#django

subleq: Even models.ON_DELETE does it in application code, from what I've just seen.

I thought there was a way to get fields to include *something* in the migration SQL, but maybe that's just the db_type.

mikeliss: Do you really want to prefetch all of those? That does a seperate query for each model type it needs to get: often a select_related will work on FK relations.

(Although, many of the names indicate they are to-many, in which case they will not work with a select_related)

If you just need an array of tags from the recap documents, for instance, you might be able to get it another way: using a Subquery sometimes works.

Where should I put my loop that listens to an RFID scanner? It would be nice if i could start an stop it from the webservice, but I can't work out how to reattach to the MultiProcess object.

Should it maybe just be it's own process?

Each request is a single instance right? Once the request has been handled, the instance is killed off. So where would I create the multiprocessing.process so that I can attach to it again?

Maybe I should write this part in C++. :/

no, usually the workers are kept around, at least for a while

But would my next request connect to it again so I can pick up the objects created?

no, also that sounds like a bad idea

I'm coming across from C++ so struggling to wrap my head around the ephemeral nature of reuquests.

http is stateless to begin with ;)

Yeh, exactly my problem.

confusion.

i'm reminded of the various IoT stacks…

sounds like you should build a daemon that you can talk to stateless as well

Yeh, I agree.

the prefered way to do background work is a task queue, but maybe you could open a socket at each request?

i don't think it would be necessary to keep these connections open, but if so, you could hack something into django that works like the connection pool for the db

gcain last I read, django uses thread locals to store shared connection objects. Something similar ought to work. If you created a django app, then in its apps.py AppConfig class, you define a `ready()` method where you could initialize it on django process start

could work, but could make testing and management commands a pain

Hello Folks how are u tonight