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Is Django post_save triggered before/after saving instance to database?


Is Django post_save triggered before/after saving instance to database?

By : Shubham Khandelwal
Date : November 21 2020, 12:01 PM
should help you out Although this is a completely wrong approach(*), the problem is probably in database transactions. Current thread saves the article but within this uncommited transaction you are trying to get these data through another thread (through web server). In that case, this behaviour is fully correct. Either you need to commit before retrieving through another thread or get the HTML by another way.
(*) should be done asynchronously on the background (Celery or other more lightweight async queue app) or you can call the view directly if you want to get the HTML (depending on your view, you may have to forge the request; if too complicated, you can create a helper function that cherrypicks minimal code to render the template). If you only need to call a 3rd party API after you save something, you want to do it asynchronously. If you don't do it, the success of your "save() code" will depend on the availability of your connection or the 3rd party service and you will need to deal with transactions on place where you won't to deal with transactions ;)
code :


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post_save in django to update instance immediately

post_save in django to update instance immediately


By : clobber_
Date : March 29 2020, 07:55 AM
With these it helps When you find yourself using a post_save signal to update an object of the sender class, chances are you should be overriding the save method instead. In your case, the model definition would look like:
code :
class Test(models.Model):
    title = models.CharField('title', max_length=200)
    blah = models.CharField('blah', max_length=200)

    def save(self, force_insert=False, force_update=False):
        if not self.blah:
            self.blah = 'hello'
        super(Test, self).save(force_insert, force_update)
Django post_save signal seemingly triggered only on 2nd save or after

Django post_save signal seemingly triggered only on 2nd save or after


By : user3033855
Date : March 29 2020, 07:55 AM
hop of those help? The signal is sent when the Product instance is saved, not when the Color and Size instances are saved. Therefore, on the first try, your post_save() function's Product instance will not (yet) have the Color and Size instances, as they are not saved through the Product model's save() method.
Check out these two links:
Django post_save get attribute of instance

Django post_save get attribute of instance


By : user2774854
Date : March 29 2020, 07:55 AM
this will help kwargs.get('instance') will get you the instance of the sender object.
Once we have the instance object, we could perform dot notation lookups on the instance to get attributes.
code :
kwargs.get('instance').yourattribute
@receiver(post_save, sender=Subscription)
def create_product_subscription(sender, instance, created, **kwargs):
    subscription = Category.objects.get(name="Subscription")
    if created:
        Product.objects.get_or_create(name=instance, 
        slug=slugify(instance), 
        price=44.98, 
        quantity='3000', 
        publish_date=instance.start_date, //this is where I'd like to pass an attribute of the instance
        categories=subscription)
How to get inline model in post_save instance (Django Signals)?

How to get inline model in post_save instance (Django Signals)?


By : Req Timeout
Date : March 29 2020, 07:55 AM
Does that help So, the best practice is not to use Django Signals at all. Especially when there are built-in methods, such as ModelAdmin.response_add, and leave from the model to admin.py:
code :
# ./app/utils.py

def send_mail_to_admin(obj):
    hotels = obj.hotels.all().order_by('cost')

    message = 'Tour ID ' + obj.pk + '\n'
    message += 'Country: ' + obj.country_name + ' City: ' + obj.city_name + '\n'
    message += 'Hotels: \n'
    for hotel in hotels:
        message += hotel.name + ' ' + hotel.star + ' ' + hotel.cost + '\n'

    send_mail(
        'From Admin',
        message,
        'no-reply@example.com',
        ['admin@example.com'],
        fail_silently=False,
    )

# ./app/admin.py

from .utils import send_mail_to_admin


class ToursAdmin(admin.ModelAdmin):
    exclude = ('created_at',)
    list_display = ('country_name',)
    ordering = ('created_at',)
    inlines = (HotelsInline,)

    def response_add(self, request, obj, post_url_continue=None):
        send_mail_to_admin(obj)
        return super().response_add(request, obj, post_url_continue)
save user instance to another model after post_save django

save user instance to another model after post_save django


By : user3289118
Date : March 29 2020, 07:55 AM
I wish did fix the issue. I have to two models: CustomUser and Artist. ,
EDITED
code :
def create_artist(sender, instance, created, **kwargs):
    if created:
        data = {
                'name' : instance.name,
                'artist_category' : instance.artist_category,
                'bio' : instance.bio
               }
        Artist.objects.create(**data)
post_save.connect(create_artist, sender=CustomUser)
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