Voxeo Developer’s Corner

What if you wanted to share your telephony “presence” information with another application? i.e. you wanted to let the application know whether or not you were on the phone? For instance, when someone called you a message that you were “on the phone” could then be displayed in the other application…. perhaps a web page with a directory of staff - showing who’s on the phone… perhaps an instant messaging client…

Well, out at eComm 2008 in March, our CTO, RJ Auburn, demonstrated exactly that kind of integration using just CCXML and web services. In his talk he showed a quick application in CCXML that would send out your presence information on the current web 2.0 darling Twitter. Essentially, what happens is this:

• Someone calls a phone number (presumably because you gave it to them)

• Call is connected to your actual phone
• Call presence information is sent out in your Twitter stream.

For instance, if you call one of these numbers (please do so only if you actually want to talk to me, and please only from 9am-5pm Eastern US time- thanks!):

• Direct Local # (857) 362-8469

• Skype +99000936 9996075436
• SIP VoIP sip:9996075436@sip.voxeo.net

You’ll reach me (or my voicemail) and the corresponding status updates will appear in my Twitter stream (shown in reverse chronological order):

Now I don’t know that I would really personally want to send out this information in my twitter stream every time someone called me (although in all honesty I don’t talk on the phone as much as I used to), but you get the idea. Your “telephony presence” can be sent out to another application. It’s to me a very cool example of how you can easily mashup voice with web services. While Twitter is used here for this example, the code could basically be used to send this presence information to any type of service that lets you communicate using simple web services. Let’s dive in a bit further…

The eComm Slides

First, though, I should mention that this example was part of RJ’s talk at eComm 2008 and you can see it in his slide deck starting at slide 27:

| View | Upload your own

As soon as audio is available for the presentation, we’ll provide a link here to actually listen to the presentation.

The Web Service

Now to jump into the actual code, RJ was able to do this so easily largely because Twitter’s API is so incredibly simple to use, as I discussed in a previous post about Twitter. The full CCXML code is below, but here’s the key part where RJ defined the URL to use to update Twitter:

  <var name="tURL"
       expr="'http://zscgeek:password@twitter.com/statuses/

That’s it. (Note that while RJ is on Twitter as zscgeek, you can rest assured that his real password is NOT “password”!)

After creating this variable “tURL” (as in “target URL”), RJ proceeds to simply assign some text to a variable “status” and then call the target URL with that “status” variable as an argument. For example:

      <var name="status" expr="'RJ is on the phone'"/>
      <send targettype="'basichttp'" name="'update'"
            target="tURL" namelist="status"/>

Here “RJ is on the phone” is assigned to “status” and then the Twitter API is called. As shown in the code below, this same block of code is re-used with each different telephony state (and obviously with a different status message).

The Code

So here’s the code… nice and short and sweet… just enough to fit on a Keynote slide without straining eyesight (yes, it would probably fit on a PowerPoint slide, too, but remember that we’re Mac fans here). I’m not going to walk through each step of the code, but if you scan down you can see that basically the code is:

• Upon connection of the call:
  1. connecting the call to RJ’s cell phone (not his real number)
  2. sending the “RJ is on the phone” status update to Twitter
• Upon entering one of the other states (no answer, call disconnected), sending the appropriate Twitter status update.

Now if you aren’t familiar with the power of CCXML, you might want to look at our documentation and tutorial on CCXML or view one of the video tutorials on CCXML that we recently posted.

With that, here’s the code:

<?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:password@twitter.com/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$.connectionid"/>
      <createcall dest="'tel:+18315551111'"/>
    </transition>
    <transition event="connection.connected" state="calling">
      <assign name="state" expr="'connected'"/>
      <join id1="event$.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>

Feel free to use it, modify it, etc., etc. (And if you do something cool with it, please do let us know, either as a reply to this post or via email.) While this is with Twitter, we’d love to hear where else you can think of sending telephony presence info…

P.S. If you’d like to experiment with this but are not sure of how to get started, head on over to www.voxeo.com/free and either sign up for a free developer account on our Evolution portal or download our free Prophecy software to run it on your own server.

Technorati Tags:
applications, ccxml, xml, voice, voice mashups, mashups, voxeo, twitter, presence, telephony, phone mashups

Who will win the 2008 SuperBowl this weekend? The Patriots or the Giants? And by how many points will they win?

With those two questions in mind, please call now into one of these numbers using either your regular phone, Skype or a SIP phone:

• 1-617-500-5331

• Skype: +990009369996072341
• SIP: 9996072341@sip.voxeo.net

Once you have answered those two questions, check out:

http://twitter.com/superbowlguess

Ta da… you have just participated in a voice “mashup” between our services and the Twitter micro-blogging platform!

So what’s going on here? At a high level, you called into our servers where an XML document outlined a series of prompts, collected some information and then sent the result over to a Twitter account for posting. (If you aren’t familiar with Twitter, here’s a post I wrote about it.)

There’s obviously a bit more to it (see our Quick Start guide) and over the next few weeks I’m going to explain both what I did and perhaps more importantly how it can be improved! In this part 1 you are seeing a basic call flow with Text-To-Speech prompts. While TTS is fast and, as you will see, extremely easy to create, the voice does sound… well… computer-generated! (Duh!) So in the next installment in this series I’ll talk about adding recorded prompts (and how incredibly simple it is to do through our platform). Future parts to the series will cover such things as better error handling, moving the XML over into VoiceXML/CCXML, adding other content to the output to Twitter, etc.

Naturally by the time this series is done the SuperBowl will long be over and the <deleted> will of course be victorious! However, we’ll just have to come up with some other event for the final script, eh?

Now, if you are impatient and don’t want to wait, your best bet is to head on over to our excellent CallXML documentation to learn what you need to do. Of course, you should also sign up for a free developer account on our Evolution developer site where you can create all of these applications and whatever other apps you can think of related to voice.

Before I start walking through the code, let’s talk about the version of XML I am using. Here at Voxeo we support three different kinds of XML for developing voice applications (as outlined on our Choosing a Platform page): our own CallXML and then the VoiceXML and CCXML standards of the W3C. We created our CallXML first and then have been and continue to be very involved with the development of VoiceXML and CCXML. (For instance, our CTO RJ Auburn chairs the CCXML Working Group within the W3C and Dan Burnett is very active within those groups as well.) We are huge supporters of open standards and are extremely pleased to be leading the industry in terms of compliance with VoiceXML and CCXML standards. As part of this series, I’ll take you on a tour of how those specifications work.

To keep this first post simple, though, I’ve written this first mashup example in CallXML because the code is easier to understand as we walk through it. In a future part, you’ll see how this looks in VoiceXML.

But enough already, let’s dive into the code…

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