This section builds on xref:servlet/architecture.adoc#servlet-architecture[Servlet Architecture and Implementation] by digging deeper into how xref:servlet/authorization/index.adoc#servlet-authorization[authorization] works within Servlet based applications.
The {security-api-url}org/springframework/security/web/access/intercept/FilterSecurityInterceptor.html[`FilterSecurityInterceptor`] provides xref:servlet/authorization/index.adoc#servlet-authorization[authorization] for ``HttpServletRequest``s.
It is inserted into the xref:servlet/architecture.adoc#servlet-filterchainproxy[FilterChainProxy] as one of the xref:servlet/architecture.adoc#servlet-security-filters[Security Filters].
* image:{icondir}/number_1.png[] First, the `FilterSecurityInterceptor` obtains an xref:servlet/authentication/architecture.adoc#servlet-authentication-authentication[Authentication] from the xref:servlet/authentication/architecture.adoc#servlet-authentication-securitycontextholder[SecurityContextHolder].
* image:{icondir}/number_2.png[] Second, `FilterSecurityInterceptor` creates a {security-api-url}org/springframework/security/web/FilterInvocation.html[`FilterInvocation`] from the `HttpServletRequest`, `HttpServletResponse`, and `FilterChain` that are passed into the `FilterSecurityInterceptor`.
// FIXME: link to FilterInvocation
* image:{icondir}/number_3.png[] Next, it passes the `FilterInvocation` to `SecurityMetadataSource` to get the ``ConfigAttribute``s.
* image:{icondir}/number_4.png[] Finally, it passes the `Authentication`, `FilterInvocation`, and ``ConfigAttribute``s to the xref:servlet/authorization.adoc#authz-access-decision-manager`AccessDecisionManager`.
In this case the xref:servlet/architecture.adoc#servlet-exceptiontranslationfilter[`ExceptionTranslationFilter`] handles the `AccessDeniedException`.
** image:{icondir}/number_6.png[] If access is granted, `FilterSecurityInterceptor` continues with the xref:servlet/architecture.adoc#servlet-filters-review[FilterChain] which allows the application to process normally.
== Apply FilterSecurityInterceptor to every request
By default, the `FilterSecurityInterceptor` only applies once to a request.
This means that if a request is dispatched from a request that was already filtered, the `FilterSecurityInterceptor` will back-off and not perform any authorization checks.
In some scenarios, you may want to apply the filter to every request.
You can configure Spring Security to apply the authorization rules to every request by using the `filterSecurityInterceptorOncePerRequest` method:
.Set filterSecurityInterceptorOncePerRequest to false