developing sip applications

© Voxeo Corporation

Sep 16th, 2008

TMC Communication Developer Conference

RJ [email protected]

Developing SIP Applications

mailto:[email protected]



Telephony

© Voxeo Corporation - Confidential

Sucks


Complex


Arcane


Proprietary


This is not how it should be...


Simple


Ubiquitous


Open


What to do?


Leverage The Web Model


Utilize Standards

© Voxeo Corporation - Confidential

SOAP/REST


What Does It Look Like?

© Voxeo Corporation16

Application

Platform

API XML Tools


Application

Prophecy

JSR289, REST, SOAP

CCXML&

VoiceXMLDesigner


ApplicationApplication

Platform

API XML Tools


Building Blocks


Session Initiation Protocol

- Session Initiation Protocol (SIP)defines how to establish a communication session betweentwo endpoints

- Primarily used for voice, but can for IM or virtually any other protocol

- Almost always used in client/server configuration with "SIP proxies" in control of "SIP endpoints"- Work going on in P2PSIP - see www.p2psip.org

- Text-based protocol, originally modeled on HTTP


SIP Communication

Alice Bob

RTP (voice)

INVITE

180 RINGING200 OK

ACK

BYE200 OK


Alice Bob

ProxyA

ProxyBSIP

SIP

RTP

SIP


SIP Resources

- Internet Engineering Task Force (IETF)- RFC 3261- Hitchhiker’s Guide to SIP

- Open Source Info- VoIP Info Wiki: www.voip-info.org

- Industry Sites- SIP Forum: www.sipforum.org- SIP Foundry: www.sipfoundry.org- OpenSBC: www.opensourcesip.org


Open Source SIP Software

- Systems- Asterisk: www.asterisk.org- sipXecs: www.sipfoundry.org- FreeSWITCH: www.freeswitch.org- OpenSER: www.openser.org

- SIP Stacks- reSIProcate: www.resiprocate.org

- Phones:- Gizmo: www.gizmoproject.org

- MANY, many more: www.voip-info.org


Religion


XML


CCXML

- Call Control XML (CCXML) is the W3C standard for call control using XML

- Sister standard to VoiceXML- Integrates with VoiceXML for dialog control- Provides a framework for issuing call control commands and handling call control events

- http://www.w3.org/TR/ccxml/


CCXML Hello World<?xml version="1.0" encoding="UTF-8"?><ccxml version="1.0"> <eventprocessor>

<transition event="connection.alerting"> <log expr="'***** CONNECTION ALERTING *****'"/> <if cond="event$.connection.remote == '8315551234'"> <reject/> <else/> <accept/> </if> </transition>

<transition event="connection.connected"> <log expr="'***** CALL WAS ANSWERED *****'"/> </transition>

<transition event=”connection.disconnected”> <log expr=”‘*** Call was disconnected ***’”/> <exit/> </transition>

<transition event="error.*"> <log expr="'an error has occured (' + event$.reason + ')'"/> <exit/> </transition> </eventprocessor></ccxml>


Java?


SIP Servlets

- Standard Java based API for writing SIP applications.

- 1.0 standardized as JSR-116. - 2.0 just released as JSR-289- Extends the HTTP Servlet model to support SIP and telephony applications

- http://www.sipservlet.com/- Supported by a large number of application servers including Oracle (BEA), IBM, Sun, Voxeo.

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http://www.sipservlet.org

http://www.sipservlet.org


Converged Applications


JSR-309

- Java Media Server API- Based on the CCXML media model - Still in draft stage- Provides dialog resources, conferencing, media routing to Java applications

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Example Application


Sample Application Overview

- Caller dials in to the application

- Caller is bridged to the subscriber

- Results of the call attempt are posted to Twitter via their REST API

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<?xml version="1.0" encoding="UTF-8"?><ccxml xmlns="http://www.w3.org/2002/09/ccxml" version="1.0"> <var name="state" expr="'init'"/> <var name="incomingcall"/> <var name="tURL" expr="'http://zscgeek:[email protected]/statuses/update.xml'"/> <eventprocessor statevariable="state"> <transition event="connection.alerting" state="init"> <accept/> </transition> <transition event="connection.connected" state="init"> <assign name="state" expr="'calling'"/> <assign name="incomingcall" expr="event$.connectionid"/> <createcall dest="'tel:+18312392883'"/> </transition> <transition event="connection.connected" state="calling"> <assign name="state" expr="'connected'"/> <join id1="event$.connectionid" id2="incomingcall"/> <var name="status" expr="'RJ is on the phone'"/> <send targettype="'basichttp'" name="'update'" target="tURL" namelist="status"/> </transition> <transition event="connection.failed" state="calling"> <assign name="state" expr="'done'"/> <var name="status" expr="'RJ is not answering his phone'"/> <send targettype="'basichttp'" name="'update'" target="tURL" namelist="status"/> </transition> <transition event="connection.disconnected" state="connected"> <assign name="state" expr="'done'"/> <var name="status" expr="'RJ is off the phone'"/> <send targettype="'basichttp'" name="'update'" target="tURL" namelist="status"/> </transition> <transition event="send.successful" state="done"> <exit/> </transition> </eventprocessor></ccxml>

Follow Me/Find Me + Twitter

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http://www.w3.org/2002/09/ccxml


http://zscgeek:[email protected]/statuses/update.xml'





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<?xml version="1.0" encoding="UTF-8"?><ccxml version="1.0" xmlns="http://www.w3.org/2002/09/ccxml"></ccxml>








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<var name="state" expr="'init'"/><var name="incomingcall"/><var name="tURL" expr="'http://zscgeek:[email protected]/statuses/update.xml'"/>

<eventprocessor statevariable="state"></eventprocessor>










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<transition event="connection.alerting" state="init"> <accept/></transition>








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<transition event="connection.connected" state="init"> <assign name="state" expr="'calling'"/> <assign name="incomingcall" expr="event$.connectionid"/> <createcall dest="'tel:+18312392883'"/></transition>








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<transition event="connection.connected" state="calling"> <assign name="state" expr="'connected'"/> <join id1="event$.connectionid" id2="incomingcall"/> <var name="status" expr="'RJ is on the phone'"/> <send targettype="'basichttp'" name="'update'" target="tURL" namelist="status"/></transition>








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<transition event="connection.failed" state="calling"> <assign name="state" expr="'done'"/> <var name="status" expr="'RJ is not answering his phone'"/> <send targettype="'basichttp'" name="'update'" target="tURL" namelist="status"/></transition>








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<transition event="connection.disconnected" state="connected"> <assign name="state" expr="'done'"/> <var name="status" expr="'RJ is off the phone'"/> <send targettype="'basichttp'" name="'update'" target="tURL" namelist="status"/></transition>








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<transition event="send.successful" state="done"> <exit/></transition>








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We Got Java Bean!


package com.voxeo.rj.fmdemo;

import java.io.IOException;import java.util.ArrayList;import java.util.List;import javax.servlet.ServletException;import javax.servlet.sip.*;import net.unto.twitter.Api;import net.unto.twitter.TwitterException;

public class FMServlet extends SipServlet { Api twitter_api; List<URI> targets; public void init() throws ServletException { twitter_api = new Api("zscgeek", "password"); SipFactory sipFactory = (SipFactory)getServletContext().getAttribute(SIP_FACTORY); targets = new ArrayList<URI>(); targets.add(sipFactory.createURI("sip:[email protected]")); targets.add(sipFactory.createURI("sip:[email protected]")); targets.add(sipFactory.createURI("sip:[email protected]")); }

protected void doInvite(SipServletRequest req) throws ServletException, IOException { if (req.isInitial()) { Proxy proxy = req.getProxy(); proxy.setRecordRoute(true); proxy.setParallel(true); proxy.proxyTo(targets); } }

protected void doSuccessResponse(SipServletResponse resp) throws IOException { if (resp.getMethod().equalsIgnoreCase("invite")) { try { twitter_api.updateStatus("RJ is taking a phone call from " + resp.getRequest().getRequestURI()); } catch (TwitterException e) {log("failed to update twitter",e);} } }}


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public class FMServlet extends SipServlet { public void init() throws ServletException { }

protected void doInvite(SipServletRequest req) throws ServletException, IOException { }

protected void doSuccessResponse(SipServletResponse resp) throws IOException { }}








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Api twitter_api;List<URI> targets;

public void init() throws ServletException { twitter_api = new Api("zscgeek", "password"); SipFactory sipFactory = (SipFactory)getServletContext().getAttribute(SIP_FACTORY); targets = new ArrayList<URI>(); targets.add(sipFactory.createURI("sip:[email protected]")); targets.add(sipFactory.createURI("sip:[email protected]")); targets.add(sipFactory.createURI("sip:[email protected]"));}














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protected void doInvite(SipServletRequest req) throws ServletException, IOException { if (req.isInitial()) { Proxy proxy = req.getProxy(); proxy.setRecordRoute(true); proxy.setParallel(true); proxy.proxyTo(targets); }}








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protected void doSuccessResponse(SipServletResponse resp) throws IOException { if (resp.getMethod().equalsIgnoreCase("invite")) { try { twitter_api.updateStatus("RJ is taking a phone call from " + resp.getRequest().getRequestURI()); } catch(TwitterException e){log("failed to update twitter",e);} }}








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So why is this important?


Web Developers

Phone Developers Web Developers


Web


Ideas We have Never Thought Of


Standards Matter


Example Usage


Project Green Phone

- By Mark Headd- http://www.voiceingov.org/blog/?p=135- VoiceXML, JavaScript, CCXML, PHP- Application:

- Caller dials in to app- App uses ANI/Caller ID and makes web service query to a database to determine location

- Makes another web service query to find location of nearest E85/Biodiesel stations

- Relays information to caller- Sends caller a SMS text msg with info

http://www.voiceingov.org/blog/?p=135

http://www.voiceingov.org/blog/?p=135


Rocketsource.org

- www.rocketsource.org

- Vox-Attendant- A VoiceXML-based, speech-driven auto attendant that can connect callers

with any person or group with an enterprise, via their desk, cellular, or VoIP phones.

- Vox-Mail- A VoiceXML-based, speech-driven voicemail application that can store

messages locally or integrate with any IMAP email server to provide basic unified messaging.

- Voice Conference Manager- A VoiceXML and CCXML-based, speech-driven conference manager that

features both phone and web-based conference call creation, access, and management.

- VoiceXML, CCXML, grXML, JavaScript, Java, and Python


Wrapping Up


Look at the big picture

http://flickr.com/photos/txd/100437832




More then one way to skin a cat!


Avoid the Mouse Trap


Be ready to scale


RJ [email protected]

http://www.voxeo.com/prophecyhttp://evolution.voxeo.com

http://www.voxeo.com/prophecy




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