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

Nir Simionovich nir.simionovich at gmail.com
Sat Oct 11 16:46:24 CDT 2014


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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>> _____________________________________________________________________
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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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