Implementing WURFL Cloud API in java using playframework

Question

I have been trying to implement the WURFL Cloud API in my application using the play framework 1.2.4. Unfortunately, play doesn't have the HttpServletRequest and HttpServletResponse nonetheless has a Request and a Response object that can be cast to HttpServeletRequest and HttpServletResponse but when i tried this, i had a NullPointerException .... can any one please help me address this issue or better still guide me as to the implementation. I also looked at this module ( https://github.com/revbingo/play-wurfl ) but there is little information as to its implementation..

below is my code snippet

package controllers;

import play.*;
import play.mvc.*;
import play.mvc.Http.Request;
import play.mvc.Http.Response;
import play.mvc.Http.Header;
import play.server.ServletWrapper;

import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.scientiamobile.wurflcloud.CloudClientLoader;
import com.scientiamobile.wurflcloud.CloudClientManager;
import com.scientiamobile.wurflcloud.device.AbstractDevice;
import com.sun.xml.internal.ws.client.RequestContext;

import net.sourceforge.wurfl.core.Device;
import net.sourceforge.wurfl.core.WURFLHolder;
import net.sourceforge.wurfl.core.WURFLManager;

import models.*;

public class Application extends Controller {
    private static final String API_KEY = "xxxx:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";

    public static void index() throws Exception {       
        HttpServletRequest request = (HttpServletRequest) Request.current().args.get(ServletWrapper.SERVLET_REQ);       
        HttpServletResponse response = (HttpServletResponse) Request.current().args.get(ServletWrapper.SERVLET_RES);

        CloudClientLoader loader = new CloudClientLoader(API_KEY);
        CloudClientManager manager = (CloudClientManager) loader.getClientManager();

        try{
            AbstractDevice device = manager.getDeviceFromRequest(request,response);
            Object deviceCapability = device.getCapabilities();

            render(request, response, deviceCapability);
        }catch(NullPointerException ex){
            render(request, response);
        }
    }
}

Answer 1

Taking a look at the github link you posted, the way it gets the request is different: request is actually a protected field in the Controller class you are already extending.

First of all, I would try to use it instead of Request.current(), as it is suggested here: https://stackoverflow.com/a/17006963/2617826

If you still get a null reference, notice that HttpServletRequest is an interface, hence you could just write a wrapper, from Play Framework play.mvc.Http.Request . WURFL should only use HttpServletRequest.getHeader() and HttpServletRequest.getHeaderNames() methods to perform the matches. You can try to wrap the play.mvc.Http.Request like this:

import play.mvc.Http.Request;

class HttpServletRequestWrapper implements HttpServletRequest {

    private Http.Request mRequest;

    public HttpServletRequestWrapper(Http.Request request) {
        mRequest = request;
    }

    public String getHeader(String name) {
        Http.Header header = mRequest.headers.get(name);
        if (header != null) {
            return header.value();
        } else {
            return null;
        }
    }

    public Enumeration<String> getHeaderNames() {
        Vector<String> headerNames = new Vector<String>();
        for (String header : mRequest.headers.keySet()) {
            headerNames.add(header);
        }
        return headerNames.elements();
    }
}

and returning null for all others inherited methods.