No user-agent (getAgent) in filter preceding resource

Question

I'm trying to extract user-agent in my custom filter:

public class MyFilter extends Filter {
   @Override
   protected int beforeHandle(Request request, Response response) {
      String ua = request.getClientInfo().getAgent();
   }
}

But I always get ua null.

When the request proceeds to my Resource, I do manage to extract the user-agent using the call:

String ua = getRequest().getClientInfo().getAgent();

Questions:

1. Why does it happen?
2. How can I overcome this?

Answer 1

I just did a test of your use case with version 2.3.1 of Restlet and I can't reproduce your problem. Could you give us more hints about your context.

Here is what I used.

• pom.xml

  <project xmlns="http://maven.apache.org/POM/4.0.0" 
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
                      http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>org.restlet</groupId>
      <artifactId>restlet-user-agent</artifactId>
      <name>${project.artifactId}</name>
      <packaging>jar</packaging>
      <version>1.0.0-snapshot</version>
  
      <properties>
          <java-version>1.7</java-version>
          <restlet-version>2.3.1</restlet-version>
      </properties>
  
      <dependencies>
          <dependency>
              <groupId>org.restlet.jse</groupId>
              <artifactId>org.restlet</artifactId>
              <version>${restlet-version}</version>
          </dependency>
      </dependencies>
  
      <repositories>
          <repository>
              <id>maven-restlet</id>
              <name>Public online Restlet repository</name>
              <url>http://maven.restlet.com</url>
          </repository>
      </repositories>
  </project>
  

• Filter

  public class MyFilter extends Filter {
      public MyFilter() {
          super();
      }
  
      public MyFilter(Context context, Restlet next) {
          super(context, next);
      }
  
      public MyFilter(Context context) {
          super(context);
      }
  
      @Override
      protected int beforeHandle(Request request, Response response) {
          String ua = request.getClientInfo().getAgent();
          System.out.println("[filter] ua = " + ua);
          return Filter.CONTINUE;
      }
  }
  

• Server resource

  public class MyServerResource extends ServerResource {
      @Get
      public String test() {
          String ua = getRequest().getClientInfo().getAgent();
          System.out.println("[server resource] ua = " + ua);
          return "test";
      }
  }
  

• Application

  public class RestletApplication extends Application {
      @Override
      public Restlet createInboundRoot() {
          Router router = new Router(getContext());
  
          router.attach("/test", MyServerResource.class);
          MyFilter filter = new MyFilter(getContext(), router);
          return filter;
      }
  }
  

Here are the traces I got using Postman in Chrome:

[filter] ua = Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.130 Safari/537.36
[server resource] ua = Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.130 Safari/537.36

Hope it helps you nevertheless. Thierry