Http verb decorator for Django?

Question

In ASP.NET MVC, you can use the AcceptVerbs attribute to correlate a view function with a verb:

public ActionResult Create()
{
    // do get stuff
} 

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(FormCollection collection)
{
    // do post stuff
}

The Django Book suggests something like this:

def method_splitter(request, *args, **kwargs):
    get_view = kwargs.pop('GET', None)
    post_view = kwargs.pop('POST', None)
    if request.method == 'GET' and get_view is not None:
        return get_view(request, *args, **kwargs)
    elif request.method == 'POST' and post_view is not None:
        return post_view(request, *args, **kwargs)
    raise Http404

urls.py:

urlpatterns = patterns('',
    # ...
    (r'^somepage/$', views.method_splitter, {'GET': views.some_page_get, 
        'POST': views.some_page_post}),
    # ...
)

That seems a little ugly to me - is there a decorator that can associate an HTTP verb with a view, ASP.NET MVC-style, or another accepted way to do this?

Answer 1

There are standard built-in decorators for requiring particular HTTP method or list of allowed methods.

See the code: http://code.djangoproject.com/browser/django/trunk/django/views/decorators/http.py.

Answer 2

Updated answer in 2016: Modern Django has everything necessary built-in and available through the class-based views. In the most raw form, the canonical approach is subclasssing django.views.generic.View and implementing class methods that are named after the HTTP verbs:

class MyView(View):
    def get(self, request, *args, **kwargs):
        # ...

    def post(self, request, *args, **kwargs):
        # ...

Internally, this works in a way very similar to my ancient code below (which was written before Django had class-based views). There is a View.dispatch method that basically looks up what to call, or return 405 if it can't find anything: getattr(self, request.method.lower(), self.http_method_not_allowed).

Of course, if you do form processing, template rendering or common CRUD stuff, be sure to check out the available View subclasses.

---

Legacy answer from 2009 below. The code still works in 2016, but isn't a DRY solution, so don't use it. In 2011 Django got class-based views and nowadays they're the standard way how things should be done. I'm keeping this here solely for historical purposes. Old answer text follows:

In one particular view where I need to have separate code for different HTTP methods (this is my tiny WebDAV implementation), I'm doing something like this:

class SomeView(object):
    def method_get(self, request, ...):
        ...

    def __call__(self, request, *args, **kwargs):
        m = getattr(self, 'method_%s' % request.method.lower(), None)
        if m is not None:
            return m(request, user, *args, **kwargs)
        return HttpResponseNotAllowed("405 Method Not Allowed")

# Then url(r'...', SomeView()),

Added/edited: Well, I've thought a bit and actually implemented decorator approach. It is not as bad as I initially thought.

def method_not_allowed_view(request, *args, **kwargs):
    return HttpResponseNotAllowed("405 Method Not Allowed")

def http_method(*methods):
    methods = map(lambda m: m.lower(), methods)
    def __method_wrapper(f):
        this_module = __import__(__name__)
        chain = getattr(this_module, f.__name__, method_not_allowed_view)
        base_view_func = lambda request, *args, **kwargs: \
            f(request, *args, **kwargs) if request.method.lower() in methods \
                                        else chain(request, *args, **kwargs)
        setattr(this_module, f.__name__, base_view_func)
        return base_view_func
    return __method_wrapper

@http_method('get')
def my_view(request):
    return HttpResponse("Thank you for GETting.")

@http_method('post', 'put')
def my_view(request):
    return HttpResponse("Thank you for POSTing or PUTting.")

# url(r'...', 'app.my_view'),

This post is a community wiki, anyway, so feel free to improve if you like the idea! And the revision history also contains some a bit different approaches I tried before writing this...

Answer 3

You can use View Decorators

From the docs:

from django.views.decorators.http import require_http_methods

@require_http_methods(["GET", "POST"])
def my_view(request):
    # I can assume now that only GET or POST requests make it this far
    # ...
    pass