[Voiceglue] Using the vxml <transfer> tag

[Rob Anderson]

After a day and a half of trying to get the <transfer> tag to work with
Voiceglue I've come up with a fix that works for me.  It requires a minor
monkey patch to the voiceglue code to get it to work.

The problem

A vxml transfer tag like this

<transfer dest='some phone number'></transfer>

just didn't work for me.  The call immediately hangs up, and Asterisk
reports that it failed to spawn an extension, so I suspect that the problem
lies with my Asterisk installation.

I was also unable to get the TRANSFER command to work in any asterisk
dialplan, which tends to reinforce the above.

After much research I concluded that the TRANSFER command is a little flaky
and hard to understand.  DIAL seemed easier to use, and always worked in my
dialplans.

However setting the following in voiceglue.conf

blind_xfer_method = dial

resulted in the error reported here:

http://www.voiceglue.org/pipermail/voiceglue/2009-December/000625.html

Note that I'm trying to transfer the call to an external phone number, which
may explain my problem.  In a dialplan, executing DIAL(SIP/my external phone
number) fails as well.  To get DIAL to call an external number I needed to
do this: DIAL(Local/some_phone_number at from-internal)

So I tried

<transfer dest="Local/some_phone_number at from-internal"></transfer>

but this failed, and Asterisk reported that we were trying to dial
"SIP/Local/some_phone_number at from-internal".  So obviously Voiceglue is
trying to massage the URL a little - commenting out the following code in
voiceglue_0.12/vocieglue/voiceglue (or if you have already installed, in
/usr/bin/voiceglue) did the trick

    ##  Generate the transfer command
    $url = $ovximsg->{"url"};
    # comment out these lines to allow Local/ to pass through unmolested
    #     if ($url =~ /^sip:/i)
    #     {
    # $url =~ s/^sip:/sip\//i;
    #     }
    #     else
    #     {
    # $url = "sip/" . $url;
    #     };
    $satc_command = {Satc::MSGTYPE => Satc::TRANSFER,
     Satc::CALLID => $callid,
     Satc::URL => $url,
     Satc::FLAG =>
     (($::Blind_transfer_method eq "dial") ? 1 : 0)};


This would clearly break things like <transfer dest='1234'></transfer> so I
guess someone better at Perl than me could match the ^local pattern and
leave it alone instead.
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