[asterisk-dev] [Code Review] CCSS Proposal to add Asterisk DEVSTATEs to generic agents to use with hints

[p_lindheimer]

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https://reviewboard.asterisk.org/r/1105/
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(Updated 2011-02-11 14:36:45.145549)


Review request for Asterisk Developers.


Changes
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Just added a notice at the bottom that I realized this patch also included a proposed bug fix for the following ticket that is not really part of this but fixes that other issue:

https://issues.asterisk.org/view.php?id=18763


Summary (updated)
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CCSS Proposal to add Asterisk DEVSTATE to generic agents to use in hints

originally submitted to: https://issues.asterisk.org/view.php?id=18788

Proposal to Add Asterisk Device State information and callbacks to the
Call Completion Supplemental Services for generic agents.

There are currently not many devices that have native support for CCSS and
even as they come available there may be other reasons why one may choose not
to take advantage of the native abilities and stick with the generic
implementation which is quite capable and could be greatly enhanced by adding
device state capabilities that a phone could subscribe to with a BLF key in
conjuction with Asterisk hints.

The advantages of this would allow a single button that could be programmed to
trigger a CCSS related feature code that can be used to both Request and
Cancel CCSS requests as well as display the current state of a CCSS Request.

By example, I may have a single button that when no lit, there is no active 
CCSS request. When I press that button, my dialplan can query the state
DEVICE_STATE() associated with that Caller to determine whether they should be
calling CallCompletionRequest() or CallCompletionCancel(). If there is
currently a pending request, then the dialplan would Cancel() it. This also has
the advantage of showing the true state of a Request() which is an
asynchronous call and even when Request() thinks it was successful, the actual
request could ultimately fail. Once lit, further feedback can now be provided
to the Caller about the current state of their Request() since it will be
updated by the CCSS State Machine as appropriate.

The DEVICE_STATE mappings should be configurable since the BLF being 
used on a give phone type may vary. The idea is to allow some level of 
customization as to the phone's behavior.

As an example, I may want my BLF key to go solid once I have requested a
callback. I may then want my led to blink (typically ringing) when either the
callback is in process which is a visual indication that the incoming call is
the desired callback, or I may want it to blink when the callee is ready buy I
am busy, giving me a visual indication that the target is available as I may
want to get off the line so that the callback can be successful.

The proposal is to send device state information back via the
ast_devstate_prov_add callback for any device (or at least generic device)
as they traverse through the state machine. We simply provide a map
between CC_STATE values and corresponding AST_DEVICE state values.

We could then generate hints against these States similar to what is possible
today with Custom Devstates or MeetMe states. By example, I may have an extension 
3000 that is currently associated with device SIP/3000. I could then create a 
feature code for that extension that may look something like:

exten => *823000,hint,ccss:sip/3000

One would then subscribe a blf button to *823000 which would point to the dialplan 
that handled my CCSS Requests/Cancels using the available DEVICE_STATE() 
information about ccss:sip/3000 to make the decsions what to do.

NOTICE: This patch happens to have a proposed bug fix patch in it as well from ticket:

https://issues.asterisk.org/view.php?id=18763

I just noticed that, not related to the proposed change, but does fix the fact that 
CallCompletionRequest() and CallCompletionCancel() fail with non-zero codes in some
circumstances.


Diffs
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  /branches/1.8/main/ccss.c 307674 

Diff: https://reviewboard.asterisk.org/r/1105/diff


Testing
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Testing that has been done so far:

Created 2 phones:
SIP/3000 and SIP/3001

Created hints and some simple dialplan for testing:

exten => *823000,hint,ccss:SIP/3000
exten => *823000,1,Noop(STATE OF HINT IS ${DEVICE_STATE(ccss:SIP/3000)}})

exten => *823001,hint,ccss:SIP/3001
exten => *823001,1,Noop(STATE OF HINT IS ${DEVICE_STATE(ccss:SIP/3001)}})

Ran through scenarios with CCSS checking the values with 'core show hints' as different states were introduced including the main ones of:

CC_ACTIVE, CC_CALLEE_READY, CC_CALLEE_BUSY, CC_RECALLING

Tested changing the defaults with a single entry in ccss.conf of:

cc_caller_busy_devstate = RINGING

and verified that the CC_CALLEE_BUSY changed from the RINGINUSE to the RINGING state when tested.

Verified general operation of CCSS was not changed from these new addtions.


Thanks,

p_lindheimer

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