Example of using Django forms to load CSVs

forms.py

from simplecart.discounts.models import *
from simplecart.orders.models import SKU

from decimal import Decimal
import datetime

from django import forms

class r(str):
    pass

DISCOUNT_CHOICES = [
    'absolute',
    'percent',
    #'free_ship',
]

class CouponForm(forms.Form):
    coupon = forms.CharField()
    discount = forms.DecimalField()
    coupon_type = forms.ChoiceField(choices=zip(DISCOUNT_CHOICES, DISCOUNT_CHOICES))
    productid = forms.IntegerField(required=False)
    categoryid = forms.IntegerField(required=False)
    minimum = forms.IntegerField()
    times = forms.IntegerField()
    times_used = forms.IntegerField()
    expire = forms.CharField()

    def clean_expire(self):
        expire = self.cleaned_data.get('expire')
        #Friday 06 May 2011 12:00:00 AM
        try:
            return datetime.datetime.strptime(expire, '%A %d %B %Y %I:%M:%S %p')
        except ValueError, e:
            raise forms.ValidationError(str(e))
    
    def get_coupon(self):
        try:
            coupon = Coupon.objects.get(code=self.cleaned_data['coupon'])
            coupon.discounts.all().delete()
        except Coupon.DoesNotExist:
            coupon = Coupon(code=self.cleaned_data['coupon'], rules={})
        if self.cleaned_data['times']:
            coupon.max_uses = self.cleaned_data['times'] - self.cleaned_data['times_used']
        else:
            coupon.max_uses = None
        if self.cleaned_data['minimum']:
            coupon.min_amount = self.cleaned_data['minimum']
        else:
            coupon.min_amount = None
        coupon.name = coupon.code
        coupon.expiration_date = self.cleaned_data['expire']
        coupon.save()
        return coupon
    
    def get_discount_type(self):
        if self.cleaned_data['coupon_type'] == 'absolute':
            return 'A'
        if self.cleaned_data['coupon_type'] == 'percent':
            return 'P'
    
    def do_product_discount(self):
        coupon = self.get_coupon()
        ProductDiscount(rules={"prototype": "if", 
                               "evaluation": "TRUE", 
                               "concatenation": "ALL",
                               "conditions": [{"prototype": "product", 
                                               "product":self.cleaned_data['productid'],}]},
                        coupon=coupon,
                        short_description='Product Discount',
                        discount=self.cleaned_data['discount'],
                        discount_type=self.get_disocunt_type(),).save()
        return coupon
    
    def do_category_discount(self):
        coupon = self.get_coupon()
        ProductDiscount(rules={"prototype": "if", 
                               "evaluation": "TRUE", 
                               "concatenation": "ALL",
                               "conditions": [{"prototype": "productcategory", 
                                               "category":self.cleaned_data['categoryid'],}]},
                        coupon=coupon,
                        short_description='Product Discount',
                        discount=self.cleaned_data['discount'],
                        discount_type=self.get_discount_type(),).save()
        return coupon
    
    def do_order_discount(self):
        coupon = self.get_coupon()
        discount = OrderDiscount(coupon=coupon,
                                 rules={},
                                 short_description='Order Discount',
                                 discount=self.cleaned_data['discount'],
                                 discount_type=self.get_discount_type(),
                                 stop_other_discounts=True)
        discount.save()
        return coupon
    
    def save(self):
        if self.cleaned_data['productid']:
            return self.do_product_discount()
        if self.cleaned_data['categoryid']:
            return self.do_category_discount()
        return self.do_order_discount()

import_coupons.py

from django.core.management.base import BaseCommand
from django.utils.datastructures import MultiValueDict

import csv

class Command(BaseCommand):
    help = "Imports a csv file describing a set of coupons"
    args = "<coupon.csv>"
    
    def make_dictionary(self, header, row):
        data = MultiValueDict()
        for key, value in zip(header, row):
            data.appendlist(key, value.strip())
        return data

    def prep_header(self, header):
        ret = list()
        for row in header:
            ret.append(row.lower().strip('!').strip())
        return ret

    def handle(self, filename, *args, **options):
        from couponimporter.forms import CouponForm
        rows = csv.reader(open(filename, 'r'))
        rows.next() #first row is junk
        header = self.prep_header(rows.next())
        
        form_cls = CouponForm
        for index, row in enumerate(rows):
            form = form_cls(data=self.make_dictionary(header, row))
            if form.is_valid():
                form.save()
            else:
                row_num = index + 2
                print 'Row %s is not valid.' % row_num
                print 'Row %s contained: %s' % (row_num, form.data)
                print 'It had the following errors:'
                print form.errors