rollback aggregate to a given revision about node-cqrs-domain HOT 5 OPEN

Sorry for not answering in a more complete way... have not that much time right now...

The first question I had when reading quickly what you described: Aren’t you denormalizing the events? i.e. with cqrs-eventdenormalizer?

A basic example here: https://github.com/adrai/cqrs-sample

Sorry, again.

from node-cqrs-domain.

ah, no we are not using cqrs-eventdenormalizer.
Indeed, since our frontend was not able to handle async notifications (e.g. websockets as in your cqrs-sample) we did a nasty workaround, by hooking to the command callback of the domain.handle() call, manually generate our pseudo-viewmodel form the returned aggregate, store it in our read db (just another mongo collection) and return it in the response for the PATCH http request. I still feel a bit guilty when I think about this, but just say it was recorded as technical debt.

Now, thanks for the hint and I will dig into the docs of cqrs-eventdenormalizer and scratch my head how it could fit in our current setup. Of course any further help when time allows it would be more than welcome!

from node-cqrs-domain.

you don’t need any websocket or handling of events in the client...
Just fetch the denormalized data, like here: https://github.com/adrai/cqrs-sample/blob/master/host/app/routes.js

from node-cqrs-domain.

Of course, no need for that when handling queries (basically GET requests).

But when it comes to commands (PUT, PATCH, DELETE) I can see only 2 possibilities given the current limitation of our UI/UX which involves providing feedback to the user in the form of the updated resource:

• synchronous, the response of http requests for commands containing the updated info (current workaround)
• asynchronous, domain handle commands and emit events, denormalizer handle event and emit notifications, but in this case, in order to send the info to the frontend a websocket or polling needs to be in place, no?

fetcing the denormalized data in the callback of domain.handle would not ensure (and most likely not work) the updated data cos i have no clue when such async task will end

correct?

from node-cqrs-domain.

It depends... but if you want to go full sync... you could:
create a POST request (or similar) containing the command, in the route handle, pass the command to the domain (via bus or whatever), you could also use evented-command to wait for the event to emit: https://github.com/adrai/node-evented-command#send-commands and finally respond to the POST request with the received event in the payload.

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