SuperfeedrServlet for accessing private (aka authenticated) feeds

SuperfeedrServlet.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.http.NameValuePair;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

@SuppressWarnings("serial")
public class SuperfeedrServlet extends HttpServlet {

   static URI hubbubUri;

   public static URI getHubbubUri() throws URISyntaxException {
      if (hubbubUri == null) hubbubUri = new URI("http://superfeedr.com/hubbub");

      return hubbubUri;
   }


   @Override
   protected void doGet(HttpServletRequest request,
         HttpServletResponse response) throws ServletException, IOException {
      System.out.println("superfeedr calls via GET");

      // the credentials you're using to sign into superfeedr.
      UsernamePasswordCredentials credentials; // new UsernamePasswordCredentials("USERNAME", "PASSWORD");

      // the URL superfeedr should poll every now and then. This URL should point to a servlet you're hosting, which fetches and returns a private feed / website.
      String feedUrl; // "http://tomtasche.at/gmail/feed"
      // the URL superfeedr should call when a new "notification" is ready for you.
      String yourUrl; // "http://tomtasche.at/superfeedr/"

      printRequest(request, response);

      String challenge = request.getParameter("hub.challenge");
      if (challenge != null) {
         response.getWriter().println(challenge);
         
         response.setStatus(HttpServletResponse.SC_OK);
      } else {
         try {
            subscribeToFeed(feedUrl, yourUrl, credentials);
         } catch (URISyntaxException e) {
            e.printStackTrace();

            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage());
         }
      }
   }

   @Override
   protected void doPost(HttpServletRequest request,
         HttpServletResponse response) throws ServletException, IOException {
      System.out.println("superfeedr calls via POST");

      printRequest(request, response);
      
      // parse the superfeedr notification...
   }


   private static void subscribeToFeed(String topic, String callback, UsernamePasswordCredentials credentials) throws IOException, URISyntaxException {
      DefaultHttpClient client = Http.getHttpClient();

      CredentialsProvider credentialProvider = client.getCredentialsProvider();
      AuthScope scope = new AuthScope("superfeedr.com", AuthScope.ANY_PORT);
      if (credentialProvider.getCredentials(scope) == null) {
         credentialProvider.setCredentials(scope, credentials);
      }

      List<NameValuePair> formparams = new ArrayList<NameValuePair>();
      formparams.add(new BasicNameValuePair("hub.mode", "subscribe"));
      formparams.add(new BasicNameValuePair("hub.callback", callback));
      formparams.add(new BasicNameValuePair("hub.topic", topic));
      formparams.add(new BasicNameValuePair("hub.verify", "async"));
      formparams.add(new BasicNameValuePair("superfeedr.private", "true"));

      UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams, "UTF-8");

      HttpPost post = new HttpPost(getHubbubUri());
      // comment this line out if you want to receive XML notifications.
      // P.S. XML is evil.
      post.addHeader("Accept", "application/json");
      post.setEntity(entity);

      client.execute(post);
   }

   private static void printRequest(HttpServletRequest request) throws IOException {
      System.out.println("---");

      Map<String, Object> parameters = request.getParameterMap();
      for (String s : parameters.keySet()) {
         String line = s + " => " + request.getParameter(s);

         System.out.println(line);
      }

      System.out.println("---");

      InputStreamReader reader = new InputStreamReader(request.getInputStream());
      BufferedReader bufferedReader = new BufferedReader(reader);

      StringBuilder builder = new StringBuilder();
      for (String s = bufferedReader.readLine(); s != null; s = bufferedReader.readLine()) {
         builder.append(s);
      }

      System.out.println(builder.toString());

      System.out.println("---");
   }
}

Beware, the endpoint at http://superfeedr.com/hubbub as been deprecated in favor of https://push.superfeedr.com!