Can a spring boot @RestController be enabled/disabled using properties?

Question

Given a "standard" spring boot application with a @RestController, eg

@RestController
@RequestMapping(value = "foo", produces = "application/json;charset=UTF-8")
public class MyController {
    @RequestMapping(value = "bar")
    public ResponseEntity<String> bar(
        return new ResponseEntity<>("Hello world", HttpStatus.OK);
    }
}

Is there an annotation or technique that prevents the endpoint from starting at all if/unless a certain application property exists/doesn't exist.

Note: Testing a property inside the method and exploding is not a solution, because the endpoint will exist.

I don't care about the granularity: ie enabling/disabling just a method or the whole class are both fine.

---

Because a profile is not a property, control via profiles does not solve my problem.

Answer 1

I found a simple solution using @ConditionalOnExpression:

@RestController
@ConditionalOnExpression("${my.controller.enabled:false}")
@RequestMapping(value = "foo", produces = "application/json;charset=UTF-8")
public class MyController {
    @RequestMapping(value = "bar")
    public ResponseEntity<String> bar(
        return new ResponseEntity<>("Hello world", HttpStatus.OK);
    }
}

With this annotation added, unless I have

my.controller.enabled=true

in my application.properties file, the controller won't start at all.

You can also use the more convenient:

@ConditionalOnProperty("my.property")

Which behaves exactly as above; if the property is present and "true", the component starts, otherwise it doesn't.

Answer 2

Adding to this question and another question here.

This is my answer:

I would actually used the @RefreshScope Bean and then when you want to stop the Rest Controller at runtime, you only need to change the property of said controller to false.

SO's link referencing to changing property at runtime.

Here are my snippets of working code:

@RefreshScope
@RestController
class MessageRestController(
    @Value("\${message.get.enabled}") val getEnabled: Boolean,
    @Value("\${message:Hello default}") val message: String
) {
    @GetMapping("/message")
    fun get(): String {
        if (!getEnabled) {
            throw NoHandlerFoundException("GET", "/message", null)
        }
        return message
    }
}

And there are other alternatives of using Filter:

@Component
class EndpointsAvailabilityFilter @Autowired constructor(
    private val env: Environment
): OncePerRequestFilter() {
    override fun doFilterInternal(
        request: HttpServletRequest,
        response: HttpServletResponse,
        filterChain: FilterChain
    ) {
        val requestURI = request.requestURI
        val requestMethod = request.method
        val property = "${requestURI.substring(1).replace("/", ".")}." +
                "${requestMethod.toLowerCase()}.enabled"
        val enabled = env.getProperty(property, "true")
        if (!enabled.toBoolean()) {
            throw NoHandlerFoundException(requestMethod, requestURI, ServletServerHttpRequest(request).headers)
        }
        filterChain.doFilter(request, response)
    }
}

My Github explaining how to disable at runtime

Answer 3

I assume this question comes from the fact that you are using different application.properties files for your different enviroments. In this case you can use spring profiles and separate configurations into different files with profile name suffix for example:

application.properties:

spring.profiles.active=@activatedProperties@

application-local.properties:

 //some config

application-prod.properties:

//some config

then in your build paramethers you can specify which enviroment are you building by adding option:

-Dspring.profiles.active= //<-put here profile local or prod

then in your application you can enable/disable any spring bean by adding

@Profile("put here profile name")

for example:

@RestController
@Profile("local")
@RequestMapping("/testApi")
public class RestForTesting{

//do some stuff

}

now my RestForTesting will be created only if im running a build created with

-Dspring.profiles.active=local

Answer 4

In some case, the @ConditionalOnXXX cannot work, for example, depends on another bean instance to check condition. (XXXCondition class cannot invoke a bean).

In such case, register controller in Java configuration file.

See source code(Spring webmvc 5.1.6):

org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.isHandler(Class<?>)
 
       @Override
       protected boolean isHandler(Class<?> beanType) {
              return (AnnotatedElementUtils.hasAnnotation(beanType, Controller.class) ||
                           AnnotatedElementUtils.hasAnnotation(beanType, RequestMapping.class));
       }

Should add @RequestMapping annotation on type level for the controller bean. See:

@RequestMapping // Make Spring treat the bean as request handler
public class MyControllerA implements IMyController {
    @RequestMapping(path = { "/path1" })
    public .. restMethod1(...) {
  ........
    }
}

@RequestMapping // Make Spring treat the bean as request handler
public class MyControllerB implements IMyController {
    @RequestMapping(path = { "/path1" })
    public .. restMethod1(...) {
  ........
    }
}

@Configuration
public class ControllerConfiguration {

    /**
     *
     * Programmatically register Controller based on certain condition.
     *
     */
    @Bean
    public IMyController myController() {
        IMyController controller;
        if (conditionA) {
            controller = new MyControllerA();
        } else {
            controller = new MyControllerB();
        }
        return controller;
    }
}