ce8453f57c
(closes issue #12705) Reported by: ctooley Patches: new_externalivr_argument_format-v2.diff uploaded by ctooley (license 136) new_externalivr_documentation.diff uploaded by ctooley (license 136) and a few additional fixes by me git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@117725 65c4cc65-6c06-0410-ace0-fbb531ad65f3
162 lines
6.2 KiB
Text
162 lines
6.2 KiB
Text
Asterisk External IVR Interface
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-------------------------------
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If you load app_externalivr.so in your Asterisk instance, you will
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have an ExternalIVR() application available in your dialplan. This
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application implements a simple protocol for bidirectional
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communication with an external process, while simultaneous playing
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audio files to the connected channel (without interruption or
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blocking).
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The arguments to ExternalIVR() consist of the command to execute and
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any arguments to pass to it, the same as the System() application
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accepts. The external command can be executed in a child process,
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with its standard file handles connected to the Asterisk process as
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follows:
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stdin (0) - DTMF and hangup events will be received on this handle
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stdout (1) - Playback and hangup commands can be sent on this handle
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stderr (2) - Error messages can be sent on this handle
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The external command can also be executed on another host entirely
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(specified by the ivr:// prefix), with its standard file handles
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connected to the Asterisk process as follows:
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stdin (0) - DTMF and hangup events will be received on this handle
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stdout (1) - Playback and hangup commands can be sent on this handle
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There are no error messages available when using ExternalIVR over TCP,
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use the 'L' command as a replacement for this.
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The application will also create an audio generator to play audio to
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the channel, and will start playing silence. When your application
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wants to send audio to the channel, it can send a command (see below)
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to add file(s) to the generator's playlist. The generator will then
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work its way through the list, playing each file in turn until it
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either runs out of files to play, the channel is hung up, or a command
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is received to clear the list and start with a new file. At any time,
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more files can be added to the list and the generator will play them
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in sequence.
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While the generator is playing audio (or silence), any DTMF events
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received on the channel will be sent to the child process (see
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below). Note that this can happen at any time, since the generator,
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the child process and the channel thread are all executing
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independently. It is very important that your external application be
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ready to receive events from Asterisk at all times (without blocking),
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or you could cause the channel to become non-responsive.
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If the child process dies, ExternalIVR() will notice this and hang up
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the channel immediately (and also send a message to the log).
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ExternalIVR() Options
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----------------------
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n: 'n'oanswer, don't answer an otherwise unanswered channel.
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i: 'i'gnore_hangup, instead of sending an 'H' event and exiting
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ExternalIVR() upon channel hangup, it instead sends an 'I' event
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and expects the external application to exit the process.
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d: 'd'ead, allows the operation of ExternalIVR() on channels that
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have already been hung up.
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DTMF (and other) events
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-----------------------
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All events will be newline-terminated strings.
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Events send to the child's stdin will be in the following format:
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tag,timestamp[,data]
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The tag can be one of the following characters:
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0-9: DTMF event for keys 0 through 9
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A-D: DTMF event for keys A through D
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*: DTMF event for key *
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#: DTMF event for key #
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H: the channel was hung up by the connected party
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E: the script requested an exit
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Z: the previous command was unable to be executed (file does not
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exist, etc.)
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T: the play list was interrupted (see below)
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D: a file was dropped from the play list due to interruption (the
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data element will be the dropped file name)
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F: a file has finished playing (the data element will be the file
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name)
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P: a response to the 'P' command (see below)
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G: a response to the 'G' command (see below)
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I: a Inform message, meant to "inform" the client that something
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has occured. (see Inform Messages below)
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The timestamp will be 10 digits long, and will be a decimal
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representation of a standard Unix epoch-based timestamp.
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Commands
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--------
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All commands must be newline-terminated strings.
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The child process can send commands on stdout in the following formats:
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S,filename
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A,filename
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H,message
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E,message
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O,option
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V,name=value[,name=value[,name=value]]
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G,name[,name[,name]]
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L,log_message
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P,TIMESTAMP
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T,TIMESTAMP
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The 'S' command checks to see if there is a playable audio file with
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the specified name, and if so, clear's the generator's playlist and
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places the file onto the list. Note that the playability check does
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not take into account transcoding requirements, so it is possible for
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the file to not be played even though it was found. If the file cannot
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be found, a 'Z' event (see above) will be sent to the child. If the
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generator is not currently playing silence, then T and D events will
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be sent to the child to signal the playlist interruption and notify
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it of the files that will not be played.
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The 'A' command checks to see if there is a playable audio file with
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the specified name, and if so, adds it to the generator's
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playlist. The same playability and exception rules apply as for the
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'S' command.
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The 'E' command stops the generator and continues execution in the dialplan,
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and logs the supplied message to the Asterisk log.
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The 'H' command stops the generator and hangs up the channel, and logs
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the supplied message to the Asterisk log.
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The 'O' command allows the child to set/clear options in the
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ExternalIVR() application. The supported options are:
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autoclear/noautoclear:
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Automatically interrupt and clear the playlist upon reception
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of DTMF input.
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The 'T' command will answer and unanswered channel. If it fails either
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answering the channel or starting the generator it sends a Z response
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of "Z,TIMESTAMP,ANSWER_FAILED" or "Z,TIMESTAMP,GENERATOR_FAILED"
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respectively.
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The 'V' command sets the specified channel variable(s) to the specified
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value(s).
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The 'G' command gets the specified channel variable(s). Multiple
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variables are separated by commas. Response is in name=value format.
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The 'P' command gets the parameters passed into ExternalIVR() minus
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the options to ExternalIVR() itself:
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If ExternalIVR() is executed as:
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ExternalIVR(/usr/bin/foo(arg1,arg2),n)
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The response to the 'P' command would be:
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P,TIMESTAMP,/usr/bin/foo|arg1|arg2
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The 'L' command puts a message into the Asterisk log.
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Errors
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------
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Any newline-terminated output generated by the child process on its
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stderr handle will be copied into the Asterisk log.
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