Moving away from single-file VXML

• So far, we've been using a single file in the BeVocal Cafe for our applications
• Most times, we'll want to break up each state into a separate file
• This keeps your files more modular and makes it easier to develop your applications

Another use of the goto tag

• the goto tag doesn't have to point to another form in your document
• ...it can point to another file entirely
• Example:

<goto next="1001_choose_category.vxml"/>

Multiple Files

• I'd suggest using a single file per state
• This allows many niceties:
• 1) You can have multiple people working on different parts of the application at the same time
• 2) Debugging is easier -- your entire app doesn't break, just a single state
• 3) Its easier to manage, less code in one file is more readable
• Try to limit it to one form per file - doesn't have to necessarily be one per state

Generating your VXML

• For most of your projects, you'll have to generate your VXML based on some data
• There are many ways to do this, using any number of programming languages
• Today, we'll go over the architecture and an example using Ruby

Architecture of Generational VXML

No more .vxml files

• When generating VXML, we don't write VXML files directly
• Scripts will generate our VXML for us
• Today, we'll go over a couple examples of Ruby and its Builder library generating VXML

Hello World, from Ruby

#!/usr/bin/env ruby

require 'rubygems'
require 'cgi'
require 'builder'

cgi = CGI.new

output = ""

vxml = Builder::XmlMarkup.new(:indent=>2, :target=>output)

vxml.instruct! :xml, :version=>"1.0"
vxml.declare! :DOCTYPE, :vxml, 
	:PUBLIC, "-//BeVocal Inc//VoiceXML 2.0//EN", 
	"http://cafe.bevocal.com/libraries/dtd/vxml2-0-bevocal.dtd"
vxml.vxml(:version=>"2.0", :xmlns=>"http://www.w3.org/2001/vxml") {
  vxml.form(:id=>"form") {
    vxml.block {
      vxml.prompt("Hello world!")
    }
  }
}

cgi.out("application/xml") { 
  output
}

That produces...

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE vxml PUBLIC "-//BeVocal Inc//VoiceXML 2.0//EN" "http://cafe.bevocal.com/libraries/dtd/vxml2-0-bevocal.dtd">
<vxml version="2.0" xmlns="http://www.w3.org/2001/vxml">
  <form id="form">
    <block>
      <prompt>Hello world!</prompt>
    </block>
  </form>
</vxml>

But why do this at all?

• We can insert the returns from functions into our VXML
• Suppose we wanted to say a random phrase, from a set of predefined random phrases, to the caller
• We could write a function to give us a random phrase, and call that in the Builder code

Random Phrase

#!/usr/bin/env ruby

require 'rubygems'
require 'cgi'
require 'builder'

cgi = CGI.new

output = ""

vxml = Builder::XmlMarkup.new(:indent=>2, :target=>output)

phrases = ["Hello World", "Hello Matz!", "Hey Chris!"]

def randomPhrase(phraseSet)
  return phraseSet[rand(phraseSet.length)]
end

vxml.instruct! :xml, :version=>"1.0"
vxml.declare! :DOCTYPE, :vxml, 
	:PUBLIC, "-//BeVocal Inc//VoiceXML 2.0//EN", 
	"http://cafe.bevocal.com/libraries/dtd/vxml2-0-bevocal.dtd"
vxml.vxml(:version=>"2.0", :xmlns=>"http://www.w3.org/2001/vxml") {
  vxml.form(:id=>"form") {
    vxml.block {
      vxml.prompt(randomPhrase(phrases))
    }
  }
}

cgi.out("application/xml") { 
  output
}

URL Parameters and goto

• goto has a expr attribute
• you can use it to generate the URL to go to
• for example, goto could look like this:

<goto expr="'http://web.mit.edu/esd.951/www/apps/1001_get_callerid.cgi?callerid=' + session.telephone.ani"/>

• and in Ruby...

cgi = CGI.new
callerid = cgi['callerid']

In-class example

	<field name="myfield">
	  <prompt>Say a number</prompt>
	  <grammar>
	     Digit [1 2 3 4 5 6 7 8 9 0]
	  </grammar>
	  <filled>
	    <goto expr="'myrubyfile.cgi?numberChosen=' + myfield + '&othernum1=' + myfield + '&othernum2=' + myfield + '&othernum3=' + myfield"/>
	  </filled>
	</field>

Scraping the Internet for Prompts

• Many of you would like to use data collected from the internet in your applications
• Using Ruby (or the language of your choice), you can do this
• Imagine we had the randomPhrase method go out and get a phrase from wikipedia
• It'd act the same, still output VXML, but use some of Ruby's conveniences and libraries to do this

Architecture of Scraping Application

Screen Scraping Libraries

• There are screen scraping libraries for many languages
• Ruby has Hpricot, RubyfulSoup, and open-uri
• PHP has a built in DOMDocument, and a library called Simple HTML DOM Parser
• Python has ElementSoup and urllib
• Java has many options

Screen Scraping and You

• I will not be going over any of these libraries in class
• ...nor do I know how to use all of them
• Choose a language you're comfortable programming in and is suited to your project
• Use Google - simple queries yield powerful results and code examples
• 'ruby screen scraping example'
• 'php generate xml'
• 'python elementsoup scraping tutorial'

Some links to get you started

• Ruby Mechanize
• PHP Simple HTML DOM Parser
• PHP DOMDocument
• Python ElementSoup
• Java Scraping Resources