AOP @Around: return BAD_REQUEST response

问题

In a Spring rest application, every single URL must start with an application id (appId). This appId must be validated in every single rest service. Instead of duplicating code, I tried to create an @Aspect with an @Around advice. This is correctly executed before any rest method.

However, if the application id is unknown, I do not want neither to create a stack trace or neither to return a 200 (response OK). Instead I do want to return a BAD_REQUEST response code.

If I throw an exception in my advice, I get a stack trace and no HTTP response. If I on the other hand return anything else (but do not call the pjp.proceed), I get a return code of 200.

Could anyone please assist me on returning a response code 400 to the requestor?

Below my code so far:

@Component
@Aspect
public class RequestMappingInterceptor {

    @Autowired
    ListOfValuesLookupUtil listOfValuesLookupUtil;

    @Around("@annotation(requestMapping)")
    public Object around(ProceedingJoinPoint pjp, RequestMapping requestMapping) throws Throwable {
        Object[] arguments = pjp.getArgs();
        if(arguments.length == 0 || !listOfValuesLookupUtil.isValidApplication(arguments[0].toString())) {
            // toto : return bad request here ...
            throw new BadRequestException("Application id unknown!");
        } else {
            return pjp.proceed();
        }
    }
}

回答1:

you can try returning a response entity

  if(arguments.length == 0 || !listOfValuesLookupUtil.isValidApplication(arguments[0].toString())) {
      return new ResponseEntity<>("Application id unknown!", HttpStatus.BAD_REQUEST);
  }else

回答2:

You need to access the HttpServletResponse and use that to send the error code. You can do this via the RequestContextHolder

@Around("@annotation(requestMapping)")
public Object around(ProceedingJoinPoint pjp, RequestMapping requestMapping) throws Throwable {
    Object[] arguments = pjp.getArgs();
    if(arguments.length == 0 || !listOfValuesLookupUtil.isValidApplication(arguments[0].toString())) {
        HttpServletResponse response = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getResponse());
        response.sendError(HttpStatus.PRECONDITION_FAILED.value(), "Application Id Unknown!");
        return null;
    } else {
        return pjp.proceed();
    }
}

回答3:

You could try using a OncePerRequestFilter rather than an Aspect.

Create a filter class

public class URLFilter extends OncePerRequestFilter {

  @Override
  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
  FilterChain filterChain) throws ServletException, IOException {
    if(!request.getRequestURL().toString().contains("appId") { 
      response.setStatus(401);
      return;
    }
    filterChain.doFilter(request, response);
  }

Create a Spring bean for your filter in your configuration (or use @Component)

<bean id="urlFilter" class="com.xyz.filter.URLFilter" />

Then add the filter to your web.xml

<filter>
    <filter-name>urlFilter</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>

<filter-mapping>
    <filter-name>urlFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Caveat: Not tested, and you could probably implement the filter in a cleaner way

来源：https://stackoverflow.com/questions/31075594/aop-around-return-bad-request-response

标签

Spring

aop

spring-aop

bad-request