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".

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.

Spring Boot 2.0 Sample

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

This section shows how to configure the OAuth 2.0 Login WebFlux 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.

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.

The default redirect URI template is {baseUrl}/login/oauth2/code/{registrationId}. The registrationId is a unique identifier for the ClientRegistration. For our example, the registrationId is google.
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 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 2.0 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.

Using OpenID Provider Configuration

For well known providers, Spring Security provides the necessary defaults for the OAuth Authorization Provider’s configuration. If you are working with your own Authorization Provider that supports OpenID Provider Configuration or Authorization Server Metadata, the OpenID Provider Configuration Response's issuer-uri can be used to configure the application.

spring:
  security:
    oauth2:
      client:
        provider:
          keycloak:
            issuer-uri: https://idp.example.com/auth/realms/demo
        registration:
          keycloak:
            client-id: spring-security
            client-secret: 6cea952f-10d0-4d00-ac79-cc865820dc2c
Spring Security will query the endpoints one at a time, stopping at the first that gives a 200 response.

The client-id and client-secret are linked to the provider because keycloak is used for both the provider and the registration.

Explicit OAuth2 Login Configuration

A minimal OAuth2 Login configuration is shown below:

Example 2. Minimal OAuth2 Login
Java
@Bean
ReactiveClientRegistrationRepository clientRegistrations() {
	ClientRegistration clientRegistration = ClientRegistrations
			.fromIssuerLocation("https://idp.example.com/auth/realms/demo")
			.clientId("spring-security")
			.clientSecret("6cea952f-10d0-4d00-ac79-cc865820dc2c")
			.build();
	return new InMemoryReactiveClientRegistrationRepository(clientRegistration);
}

@Bean
SecurityWebFilterChain springSecurityFilterChain(ServerHttpSecurity http) {
	http
		// ...
		.oauth2Login(withDefaults());
	return http.build();
}
Kotlin
@Bean
fun clientRegistrations(): ReactiveClientRegistrationRepository {
    val clientRegistration: ClientRegistration = ClientRegistrations
            .fromIssuerLocation("https://idp.example.com/auth/realms/demo")
            .clientId("spring-security")
            .clientSecret("6cea952f-10d0-4d00-ac79-cc865820dc2c")
            .build()
    return InMemoryReactiveClientRegistrationRepository(clientRegistration)
}

@Bean
fun webFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
    return http {
        oauth2Login { }
    }
}

Additional configuration options can be seen below:

Example 3. Advanced OAuth2 Login
Java
@Bean
SecurityWebFilterChain springSecurityFilterChain(ServerHttpSecurity http) {
	http
		// ...
		.oauth2Login(oauth2 -> oauth2
			.authenticationConverter(converter)
			.authenticationManager(manager)
			.authorizedClientRepository(authorizedClients)
			.clientRegistrationRepository(clientRegistrations)
		);
	return http.build();
}
Kotlin
@Bean
fun webFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
    return http {
        oauth2Login {
            authenticationConverter = converter
            authenticationManager = manager
            authorizedClientRepository = authorizedClients
            clientRegistrationRepository = clientRegistration
        }
    }
}

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

Example 4. GrantedAuthoritiesMapper Bean
Java
@Bean
public GrantedAuthoritiesMapper userAuthoritiesMapper() {
    ...
}

@Bean
SecurityWebFilterChain springSecurityFilterChain(ServerHttpSecurity http) {
	http
		// ...
		.oauth2Login(withDefaults());
	return http.build();
}
Kotlin
@Bean
fun userAuthoritiesMapper(): GrantedAuthoritiesMapper {
   // ...
}

@Bean
fun webFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
    return http {
        oauth2Login { }
    }
}