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Updated ExternalIVR documentation

Browse Source 
Rewrote a large portion of the existing documentation
and added information about the TCP/IP socket interface


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@240973 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
David Ruggles
2010-01-18 17:51:09 +00:00
parent f0cc6a885a
commit cfb0ba32ee
1 changed files with 96 additions and 58 deletions
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154
doc/externalivr.txt
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@@ -8,52 +8,75 @@ communication with an external process, while simultaneous playing
audio files to the connected channel (without interruption or
blocking).
The arguments to ExternalIVR() consist of the command to execute and
any arguments to pass to it, the same as the System() application
accepts. The external command can be executed in a child process,
with its standard file handles connected to the Asterisk process as
follows:
There are two ways to use ExternalIVR(); you can execute an
application on the local system or you can establish a socket
connection to a TCP/IP socket server.
stdin (0) - DTMF and hangup events will be received on this handle
stdout (1) - Playback and hangup commands can be sent on this handle
stderr (2) - Error messages can be sent on this handle
To execute a local application use the form:
ExternalIVR(/full/path/to/applcation[(arguments)],options)
The application will also create an audio generator to play audio to
the channel, and will start playing silence. When your application
wants to send audio to the channel, it can send a command (see below)
to add a file to the generator's playlist. The generator will then
work its way through the list, playing each file in turn until it
either runs out of files to play, the channel is hung up, or a command
is received to clear the list and start with a new file. At any time,
more files can be added to the list and the generator will play them
in sequence.
The arguments are optional, however if they exist they must be
enclosed in parentheses. The external application will be executed
in a child process, with its standard file handles connected to the
Asterisk process as follows:
stdin (0) - events will be received on this handle
stdout (1) - commands can be sent on this handle
stderr (2) - messages can be sent on this handle
* Use of stderr for message communication is discouraged because
it is not supported by a socket connection.
To create a socket connection use the form:
ExternalIVR(ivr://host[:port][(arguments)],options)
The host can be a fqdn or an ip address. The port is optional, if
not specified the default of 2949 will be used. The arguments are
optional however if they exist they must be enclosed in parentheses.
TheExternalIVR application will connect to the specified socket
server and establish a bi-directional socket connection, where
events will be sent to the TCP/IP server and commands received
from it.
The specific ExternalIVR options, events and commands are detailed
below.
Upon execution, if not specifically prevented by an option, the
ExternalIVR application will answer the channel (if it's not
already answered), create an audio generator, and start playing
silence. When your application wants to send audio to the channel,
it can send a command (see below) to add a file to the generator's
playlist. The generator will then work its way through the list,
playing each file in turn until it either runs out of files to
play, the channel is hung up, or a command is received to clear
the list and start with a new file. At any time, more files can
be added to the list and the generator will play them in sequence.
While the generator is playing audio (or silence), any DTMF events
received on the channel will be sent to the child process (see
below). Note that this can happen at any time, since the generator,
the child process and the channel thread are all executing
independently. It is very important that your external application be
ready to receive events from Asterisk at all times (without blocking),
or you could cause the channel to become non-responsive.
independently. It is very important that your external application
be ready to receive events from Asterisk at all times (without
blocking), or you could cause the channel to become non-responsive.
If the child process dies, ExternalIVR() will notice this and hang up
the channel immediately (and also send a message to the log).
If the child process dies, or the remote server disconnects,
ExternalIVR() will notice this and hang up the channel
immediately (and also send a message to the log).
ExternalIVR() Options
----------------------
---------------------
n: 'n'oanswer, don't answer an otherwise unanswered channel.
i: 'i'gnore_hangup, instead of sending an 'H' event and exiting
ExternalIVR() upon channel hangup, it instead sends an 'I' event
and expects the external application to exit the process.
ExternalIVR() upon channel hangup, it instead sends an 'I'
event and expects the external application to exit the process.
d: 'd'ead, allows the operation of ExternalIVR() on channels that
have already been hung up.
have already been hung up.
DTMF (and other) events
-----------------------
Events
------
All events will be newline-terminated strings.
Events sent to the child's stdin will be in the following format:
All events are be newline-terminated strings and are sent in the
following format:
tag,timestamp[,data]
@@ -65,18 +88,20 @@ A-D: DTMF event for keys A through D
#: DTMF event for key #
H: the channel was hung up by the connected party
E: the script requested an exit
Z: the previous command was unable to be executed
Z: the previous command was unable to be executed. There may be a
data element if appropriate, see specific commands below for
details
T: the play list was interrupted (see S command below)
D: a file was dropped from the play list due to interruption (the
data element will be the dropped file name) NOTE: this tag conflicts
with the D DTMF event tag. The existence of the data element is used
to differentiate between the two cases
data element will be the dropped file name) NOTE: this tag
conflicts with the D DTMF event tag. The existence of the data
element is used to differentiate between the two cases
F: a file has finished playing (the data element will be the file
name)
name)
P: a response to the 'P' command (see below)
G: a response to the 'G' command (see below)
I: a Inform message, meant to "inform" the client that something
has occured. (see Inform Messages below)
has occurred. (see Inform Messages below)
The timestamp will be 10 digits long, and will be a decimal
representation of a standard Unix epoch-based timestamp.
@@ -84,9 +109,9 @@ representation of a standard Unix epoch-based timestamp.
Commands
--------
All commands must be newline-terminated strings.
All commands are newline-terminated strings.
The child process can send commands on stdout in the following formats:
The child process can send one of the following commands:
S,filename
A,filename
@@ -106,27 +131,29 @@ not take into account transcoding requirements, so it is possible for
the file to not be played even though it was found. If the file does
not exist it sends a Z response with the data element set to the file
requested. If the generator is not currently playing silence, then T
and D events will be sent to the child to signal the playlist
interruption and notify it of the files that will not be played.
and D events will be sent to signal the playlist interruption and
notify it of the files that will not be played.
The 'A' command checks to see if there is a playable audio file with
the specified name, and if so, adds it to the generator's
playlist. The same playability and exception rules apply as for the
'S' command.
the specified name, and if so, appends it to the generator's playlist.
The same playability and exception rules apply as for the 'S' command.
The 'E' command stops the generator and continues execution in the dialplan,
and logs the supplied message to the Asterisk log.
The 'E' command logs the supplied message to the Asterisk log, stops
the generator and terminates the ExternalIVR application, but continues
execution in the dialplan.
The 'H' command stops the generator and hangs up the channel, and logs
the supplied message to the Asterisk log.
The 'H' command logs the supplied message to the Asterisk log, stops
the generator, hangs up the channel and terminates the ExternalIVR
application.
The 'O' command allows the child to set/clear options in the
ExternalIVR() application. The supported options are:
autoclear/noautoclear:
Automatically interrupt and clear the playlist upon reception
of DTMF input.
ExternalIVR() application.
The 'T' command will answer and unanswered channel. If it fails either
The supported options are:
(no)autoclear: Automatically interrupt and clear the playlist
upon reception of DTMF input.
The 'T' command will answer an unanswered channel. If it fails either
answering the channel or starting the generator it sends a Z response
of "Z,TIMESTAMP,ANSWER_FAILED" or "Z,TIMESTAMP,GENERATOR_FAILED"
respectively.
@@ -139,12 +166,23 @@ variables are separated by commas. Response is in name=value format.
The 'P' command gets the parameters passed into ExternalIVR() minus
the options to ExternalIVR() itself:
If ExternalIVR() is executed as:
ExternalIVR(/usr/bin/foo(arg1,arg2),n)
The response to the 'P' command would be:
P,TIMESTAMP,/usr/bin/foo|arg1|arg2
If ExternalIVR() is executed as:
ExternalIVR(/usr/bin/foo(arg1,arg2),n)
The response to the 'P' command would be:
P,TIMESTAMP,/usr/bin/foo,arg1,arg2
NOTE: This is the only way for a TCP/IP server to be able to get retrieve
the arguments.
The 'L' command puts a message into the Asterisk log.
The 'L' command puts a message into the Asterisk log. NOTE: This is
prefered to using stderr and is the only way for a TCP/IP server to
log a message.
Inform Messages
---------------
The only inform message that currently exists is a HANGUP message,
in the form I,TIMESTAMP,HANGUP and is used to inform of a hangup
when the i option is specified.
Errors
------