minte9
LearnRemember   SPRING





Architecture

Spring Security is a framework that handles: - Authentication (who you are?) - Authorization (what can you access?) - Protection against common attacks (CSRF, session fixation, etc) It integrates seamlessly with the Spring ecosystem. It works mainly through a chain of filters that intercept HTTP requests. 
 
//Simplified flow:

Client Request
    ↓
Security Filter Chain
    ↓
Authentication Filter
    ↓
Authentication Manager
    ↓
UserDetailsService (loads user)
    ↓
Security Context (stores authenticated user)
    ↓
Controller (if authorized)

Security Filter Chain

Every request passes through multiple filters. It's like a pipeline, if something fails, the request is blocked. 
 
// Example filters:

UsernamePasswordAuthenticationFilter
BasicAuthenticationFilter
CsrfFilter
ExceptionTranslationFilter

Security Context

It stores current user, roles/authorities, authentication status. It's how spring knows who is making the request. 
 
// After successful authentication:

SecurityContextHolder.getContext().getAuthentication();