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FIWARE / context.Orion-LD

Context Broker and CEF building block for context data management which supports both the NGSI-LD and the NGSI-v2 APIs
https://www.etsi.org/deliver/etsi_gs/CIM/001_099/009/01.06.01_60/gs_CIM009v010601p.pdf
GNU Affero General Public License v3.0
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Is there an alternative to the attribute payload for LD subscription? #1301

Open yclausen opened 1 year ago

yclausen commented 1 year ago

In V2 you could set a payload attribute under httpCustom next to the url attribute. This allowed you to create your own payload. Is there also something like this in LD? Didn't find anything in the documentation.

kzangeli commented 1 year ago

Yes, custom notifications is an NGSIv2 feature. And no, that feature is not part of NGSI-LD, sorry.

I took it up once a few years ago inn ETSI ISG CIM but I got rejected. Could try again if you find this feature especially useful ...

kzangeli commented 1 year ago

So, I remembered why this was shut down in ETSI when I took it up the last time ... It's all about "Distributed Operations". If it's just you and your broker, no forwarding, nothing, there would not be a problem (that's a little the approach of Orion/NGSIv2). NGSI-LD has a strong fopcus on distributed operations, and for that to fully work, an NGSI-LD broker needs to be able to process incoming requests. Part of this is being able to subscribe to events on other, federated brokers. However, even if the notifications arrive correctly, if the broker is unable to interpret the notification data, the federation will just not work. And this is exactly what will happen if a subscription uses "non-standard notifications", a.k.a. "Custom Notifications".

Now, I can still raise the issue with the API team (and I will), cause, we could "document it well" (as if anybody ever read the documentaion ...) and that way "protect ourselves for misuse.

It will never get very high on the ETSI ISG CIM backlog though, that I can unfortunately promise. [ If you work for a company that is an ETSI member, you can prepare the contribution yourself and that would REALLY speed up the whole thing. Still needs to be accepted, of course. If this is an option for you, I'd be happy to help ]