How to do field validation in django-import-export - django

Question

Following is my model:
class Product(models.Model):
product_title = models.CharField(max_length=100, null=False,
verbose_name='Product title')
product_description = models.TextField(max_length=250,
verbose_name='Product description')
product_qty = models.IntegerField(verbose_name='Quantity')
product_mrp = models.FloatField(verbose_name='Maximum retail price')
product_offer_price = models.FloatField(verbose_name='Selling price')
I wanted to have a validation for product_offer_price field before save for which I had posted a QUESTION and it was answered with the working solution.
Validation needed is:
if product_offer_price > product_mrp:
raise ValidationError
Now the solution to above question works perfectly for the admin forms.
But, I have implemented django-import-export, in which I am importing Product Data in bulk in admin, and I need similar validation during bulk import.
How to achieve this?

Answer 1

Well, here was a little research process.
And finally I got it.
The trouble is avoiding ProductForm in import-export library.
Inside library import invoke method save() of instance, but if we raise ValidationError in Model (not in Form) = 500 with DEBUG = False, and traceback page with DEBUG = True.
So we should use "before_import" method in import_export Resource and "clean" method in django.forms Form.
admin.py
from forms import ProductForm
from models import Product
from import_export import resources
from import_export.admin import ImportExportActionModelAdmin
from django.forms import ValidationError
class ProductResource(resources.ModelResource):
class Meta:
model = Product
def before_import(self, dataset, using_transactions, dry_run, **kwargs):
for row in dataset:
if int(row[4]) < int(row[5]):
raise ValidationError('Product offer price cannot be greater than Product MRP. '
'Error in row with id = %s' % row[0])
class ProductAdmin(ImportExportActionModelAdmin):
list_display = ('product_title', 'product_description', 'product_qty', 'product_mrp', 'product_offer_price')
form = ProductForm
resource_class = ProductResource
admin.site.register(Product, ProductAdmin)
forms.py
from django import forms
from models import Product
class ProductForm(forms.ModelForm):
class Meta:
model = Product
exclude = [id, ]
def clean(self):
product_offer_price = self.cleaned_data.get('product_offer_price')
product_mrp = self.cleaned_data.get('product_mrp')
if product_offer_price > product_mrp:
raise forms.ValidationError("Product offer price cannot be greater than Product MRP.")
return self.cleaned_data
models.py
class Product(models.Model):
product_title = models.CharField(max_length=100, null=False, verbose_name='Product title')
product_description = models.TextField(max_length=250, verbose_name='Product description')
product_qty = models.IntegerField(verbose_name='Quantity')
product_mrp = models.FloatField(verbose_name='Maximum retail price')
product_offer_price = models.FloatField(verbose_name='Selling price')

Answer 2

An easier way might be to hook into the import/export workflow by adding a custom before_import_row method to your resource class:
class ProductResource(resources.ModelResource):
class Meta:
model = Product
def before_import_row(self, row, **kwargs):
if int(row[4]) < int(row[5]):
raise ValidationError('Product offer price cannot be greater than Product MRP. '
'Error in row with id = %s' % row[0])

Answer 3

here is another Simple Way For Django Rest Framework
def importcsv(request, company):
for row in dataset['company']:
if(row != company):
raise PermissionDenied("You do not have permission to Enter Clients in Other Company, Be Careful")