Grails 3 Interceptor and render custom JSON view

Question

I am trying to write a Grails 3 interceptor that should check if certain variables are present in the HTTP Headers. If they are not present i would like to render a specific json view but it seems that the render method is not availble in the before() method.

boolean before() {
   String header = request.getHeader("Authorization")

   if(!header) {
       BaseException exception = new BadRequestException("test")
       render view: "/genericErrorReponse", model: [e: exception]
       return false
   }

Is there a better way to achieve the desired result?

I am getting the following error when trying to render the JSON view.

No qualifying bean of type [org.springframework.web.servlet.ViewResolver] is defined.
No qualifying bean of type [org.springframework.web.servlet.ViewResolver] is defined: expected single matching bean but found 4: groovyMarkupViewResolver,jsonViewResolver,beanNameViewResolver,mvcViewResolver. Stacktrace follows:
org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [org.springframework.web.servlet.ViewResolver] is defined: expected single matching bean but found 4: groovyMarkupViewResolver,jsonViewResolver,beanNameViewResolver,mvcViewResolver
at grails.artefact.Interceptor$Trait$Helper.render(Interceptor.groovy:254) ~[grails-plugin-interceptors-3.1.1.jar:3.1.1]
at device.registration.RegistrationInterceptor.before(RegistrationInterceptor.groovy:13) ~[main/:na]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_66]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) ~[na:1.8.0_66]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_66]

Interceptor Code

class RegistrationInterceptor {

    boolean before() {
        String header = request.getHeader("Authorization")

        if(!header) {
            render view: "/genericErrorResponse", model: [e: new BadRequestException()]
        }

        false
    }

    boolean after() { true }

    void afterView() {
        // no-op
    }
}

JSON View [/genericErrorResponse]

model {
    BaseException e
}

response.status e.status

json {
    message e.message
    error e.error
    status e.status
    timestamp e.timestamp
}

Answer 1

It seemed that it actually was a bug inside Grails 3. Please see https://github.com/grails/grails-core/issues/9688

Answer 2

Stacktrace shows that you are trying to get a bean of type org.springframework.web.servlet.ViewResolver at RegistrationInterceptor.groovy:13. Grails has by default 4 different implementations for ViewResolver and you have to be specific which one do you want to use.