Question

I’m having a problem accessing a Django Form POST data.

I need to pass request.user to the form, so:

class TradeForForm(forms.Form):
def __init__(self, *args, **kwargs):
    user = kwargs.pop('user')
    else:
        request = kwargs.pop('request')
    super(TradeForForm, self).__init__(*args, **kwargs)

    #Obtain items for user
    if user:
        print user
        items = Item.objects.filter(user=user)
        choices = []
        for i in range(len(items)):
            choices.append([i,items[i].name])

        self.fields['item_to_be_traded_for'].choices = choices

trade_type = forms.ChoiceField(
    widget=RadioSelect(),
    choices = [
        ['0','Item'],
        ['1','Money offer'],
    ]
)

item_to_be_traded_for = forms.ChoiceField()

and then call it using:

def trade_for(request, item_id):
item = Item.objects.get(id=item_id)

if request.method == 'POST':
    form = TradeForForm(request.POST)

    if form.is_valid():
       pass
else:
    form = TradeForForm(user=request.user)

variables = RequestContext(request, {
    'form': form,
    'item': item,
})

return render_to_response('trade_for.html', variables)

Now the problem is, when doing GET to access the empty form, it works just fine. But when I post it, I received an error:

KeyError at /trade_for/1/
'user'
Request Method: POST
Request URL:    http://localhost:8000/trade_for/1/
Django Version: 1.3.1
Exception Type: KeyError
Exception Value:    
'user'

Now how can this be fixed? I assume it’s because the user variable is not passed to the form when creating it using the request.POST data, but I want to be able to create the form with the user parameter and without it, both working.

Answer 1

you should probably pass the user to the form creator even with POST data so the choices can be validated properly, so

TradeForForm(request.POST, user=request.user)

if you don’t want this, you need to change user = kwargs.pop('user') to something like

user = kwargs.pop('user', None)
# if kwargs has no key 'user', user is assigned None
# make sure your code handles this case gracefully