Mixin to any view or viewset to get kwargs with lowercase values. Based on a `lookup_field` attribute.

case_insensitive_lookup_mixin.py

from rest_framework.generics import get_object_or_404

class CaseInsensitiveLookupMixin(object):
    """
    Apply this mixin to any view or viewset to get kwargs with lowercase
    values. Based on a `lookup_field` attribute.
    """
	
    def get_object(self):
        queryset = self.get_queryset()  # Get the base queryset
        queryset = self.filter_queryset(queryset)  # Apply any filter backends
        filter = {self.lookup_field: self.kwargs[self.lookup_field]}
        if isinstance(self.kwargs[self.lookup_field], str):
            filter = {self.lookup_field: self.kwargs[self.lookup_field].lower()}
        return get_object_or_404(queryset, **filter)  # Lookup the object