Question

I’m trying to adopt the Django documentation example on using class based views with mixins in order to be able to make a simple way of downloading the objects in a list view in CSV format, but I am failing miserably and do not really see what I am doing wrong.

I have a view defined as:

class MyObjectList(CSVResponseMixin,
                   MultipleObjectTemplateResponseMixin,
                   BaseListView
                   ):
    object_type = None
    def get_context_data(self, **kwargs):
        object_type = self.object_type
        ...some code...
        return context

    def render_to_response(self, context, **kwargs):
        if self.request.GET.get('format', '') == 'csv':
            return CSVReponseMixin.render_to_response(self, context, **kwargs)
        else:
            return MultipleObjectTemplateResponseMixin.render_to_response(self, context, **kwargs)

the mixin is:

class CSVResponseMixin(object):
    def render_to_response(self, ctx, **kwargs):
        return self.HttpResponse.render_to_response(self.convert_to_csv(ctx), **kwargs)

    def conver_to_csv(ctx):
        return do_csv_magic(ctx)

and in urls.py the view is called as:

url(r'^list/foos/$',
    MyObjectList.as_view(object_type="someobject", model=models.MyModel),
    name="myobjects",
)

However when I try to access the view without the ?format=csv query, I get a TypeError

Exception Value:  __init__() got an unexpected keyword argument 'request'
Exception Location: /usr/lib/python2.6/site-packages/django/views/generic/base.py in render_to_response, line 97

EDIT: I added some details to the question and ended up implementing this with a different approach, but I still want to know what I was doing wrong.

Answer 1

In short, you’re overdoing it. I’m not sure what is your intention here, but I’ve learned that the best approach is to find the closest generic view to what you’re trying to do and simply extend it in views.py. Examples are many, but I invite you to check my code at https://bitbucket.org/BerislavLopac/resume/src/d7cfcf9c370b/resume_app/myproject/web/views.py.