https://blog.csdn.net/fengqingyuebai19/article/details/106428034/

基本原理

1. 过滤器链

• WebSecurity#performBuild()
  FilterChainProxy filterChainProxy = new FilterChainProxy(securityFilterChains);

• securityFilterChains中的过滤器

  
  
  image.png

• SecurityContextPersistenceFilter 从session中取securityContext,没有则新建。结束时清空

• AnonymousAuthenticationFilter为一些不需要认证就能访问的资源定义一个匿名user

  public AnonymousAuthenticationFilter(String key) {
      this(key, "anonymousUser", AuthorityUtils.createAuthorityList("ROLE_ANONYMOUS"));
  }
  
  Authentication auth= SecurityContextHolder.getContext().getAuthentication();
  if (auth==null || "anonymousUser".equals(auth.getPrincipal().toString())) {
  

• CsrfFilter用于csrf校验

• UsernamePasswordAuthenticationFilter校验认证

public Authentication attemptAuthentication(HttpServletRequest 
 request, HttpServletResponse response) throws AuthenticationException {
 if (this.postOnly && !request.getMethod().equals("POST")) {
   throw new AuthenticationServiceException("Authentication method not supported: " + request.getMethod());
 } else {
   String username = this.obtainUsername(request);
   username = username != null ? username : "";
   username = username.trim();
   String password = this.obtainPassword(request);
   password = password != null ? password : "";
   UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(username, password);
   this.setDetails(request, authRequest);
   return this.getAuthenticationManager().authenticate(authRequest);
 }
}

• FilterSecurityInterceptor是Filter也是Interceptor，权限认证

  
  
  springsecurityPreAuthorize流程分析.png

PreInvocationAuthorizationAdviceVoter

微服务权限案例

HttpSessionSecurityContextRepository将session和SecurityContext绑定

getPrincipal一般放userDetails

PreAuthorize方法级权限注解表达式解析

 class AbstractSecurityExpressionHandler {

    @Override
    public final EvaluationContext createEvaluationContext(Authentication authentication, T invocation) {
        SecurityExpressionOperations root = createSecurityExpressionRoot(authentication, invocation);
        StandardEvaluationContext ctx = createEvaluationContextInternal(authentication, invocation);
        ctx.setBeanResolver(this.beanResolver);
        ctx.setRootObject(root);
        return ctx;
    }

@Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        // beanResolver 注册成applicationContext
        this.beanResolver = new BeanFactoryResolver(applicationContext);
    }
}