Transfer Shadow Variables

The normal execution of the <transfer> element will populate three shadow variables: name$.duration, name$.inputmode, and name$.utterance.
There is really only one shadow variable that comes up often in most developer code though. If you want to be able to log the length of a user's call,
(such as for billing purposes), you need only access the name$.duration shadow variable within your application:



      <transfer name="MyCall" dest="tel:+12223334444"

          bridge="true" connecttimeout="20s" maxtime="60s">

            ...

        <filled>

            ...

          <prompt>

            The length of the call was <value expr="MyCall$.duration"/> seconds.

          </prompt>

        </filled>

It is important to remember that the <transfer> shadow variables are only set if the called party hangs up, not if the caller hangs up. Getting the length of a call in that case requires
some simple ECMAScript. We just initialize beginning and ending Date() objects, and check the difference when a connection.disconnect.hangup event occurs.
Note that this will give us the time from when the transfer began, and not from when the call was answered.



    <var name="beginTimer" expr="new Date();"/>

    <var name="endTimer"/>

    <var name="callDuration"/>

	

    <catch event="connection.disconnect.hangup">

         <goto next="#timer"/>

    </catch>

	

    <form id="timer">

        <block>

            <assign name="beginTimer" expr="Number(beginTimer.getTime());"/>

            <assign name="endTimer" expr="new Date();"/>

            <assign name="endTimer" expr="Number(endTimer.getTime());"/>

            <if cond="endTimer &lt; beginTimer">

                <assign name="callDuration" expr="0"/>

            <else/>

                <assign name="callDuration" expr="endTimer - beginTimer"/>

            </if>

            <log expr="'The length of the call was ' + callDuration / 1000 + ' seconds.'"/>

        </block>

    </form>

However, if using <transfer> hotwording, (see the next subsection for details), there are a few others that we can grab.
The name$.inputmode shadow variable will relay the method, (voice or dtmf), in which the transfer was terminated. The name$.utterance variable will contain the utterance/dtmf key that was entered by the caller to terminate the conference. It is also worth noting that if the transfer was terminated by speech then the application.lastresult$ will also be populated.



    <transfer name="MyCall" dest="tel:+12223334444"

            bridge="true" connecttimeout="20s" maxtime="60s">



    <grammar type="application/x-gsl">(bye)</grammar>

    <grammar type="application/x-gsl">(dtmf-1)</grammar>

         ...

    <filled>

             <prompt>

               The length of the call was <value expr="MyCall$.duration"/>

               The input mode of the call was <value expr="MyCall$.inputmode"/>

               The utterance of the call was <value expr="MyCall$.utterance"/>

            </prompt>

    </filled>

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Post-Dialing

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| Transfer Hotwording