.web.client.RequestAttributeClientRegistrationIdResolver.clientRegistrationId
import org.springframework.security.oauth2.client.web.client.RequestAttributePrincipalResolver.principal
import org.springframework.web.client.body

@RestController
class MessagesController(private val restClient: RestClient) {

	@GetMapping("/messages")
	fun messages(): ResponseEntity<List<Message>> {
		val messages = restClient.get()
			.uri("http://localhost:8090/messages")
			.attributes(clientRegistrationId("my-oauth2-client"))
			.attributes(principal("my-application"))
			.retrieve()
			.body<Array<Message>>()!!
			.toList()
		return ResponseEntity.ok(messages)
	}

	data class Message(val message: String)

}

When specifying a principal name via attributes as in the above example, there will only be a single access token and it will be used for all requests.

Enable an Extension Grant Type

A common use case involves enabling and/or configuring an extension grant type. For example, Spring Security provides support for the jwt-bearer and token-exchange grant types, but does not enable them by default because they are not part of the core OAuth 2.0 specification.

With Spring Security 6.2 and later, we can simply publish a bean for one or more OAuth2AuthorizedClientProvider and they will be picked up automatically. The following example simply enables the jwt-bearer grant type:

Enable jwt-bearer Grant Type

Java
Kotlin

@Configuration
public class SecurityConfig {

	@Bean
	public OAuth2AuthorizedClientProvider jwtBearer() {
		return new JwtBearerOAuth2AuthorizedClientProvider();
	}

}

@Configuration
class SecurityConfig {

	@Bean
	fun jwtBearer(): OAuth2AuthorizedClientProvider {
		return JwtBearerOAuth2AuthorizedClientProvider()
	}

}

A default OAuth2AuthorizedClientManager will be published automatically by Spring Security when one is not already provided.

Any custom OAuth2AuthorizedClientProvider bean will also be picked up and applied to the provided OAuth2AuthorizedClientManager after the default grant types.

In order to achieve the above configuration prior to Spring Security 6.2, we had to publish this bean ourselves and ensure we re-enabled default grant types as well. To understand what is being configured behind the scenes, here’s what the configuration might have looked like:

Enable jwt-bearer Grant Type (prior to 6.2)

Java
Kotlin

@Configuration
public class SecurityConfig {

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

		OAuth2AuthorizedClientProvider authorizedClientProvider =
			OAuth2AuthorizedClientProviderBuilder.builder()
				.authorizationCode()
				.refreshToken()
				.clientCredentials()
				.password()
				.provider(new JwtBearerOAuth2AuthorizedClientProvider())
				.build();

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

		return authorizedClientManager;
	}

}

@Configuration
class SecurityConfig {

	@Bean
	fun authorizedClientManager(
		clientRegistrationRepository: ClientRegistrationRepository,
		authorizedClientRepository: OAuth2AuthorizedClientRepository
	): OAuth2AuthorizedClientManager {
		val authorizedClientProvider = OAuth2AuthorizedClientProviderBuilder.builder()
			.authorizationCode()
			.refreshToken()
			.clientCredentials()
			.password()
			.provider(JwtBearerOAuth2AuthorizedClientProvider())
			.build()

		val authorizedClientManager = DefaultOAuth2AuthorizedClientManager(
			clientRegistrationRepository, authorizedClientRepository
		)
		authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider)

		return authorizedClientManager
	}

}

Customize an Existing Grant Type

The ability to enable extension grant types by publishing a bean also provides the opportunity for customizing an existing grant type without the need to re-define the defaults. For example, if we want to customize the clock skew of the OAuth2AuthorizedClientProvider for the client_credentials grant, we can simply publish a bean like so:

Customize Client Credentials Grant Type

Java
Kotlin

@Configuration
public class SecurityConfig {

	@Bean
	public OAuth2AuthorizedClientProvider clientCredentials() {
		ClientCredentialsOAuth2AuthorizedClientProvider authorizedClientProvider =
				new ClientCredentialsOAuth2AuthorizedClientProvider();
		authorizedClientProvider.setClockSkew(Duration.ofMinutes(5));

		return authorizedClientProvider;
	}

}

@Configuration
class SecurityConfig {

	@Bean
	fun clientCredentials(): OAuth2AuthorizedClientProvider {
		val authorizedClientProvider = ClientCredentialsOAuth2AuthorizedClientProvider()
		authorizedClientProvider.setClockSkew(Duration.ofMinutes(5))
		return authorizedClientProvider
	}

}

Customize Token Request Parameters

The need to customize request parameters when obtaining an access token is fairly common. For example, let’s say we want to add a custom audience parameter to the token request because the provider requires this parameter for the authorization_code grant.

With Spring Security 6.2 and later, we can simply publish a bean of type OAuth2AccessTokenResponseClient with the generic type OAuth2AuthorizationCodeGrantRequest and it will be used by Spring Security to configure OAuth2 Client components.

The following example customizes token request parameters for the authorization_code grant without the DSL:

Customize Token Request Parameters for Authorization Code Grant

Java
Kotlin

@Configuration
public class SecurityConfig {

	@Bean
	public OAuth2AccessTokenResponseClient<OAuth2AuthorizationCodeGrantRequest> authorizationCodeAccessTokenResponseClient() {
		OAuth2AuthorizationCodeGrantRequestEntityConverter requestEntityConverter =
			new OAuth2AuthorizationCodeGrantRequestEntityConverter();
		requestEntityConverter.addParametersConverter(parametersConverter());

		DefaultAuthorizationCodeTokenResponseClient accessTokenResponseClient =
			new DefaultAuthorizationCodeTokenResponseClient();
		accessTokenResponseClient.setRequestEntityConverter(requestEntityConverter);

		return accessTokenResponseClient;
	}

	private static Converter<OAuth2AuthorizationCodeGrantRequest, MultiValueMap<String, String>> parametersConverter() {
		return (grantRequest) -> {
			MultiValueMap<String, String> parameters = new LinkedMultiValueMap<>();
			parameters.set("audience", "xyz_value");

			return parameters;
		};
	}

}

@Configuration
class SecurityConfig {

	@Bean
	fun authorizationCodeAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<OAuth2AuthorizationCodeGrantRequest> {
		val requestEntityConverter = OAuth2AuthorizationCodeGrantRequestEntityConverter()
		requestEntityConverter.addParametersConverter(parametersConverter())

		val accessTokenResponseClient = DefaultAuthorizationCodeTokenResponseClient()
		accessTokenResponseClient.setRequestEntityConverter(requestEntityConverter)

		return accessTokenResponseClient
	}

	private fun parametersConverter(): Converter<OAuth2AuthorizationCodeGrantRequest, MultiValueMap<String, String>> {
		return Converter<OAuth2AuthorizationCodeGrantRequest, MultiValueMap<String, String>> { grantRequest ->
			LinkedMultiValueMap<String, String>().also { parameters ->
				parameters["audience"] = "xyz_value"
			}
		}
	}

}

Notice that we don’t need to customize the SecurityFilterChain bean in this case, and can stick with the defaults. If using Spring Boot with no additional customizations, we can actually omit the SecurityFilterChain bean entirely.

Prior to Spring Security 6.2, we had to ensure that this customization was applied for both OAuth2 Login (if we are using this feature) and OAuth2 Client components using the Spring Security DSL. To understand what is being configured behind the scenes, here’s what the configuration might have looked like:

Customize Token Request Parameters for Authorization Code Grant (prior to 6.2)

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		OAuth2AuthorizationCodeGrantRequestEntityConverter requestEntityConverter =
			new OAuth2AuthorizationCodeGrantRequestEntityConverter();
		requestEntityConverter.addParametersConverter(parametersConverter());

		DefaultAuthorizationCodeTokenResponseClient accessTokenResponseClient =
			new DefaultAuthorizationCodeTokenResponseClient();
		accessTokenResponseClient.setRequestEntityConverter(requestEntityConverter);

		http
			.authorizeHttpRequests((authorize) -> authorize
				.anyRequest().authenticated()
			)
			.oauth2Login((oauth2Login) -> oauth2Login
				.tokenEndpoint((tokenEndpoint) -> tokenEndpoint
					.accessTokenResponseClient(accessTokenResponseClient)
				)
			)
			.oauth2Client((oauth2Client) -> oauth2Client
				.authorizationCodeGrant((authorizationCode) -> authorizationCode
					.accessTokenResponseClient(accessTokenResponseClient)
				)
			);

		return http.build();
	}

	private static Converter<OAuth2AuthorizationCodeGrantRequest, MultiValueMap<String, String>> parametersConverter() {
		// ...
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		val requestEntityConverter = OAuth2AuthorizationCodeGrantRequestEntityConverter()
		requestEntityConverter.addParametersConverter(parametersConverter())

		val tokenResponseClient = DefaultAuthorizationCodeTokenResponseClient()
		tokenResponseClient.setRequestEntityConverter(requestEntityConverter)

		http {
			authorizeHttpRequests {
				authorize(anyRequest, authenticated)
			}
			oauth2Login {
				tokenEndpoint {
					accessTokenResponseClient = tokenResponseClient
				}
			}
			oauth2Client {
				authorizationCodeGrant {
					accessTokenResponseClient = tokenResponseClient
				}
			}
		}

		return http.build()
	}

	private fun parametersConverter(): Converter<OAuth2AuthorizationCodeGrantRequest, MultiValueMap<String, String>> {
		// ...
	}

}

For other grant types we can publish additional OAuth2AccessTokenResponseClient beans to override the defaults. For example, to customize token requests for the client_credentials grant we can publish the following bean:

Customize Token Request Parameters for Client Credentials Grant

Java
Kotlin

@Configuration
public class SecurityConfig {

	@Bean
	public OAuth2AccessTokenResponseClient<OAuth2ClientCredentialsGrantRequest> clientCredentialsAccessTokenResponseClient() {
		OAuth2ClientCredentialsGrantRequestEntityConverter requestEntityConverter =
			new OAuth2ClientCredentialsGrantRequestEntityConverter();
		requestEntityConverter.addParametersConverter(parametersConverter());

		DefaultClientCredentialsTokenResponseClient accessTokenResponseClient =
				new DefaultClientCredentialsTokenResponseClient();
		accessTokenResponseClient.setRequestEntityConverter(requestEntityConverter);

		return accessTokenResponseClient;
	}

	private static Converter<OAuth2ClientCredentialsGrantRequest, MultiValueMap<String, String>> parametersConverter() {
		// ...
	}

}

@Configuration
class SecurityConfig {

	@Bean
	fun clientCredentialsAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<OAuth2ClientCredentialsGrantRequest> {
		val requestEntityConverter = OAuth2ClientCredentialsGrantRequestEntityConverter()
		requestEntityConverter.addParametersConverter(parametersConverter())

		val accessTokenResponseClient = DefaultClientCredentialsTokenResponseClient()
		accessTokenResponseClient.setRequestEntityConverter(requestEntityConverter)

		return accessTokenResponseClient
	}

	private fun parametersConverter(): Converter<OAuth2ClientCredentialsGrantRequest, MultiValueMap<String, String>> {
		// ...
	}

}

Spring Security automatically resolves the following generic types of OAuth2AccessTokenResponseClient beans:

OAuth2AuthorizationCodeGrantRequest (see DefaultAuthorizationCodeTokenResponseClient)
OAuth2RefreshTokenGrantRequest (see DefaultRefreshTokenTokenResponseClient)
OAuth2ClientCredentialsGrantRequest (see DefaultClientCredentialsTokenResponseClient)
OAuth2PasswordGrantRequest (see DefaultPasswordTokenResponseClient)
JwtBearerGrantRequest (see DefaultJwtBearerTokenResponseClient)
TokenExchangeGrantRequest (see DefaultTokenExchangeTokenResponseClient)

Publishing a bean of type OAuth2AccessTokenResponseClient<JwtBearerGrantRequest> will automatically enable the jwt-bearer grant type without the need to configure it separately.

Publishing a bean of type OAuth2AccessTokenResponseClient<TokenExchangeGrantRequest> will automatically enable the token-exchange grant type without the need to configure it separately.

Customize the `RestOperations` used by OAuth2 Client Components

Another common use case is the need to customize the RestOperations used when obtaining an access token. We might need to do this to customize processing of the response (via a custom HttpMessageConverter) or to apply proxy settings for a corporate network (via a customized ClientHttpRequestFactory).

With Spring Security 6.2 and later, we can simply publish beans of type OAuth2AccessTokenResponseClient and Spring Security will configure and publish an OAuth2AuthorizedClientManager bean for us.

The following example customizes the RestOperations for all of the supported grant types:

Customize RestOperations for OAuth2 Client

Java
Kotlin

@Configuration
public class SecurityConfig {

	@Bean
	public OAuth2AccessTokenResponseClient<OAuth2AuthorizationCodeGrantRequest> authorizationCodeAccessTokenResponseClient() {
		DefaultAuthorizationCodeTokenResponseClient accessTokenResponseClient =
			new DefaultAuthorizationCodeTokenResponseClient();
		accessTokenResponseClient.setRestOperations(restTemplate());

		return accessTokenResponseClient;
	}

	@Bean
	public OAuth2AccessTokenResponseClient<OAuth2RefreshTokenGrantRequest> refreshTokenAccessTokenResponseClient() {
		DefaultRefreshTokenTokenResponseClient accessTokenResponseClient =
			new DefaultRefreshTokenTokenResponseClient();
		accessTokenResponseClient.setRestOperations(restTemplate());

		return accessTokenResponseClient;
	}

	@Bean
	public OAuth2AccessTokenResponseClient<OAuth2ClientCredentialsGrantRequest> clientCredentialsAccessTokenResponseClient() {
		DefaultClientCredentialsTokenResponseClient accessTokenResponseClient =
			new DefaultClientCredentialsTokenResponseClient();
		accessTokenResponseClient.setRestOperations(restTemplate());

		return accessTokenResponseClient;
	}

	@Bean
	public OAuth2AccessTokenResponseClient<OAuth2PasswordGrantRequest> passwordAccessTokenResponseClient() {
		DefaultPasswordTokenResponseClient accessTokenResponseClient =
			new DefaultPasswordTokenResponseClient();
		accessTokenResponseClient.setRestOperations(restTemplate());

		return accessTokenResponseClient;
	}

	@Bean
	public OAuth2AccessTokenResponseClient<JwtBearerGrantRequest> jwtBearerAccessTokenResponseClient() {
		DefaultJwtBearerTokenResponseClient accessTokenResponseClient =
			new DefaultJwtBearerTokenResponseClient();
		accessTokenResponseClient.setRestOperations(restTemplate());

		return accessTokenResponseClient;
	}

	@Bean
	public OAuth2AccessTokenResponseClient<TokenExchangeGrantRequest> tokenExchangeAccessTokenResponseClient() {
		DefaultTokenExchangeTokenResponseClient accessTokenResponseClient =
			new DefaultTokenExchangeTokenResponseClient();
		accessTokenResponseClient.setRestOperations(restTemplate());

		return accessTokenResponseClient;
	}

	@Bean
	public RestTemplate restTemplate() {
		// ...
	}

}

@Configuration
class SecurityConfig {

	@Bean
	fun authorizationCodeAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<OAuth2AuthorizationCodeGrantRequest> {
		val accessTokenResponseClient = DefaultAuthorizationCodeTokenResponseClient()
		accessTokenResponseClient.setRestOperations(restTemplate())

		return accessTokenResponseClient
	}

	@Bean
	fun refreshTokenAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<OAuth2RefreshTokenGrantRequest> {
		val accessTokenResponseClient = DefaultRefreshTokenTokenResponseClient()
		accessTokenResponseClient.setRestOperations(restTemplate())

		return accessTokenResponseClient
	}

	@Bean
	fun clientCredentialsAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<OAuth2ClientCredentialsGrantRequest> {
		val accessTokenResponseClient = DefaultClientCredentialsTokenResponseClient()
		accessTokenResponseClient.setRestOperations(restTemplate())

		return accessTokenResponseClient
	}

	@Bean
	fun passwordAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<OAuth2PasswordGrantRequest> {
		val accessTokenResponseClient = DefaultPasswordTokenResponseClient()
		accessTokenResponseClient.setRestOperations(restTemplate())

		return accessTokenResponseClient
	}

	@Bean
	fun jwtBearerAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<JwtBearerGrantRequest> {
		val accessTokenResponseClient = DefaultJwtBearerTokenResponseClient()
		accessTokenResponseClient.setRestOperations(restTemplate())

		return accessTokenResponseClient
	}

	@Bean
	fun tokenExchangeAccessTokenResponseClient(): OAuth2AccessTokenResponseClient<TokenExchangeGrantRequest> {
		val accessTokenResponseClient = DefaultTokenExchangeTokenResponseClient()
		accessTokenResponseClient.setRestOperations(restTemplate())

		return accessTokenResponseClient
	}

	@Bean
	fun restTemplate(): RestTemplate {
		// ...
	}

}

A default OAuth2AuthorizedClientManager will be published automatically by Spring Security when one is not already provided.

Prior to Spring Security 6.2, we had to ensure this customization was applied to both OAuth2 Login (if we are using this feature) and OAuth2 Client components. We had to use both the Spring Security DSL (for the authorization_code grant) and publish a bean of type OAuth2AuthorizedClientManager for other grant types. To understand what is being configured behind the scenes, here’s what the configuration might have looked like:

Customize RestOperations for OAuth2 Client (prior to 6.2)

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		DefaultAuthorizationCodeTokenResponseClient accessTokenResponseClient =
			new DefaultAuthorizationCodeTokenResponseClient();
		accessTokenResponseClient.setRestOperations(restTemplate());

		http
			// ...
			.oauth2Login((oauth2Login) -> oauth2Login
				.tokenEndpoint((tokenEndpoint) -> tokenEndpoint
					.accessTokenResponseClient(accessTokenResponseClient)
				)
			)
			.oauth2Client((oauth2Client) -> oauth2Client
				.authorizationCodeGrant((authorizationCode) -> authorizationCode
					.accessTokenResponseClient(accessTokenResponseClient)
				)
			);

		return http.build();
	}

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

		DefaultRefreshTokenTokenResponseClient refreshTokenAccessTokenResponseClient =
			new DefaultRefreshTokenTokenResponseClient();
		refreshTokenAccessTokenResponseClient.setRestOperations(restTemplate());

		DefaultClientCredentialsTokenResponseClient clientCredentialsAccessTokenResponseClient =
			new DefaultClientCredentialsTokenResponseClient();
		clientCredentialsAccessTokenResponseClient.setRestOperations(restTemplate());

		DefaultPasswordTokenResponseClient passwordAccessTokenResponseClient =
			new DefaultPasswordTokenResponseClient();
		passwordAccessTokenResponseClient.setRestOperations(restTemplate());

		DefaultJwtBearerTokenResponseClient jwtBearerAccessTokenResponseClient =
			new DefaultJwtBearerTokenResponseClient();
		jwtBearerAccessTokenResponseClient.setRestOperations(restTemplate());

		JwtBearerOAuth2AuthorizedClientProvider jwtBearerAuthorizedClientProvider =
			new JwtBearerOAuth2AuthorizedClientProvider();
		jwtBearerAuthorizedClientProvider.setAccessTokenResponseClient(jwtBearerAccessTokenResponseClient);

		DefaultTokenExchangeTokenResponseClient tokenExchangeAccessTokenResponseClient =
			new DefaultTokenExchangeTokenResponseClient();
		tokenExchangeAccessTokenResponseClient.setRestOperations(restTemplate());

		TokenExchangeOAuth2AuthorizedClientProvider tokenExchangeAuthorizedClientProvider =
			new TokenExchangeOAuth2AuthorizedClientProvider();
		tokenExchangeAuthorizedClientProvider.setAccessTokenResponseClient(tokenExchangeAccessTokenResponseClient);

		OAuth2AuthorizedClientProvider authorizedClientProvider =
			OAuth2AuthorizedClientProviderBuilder.builder()
				.authorizationCode()
				.refreshToken((refreshToken) -> refreshToken
					.accessTokenResponseClient(refreshTokenAccessTokenResponseClient)
				)
				.clientCredentials((clientCredentials) -> clientCredentials
					.accessTokenResponseClient(clientCredentialsAccessTokenResponseClient)
				)
				.password((password) -> password
					.accessTokenResponseClient(passwordAccessTokenResponseClient)
				)
				.provider(jwtBearerAuthorizedClientProvider)
				.provider(tokenExchangeAuthorizedClientProvider)
				.build();

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

		return authorizedClientManager;
	}

	@Bean
	public RestTemplate restTemplate() {
		// ...
	}

}

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class SecurityConfig {

	@Bean
	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
		val tokenResponseClient = DefaultAuthorizationCodeTokenResponseClient()
		tokenResponseClient.setRestOperations(restTemplate())

		http {
			// ...
			oauth2Login {
				tokenEndpoint {
					accessTokenResponseClient = tokenResponseClient
				}
			}
			oauth2Client {
				authorizationCodeGrant {
					accessTokenResponseClient = tokenResponseClient
				}
			}
		}

		return http.build()
	}

	@Bean
	fun authorizedClientManager(
		clientRegistrationRepository: ClientRegistrationRepository?,
		authorizedClientRepository: OAuth2AuthorizedClientRepository?
	): OAuth2AuthorizedClientManager {
		val refreshTokenAccessTokenResponseClient = DefaultRefreshTokenTokenResponseClient()
		refreshTokenAccessTokenResponseClient.setRestOperations(restTemplate())

		val clientCredentialsAccessTokenResponseClient = DefaultClientCredentialsTokenResponseClient()
		clientCredentialsAccessTokenResponseClient.setRestOperations(restTemplate())

		val passwordAccessTokenResponseClient = DefaultPasswordTokenResponseClient()
		passwordAccessTokenResponseClient.setRestOperations(restTemplate())

		val jwtBearerAccessTokenResponseClient = DefaultJwtBearerTokenResponseClient()
		jwtBearerAccessTokenResponseClient.setRestOperations(restTemplate())

		val jwtBearerAuthorizedClientProvider = JwtBearerOAuth2AuthorizedClientProvider()
		jwtBearerAuthorizedClientProvider.setAccessTokenResponseClient(jwtBearerAccessTokenResponseClient)

		val tokenExchangeAccessTokenResponseClient = DefaultTokenExchangeTokenResponseClient()
		tokenExchangeAccessTokenResponseClient.setRestOperations(restTemplate())

		val tokenExchangeAuthorizedClientProvider = TokenExchangeOAuth2AuthorizedClientProvider()
		tokenExchangeAuthorizedClientProvider.setAccessTokenResponseClient(tokenExchangeAccessTokenResponseClient)

		val authorizedClientProvider = OAuth2AuthorizedClientProviderBuilder.builder()
			.authorizationCode()
			.refreshToken { refreshToken ->
				refreshToken.accessTokenResponseClient(refreshTokenAccessTokenResponseClient)
			}
			.clientCredentials { clientCredentials ->
				clientCredentials.accessTokenResponseClient(clientCredentialsAccessTokenResponseClient)
			}
			.password { password ->
				password.accessTokenResponseClient(passwordAccessTokenResponseClient)
			}
			.provider(jwtBearerAuthorizedClientProvider)
			.provider(tokenExchangeAuthorizedClientProvider)
			.build()

		val authorizedClientManager = DefaultOAuth2AuthorizedClientManager(
			clientRegistrationRepository, authorizedClientRepository
		)
		authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider)

		return authorizedClientManager
	}

	@Bean
	fun restTemplate(): RestTemplate {
		// ...
	}

}

OAuth2

Overview

OAuth2 Resource Server

Protect Access with an OAuth2 Access Token

JWT Support

Opaque Token Support

Protect Access with a custom JWT

OAuth2 Client

Log Users In with OAuth2

Access Protected Resources

Access Protected Resources with WebClient

Access Protected Resources for the Current User

Use the Client Credentials Grant

Enable an Extension Grant Type

Customize an Existing Grant Type

Customize Token Request Parameters

Customize the RestOperations used by OAuth2 Client Components

Further Reading

Access Protected Resources with `WebClient`

Customize the `RestOperations` used by OAuth2 Client Components