Spring AOP & HttpServletRequest - spring

Question

I am working on an annotation that will be sending some audit events to the other microservice.
Say, I am creating an entity and I have a method add on my Rest controller.
#PostMapping
#Audit
public ResponseEntity<EntityDTO> add(EntityDTO entity){
...
}
I have an appropriate Aspect defined, that is associated with the #Audit annotation.
But here is a trick, the nature of an audit event dictates that I need to extract some metadata from the HttpServletRequest itself.
And I do not want to modify my signature by adding (or replacing my only argument) HttpServletRequest object.
How can I pass HttpServletRequest into my aspect? Is there some elegant way?

Answer 1

Since you're using spring MVC, consider Spring MVC interceptors instead of "generic" aspects.
These are natively supported by Spring MVC and can provide access to both the handler and HttpServletRequest object
See this tutorial for using the interceptors and general configuration
See This thread for some information about the handler
final HandlerMethod handlerMethod = (HandlerMethod) handler; // this is what you'll get in the methods of the interceptor in the form of Object
final Method method = handlerMethod.getMethod();

Answer 2

Following is how it can be done with Spring AOP .
Example annotation.
#Retention(RUNTIME)
#Target({ TYPE, METHOD })
public #interface Audit {
String detail();
}
And the corresponding aspect
#Component
#Aspect
public class AuditAspect {
#Around("#annotation(audit) && within(com.package.web.controller..*)")
public Object audit(ProceedingJoinPoint pjp, Audit audit) throws Throwable {
// Get the annotation detail
String detail = audit.detail();
Object obj = null;
//Get the HttpServletRequest currently bound to the thread.
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes())
.getRequest();
try {
// audit code
System.out.println(detail);
System.out.println(request.getContextPath());
obj = pjp.proceed();
} catch (Exception e) {
// Log Exception;
}
// audit code
return obj;
}
}
NB : Op has accepted interceptor based answer. This answer is to demonstrate the Spring AOP code to achieve the requirement.
Hope this helps