[FIXED] How to define a default value for a get parameters with Django?

Issue

I do not understand why I cannot define a default value for a get parameter even after reading the document about QueryDict. This is what I have:

def find_users(request):

    selected_zipcode = request.GET.get('zipcode', 75000)
    selected_service = request.GET.get('service', 1)

    # raise Exception(request.GET)

    users = User.objects.filter(
        Q(zipcode=selected_zipcode),
        Q(proposals__pk=selected_service)
    )
    return render(
        request,
        'users.html', {users
        'users': pet_sitters,
    })

I can get my parameter if set in my url but if I do not define a zipcode parameter, i do not get 75000 as value. I only have 75000 if zipcode parameter does not exists.

Solution

It is possible that you wrote the querystring as ?zipcode, or as ?zipcode=. In that case the key is set and maps on the empty string.

You can set another value in that case by implementing this as:

selected_zipcode = request.GET.get('zipcode', 75000) or 75000

This will in case the result of request.GET.get(…) has truthiness False, return the second operand so 75000.

It might however be better to work with a form, and pass the request.GET as data, so:

class MyForm(forms.Form):
    zipcode = forms.IntegerField(initial=75000, required=False)
    service = form.IntegerField(initial=1, required=False)

and work in the view with:

def find_users(request):
    form = MyForm(request.GET)
    if form.is_valid():
        selected_zipcode = myform.cleaned_data['zipcode']
        selected_service = myform.cleaned_data['service']
        # …
    # …

Answered By - Willem Van Onsem