i have models in django like this:
class Client(models.Model):
type = (choices)
class Bill(models.Model):
client = models.ForeignKey(Client)
class Detail(models.Model):
total = models.MoneyField() # i used currency package
bill = models.ForeignKey(Bill)
Detail class contains sales detail for the Bill, i already made a transaction to save bill and details at the same time in Bill.save() method but i want to pass Client.type from Bill.save() to Detail.Save(), i want something like that
def save(self, *args, **kwargs): #this is Bill save method
client = self.Client
transaction.atomic:
super(Bill, self).save(*args, **kwargs)
for detail in self.details
detail.save(client)
def save(self, *args, **kwargs): #this is Detail save method
self.pricing(client)
super(Detail, self).save(*args, **kwargs)
def pricing(self, client):
if client.type = 'value1':
self.total = self.total - (self.total*5/100)
elif client.type = 'value2':
self.total = self.total - (self.total*7/100)
else:
self.total = self.total - (self.total*10/100)
i don't know how passing arguments works on python and Django, what is the cleanest solution to solve this problem? in short i want the bill.save method to pick the client.type value and passe it through detail.save to calculate total with cases.
Thanks
You can pass the parameter in kwargs in save method try the following code to pass the client variable (detail.save(client=client)) in another save method and access this variable by using client = kwargs.get('client')
def save(self, *args, **kwargs): #this is Bill save method
client = self.Client
transaction.atomic:
super(Bill, self).save(*args, **kwargs)
for detail in self.details
detail.save(client=client)
def save(self, *args, **kwargs): #this is Detail save method
client = kwargs.get('client')
self.pricing(client)
super(Detail, self).save(*args, **kwargs)
May be this helps you..
In your case, you can simple use self property:
def save(self, *args, **kwargs): #this is Detail save method
self.pricing(self.bill.client)
# ^^^^^^^^^^^
super(Detail, self).save(*args, **kwargs)
Related
I've got a Django models:
class Item_received_log(models.Model):
name = models.CharField(max_length=250)
quantity = models.FloatField(default=1)
class Inventory (models.Model):
name = models.CharField(max_length=250)
quantity = models.FloatField(default=1)
I would like to update Inventory.quantity each time new item to Item_received_log is posted with matching name. I am not sure if it is right but I've decided to override save method of Item_received_log class so it updates Inventory list upon saving:
def save(self, *args, **kwargs):
obj, created = Inventory.objects.update_or_create(
name=self.name,
defaults = {'quantity':(quantity + self.quantity)})
super(Item_received_log, self).save(*args, **kwargs)
And in returns:
NameError at /admin/accountable_persons/item_received_log/17/change/
global name 'quantity' is not defined
How can I resolve my issue or come up with better solution?
Would have been a lot easier if we could simply throw in an F() expression into the default part of update_or_create to do all the magic, but the issue requesting this feature is still open.
You can, however, use a more verbose approach for now:
from django.db.models import F
def save(self, *args, **kwargs):
obj, created = Inventory.objects.get_or_create(name=self.name)
obj.quantity = F('quantity') + self.quantity
obj.save()
super(Item_received_log, self).save(*args, **kwargs)
I am trying to override django's default model save method like this:
def save(self, *args, **kwargs):
if not self.pk:
ct = Cart()
ct.save()
dct = Dummycart()
dct.save()
self.cart=ct
self.dummycart = dct
self.password = make_password(self.password)
super(User,self).save(self, *args, **kwargs)
but this is creating new object every time i update thid model,it's strange behaviour
You should call super like this:
super(User, self).save(*args, **kwargs)
I am trying to override the save method on a model in order to generate a unique, second auto-incrementing id.
I create my class and override the save() method, but for some reason it is erroring out with the following error:
TypeError: %d format: a number is required, not NoneType
Here's the code:
class Person(models.Model):
target = models.OneToOneField(Target)
person = models.OneToOneField(User)
gender = models.CharField(max_length=1)
gender_name = models.CharField(max_length=100)
person_id = models.CharField(max_length=100)
def save(self, *args, **kwargs):
self.person_id = "%07d" % self.id
super(Person, self).save(*args, **kwargs)
Is it because I didn't pass an id parameter and it hasn't saved yet? Is there anyway to generate a value from the id?
Safest and easiest way to achieve what you want is to use a post_save signal because it is fired right after save is called, but before the transaction is committed to the database.
from django.dispatch import receiver
from django.db.models.signals import post_save
#receiver(post_save, sender=Person)
def set_person_id(sender, instance, created, **kwargs):
if created:
instance.person_id = "%07d" % instance.id
instance.save()
Yes, self.id will be Nonein some cases, and then the assignment will fail.
However you cannot just the assignment and the call to super, as suggested in the comments, because then you wouldn't be persisting the assignment to the database layer.
You need to check whether the model has an id and then proceed differently:
def save(self, *args, **kwargs):
if not self.id: # Upon instance creation
super(Person, self).save(*args, **kwargs) # Acquire an ID
self.person_id = "%07d" % self.id # Set the person_id
return super(Person, self).save(*args, **kwargs)
This issues two save operations to the database. You will want to wrap them in a transaction to make sure your database receives these two fields simultaneously.
from django.db import IntegrityError, transaction
class Person(models.Model):
target = models.OneToOneField(Target)
person = models.OneToOneField(User)
gender = models.CharField(max_length=1)
gender_name = models.CharField(max_length=100)
person_id = models.CharField(max_length=100)
def create_person_id(self):
if not self.id: # Upon instance creation
super(Person, self).save(*args, **kwargs) # Acquire an ID
self.person_id = "%07d" % self.id
def save(self, *args, **kwargs):
try:
with transaction.atomic():
self.create_person_id
return super(Person, self).save(*args,**kwargs)
except IntegrityError:
raise # or deal with the error
I agree that signals might be the better option, if not, try using pk instead of id.
class Person(models.Model):
# [ . . . ]
def save(self, *args, **kwargs):
self.person_id = "%07d" % self.pk
super(Person, self).save(*args, **kwargs)
First the code:
class CommentForm(forms.ModelForm):
categories = forms.ModelChoiceField(queryset = Category.objects.all(), required = False)
class CommentAdmin(admin.ModelAdmin):
form = CommentForm
When I'm editing my comment I'd like it categories field have the initial value of what's been selected when I saved it for the last time. How do I do that?
def get_form(self, *args, **kwargs):
f = super(CommentAdmin, self).get_form(*args, **kwargs)
f.base_fields['categories'].initial = 1
return f
This code placed in CommentAdmin did the trick...
EDIT:
def __init__(self, *args, **kwargs):
super(CommentForm, self).__init__(*args, **kwargs)
self.fields['categories'].initial = self.instance.object_id
Or this code placed in CommentForm
You want to have the current model value selected by default in the generated form? If that's the case I think what you are looking for in your view is
form = CommentForm(instance = commentinstance)
Where commentinstance is the instance that you are editing.
(This would be form = CommentForm(request.POST, instance = commentinstance) in case of a POST request)
EDIT:
If you want to do this in the form, you can just provide the instance argument from __init__, like so:
def __init__(self, *args, **kwargs):
instance = kwargs.pop('instance', YOUR_DEFAULT_INSTANCE)
super(CommentForm, self).__init__(instance = instance, *args, **kwargs)
That even leaves the default instance if you do provide one from your view.
I guess there are a few ways to solve this.
Here is how I done before:
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
if 'ref' in kwargs:
ref = kwargs['ref']
item = MyModel.objects.get(pk=ref)
kwargs['instance'] = item
super(MyForm, self).__init__(*args, **kwargs)
class Meta:
model = MyModel
The important part is to put your populated model object into the keyword variable instance.
Before saving model I'm re-size a picture. But how can I check if new picture added or just description updated, so I can skip rescaling every time the model is saved?
class Model(model.Model):
image=models.ImageField(upload_to='folder')
thumb=models.ImageField(upload_to='folder')
description=models.CharField()
def save(self, *args, **kwargs):
if self.image:
small=rescale_image(self.image,width=100,height=100)
self.image_small=SimpleUploadedFile(name,small_pic)
super(Model, self).save(*args, **kwargs)
I want to rescale only if new image loaded or image updated, but not when description updated.
Some thoughts:
class Model(model.Model):
_image=models.ImageField(upload_to='folder')
thumb=models.ImageField(upload_to='folder')
description=models.CharField()
def set_image(self, val):
self._image = val
self._image_changed = True
# Or put whole logic in here
small = rescale_image(self.image,width=100,height=100)
self.image_small=SimpleUploadedFile(name,small_pic)
def get_image(self):
return self._image
image = property(get_image, set_image)
# this is not needed if small_image is created at set_image
def save(self, *args, **kwargs):
if getattr(self, '_image_changed', True):
small=rescale_image(self.image,width=100,height=100)
self.image_small=SimpleUploadedFile(name,small_pic)
super(Model, self).save(*args, **kwargs)
Not sure if it would play nice with all pseudo-auto django tools (Example: ModelForm, contrib.admin etc).
Check the model's pk field. If it is None, then it is a new object.
class Model(model.Model):
image=models.ImageField(upload_to='folder')
thumb=models.ImageField(upload_to='folder')
description=models.CharField()
def save(self, *args, **kwargs):
if 'form' in kwargs:
form=kwargs['form']
else:
form=None
if self.pk is None and form is not None and 'image' in form.changed_data:
small=rescale_image(self.image,width=100,height=100)
self.image_small=SimpleUploadedFile(name,small_pic)
super(Model, self).save(*args, **kwargs)
Edit: I've added a check for 'image' in form.changed_data. This assumes that you're using the admin site to update your images. You'll also have to override the default save_model method as indicated below.
class ModelAdmin(admin.ModelAdmin):
def save_model(self, request, obj, form, change):
obj.save(form=form)
You may supply extra argument for confirming a new image is posted.
Something like:
def save(self, new_image=False, *args, **kwargs):
if new_image:
small=rescale_image(self.image,width=100,height=100)
self.image_small=SimpleUploadedFile(name,small_pic)
super(Model, self).save(*args, **kwargs)
or pass request variable
def save(self, request=False, *args, **kwargs):
if request and request.FILES.get('image',False):
small=rescale_image(self.image,width=100,height=100)
self.image_small=SimpleUploadedFile(name,small_pic)
super(Model, self).save(*args, **kwargs)
I think these wont break your save when called simply.
You may put this in your admin.py so that this work with admin site too (for second of above solutions):
class ModelAdmin(admin.ModelAdmin):
....
def save_model(self, request, obj, form, change):
instance = form.save(commit=False)
instance.save(request=request)
return instance
Query the database for an existing record with the same PK. Compare the file sizes and checksums of the new and existing images to see if they're the same.
What I did to achieve the goal was to make this..
# I added an extra_command argument that defaults to blank
def save(self, extra_command="", *args, **kwargs):
and below the save() method is this..
# override the save method to create an image thumbnail
if self.image and extra_command != "skip creating photo thumbnail":
# your logic here
so when i edit some fields but not editing the image, I put this..
Model.save("skip creating photo thumbnail")
you can replace the "skip creating photo thumbnail" with "im just editing the description" or a more formal text.
Hope this one helps!
In new version it is like this:
def validate(self, attrs):
has_unknown_fields = set(self.initial_data) - set(self.fields.keys())
if has_unknown_fields:
raise serializers.ValidationError("Do not send extra fields")
return attrs
I have found one another simple way to store the data into the database
models.py
class LinkModel(models.Model):
link = models.CharField(max_length=500)
shortLink = models.CharField(max_length=30,unique=True)
In database I have only 2 variables
views.py
class HomeView(TemplateView):
def post(self,request, *args, **kwargs):
form = LinkForm(request.POST)
if form.is_valid():
text = form.cleaned_data['link'] # text for link
dbobj = LinkModel()
dbobj.link = text
self.no = self.gen.generateShortLink() # no for shortLink
dbobj.shortLink = str(self.no)
dbobj.save() # Saving from views.py
In this I have created the instance of model in views.py only and putting/saving data into 2 variables from views only.