VoiceXML and SIP Incoming Header Access

The specification for VoiceXML defines some protocol-independent connection-related variables that can be used to return related connection data. Blueworx Voice Response for Linux Version 7 supports such session variables for the SIP protocol. The settings for the protocol independent connection variables defined by VoiceXML are listed in Table 1:

The settings for the generic protocol specific variables defined by VoiceXML are listed in Table 2:

All SIP headers made available by Blueworx Voice Response are also available as independent VoiceXML variables (in lower case), if the header is present in the call. Headers are returned as a key where the key is the header name. To read a header value use key.value, to read an attribute use key.attribute_name. All key and attribute_names are in lower case. The header and attribute values returned have their case preserved.

In SIP, the TO_HDR contains header data. The corresponding VoiceXML variables are:

session.connection.protocol.sip.to_hdr
session.connection.protocol.sip.to_hdr.value

To check if this variable is currently available, you can use the approach in the following SIP example:

<if cond="session.connection.protocol.sip.to_hdr != undefined">
   <log>;session.connection.protocol.sip.to_hdr.value:
      <value expr="session.connection.protocol.sip.to_hdr.value"/>
   </log>
</if>

Using the SIP REQ_HDR header information in VoiceXML is more complicated because any key value pairs after the first terminator (";" or "&") on the REQ_HDR are returned as variables. For example, the following REQ_HDR:

<'REQ_HDR'='sip:1234@siphost.blueworx.com;uui=uui1;aai=aai1;
            voicexml=Weather.vxml;maxage=3600;maxstale=0'>

resolves to the following independent VoiceXML session.* variables shown in the following VoiceXML example:

<log>session.connection.protocol.sip.req_hdr.value:
     <value expr="session.connection.protocol.sip.req_hdr.value"/></log>
<log>session.connection.protocol.sip.req_hdr.aai:
     <value expr="session.connection.protocol.sip.req_hdr.aai"/></log>
<log>session.connection.protocol.sip.req_hdr.uui:
     <value expr="session.connection.protocol.sip.req_hdr.uui"/></log>
<log>session.connection.protocol.sip.req_hdr.voicexml:
     <value expr="session.connection.protocol.sip.req_hdr.voicexml"/></log>
<log>session.connection.protocol.sip.req_hdr.maxage:
     <value expr="session.connection.protocol.sip.req_hdr.maxage"/></log>
<log>session.connection.protocol.sip.req_hdr.maxstale:
     <value expr="session.connection.protocol.sip.req_hdr.maxstale"/></log>

The last key of aai in the REQ_HDR header is also mapped into the session.connection.aai session variable. If no aai keys are present, the last uui key is mapped. If no aai or uui keys are present, the session.connection.aai session variable is empty.

<http://www.code.com/my-picture.jpg>;purpose=icon
<http://www.example.com/alice/>;purpose=info
<http://www.google.com>;purpose=info;username=access;single

session.connection.protocol.sip.callinfo_hdr.value:
	<http://www.code.com/my-picture.jpg>;purpose=icon,
	<http://www.example.com/alice/>;purpose=info,
	<http://www.google.com>;purpose=info;username=access;single=
session.connection.protocol.sip.callinfo_hdr.count: 3
session.connection.protocol.sip.callinfo_hdr.info1.uri: http://www.code.com/my-picture.jpg
session.connection.protocol.sip.callinfo_hdr.info1.purpose: icon
session.connection.protocol.sip.callinfo_hdr.info2.uri: http://www.example.com/alice/
session.connection.protocol.sip.callinfo_hdr.info2.purpose: info
session.connection.protocol.sip.callinfo_hdr.info3.uri: http://www.google.com
session.connection.protocol.sip.callinfo_hdr.info3.purpose: info
session.connection.protocol.sip.callinfo_hdr.info3.username: access
session.connection.protocol.sip.callinfo_hdr.info3.single:

<if cond="session.connection.protocol.sip.header name != undefined">
   <log>session.connection.protocol.sip.header name.value:
      <value expr="session.connection.protocol.sip.header name.value"/>
   </log>
<else/>
   <log>session.connection.protocol.sip.header name.value: undefined</log>
</if>

<if cond="session.connection.protocol.sip.supported != undefined">
   <log>session.connection.protocol.sip.supported.value:
      <value expr="session.connection.protocol.sip.supported.value"/>
   </log>
<else/>
   <log>session.connection.protocol.sip.supported.value: undefined</log>
</if>

<if cond="session.connection.protocol.sip['user-to-user'] != undefined">
   <log>session.connection.protocol.sip['user-to-user'].value:
      <value expr="session.connection.protocol.sip['user-to-user'].value"/>
   </log>
<else/>
   <log>session.connection.protocol.sip['user-to-user'].value: undefined</log>
</if>

<if cond="session.connection.protocol.sip.allow != undefined">
   <log>session.connection.protocol.sip.allow.value:
      <value expr="session.connection.protocol.sip.allow.value"/></log>
<else/>
   <log>session.connection.protocol.sip.allow.value: undefined</log>
</if>