[SR-Users] evapi:message-received and state

[Daniel-Constantin Mierla]

Probably the data received via evapi connection is in a local buffer,
but I don't recall if json parsing (as I haven't implement it) does any
caching. After all, anyhow it will be an extra copy in memory, which is
probably negligible if it is not in range of mega bytes of data.

Eventually, you can try leveraging app_jsdt with a javascript global
variable -- I haven't tested performances, but jsdt has built-in json
parser that translates to a js object which allows accessing fields in a
structure fashion. I used app_jsdt when I had to do some "heavy"
transformation of json data (e.g., update content, reorder fields, ...).
The module has no external dependency.

Cheers,
Daniel

On 07.11.22 13:31, Alex Balashov wrote:
> I was not sure if there were some static buffer size. You are right, of course, and given modern resources the concern about compute-heavy JSON parsing is probably rather academic.
>
> I require fairly extensive deserialisation into non-scalar AVP structures which are also transaction-persistent. This in effect would require two stages of marshalling. I would rather do it in one place and take the hit on compute-heavy inspection of the JSON payload twice, especially since it’s wrapped behind the convenience of libjansson.
>
> Thank you for the insights!
>
> — Alex
>
> —
> Sent from mobile, apologies for brevity and errors.
>
>> On Nov 7, 2022, at 7:01 AM, Daniel-Constantin Mierla <miconda at gmail.com> wrote:
>>
>> Hello,
>>
>> $var() uses pkg memory, so it is available pkg at that moment that sets
>> the limit of how much a $var() can store.
>>
>> If you need only specific values from json, you can store only them in
>> some variables to avoid reparsing. On the other hand, the operations are
>> in memory, so probably not big penalty.
>>
>> Cheers,
>> Daniel
>>
>>> On 07.11.22 12:29, Alex Balashov wrote:
>>> Hi Daniel, 
>>>
>>> Thank you. It’s just a pity because it’s a large JSON blob, so would have to be parsed twice (it also contains the transaction ID/label). I can change the wire format so as to not require this, probably, though. 
>>>
>>> Do you know offhand what the maximum length of the value that can be assigned to a $var is?
>>>
>>> —
>>> Sent from mobile, apologies for brevity and errors.
>>>
>>>>> On Nov 7, 2022, at 2:56 AM, Daniel-Constantin Mierla <miconda at gmail.com> wrote:
>>>> Hello,
>>>>
>>>> iirc, the continue is done by the same worker process that executes the
>>>> event route, so you can pass it via $var(...), otherwise you can
>>>> propagate it to other process via mqueue (+rtimer). Using htable with a
>>>> key based on transaction ids should be fine as well, at the end htable
>>>> is designed as a fast key/value in-memory storage.
>>>>
>>>> Cheers,
>>>> Daniel
>>>>
>>>>> On 07.11.22 05:36, Alex Balashov wrote:
>>>>> Hi,
>>>>>
>>>>> I am t_continue()ing a transaction inside of event_route[evapi:message-received]. The $evapi(msg) has quite a bit of payload that will be needed by the resumed transaction.
>>>>>
>>>>> Is there a good way to inject this data into the transaction scope externally? No [X]AVPs created in the event_route persist, of course, since the route is scoped outside of the transaction.
>>>>>
>>>>> I have been using htable to pass data into the transaction, keyed by the index and label. But, this strikes me as a kind of clumsy memory synchronisation anti-pattern. Is there a better way?
>>>>>
>>>>> Cheers,
>>>>>
>>>>> — Alex
>>>>>
>>>>> -- 
>>>>> Alex Balashov | Principal | Evariste Systems LLC
>>>>>
>>>>> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
>>>>> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
>>>>>
>>>>>
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>>>> -- 
>>>> Daniel-Constantin Mierla -- www.asipto.com
>>>> www.twitter.com/miconda -- www.linkedin.com/in/miconda
>>>>
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>> -- 
>> Daniel-Constantin Mierla -- www.asipto.com
>> www.twitter.com/miconda -- www.linkedin.com/in/miconda
>>
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-- 
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda