Back
Feb 28, 2010

Composing multiple views in Django

In UNIX way, each view should solve single task. This is good idea, but sometimes we need to mix logic of different views on same page. Filter, sort, paginate, or, for example, add comment on product page. In this article I'll show how we can mix such multiple views.

Idea

We can write views as decorators.

Example

Simplified filtration can look like this:

from django.views.generic.list_detail import object_list


def filtered_list(request, filterset_class, queryset, *args, **kwargs):
    filterset = filterset_class(request.GET)
    queryset = filterset.filter(queryset)
    kwargs['extra_context']['filterset'] = filterset

    return object_list(request, queryset, *args, **kwargs)

This is simple and straightforward, but in order to add some tricky pagination, we have to copy entire view and add more code to it.

Instead, we can create decorator like this:

def filtered(view):
    def wrapped(request, filterset_class, queryset, *args, **kwargs):
        filterset = filterset_class(request.GET)
        queryset = filterset.filter(queryset)
        kwargs['extra_context']['filterset'] = filterset
        return view(request, queryset, *args, **kwargs)

    return wrapped

Result

Assuming, that we have similar decorators, sorted и paginated, we can easily combine them:

@filtered
@paginated
def technic_list(*args, **kwargs):
    # ...

Or even like this, in lisp style:

url(r'^technic/$', filtered(sorted(paginated(object_list))), {
    'filterset_class': FilterSet,
     # ...
}, name='technic_list'),

Subscribe for the news and updates

More thoughts
Jul 27, 2022Technology
Forge Viewer: Our Experience with an Unusual Project

Once we received an interesting task from a client. They needed to allow their users to upload a 3D model of the building and show it in a timelapse video from the construction site.

Jun 1, 2018Technology
Site search organization: basic concepts

Now it's time to get acquainted with Elasticsearch. This NoSQL database is used to store logs, analyze information and - most importantly - search.

May 22, 2017Technology
Web Application Security: 10 Best Practices

Protection of WEB App is of paramount importance and it should be afforded the same level of security as the intellectual rights or private property. I'm going to cover how to protect your web app.

Oct 22, 2016Technology
Solr Sharding

When dealing with one of our projects (LookSMI media monitoring platform) we have to handle the huge volume of data – and its quantity is constantly growing. At the same time, we must run quick searches with smart rules. In this article I'll explain how we have achieved required performance.

Sep 23, 2010Technology
Dynamic class generation, QuerySetManager and use_for_related_fields

It appears that not everyone knows that in python you can create classes dynamically without metaclasses. I'll show an example of how to do it.So we've learned how to use custom QuerySet to chain requests:Article.objects.old().public()Now we need to make it work for related objects:user.articles.old().public()This is done using use_for_related_fields, but it needs a little trick.

Feb 18, 2010Technology
User profiles with inheritance in Django

Usually users' profiles are stored in single model. When there are multiple user types, separation is made by some field like user_type.Situation is a little more complicated when different data is needed for each user type.In this article I'll describe how I solve this task.