Implementing Date Range Constraints in Django Filters

To modify your DateFromToRangeFilter to enforce that the start date must be less than or equal to today and the end date must be greater than today, you need to update your filter_by_range method to include these validation checks.

Here's how you can modify your implementation:

PYTHONCopied
import datetime
from django.core.exceptions import ValidationError

class PartLogFilter(django_filters.FilterSet):
    date_range = django_filters.DateFromToRangeFilter(
        label='By Date Range',
        method='filter_by_range',
        widget=RangeWidget(attrs={'class': 'datepicker', 'type': 'date'})
    )
    
    class Meta:
        model = PartLog
        fields = ['date_range']
    
    def filter_by_range(self, queryset, name, value):
        today = datetime.date.today()
        start = value.start
        end = value.stop
        
        # Apply validation constraints
        if start and start > today:
            # Option 1: Return empty queryset if validation fails
            return queryset.none()
            # Option 2: Adjust the start date to today
            # start = today
        
        if end and end <= today:
            # Option 1: Return empty queryset if validation fails
            return queryset.none()
            # Option 2: Adjust the end date to tomorrow
            # end = today + datetime.timedelta(days=1)
        
        # Apply filters based on available values
        if start:
            queryset = queryset.filter(transaction_time__gte=start)
        if end:
            queryset = queryset.filter(transaction_time__lte=end)
        
        return queryset

Alternative Approach with Form Validation

If you want to provide feedback to the user about invalid date ranges, you could also implement validation in a form:

PYTHONCopied
class PartLogFilterForm(django_filters.FilterSet):
    date_range = django_filters.DateFromToRangeFilter(
        label='By Date Range',
        widget=RangeWidget(attrs={'class': 'datepicker', 'type': 'date'})
    )
    
    class Meta:
        model = PartLog
        fields = ['date_range']
    
    def clean(self):
        cleaned_data = super().clean()
        date_range = cleaned_data.get('date_range')
        
        today = datetime.date.today()
        
        if date_range:
            start = date_range.start
            end = date_range.stop
            
            if start and start > today:
                raise ValidationError("Start date must be less than or equal to today.")
            
            if end and end <= today:
                raise ValidationError("End date must be greater than today.")
        
        return cleaned_data

Choose the approach that best fits your application's needs. The first option silently enforces the constraints, while the second provides explicit validation feedback to users.