user3601503 user3601503 - 8 months ago 51
Python Question

How to set a Django filter to select all

I have a view in Django that will read a get request and its parameters and make a query based on the parameters. Currently my view looks like this:

def getInventory(request):
c = request.GET.get('category', '')
g = request.GET.get('gender', '')
s = request.GET.get('size', '')

available = Item.objects.filter(gender=g,category=c,size=s)
data = serializers.serialize('json',available)
return HttpResponse(data,'json')

Sometimes, though, one of the parameters is not specified. I would like this to result in a value representing 'all' rather than an individual value. Is this possible in the way I've done it? I've tried
but that just results in an empty list.


You need to apply a filter only if you want to filter something. You could do something like this:

# Start off with a base queryset
available = Item.objects.all()

allowed_filters = ['category', 'gender', 'size']
for f in allowed_filters:
    if request.GET.get(f):
        available = available.filter(**{f: request.GET[f]})

data = serializers.serialize('json',available)
return HttpResponse(data,'json')

That said, you might want to consider using the Forms API to validate the inputs before passing them to your queryset.