Synnefo

/*

 * Copyright 2008, 2009 Electronic Business Systems Ltd.

 *

 * This file is part of GSS.

 *

 * GSS is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * GSS 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with GSS.  If not, see <http://www.gnu.org/licenses/>.

 */

package gr.ebs.gss.server;

import static gr.ebs.gss.server.configuration.GSSConfigurationFactory.getConfiguration;

import gr.ebs.gss.client.exceptions.ObjectNotFoundException;

import gr.ebs.gss.client.exceptions.RpcException;

import gr.ebs.gss.server.domain.Nonce;

import gr.ebs.gss.server.domain.User;

import gr.ebs.gss.server.ejb.ExternalAPI;

import java.io.IOException;

import java.io.PrintWriter;

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import javax.rmi.PortableRemoteObject;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

/**

 * The servlet that handles nonce creation.

 *

 * @author past

 */

public class NonceIssuer extends HttpServlet {

        /**

         * The serial version UID of the class.

         */

        private static final long serialVersionUID = 1L;

        /**

         * The request parameter name for the user.

         */

        private static final String USER_PARAM = "user";

        /**

         * The logger.

         */

        private static Log logger = LogFactory.getLog(NonceIssuer.class);

        /**

         * A helper method that retrieves a reference to the ExternalAPI bean and

         * stores it for future use.

         *

         * @return an ExternalAPI instance

         * @throws RpcException in case an error occurs

         */

        private ExternalAPI getService() throws RpcException {

                try {

                        final Context ctx = new InitialContext();

                        final Object ref = ctx.lookup(getConfiguration().getString("externalApiPath"));

                        return (ExternalAPI) PortableRemoteObject.narrow(ref, ExternalAPI.class);

                } catch (final NamingException e) {

                        logger.error("Unable to retrieve the ExternalAPI EJB", e);

                        throw new RpcException("An error occurred while contacting the naming service");

                }

        }

        @Override

        public void service(HttpServletRequest request, HttpServletResponse response) throws IOException {

                String username = request.getParameter(USER_PARAM);

                User user = null;

                Nonce nonce = null;

                if (username == null) {

                        String error = "No username supplied";

                        logger.info(error);

                        response.setContentType("text/html");

                        response.sendError(HttpServletResponse.SC_FORBIDDEN, error);

                        return;

                }

                try {

                        user = getService().findUser(username);

                        if (user == null) {

                                String error = "User was not found";

                                logger.error(error);

                                response.setContentType("text/html");

                                response.sendError(HttpServletResponse.SC_FORBIDDEN, error);

                                return;

                        }

                        nonce = getService().createNonce(user.getId());

                } catch (RpcException e) {

                        String error = "An error occurred while communicating with the service";

                        logger.error(error, e);

                        response.setContentType("text/html");

                        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, error);

                        return;

                } catch (ObjectNotFoundException e) {

                        // The user might not be found in createNonce() since there

                        // is no transaction spanning the consecutive service calls.

                        String error = "The user was not found";

                        logger.error(error, e);

                        response.setContentType("text/html");

                        response.sendError(HttpServletResponse.SC_FORBIDDEN, error);

                        return;

                }

                if (logger.isDebugEnabled())

                        logger.debug("user: "+user.getUsername()+" nonce: "+nonce.getEncodedNonce());

                response.setContentType("text/plain");

            PrintWriter out = response.getWriter();

            out.println(nonce.getEncodedNonce());

        }

}