Question

I need to write an interceptor/filter in my spring-jersey application, which will check every request for session and on success it will pass a code to respective controller. Passing this code is imp, because based on the code controller will decide further action.

Q:
1) Is this possible to write this kind of login filter in Spring? How?
2) Is this possible to pass some code to controller from interceptor? How?

Answer 1

We need to implement ContainerRequestFilter interface for creating Jersey filter. Following is the code sample for intercepting and modifying a request using jersey filter:

import com.sun.jersey.spi.container.ContainerRequest;
import com.sun.jersey.spi.container.ContainerRequestFilter;
import javax.ws.rs.core.MultivaluedMap;
import org.apache.log4j.Logger;

/**
 *
 * @author arnav
 */
public class MyAppFilter implements ContainerRequestFilter{


   public ContainerRequest filter(ContainerRequest request) {

      MultivaluedMap<String, String> headers = request.getRequestHeaders();

      headers.add("code", "MY_APP_CODE");
      request.setHeaders((InBoundHeaders)headers);

      return request;
   }
}

After adding this class, we need to register this filter for our web application. So now we will add following lines in our web.xml:

<servlet>
      ..........
      ..........   
      <init-param>
         <param-name>com.sun.jersey.spi.container.ContainerRequestFilters</param-name>
         <param-value>package.MyAppFilter</param-value>
      </init-param> 
</servlet>