[asterisk-dev] Asterisk ARI improper usage pattern for channels REST API

Nir Simionovich nir.simionovich at gmail.com
Sun Oct 12 17:52:42 CDT 2014


Ok,

  I've opened an issue on JIRA (
https://issues.asterisk.org/jira/browse/ASTERISK-24412) with a small patch
submission
that will correct the issue at hand - for the originate requests at this
point.

  Basically, before moving forward, I'd like to make sure I'm not off base
with the implementation - and that I've done it right.
It's the first time I'm touching that side of the code, so I would
appreciate the assistance and feedback.

Cheers,
Nir S

On Sun, Oct 12, 2014 at 12:46 AM, Nir Simionovich <nir.simionovich at gmail.com
> wrote:

> So, here's what I thought - instead of modifying the existing JSON,
> changing from "int" to "string" in priority, I think the better
> way would be to add a new variable - "label". If defined, it will
> supersede the "priority". Judging from what I see in the code,
> the "arguments" from the JSON POST are contained in the *args buffer, so I
> should now have an args->label in there.
>
> So, if I'm not mistaken, the following should translate from the label to
> the priority:ast_find_label_extension.
>
> So, I would need to add a "label" argument to
> ari_channels_handle_originate_with_id. However, and correct me if I'm wrong,
> it would seem to me that the actual channel origination is performed using
> 'ast_pbx_outgoing_exten', and that would
> return back the 'ast_channel' structure back to *chan in
> ari_channels_handle_originate_with_id.
>
> Makes the entire thing kind'a tricky - no?
>
>
>
> On Fri, Oct 10, 2014 at 9:48 PM, Scott Griepentrog <
> sgriepentrog at digium.com> wrote:
>
>> Yes, that's the function that converts a label to a priority.  You should
>> be able to use that to enable label lookup from the rest api.
>>
>> On Fri, Oct 10, 2014 at 1:38 PM, Nir Simionovich <
>> nir.simionovich at gmail.com> wrote:
>>
>>> Well,
>>>
>>>   Can I assume you are referring to the following section in the code
>>> (pbx.c):
>>>
>>> 12371    if (sscanf(pri, "%30d", &ipri) != 1) {12372       ipri = ast_findlabel_extension <http://doxygen.asterisk.org/trunk/db/de0/pbx_8h.html#0be9518646cf9aca4878b313cc02e901>(chan, context ? context : ast_channel_context <http://doxygen.asterisk.org/trunk/d5/d7b/channel_8h.html#582dee4d5ea9b2ff6f309f0c5239f6bd>(chan),12373          exten ? exten : ast_channel_exten <http://doxygen.asterisk.org/trunk/d5/d7b/channel_8h.html#a8b52fbc8168e939bc5553502367d46a>(chan), pri,12374          S_COR <http://doxygen.asterisk.org/trunk/d6/d90/strings_8h.html#38a896048b2ca84076864505f0aa8f01>(ast_channel_caller <http://doxygen.asterisk.org/trunk/d5/d7b/channel_8h.html#c2dc872b606534943c98304aed841b34>(chan)->id.number <http://doxygen.asterisk.org/trunk/d6/d49/structnumber.html>.valid, ast_channel_caller <http://doxygen.asterisk.org/trunk/d5/d7b/channel_8h.html#c2dc872b606534943c98304aed841b34>(chan)->id.number <http://doxygen.asterisk.org/trunk/d6/d49/structnumber.html>.str, NULL <http://doxygen.asterisk.org/trunk/dc/d7f/resample_8c.html#070d2ce7b6bb7e5c05602aa8c308d0c4>));12375       if (ipri < 1) {12376          ast_log <http://doxygen.asterisk.org/trunk/d1/d8c/logger_8h.html#cb8ee436a0c80c66dfcdec6b6bcc6196>(LOG_WARNING <http://doxygen.asterisk.org/trunk/d1/d8c/logger_8h.html#df4476a6a4ea6c74231c826e899d7189>, "Priority '%s' must be a number > 0, or valid label\n", pri);12377          return -1;12378       } else12379          mode = 0;12380    }
>>>
>>>
>>>   If I read it correctly, line 12372 will translate a label to a
>>> priority number.
>>>
>>>   Am I on the right track?
>>>
>>> Nir
>>>
>>>
>>> On Thu, Oct 9, 2014 at 6:39 PM, Scott Griepentrog <
>>> sgriepentrog at digium.com> wrote:
>>>
>>>> If you want to add the label option, my first thought would be to
>>>> recommend you look at the implementation of ​app GoTo() for the api to
>>>> lookup/specify a label.  Then you would need to modify the channels.json in
>>>> rest_api/api-docs to specify the new/different parameters to the rest
>>>> methods, do a make ari-stubs to rebuild the rest handlers, and finally make
>>>> the change to the method implementation in res/ari/resource_channels.c.
>>>>
>>>> On Thu, Oct 9, 2014 at 4:56 AM, Nir Simionovich <
>>>> nir.simionovich at gmail.com> wrote:
>>>>
>>>>> "Forgive me father for I have sinned, it has been over 25 years since
>>>>> I've used GWBasic/Basica - please spare thy humble servant from doom, as I
>>>>> repent my sins and go back in time 25 years" :-)
>>>>>
>>>>> Now seriously, this may work nicely for classic dialplan, but for AEL
>>>>> that's a no go - don't even want to think about LUA at this point.
>>>>>
>>>>> Any prospects in regards to this development? I've hadn't ever dug
>>>>> into this part of the code, but, how does Asterisk keep the dialplan in
>>>>> memory? is it a simple data structure? how do labels are manifested in that
>>>>> data structure?
>>>>>
>>>>> Point me in the right direction for the information (apart from the
>>>>> code itself) - and I'll have a look at it.
>>>>>
>>>>> Nir S
>>>>>
>>>>> On Wed, Oct 8, 2014 at 9:01 PM, Scott Griepentrog <
>>>>> sgriepentrog at digium.com> wrote:
>>>>>
>>>>>> The only two ARI methods I'm seeing where a priority is used are:
>>>>>>
>>>>>> 1) Channel origination (optionally sending channel to dialplan
>>>>>> instead of into a Stasis app)
>>>>>>
>>>>>> 2) Channel continue (jump out of application into a specific point in
>>>>>> dialplan)
>>>>>>
>>>>>> And yes, you are correct in pointing out that the continue is using
>>>>>> an int rather than a long, which is clearly a consistency mistake in the
>>>>>> API.
>>>>>>
>>>>>> In both cases, the priority is given as a part of typical
>>>>>> context/extension/priority method of addressing where exactly in the
>>>>>> dialplan you want to send the channel to.  The most common scenario is to
>>>>>> have a priority 1 as the starting point.  The other numbers (using same =>
>>>>>> n) are then sequential but arbitrary, and it is generally not necessary to
>>>>>> know what they actually are to jump to them directly.
>>>>>>
>>>>>> As you point out, labels in dialplan are a convenient way of allowing
>>>>>> dialplan execution to jump or goto a specific point without needing to know
>>>>>> the actual priority number.  Unfortunately, the implementation in ARI does
>>>>>> not (currently) allow for a label to be specified.  This is a limitation
>>>>>> that should probably be fixed - possibly a topic of discussion for
>>>>>> Astridevcon.
>>>>>>
>>>>>> For a workaround, I would suggest using arbitrarily large priorities
>>>>>> to jump to the correct label where this functionality is needed.
>>>>>>
>>>>>> For example:
>>>>>>
>>>>>> exten => _x.,1,Answer()
>>>>>>    same => n,GoToIf($["${GOTTAGONOW}" = "1"]?louie)
>>>>>>    same => n,Playback(tt-monkeys)
>>>>>>    same => n,Hangup()
>>>>>>    same => n(louie),Playback(lyrics-louie-louie)
>>>>>>    same => n,Hangup()
>>>>>>
>>>>>> exten => _x.,10001,GoTo(louie)
>>>>>>
>>>>>> On Wed, Oct 8, 2014 at 8:33 AM, Nir Simionovich <
>>>>>> nir.simionovich at gmail.com> wrote:
>>>>>>
>>>>>>> Hi Guys,
>>>>>>>
>>>>>>>   While working on PHPARI, I've come to a realization that the
>>>>>>> channels REST API
>>>>>>> has a slight issue - primarily, its usage of the "priority" member
>>>>>>> in the REST API.
>>>>>>>
>>>>>>>   Currently, the specification states that "priority" is either
>>>>>>> "int" or "long" (depending
>>>>>>> on the request).
>>>>>>>
>>>>>>>   The problem with that is for someone like myself, who codes
>>>>>>> dialplan in AEL or
>>>>>>> using the "same => n," or the "exten => _X.,n," methodology - we
>>>>>>> have no visibility
>>>>>>> of priority numbers - we use labels.
>>>>>>>
>>>>>>>   I'm not that familiar with the ARI part of the Asterisk code yet,
>>>>>>> as I'm focused on how
>>>>>>> to actually work with it, but this is somewhat of a show stopper in
>>>>>>> my book, as all my
>>>>>>> existing code relies heavily on label usage.
>>>>>>>
>>>>>>>   Btw, I tried pushing a label into the REST interface, got a 500
>>>>>>> error - which means
>>>>>>> it's designed to work with numbers and not labels.
>>>>>>>
>>>>>>> Regards,
>>>>>>>   Nir S
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> _____________________________________________________________________
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>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> [image: Digium logo]
>>>>>> Scott Griepentrog
>>>>>> Digium, Inc · Software Developer
>>>>>> 445 Jan Davis Drive NW · Huntsville, AL 35806 · US
>>>>>> direct/fax: +1 256 428 6239 · mobile: +1 256 580 6090
>>>>>> Check us out at: http://digium.com · http://asterisk.org
>>>>>>
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>>>>>>
>>>>>
>>>>>
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>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> [image: Digium logo]
>>>> Scott Griepentrog
>>>> Digium, Inc · Software Developer
>>>> 445 Jan Davis Drive NW · Huntsville, AL 35806 · US
>>>> direct/fax: +1 256 428 6239 · mobile: +1 256 580 6090
>>>> Check us out at: http://digium.com · http://asterisk.org
>>>>
>>>> --
>>>> _____________________________________________________________________
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>>>>
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>>>>    http://lists.digium.com/mailman/listinfo/asterisk-dev
>>>>
>>>
>>>
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>>> _____________________________________________________________________
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>>
>>
>>
>> --
>> [image: Digium logo]
>> Scott Griepentrog
>> Digium, Inc · Software Developer
>> 445 Jan Davis Drive NW · Huntsville, AL 35806 · US
>> direct/fax: +1 256 428 6239 · mobile: +1 256 580 6090
>> Check us out at: http://digium.com · http://asterisk.org
>>
>> --
>> _____________________________________________________________________
>> -- Bandwidth and Colocation Provided by http://www.api-digital.com --
>>
>> asterisk-dev mailing list
>> To UNSUBSCRIBE or update options visit:
>>    http://lists.digium.com/mailman/listinfo/asterisk-dev
>>
>
>
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