带参数、非干的Django自定义模型方法

Question

经过大量的研究和麻烦，我想出了一种非干性的解决方案，希望有人能把它弄干。

所有我试图得到的是一个计算价格，它接受一个参数，并相应地显示在模板中。我在model vehiclecategory上有一个函数get_price，它接受来自前端表单的参数持续时间。

MODELS.PY

class VehicleCategory(models.Model):

    CATEGORY_CHOICES=(
        ('E-Cycle', 'E-Cycle'),
        ('E-Scooter', 'E-Scooter')
    )
    
    main_category = models.CharField(max_length=15, choices= CATEGORY_CHOICES)
    title = models.CharField(unique=True, max_length=200)
    image = models.ImageField(
        null=True,
        blank=True,
        width_field="width_field",
        height_field= "height_field",
        default= 'e-bike.png',
        upload_to='category')
    width_field = models.IntegerField(default=250)
    height_field = models.IntegerField(default=250) 
    slug =models.SlugField(max_length=200, db_index=True, unique=True)

    
    def __str__(self):
        return self.title
   
    #GET PRICE
    def get_price(self, duration):
        for item in VehiclePrice.objects.all():
            if item.vehicle_category.title == self.title and (duration >= item.slab.start and duration <= item.slab.end):
                return item.total_price
        
    class Meta():   
        verbose_name = "Vehicle Category"
        verbose_name_plural = "Vehicle Categories"


class PriceSlab(models.Model):

    start = models.IntegerField()
    end = models.IntegerField()
    timestamp = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '%s - %s ' % (self.start, self.end)



class VehiclePrice(CustomerStatus):

    help_text= "Ensure no more than 2 digits after decimal"
    vehicle_category = models.ForeignKey(VehicleCategory, on_delete= models.SET_NULL, null=True,         related_name='vehicle_category_price')
    slab = models.ForeignKey(PriceSlab, on_delete=models.CASCADE)
    net_price = models.DecimalField(help_text= help_text, max_digits=5, decimal_places=2)
    tax_percent = models.DecimalField(help_text=help_text, max_digits=4, decimal_places=2,   default=18.00)
    discount_percent = models.DecimalField(help_text=help_text,max_digits=4, decimal_places=2, default=0, blank=True)
    
    
    @property
    def total_tax(self):    
        tax = (self.net_price * self.tax_percent)/100
        return tax

    @property
    def get_price(self):
        total = self.net_price  + self.total_tax
        return total 

    @property
    def total_discount(self):
        discount = (self.get_price * self.discount_percent)/100
        return discount

    @property
    def total_price(self):
        total = self.get_price - self.total_discount
        
        return round(total)

    class Meta():
        unique_together=('customer_status','vehicle_category' ,'slab')

    def __str__(self):
        return '%s - %s - %s' % (self.customer_status, self.vehicle_category, self.slab)

VIEWS.PY

class HomeView(ListView):

    template_name = 'app/home.html'

    def get(self, request): 
        

        if request.method == "GET":
            start_date =  request.GET.get('start_date')
            end_date =  request.GET.get('end_date')

            if start_date and end_date:
                start_date = datetime.strptime(start_date, "%d/%m/%Y").date()
                end_date = datetime.strptime(end_date, "%d/%m/%Y").date()

                duration = (end_date - start_date).days +1
                print(duration)
                
                vehiclecategory= VehicleCategory.objects.all()
                

                context = {
                    'price1': VehicleCategory.objects.get(main_category= 'E-Cycle',    title="Sporty").get_price(duration),
                    'price2': VehicleCategory.objects.get(main_category= 'E-Cycle', title="Step-Through").get_price(duration),
                    'price3': VehicleCategory.objects.get(main_category= 'E-Cycle', title="Fatbike").get_price(duration),
                    'price4': VehicleCategory.objects.get(main_category= 'E-Scooter', title="Scooter").get_price(duration),
                   
                    'vehiclecategory1': vehiclecategory.filter(main_category= 'E-Cycle', title="Sporty"),
                    'vehiclecategory1': vehiclecategory.filter(main_category= 'E-Cycle', title="Step-Through"),
                    'vehiclecategory1': vehiclecategory.filter(main_category= 'E-Cycle', title="Fatbike"),
                    'vehiclecategory2': vehiclecategory.filter(main_category= 'E-Scooter', title="Scooter"),
                   
                    'form':CartQuantityForm(),
                    'dateform': DateForm(),
                }
            else:
                context={'dateform': DateForm(),}

        

            return render(request, self.template_name, context )

在用户输入日期范围后，车辆就会显示出来，但是当你走到购物车并返回相同的页面时，页面会刷新为一个新页面。如何保持日期范围值不变，并呈现与用户第一次搜索车辆相同的页面，以便他可以添加或修改所选车辆？

Answer 1

您可以将开始日期和结束日期放入您的URL中。

您可以创建两个urls记录，发送相同的视图：

   path(r'/prices/', HomeView.as_view())
   path(r'/prices/(?P<start>\d{4}-\d{2}-\d{2})_(?P<end>\d{4}-\d{2}-\d{2})', HomeView.as_view())

然后，您需要对您的观点做一些更改：

class HomeView(ListView):

    template_name = 'app/home.html'

    def get(self, request, **kwargs):
        start = kwargs.get('start')
        end = kwargs.get('end')

        if start is None or end is None:
            # Ask for dates & Redirect to its new url with dates.

        else:
            # Check the dates, convert them to date object & do the rest. 

也许不是最好的解决方案，但我想到的第一件事就是这个。