AuthenticatedGwtServiceUtil.java

/*!
 * This program is free software; you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
 * Foundation.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
 * or from the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * Copyright (c) 2002-2013 Pentaho Corporation..  All rights reserved.
 */

package org.pentaho.gwt.widgets.login.client;

import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
import org.pentaho.gwt.widgets.client.dialogs.IDialogCallback;
import org.pentaho.gwt.widgets.client.dialogs.MessageDialogBox;
import org.pentaho.gwt.widgets.client.messages.Messages;

/**
 * This class is a wrapper class to any GWT service which needs authentication before it performs any work The class
 * first tries to execute the service and if the service returned an Response.SC_UNAUTHORIZED error, the user is
 * presented with a login dialog. Once the login is successful it performs the service which was request originally. If
 * the error is anything different than the unauthorized error, user is presented with the error dialog
 * 
 */
public class AuthenticatedGwtServiceUtil {

  private AuthenticatedGwtServiceUtil() {

  }

  /**
   * invokeCommand method tries to execute the service and incase of SC_UNAUTHORIZED error the login dialog is presented
   * where the user can enter their credentials. Once you are successfully logged in, the requested services is
   * performed again
   * 
   * @param command
   * @param theirCallback
   */
  public static void invokeCommand( final IAuthenticatedGwtCommand command, final AsyncCallback theirCallback ) {
    command.execute( new AsyncCallback() {

      public void onFailure( final Throwable caught ) {
        // The request has failed. We need to check if the request failed due to authentication
        // We will simply to a get of an image and if it responds back with Response.SC_UNAUTHORIZED
        // We will display a login page to the user otherwise we will return the error back to the
        // user
        String[] pathArray = Window.Location.getPath().split( "/" );
        String webAppPath = "/" + pathArray[1] + "/";
        RequestBuilder builder = new RequestBuilder( RequestBuilder.GET, webAppPath + "mantle/images/spacer.gif" ); //$NON-NLS-1$
        builder.setHeader( "Content-Type", "application/xml" );
        RequestCallback callback = new RequestCallback() {

          public void onError( Request request, Throwable exception ) {
            theirCallback.onFailure( caught );
          }

          public void onResponseReceived( Request request, Response response ) {
            if ( Response.SC_UNAUTHORIZED == response.getStatusCode() ) {
              doLogin( command, theirCallback );
            } else {
              theirCallback.onFailure( caught );
            }
          }
        };

        try {
          builder.sendRequest( "", callback ); //$NON-NLS-1$ //$NON-NLS-2$
        } catch ( RequestException e ) {
          e.printStackTrace();
        }
      }

      public void onSuccess( Object result ) {
        theirCallback.onSuccess( result );
      }
    } );
  }

  /**
   * Display the login screen and and validate the credentials supplied by the user if the credentials are correct, the
   * execute method is being invoked other wise error dialog is being display. On clicking ok button on the dialog box,
   * login screen is displayed again and process is repeated until the user click cancel or user is successfully
   * authenticated
   * */
  private static void doLogin( final IAuthenticatedGwtCommand command, final AsyncCallback theirCallback ) {
    if ( LoginDialog.isHidden() ) {
      LoginDialog.performLogin( new AsyncCallback<Object>() {

        public void onFailure( Throwable caught ) {
          if ( caught instanceof AuthenticationFailedException ) {
            MessageDialogBox dialogBox =
                new MessageDialogBox(
                    Messages.getString( "error" ), Messages.getString( "invalidLogin" ), false, false, true ); //$NON-NLS-1$ //$NON-NLS-2$
            dialogBox.addStyleName( "error-login-dialog" );
            dialogBox.setCallback( new IDialogCallback() {
              public void cancelPressed() {
                // do nothing
              }

              public void okPressed() {
                doLogin( command, theirCallback );
              }

            } );
            dialogBox.center();
          } else if ( caught instanceof AuthenticationCanceledException ) {
            theirCallback.onFailure( caught );
          }
        }

        public void onSuccess( Object result ) {
          invokeCommand( command, theirCallback );
        }

      } );
    }
  }
}