Develop Reference

django ecommerce product db design

I designed a database for my django ecommerce project but it have some problems, the goal of
the this design is to have products with different specifications for example a mobile cell has it's own properties and a television too,
it is my models.py:
'''
from django.db import models
from mptt.models import MPTTModel, TreeForeignKey
from django.shortcuts import reverse
from model_utils import FieldTracker
from . import uploaders
class Category(MPTTModel):
name = models.CharField(max_length=50, unique=True)
parent = TreeForeignKey('self', on_delete=models.CASCADE, null=True, blank=True,
related_name='children')
slug = models.SlugField(max_length=75, unique=True)
tracker = FieldTracker(fields=['name'])
class MPTTMeta:
order_insertion_by = ['name']
def __str__(self):
category_names = [self.name]
node = self
while node.parent:
node = node.parent
category_names.append(node.name)
return ' / '.join(category_names[::-1])
def get_absolute_url(self):
return reverse('product_by_category', args=(self.slug,))
class ProductType(models.Model):
name = models.CharField(max_length=50, unique=True)
def __str__(self):
return self.name
class ProductSpecifications(models.Model):
name = models.CharField(max_length=50)
product_type = models.ForeignKey(ProductType, on_delete=models.CASCADE,
related_name='specifications')
class Meta:
unique_together = ('name', 'product_type')
def __str__(self):
return self.name
class Product(models.Model):
name = models.CharField(max_length=100, unique=True)
product_type = models.ForeignKey(ProductType, on_delete=models.CASCADE,
related_name='products')
category = models.ForeignKey(Category, on_delete=models.CASCADE,
related_name='products')
price = models.PositiveBigIntegerField()
discount_price = models.PositiveBigIntegerField(null=True, blank=True)
description = models.TextField(null=True, blank=True)
image = models.ImageField(upload_to=uploaders.product_img_uploader)
slug = models.SlugField(max_length=150, unique=True)
tracker = FieldTracker(fields=['slug', 'name', 'product_type'])
def __str__(self):
return self.name
def set_discount(self, percentage):
self.discount_price = self.price * (1 - percentage)
self.save()
#property
def is_discounted(self):
return bool(self.discount_price)
def remove_discount(self):
self.discount_price = None
self.save()
class ProductSpecificationValue(models.Model):
specification = models.ForeignKey(ProductSpecifications, on_delete=models.CASCADE)
product = models.ForeignKey(Product, on_delete=models.CASCADE,
related_name='specifications')
value = models.CharField(max_length=75, null=True, blank=True)
def __str__(self):
return ''
class Meta:
unique_together = ('specification', 'product')
'''
And admin.py:
'''
from django.contrib import admin
from django.http import HttpResponseRedirect
from mptt.admin import MPTTModelAdmin
from .models import *
from .forms import ProductSpecForm
#admin.register(Category)
class CategoryAdmin(MPTTModelAdmin):
readonly_fields = ('slug',)
class SpecificationInline(admin.TabularInline):
model = ProductSpecifications
extra = 2
#admin.register(ProductType)
class ProductTypeAdmin(admin.ModelAdmin):
inlines = (SpecificationInline,)
class SpecificationValueInline(admin.TabularInline):
model = ProductSpecificationValue
# form = ProductSpecForm
# fields = ('specification', 'value')
# readonly_fields = ('specification',)
#
# def has_add_permission(self, request, obj):
# return False
#
# def has_delete_permission(self, request, obj=None):
# return False
#admin.register(Product)
class ProductAdmin(admin.ModelAdmin):
inlines = (SpecificationValueInline,)
readonly_fields = ('slug',)
# def response_post_save_add(self, request, obj):
# return HttpResponseRedirect(
# reverse("admin:%s_%s_change" % (self.model._meta.app_label,
# self.model._meta.model_name), args=(obj.id,)))
'''
the problem is in product admin panel when you want to add or change a product, I want the select box for specification in SpecificationValueInline form show me only specifications related to the product type not all specifications in db, the lines that I commented in admin.py with some signals and a form was my approach to solve this issue i dont know if it was the best help me please!
signals.py:
'''
from django.dispatch import receiver
from django.db.models.signals import pre_save, post_save
from .models import Category, Product, ProductSpecificationValue, ProductSpecifications
#receiver(pre_save, sender=Product)
#receiver(pre_save, sender=Category)
def initialize_slug(sender, instance, *args, **kwargs):
if (not instance.slug) or (instance.tracker.has_changed('name')):
instance.slug = instance.name.replace(' ', '_')
#receiver(post_save, sender=Product)
def initialize_specifications(sender, instance, created, **kwargs):
if created:
product_type = instance.product_type
for specification in product_type.specifications.all():
ProductSpecificationValue.objects.create(product=instance,
specification=specification)
elif instance.tracker.has_changed('product_type'):
ProductSpecificationValue.objects.filter(product=instance).delete()
product_type = instance.product_type
for specification in product_type.specifications.all():
ProductSpecificationValue.objects.create(product=instance,
specification=specification)
#receiver(post_save, sender=ProductSpecifications)
def add_new_specs_to_related_products(sender, instance, created, **kwargs):
if created:
product_type = instance.product_type
for product in product_type.products.all():
ProductSpecificationValue.objects.create(specification=instance,
product=product)
'''
forms.py:
'''
from django import forms
from django.forms import ModelChoiceField
from .models import ProductSpecificationValue, Product
class ProductSpecForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
if hasattr(self.instance, 'product'):
self.fields['specification'] = ModelChoiceField(
queryset=self.instance.product.product_type.specifications.all())
class Meta:
model = ProductSpecificationValue
fields = ('specification', 'value')
'''

you can use formfield_for_foreignkey in SpecificationValueInline
class SpecificationValueInline(admin.TabularInline):
model = ProductSpecificationValue
def formfield_for_foreignkey(self, db_field, request, **kwargs):
if db_field.name == "specification":
product_id = request.resolver_match.kwargs.get('object_id')
productType = Product.objects.get(id = product_id).product_type
kwargs["queryset"] = ProductSpecification.objects.filter(product_type=productType)
return super().formfield_for_foreignkey(db_field, request, **kwargs)

mohsen ma answer was usefull I made some changes and it got better but I still doubt it it is enough or best practice, if user changes the product type he/she should stay on change page to fill the specification idk how:
'''
#receiver(post_save, sender=Product)
def sync_specs_with_type(sender, instance, created, **kwargs):
if created or instance.tracker.has_changed('product_type'):
if not created:
instance.specifications.all().delete()
for spec in instance.product_type.specifications.all():
ProductSpecificationValue.objects.create(product=instance, specification=spec)
class SpecificationValueInline(admin.TabularInline):
model = ProductSpecificationValue
extra = 0
def formfield_for_foreignkey(self, db_field, request, **kwargs):
product_id = request.resolver_match.kwargs.get('object_id')
if product_id and db_field.name == "specification":
product_type = Product.objects.get(id=product_id).product_type
kwargs["queryset"] = ProductSpecifications.objects.filter(product_type=product_type)
return super().formfield_for_foreignkey(db_field, request, **kwargs)
#admin.register(Product)
class ProductAdmin(admin.ModelAdmin):
readonly_fields = ('slug',)
inlines = (SpecificationValueInline,)
def response_post_save_add(self, request, obj):
messages.add_message(request, messages.INFO, 'set you product specifications')
return HttpResponseRedirect(
reverse("admin:%s_%s_change" % (self.model._meta.app_label, self.model._meta.model_name), args=(obj.id,)))
def get_inlines(self, request, obj):
if obj:
return super().get_inlines(request, obj)
return ()
'''

How to save Parent django model in related model save

Have two models - Program and Segments. I need to calculate the total times in the program entry from the fields within the associated Segments. I attempted to do that by overriding the save methods, but when entering a new segment it won't update the program model entries unless I go directly into the program form and save/update it.
I am missing how to get the segment Update to cause the Program Save/Update to happen.
How do I give it the context to call the program save method within the Segment update (After the segment has been saved).
Code of the models is:
from django.db import models
from django.urls import reverse
from datetime import datetime, timedelta
class Program(models.Model):
air_date = models.DateField(default="0000-00-00")
air_time = models.TimeField(default="00:00:00")
service = models.CharField(max_length=10)
block_time = models.TimeField(default="00:00:00")
block_time_delta = models.DurationField(default=timedelta)
running_time = models.TimeField(default="00:00:00")
running_time_delta = models.DurationField(default=timedelta)
remaining_time = models.TimeField(default="00:00:00")
remaining_time_delta = models.DurationField(default=timedelta)
title = models.CharField(max_length=190)
locked_flag = models.BooleanField(default=False)
deleted_flag = models.BooleanField(default=False)
library = models.CharField(null=True,max_length=190,blank=True)
mc = models.CharField(null=True,max_length=64)
producer = models.CharField(null=True,max_length=64)
editor = models.CharField(null=True,max_length=64)
remarks = models.TextField(null=True,blank=True)
audit_time = models.DateTimeField(null=True)
audit_user = models.CharField(null=True,max_length=32)
def calculate_time(self):
total_run_time_delta = timedelta(minutes=0)
for segs in self.segments.all():
total_run_time_delta += segs.length_time_delta
self.running_time_delta = total_run_time_delta
self.running_time = f"{self.running_time_delta}"
hold_time = self.block_time.strftime("%H:%M:%S")
t = datetime.strptime(hold_time,"%H:%M:%S")
self.block_time_delta = timedelta(hours=t.hour,
minutes=t.minute,seconds=t.second)
self.remaining_time_delta = self.block_time_delta - total_run_time_delta
self.remaining_time = f"{abs(self.remaining_time_delta)}"
def save(self, *args, **kwargs):
self.calculate_time()
super().save(*args,**kwargs)
def __str__(self):
return f"{self.pk} : {self.title}"
def get_absolute_url(self):
return reverse('program_detail', args=[str(self.id)])
#return reverse('program-update', kwargs={'pk': self.pk})
class Segment(models.Model):
program_id = models.ForeignKey(Program,
on_delete=models.CASCADE,
related_name='segments', #new link to Program
)
sequence_number = models.DecimalField(decimal_places=2,max_digits=6,default="0.00")
title = models.CharField(max_length=190)
bridge_flag = models.BooleanField(default=False)
length_time = models.TimeField(null=True,default=None, blank=True)
length_time_delta = models.DurationField(default=timedelta)
author = models.CharField(max_length=64,null=True,default=None,blank=True)
voice = models.CharField(max_length=64,null=True,default=None,blank=True)
library = models.CharField(max_length=190,null=True,default=None,blank=True)
summary = models.TextField()
audit_time = models.DateTimeField(null=True)
audit_user = models.CharField(null=True,max_length=32)
def save( self, *args, **kwargs):
super().save(*args,**kwargs)
return super(Program,self.program_id).save()
def __str__(self):
return f"{self.title}"
The views look like this...
class ProgramUpdateView(LoginRequiredMixin,UpdateView):
class Meta:
model = Program
widgets = {
'remarks': Textarea(attrs={'row':10, 'cols':80}),
}
model = Program
success_url = "/program/{id}/"
template_name = 'program_update.html'
fields = [
'title',
'service',
'library',
'air_date',
'air_time',
'producer',
'editor',
'mc',
'block_time',
'remaining_time',
'running_time',
'remarks',
]
def form_valid(self, form):
return super(ProgramUpdateView, self).form_valid(form)
class SegmentUpdate(LoginRequiredMixin,UpdateView):
model = Segment
fields = '__all__'
template_name = 'segment_update.html'
I originally thought I could do this all in the models, but now I am not so sure .
Thanks for any info you can provide....

try to directly call Program.save() method through the fk
in Segment model
def save( self, *args, **kwargs):
super().save(*args,**kwargs)
self.program_id.save()
or use django signals https://docs.djangoproject.com/en/3.1/topics/signals/
from django.db.models.signals import post_save, post_delete
#receiver([post_save, post_delete], sender=Segment)
def update_program(sender, instance, **kwargs):
program = Program.objects.get(pk=instance.program_id.pk)
program.save()

Please keep your database atomic. Don't save in it something that can be computed from other fields unless you have a very good reason to do it. The reason you're giving for doing it doesn't seem like a good one.
You want the total time of the segments when you got a list of programs ? Fine, simply annotate the querystring with a sum. You'll do it everytime ? Create a custom queryset/manager that do it for you.

Getting this name error whilst using django-taggit: name 'Tag' is not defined

For my website, I want users to be able to add tags to their posts. But I get this error:
python name 'Tag' is not defined
Here is some code
Relevant code in models.py
from taggit.managers import TaggableManager
class Post(models.Model):
author = models.ForeignKey(User, on_delete=models.CASCADE)
title = models.CharField(max_length=75)
text = models.TextField()
created_date = models.DateTimeField(default=timezone.now)
image = models.ImageField(upload_to='post_images',blank=True,null=True)
published_date = models.DateTimeField(blank=True,null=True,auto_now_add=True)
NSFW = models.BooleanField(default=False)
spoiler = models.BooleanField(default=False)
tags = TaggableManager()
def __str__(self):
return self.title
def save(self, *args, **kwargs):
super().save(*args, **kwargs)
Here is the relevant code in views.py
class TagMixin(object):
def get_context_data(self,**kwargs):
context = super(TagMixin,self).get_context_data(**kwargs)
context['tags'] = Tag.objects.all()
return context
class PostListView(TagMixin,ListView):
template_name = 'mainapp/post_list.html'
model = Post
context_object_name = 'posts'
queryset = Post.objects.all()
def get_queryset(self):
return Post.objects.filter(published_date__lte=timezone.now()).order_by('-published_date')
class TagIndexView(TagMixin,ListView):
template_name = 'mainapp/post_list.html'
context_object_name = 'posts'
model = Post
def get_queryset(self):
return Posts.objects.filter(tags__slug=self.kwargs.get('slug'))
And here is the form.
class PostForm(forms.ModelForm):
class Meta():
model = Post
fields = ['title','text','image','tags','spoiler','NSFW']
widgets = {
'title':forms.TextInput(attrs={'class':'textinputclass'}),
'text':forms.Textarea(attrs={'class':'textareaclass editable'}),
}
def __init__(self, *args, **kwargs):
super(PostForm, self).__init__(*args, **kwargs)
self.fields['image'].required = False
I am getting the error in the Mixin, on this line python context['tags'] = Tag.objects.all()
Can anyone tell me why I am getting an error of python name 'Tag' is not defined
So far I have changed the casing of the word, I have changed the name, but none of it works.
Thank you for any help you can give :)

Django-Haystack not returning exact query

I'm trying to fix my Django-haystack combined with Elasticsearch search results to be exact.
The problem I have now is that when a user try for example, the "Mexico" query, the search results also returns deals in "Melbourne" which is far from being user-friendly.
Anyone can help me to fix this problem?
This is what I've tried so far but no good results:
My forms.py
from haystack.forms import FacetedSearchForm
from haystack.inputs import Exact
class FacetedProductSearchForm(FacetedSearchForm):
def __init__(self, *args, **kwargs):
data = dict(kwargs.get("data", []))
self.ptag = data.get('ptags', [])
self.q_from_data = data.get('q', '')
super(FacetedProductSearchForm, self).__init__(*args, **kwargs)
def search(self):
sqs = super(FacetedProductSearchForm, self).search()
# Ideally we would tell django-haystack to only apply q to destination
# ...but we're not sure how to do that, so we'll just re-apply it ourselves here.
q = self.q_from_data
sqs = sqs.filter(destination=Exact(q))
print('should be applying q: {}'.format(q))
print(sqs)
if self.ptag:
print('filtering with tags')
print(self.ptag)
sqs = sqs.filter(ptags__in=[Exact(tag) for tag in self.ptag])
return sqs
My search_indexes.py
import datetime
from django.utils import timezone
from haystack import indexes
from haystack.fields import CharField
from .models import Product
class ProductIndex(indexes.SearchIndex, indexes.Indexable):
text = indexes.EdgeNgramField(
document=True, use_template=True,
template_name='search/indexes/product_text.txt')
title = indexes.CharField(model_attr='title')
description = indexes.EdgeNgramField(model_attr="description")
destination = indexes.EdgeNgramField(model_attr="destination") #boost=1.125
link = indexes.CharField(model_attr="link")
image = indexes.CharField(model_attr="image")
# Tags
ptags = indexes.MultiValueField(model_attr='_ptags', faceted=True)
# for auto complete
content_auto = indexes.EdgeNgramField(model_attr='destination')
# Spelling suggestions
suggestions = indexes.FacetCharField()
def get_model(self):
return Product
def index_queryset(self, using=None):
"""Used when the entire index for model is updated."""
return self.get_model().objects.filter(timestamp__lte=timezone.now())
My models.py
class Product(models.Model):
destination = models.CharField(max_length=255, default='')
title = models.CharField(max_length=255, default='')
slug = models.SlugField(unique=True, max_length=255)
description = models.TextField(max_length=2047, default='')
link = models.TextField(max_length=500, default='')
ptags = TaggableManager()
image = models.ImageField(max_length=500, default='images/zero-image-found.png')
timestamp = models.DateTimeField(auto_now=True)
def _ptags(self):
return [t.name for t in self.ptags.all()]
def get_absolute_url(self):
return reverse('product',
kwargs={'slug': self.slug})
def save(self, *args, **kwargs):
if not self.id:
self.slug = slugify(self.title)
super(Product, self).save(*args, **kwargs)
def __str__(self):
return self.destination
And what I have in my views.py
from haystack.generic_views import FacetedSearchView as BaseFacetedSearchView
from .forms import FacetedProductSearchForm
class FacetedSearchView(BaseFacetedSearchView):
form_class = FacetedProductSearchForm
facet_fields = ['ptags']
template_name = 'search_result.html'
paginate_by = 30
context_object_name = 'object_list'
Thank you.

I just found the solution to this problem. Please listen up if you want to avoid loosing any of you reputations by placing a bounty on the same problem.
Basically I had to replace my original destination field in my search_indexes.py document to the following line:
From this: destination = indexes.EdgeNgramField(model_attr="destination")
To this: destination = indexes.CharField(model_attr="destination")

Your issue is in your use of dict.get
self.q_from_data = data.get('q', [''])[0]
For example
data.get('q') # This will return the string "Mexico"
data.get('q')[0] # This will return the first letter "M"
The line should be
self.q_from_data = data.get('q', '')

bypass validation for form field django

class PostForm(forms.ModelForm):
description = forms.CharField(widget=PagedownWidget(show_preview=False))
class Meta:
model = Post
fields = [
'title',
'image',
'video',
'description',
'public',
'tags',
]
I am trying to bypass the required field for 'video' but having difficulty doing so. Any suggestions would be appreciated.
this is my models.py, hopefully is should help with knowing how to go on this.
from django.db import models
from django.db.models import Count, QuerySet, F
from django.utils import timezone
from django.conf import settings
from django.contrib.contenttypes.models import ContentType
from django.core.urlresolvers import reverse
from django.db.models.signals import pre_save
from django.utils.text import slugify
from markdown_deux import markdown
from django.utils.safestring import mark_safe
from embed_video.fields import EmbedVideoField
from taggit.managers import TaggableManager
from comments.models import Comment
def upload_location(instance, filename):
return "%s/%s" %(instance.slug, filename)
class Post(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, default=1 )
title = models.CharField(max_length=75)
slug = models.SlugField(unique=True)
video = EmbedVideoField()
image = models.ImageField(
upload_to=upload_location,
null=True,
blank=True,
width_field="width_field",
height_field="height_field")
height_field = models.IntegerField(default=0)
width_field = models.IntegerField(default=0)
description = models.TextField()
tags = TaggableManager()
public = models.BooleanField(default=False)
updated = models.DateTimeField(auto_now_add=False, auto_now=True)
created = models.DateTimeField(auto_now_add=True, auto_now=False)
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse("posts:detail", kwargs={"slug": self.slug})
class Meta:
ordering = ["-created", "-updated" ]
def get_markdown(self):
description = self.description
markdown_text = markdown(description)
return mark_safe(markdown_text)
#property
def comments(self):
instance = self
qs = Comment.objects.filter_by_instance(instance)
return qs
#property
def get_content_type(self):
instance = self
content_type = ContentType.objects.get_for_model(instance.__class__)
return content_type
def create_slug(instance, new_slug=None):
slug = slugify(instance.title)
if new_slug is not None:
slug = new_slug
qs = Post.objects.filter(slug=slug).order_by("-id")
exists = qs.exists()
if exists:
new_slug = "%s-%s" %(slug, qs.first().id)
return create_slug(instance, new_slug=new_slug)
return slug
def pre_save_post_receiver(sender, instance, *args, **kwargs):
if not instance.slug:
instance.slug = create_slug(instance)
pre_save.connect(pre_save_post_receiver, sender=Post)

from the docs it looks like it should support empty now since version 0.3, i would suggest trying
video = EmbedVideoField(null=True,blank=True)
the docs say it should function like a URL field, so just the standard notation should be all you need.
good luck!