How does OAuth2 login work in Spring Boot (Spring Security OAuth2 Client)? स्प्रिंग बूट में OAuth2 लॉगिन कैसे काम करता है (Spring Security OAuth2 Client)?

Spring Security's OAuth2 Client support lets an application delegate authentication to an external identity provider (Google, GitHub, Okta) using the OAuth2 Authorization Code flow. Adding spring-boot-starter-oauth2-client and configuring the provider's client ID, secret, and endpoints auto-configures the redirect, token exchange, and user-info retrieval.

After a successful login, Spring Security populates an OAuth2AuthenticationToken containing the user's attributes from the provider, and applications can map these attributes to internal roles through a custom OAuth2UserService. This is distinct from acting as an OAuth2 Resource Server, which instead validates incoming bearer tokens issued by an authorization server.

spring.security.oauth2.client.registration.google.client-id=YOUR_CLIENT_ID
spring.security.oauth2.client.registration.google.client-secret=YOUR_SECRET
spring.security.oauth2.client.registration.google.scope=email,profile