[FIXED] NullPointerException: Cannot invoke ServletRequestAttributes.getRequest because the return value of RequestContextHolder.getRequestAttributes is null

Issue

I have a service, which uses a RestTemplate and for this it needs to get information from the Token.

public RoleKeycloak getRoleId(String idRole, String projectId) {

    ResponseEntity<String> response = restTemplate.postForEntity(URL, new HttpEntity<>(query, getHeaders()), String.class);
   //more operations 
}

I obtain the Headers information through a method getHeaders(), which uses a FeignClientInterceptor, which is responsible for obtaining authorization from the header.

private HttpHeaders getHeaders() {
    headers.set(ConstantsUtils.Authorization, FeignClientInterceptor.getBearerTokenHeader());
    headers.set(ConstantsUtils.Content_Type, ConstantsUtils.GraphQL);
    return headers;
}


@Component
public class FeignClientInterceptor implements RequestInterceptor {

      public static final String getBearerTokenHeader() {
          return ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest().getHeader(AUTHORIZATION_HEADER);
      }
}


    
@Test
void createRoleTest() throws ParseException, IOException {
String response = "createRoleProject";
    ResponseEntity<String> responseEntity = new ResponseEntity<String>(response, HttpStatus.ACCEPTED);
    
    given(restTemplate.postForEntity("myurl", getHeaders(), String.class))
        .willReturn(responseEntity);
    RoleKeycloak roleKeycloak = roleServiceKeycloak.createRole("admin", "idProject");
    assertNotNull(roleKeycloak);
}

I'm trying to test this method with jUnit but I can't, not even with the information on the internet. I'm trying to mock FeignClientInterceptor but I can't, always get a NullPointerException in RequestContextHolder.getRequestAttributes();

Solution

Based on your comments & question, I am suggesting below solution:

Here, I am using mock static along with MockHttpServletRequest where in test case you can create a MockHttpServletRequest & set one header. Later on, using mockStatic, you can enable stubbing for execution of RequestContextHolder.getRequestAttributes().

@Test
    void test() {
        MockHttpServletRequest request = new MockHttpServletRequest();
        request.addHeader(HttpHeaders.AUTHORIZATION, "SomeheaderValue");

        ServletRequestAttributes attributes = new ServletRequestAttributes(request);
        RequestContextHolder.setRequestAttributes(attributes);

        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        MockedStatic<RequestContextHolder> mockedStatic = mockStatic(RequestContextHolder.class);
        mockedStatic.when(() -> RequestContextHolder.getRequestAttributes()).thenReturn(requestAttributes);

        System.out.println(FeignClientInterceptor.getBearerTokenHeader()); // this will print "SomeheaderValue"
    }

You need to use below dependency to support mock static:

         <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-inline</artifactId>
            <version>3.8.0</version>
            <scope>test</scope>
        </dependency>

You can then directly call FeignClientInterceptor.getBearerTokenHeader() from getHeaders method in unit test.

Answered By - Ashish Patil
Answer Checked By - Pedro (JavaFixing Volunteer)