DistributableCallForwardingB2BUASipServlet.java

/*
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.mobicents.servlet.sip.example;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.sip.B2buaHelper;
import javax.servlet.sip.SipFactory;
import javax.servlet.sip.SipServlet;
import javax.servlet.sip.SipServletRequest;
import javax.servlet.sip.SipServletResponse;
import javax.servlet.sip.SipSession;
import javax.servlet.sip.SipURI;

import org.apache.log4j.Logger;

/**
 * This Sip Servlet shows how a B2BUA can be used to forward a request on another call leg.
 * Based on the from address if it is in its forwarding list it forwards the INVITE to
 * the corresponding hard coded location.  
 * @author Jean Deruelle
 *
 */
public class DistributableCallForwardingB2BUASipServlet extends SipServlet {
	private static final long serialVersionUID = 1L;
	private static Logger logger = Logger.getLogger(DistributableCallForwardingB2BUASipServlet.class);
	B2buaHelper helper = null;
	private static final String RECEIVED = "Received";
	Map<String, String[]> forwardingUris = null;
	
	/** Creates a new instance of CallForwardingB2BUASipServlet */
	public DistributableCallForwardingB2BUASipServlet() {
	}

	@Override
	public void init(ServletConfig servletConfig) throws ServletException {
		logger.info("the call forwarding B2BUA sip servlet has been started");
		super.init(servletConfig);
		forwardingUris = new HashMap<String, String[]>();
		forwardingUris.put("sip:receiver@sip-servlets.com", 
				new String[]{"sip:forward-receiver@sip-servlets.com", "sip:forward-receiver@127.0.0.1:5090"});
		forwardingUris.put("sip:receiver@127.0.0.1", 
				new String[]{"sip:forward-receiver@sip-servlets.com", "sip:forward-receiver@127.0.0.1:5090"});
		forwardingUris.put("sip:receiver@127.0.0.1:5080", 
				new String[]{"sip:forward-receiver@sip-servlets.com", "sip:forward-receiver@127.0.0.1:5090"});
	}
	
	@Override
	protected void doAck(SipServletRequest request) throws ServletException,
			IOException {		
		logger.info("Got : " + request.toString());
	}

	@Override
	protected void doInvite(SipServletRequest request) throws ServletException,
			IOException {

		logger.info("Got INVITE: " + request.toString());
		logger.info(request.getFrom().getURI().toString());
		String[] forwardingUri = forwardingUris.get(request.getTo().getURI().toString());
		if(forwardingUri != null && forwardingUri.length > 0) {
			helper = request.getB2buaHelper();						
			request.getSession().setAttribute("INVITE", RECEIVED);
			request.getApplicationSession().setAttribute("INVITE", RECEIVED);			
			
			SipFactory sipFactory = (SipFactory) getServletContext().getAttribute(
					SIP_FACTORY);
			
			Map<String, List<String>> headers=new HashMap<String, List<String>>();
			List<String> toHeaderSet = new ArrayList<String>();
			toHeaderSet.add(forwardingUri[0]);
			headers.put("To", toHeaderSet);
			
			SipServletRequest forkedRequest = helper.createRequest(request, true,
					headers);
			SipURI sipUri = (SipURI) sipFactory.createURI(forwardingUri[1]);		
			forkedRequest.setRequestURI(sipUri);						
			
			logger.info("forkedRequest = " + forkedRequest);
			forkedRequest.getSession().setAttribute("originalRequest", request);
			forkedRequest.getSession().setAttribute("INVITE", RECEIVED);
			
			forkedRequest.send();
		} else {
			logger.info("INVITE has not been forwarded.");
		}
	}	
	
	@Override
	protected void doBye(SipServletRequest request) throws ServletException,
			IOException {
		logger.info("Got BYE: " + request.toString());
		//we forward the BYE
		B2buaHelper byeHelper = request.getB2buaHelper();
		SipSession linkedSipSession = byeHelper.getLinkedSession(request.getSession());
		String linkedSipSessionInviteAttribute  = (String) linkedSipSession.getAttribute("INVITE");
		String sipSessionInviteAttribute  = (String) request.getSession().getAttribute("INVITE");
		String sipApplicationSessionInviteAttribute  = (String) request.getApplicationSession().getAttribute("INVITE");		
		if(logger.isInfoEnabled()) {			
			logger.info("Distributable Simple Servlet: attributes previously set in linked sip session INVITE : "+ linkedSipSessionInviteAttribute);
			logger.info("Distributable Simple Servlet: attributes previously set in sip session INVITE : "+ sipSessionInviteAttribute);
			logger.info("Distributable Simple Servlet: attributes previously set in sip application session INVITE : "+ sipApplicationSessionInviteAttribute);
		}
		
		//we send the OK directly to the first call leg if the attributes have been correctly replicated
		if(sipSessionInviteAttribute == null  || sipApplicationSessionInviteAttribute == null || linkedSipSessionInviteAttribute == null
				|| !RECEIVED.equalsIgnoreCase(sipSessionInviteAttribute)
				|| !RECEIVED.equalsIgnoreCase(linkedSipSessionInviteAttribute) 
				|| !RECEIVED.equalsIgnoreCase(sipApplicationSessionInviteAttribute)) {
			SipServletResponse sipServletResponse = request.createResponse(SipServletResponse.SC_SERVER_INTERNAL_ERROR);
			sipServletResponse.send();
			return;
		}
		SipServletResponse sipServletResponse = request.createResponse(SipServletResponse.SC_OK);
		sipServletResponse.send();
		
		SipSession session = request.getSession();		
		SipSession linkedSession = byeHelper.getLinkedSession(session);		
		SipServletRequest forkedRequest = linkedSession.createRequest("BYE");			
		logger.info("forkedRequest = " + forkedRequest);			
		forkedRequest.send();	
		helper = byeHelper;
	}	
	
	@Override
	protected void doCancel(SipServletRequest request) throws ServletException,
			IOException {		
		logger.info("Got CANCEL: " + request.toString());		
	}
	
	@Override
	protected void doSuccessResponse(SipServletResponse sipServletResponse)
			throws ServletException, IOException {
		logger.info("Got : " + sipServletResponse.toString());
		
		SipSession originalSession =   
		    helper.getLinkedSession(sipServletResponse.getSession());
		String cSeqValue = sipServletResponse.getHeader("CSeq");
		//if this is a response to an INVITE we ack it and forward the OK 
		if(originalSession!= null && cSeqValue.indexOf("INVITE") != -1) {
			SipServletRequest ackRequest = sipServletResponse.createAck();
			logger.info("Sending " +  ackRequest);
			ackRequest.send();
			//create and sends OK for the first call leg							
			SipServletRequest originalRequest = (SipServletRequest) sipServletResponse.getSession().getAttribute("originalRequest");
			SipServletResponse responseToOriginalRequest = originalRequest.createResponse(sipServletResponse.getStatus());
			logger.info("Sending OK on 1st call leg" +  responseToOriginalRequest);
			responseToOriginalRequest.setContentLength(sipServletResponse.getContentLength());
			if(sipServletResponse.getContent() != null && sipServletResponse.getContentType() != null)
				responseToOriginalRequest.setContent(sipServletResponse.getContent(), sipServletResponse.getContentType());
			responseToOriginalRequest.send();
		}			
	}
	
	@Override
	protected void doErrorResponse(SipServletResponse sipServletResponse)
			throws ServletException, IOException {
		logger.info("Got : " + sipServletResponse.getStatus() + " "
				+ sipServletResponse.getReasonPhrase());		
						
		//create and sends the error response for the first call leg
		SipServletRequest originalRequest = (SipServletRequest) sipServletResponse.getSession().getAttribute("originalRequest");
			SipServletResponse responseToOriginalRequest = originalRequest.createResponse(sipServletResponse.getStatus());
		logger.info("Sending on the first call leg " + responseToOriginalRequest.toString());
		responseToOriginalRequest.send();		
	}
	
	@Override
	protected void doProvisionalResponse(SipServletResponse sipServletResponse)
			throws ServletException, IOException {
		SipServletRequest originalRequest = (SipServletRequest) sipServletResponse.getSession().getAttribute("originalRequest");
		SipServletResponse responseToOriginalRequest = originalRequest.createResponse(sipServletResponse.getStatus());
		logger.info("Sending on the first call leg " + responseToOriginalRequest.toString());
		responseToOriginalRequest.send();
	}
}