Question

I try to translate a code i use in my templates and js to a content_type and object_id that is being used by the wrapped function:

def translate_modelcode(function=None,redirect_field_name=None):
    """
    translate an item-code specified in settings to a content_type
    and the item-id to the object_id
    """

    def _decorator(function):
        def _wrapped_view(request, *args, **kwargs):

            item_code=request.REQUEST.get('item-code',None)
            if item_code:
                object_id = request.REQUEST.get('item-id',None)
                # resolve_modelcode get's the models name from settings
                content_type = resolve_modelcode(item_code)
                ud_dict = {'content_type':content_type,
                          'object_id':object_id}
                if request.method == 'GET':
                    request.GET.update(ud_dict)
                else:
                    request.POST.update(ud_dict)


            return function(request, *args, **kwargs)
        return _wrapped_view

    if function is None:
        return _decorator
    else:
        return _decorator(function)

The point where i am stuck is the updating of the request.POST / request.GET QueryDict. Django reports those dicts as being immutable. How can i update them?

From the djangodocs i thought .update would use the “last-value logic” described there, which i would be perfectly fine with. But that’s not happening. Creating a copy and reassigning that to request.GET doesn’t seem to work either:

request.GET = request.GET.copy().update(ud_dict)

There is a somewhat similar question on this topic here on SO, but it never got a satisfying answer. Using the same code as in that question i just get a null return for request.POST or request.GET after updating:

request._get = request.GET.copy()
import ipdb;ipdb.set_trace()

ipdb> request.GET
ipdb> 

So what can i do about this?

Answer 1

The update(...) method does not have a return value, it updates its instance in-place. So instead of request.GET = request.GET.copy().update(ud_dict) you should write

request.GET = request.GET.copy()
request.GET.update(ud_dict)