#django

djsnoops: Mmm, nope, either way you do it it does a separate join :(

.exclude(Q(foo__bars__thing='xyz') & ~Q(foo__bars__eggs='abc')) or .filter(~Q(foo__bars__thing='xyz') & Q(foo__bars__eggs='abc'))

custom sql time i think

django made me forget everything I ever knew about sql. I'm still not sure if this is a good or bad thing.

its a good thing

no, its a bad thing

:P

I have reading a lot about CQRS, DDD and other useful patterns. I was thinking how it is related to Django.

For example, I am facing a problem where I have some calls to an external service in my views.

I think it is reasonable to use Django signals but in the end I don't know if I am solving the problem or just moving it elsewhere. :)

What is your opinion?

I don’t use signals unless I have no better plan.

if I’m already in a view, I’ve got multiple better plans.

Silly question: I have an unsaved model instance.. I've already done id=somenumber to manually set the id.. but later on in the code want to change my mind and allow it to be assigned from the sequence upon insert.

alexhayes: did you try this order: filter(foo__bars_eggs=“abc”).exclude(foo__bars__thing=‘xyz')

I am trying to speed up my unit tests in 1.8. I am doing DB access, so it is building the test DB. This takes about 15 seconds to "Render Model States", then about 20 more seconds to apply migrations.. ouch

Assigning id=None doesn't work..

I think you want to filter down first, then throw some out. But I could be wrong.

oh jeebus, not again

I have tried --keepdb, but that does not seem to help. I am using sqlite as the test DB..

a_little_birdie: why are you manually setting the PK?

paste your model

tbaxter .. I have a tree structure represented in the database. Sometimes I have to save a node in the tree and find that the parents of that node do not exist yet.

no no god no

Paste your model

All ancestor nodes must be saved first/.

So, when I am iterating through stuff I don't necessarily know whether a node needs to be inserted until I've processed the whole tree. So I create a node instance to preserve the relationships.

a_little_birdie: not sure if this is relevant, but for a tree structure, you might want to look at django_mptt: https://github.com/django-mptt/django-mptt/

But I don't save them right away

Thanks I already looked at it.. we are writing our own because we have some more complex needs, eg versioning, derived values, complex data types...

paste your model

actually, paste the view, too.

tbaxter: what is your other plan

I’d just do it in the view, most likely.

I mean,, why fire off a signal for something I can just do now. it’ll be much clearer.

tbaxter: what if someones changes a field that should be updated in the thirdy party service?

tbaxter: the /admin for example.

Different problem. In that case, I’d probably write a custom save()

By design the django.contrib.auth @login_required decorator doesn't check to see if a user is_active, instead this is left to the login function to prevent an inactive user from logging in. My concern with this approach is that if a user account is deactivated, but the user has not yet been logged out then they can continue viewing pages and there is a potential of them maliciously altering data.

tbaxter: Unfortunately that still produces the same outcome, joins for the filter and subselect for the exclude

So, nobody can tell me how to tell django orm that the integer id I assigned earlier (but didn't save) isn't the one I want, that I wish to take back that assignment and make it unassigned again?

tbaxter: I am confused. The save() of a model should be only to deal with the storage, people say...

Is that a non issue? And if it is a issue what would you think the best way to solve it would be? Possibly editting the @login_required to check if the user is active or creating a middleware to check log out users that are inactive?

a_little_birdie: I’m fairly sure I can tell you. However, I’m still waiting for you to paste the model (and view)

maugzoide: who are these people?

tbaxter: lots of blogposts I am reading these days.

Seriously, though. If it’s something I need to check/do before I can safely save, I would have no problem with a custom save()

but then, I’m not a fan of signals.

I think they’re difficult to debug and make things more opaque than they need to be

tbaxter: even Martin Fowler when he talks about CQRS.

Ahh I didn't know you were asking me to paste the model.. thought that was someone else

This code is actually in a form save method.

tbaxter: You write commands and events in different files (Python) and call them when needed.

The model is dynamically generated so that's a bit complex too...

a_little_birdie: then paste the model, the view and the form

then just start with the model.

I’m not going to guess what fresh hell you have wrought

maugzoide: well, I don’t know what to tell you. I don’t know who Martin Fowler is, I’ve never heard of CQRS before today. I can only tell you what I’d do, writing real-world code for real-world developers to maintain.

Ok gimme a few minutes, thanks

If you feel more comfortable with a signal, knock yourself out. They do work.

I ended up implementing some very simple middleware that checks if a user is_active and logs them out if not. Not sure why they decided not to include this in the django.contrib.auth package by default, but seems like a pretty big security hole.

https://dpaste.de/hkgj if anyone needs it