.. _topics-http-shortcuts: ========================= Django shortcut functions ========================= .. module:: django.shortcuts :synopsis: Convience shortcuts that spam multiple levels of Django's MVC stack. .. index:: shortcuts The package ``django.shortcuts`` collects helper functions and classes that "span" multiple levels of MVC. In other words, these functions/classes introduce controlled coupling for convenience's sake. ``render_to_response`` ====================== .. function:: render_to_response(template[, dictionary][, context_instance][, mimetype]) Renders a given template with a given context dictionary and returns an :class:`~django.http.HttpResponse` object with that rendered text. Required arguments ------------------ ``template`` The full name of a template to use. Optional arguments ------------------ ``dictionary`` A dictionary of values to add to the template context. By default, this is an empty dictionary. If a value in the dictionary is callable, the view will call it just before rendering the template. ``context_instance`` The context instance to render the template with. By default, the template will be rendered with a ``Context`` instance (filled with values from ``dictionary``). If you need to use :ref:`context processors `, render the template with a ``RequestContext`` instance instead. Your code might look something like this:: return render_to_response('my_template.html', my_data_dictionary, context_instance=RequestContext(request)) ``mimetype`` .. versionadded:: 1.0 The MIME type to use for the resulting document. Defaults to the value of the :setting:`DEFAULT_CONTENT_TYPE` setting. Example ------- The following example renders the template ``myapp/index.html`` with the MIME type ``application/xhtml+xml``:: from django.shortcuts import render_to_response def my_view(request): # View code here... return render_to_response('myapp/index.html', {"foo": "bar"}, mimetype="application/xhtml+xml") This example is equivalent to:: from django.http import HttpResponse from django.template import Context, loader def my_view(request): # View code here... t = loader.get_template('myapp/template.html') c = Context({'foo': 'bar'}) r = HttpResponse(t.render(c), mimetype="application/xhtml+xml") ``redirect`` ============ .. function:: redirect(to[, permanent=False], *args, **kwargs) Returns an HttpResponseRedirect to the apropriate URL for the arguments passed. The arguments could be: * A model: the model's `get_absolute_url()` function will be called. * A view name, possibly with arguments: `urlresolvers.reverse()` will be used to reverse-resolve the name. * A URL, which will be used as-is for the redirect location. By default issues a temporary redirect; pass permanent=True to issue a permanent redirect Examples -------- You can use the :func:`redirect` function in a number of ways. 1. By passing some object; that object's :meth:`~django.db.models.Model.get_absolute_url` method will be called to figure out the redirect URL:: def my_view(request): ... object = MyModel.objects.get(...) return redirect(object) 2. By passing the name of a view and optionally some positional or keyword arguments; the URL will be reverse resolved using the :func:`~django.core.urlresolvers.reverse` method:: def my_view(request): ... return redirect('some-view-name', foo='bar') 3. By passing a hardcoded URL to redirect to:: def my_view(request): ... return redirect('/some/url/') This also works with full URLs:: def my_view(request): ... return redirect('http://example.com/') By default, :func:`redirect` returns a temporary redirect. All of the above forms accept a ``permanent`` argument; if set to ``True`` a permanent redirect will be returned:: def my_view(request): ... object = MyModel.objects.get(...) return redirect(object, permanent=True) ``get_object_or_404`` ===================== .. function:: get_object_or_404(object, *args, **kwargs) Calls :meth:`~django.db.models.QuerySet.get()` on a given model manager, but it raises ``django.http.Http404`` instead of the model's ``DoesNotExist`` exception. Required arguments ------------------ ``klass`` A ``Model``, ``Manager`` or ``QuerySet`` instance from which to get the object. ``**kwargs`` Lookup parameters, which should be in the format accepted by ``get()`` and ``filter()``. Example ------- The following example gets the object with the primary key of 1 from ``MyModel``:: from django.shortcuts import get_object_or_404 def my_view(request): my_object = get_object_or_404(MyModel, pk=1) This example is equivalent to:: from django.http import Http404 def my_view(request): try: my_object = MyModel.objects.get(pk=1) except MyModel.DoesNotExist: raise Http404 Note: As with ``get()``, an ``MultipleObjectsReturned`` exception will be raised if more than one object is found. ``get_list_or_404`` =================== .. function:: get_list_or_404(klass, *args, **kwargs) Returns the result of :meth:`~django.db.models.QuerySet.filter()` on a given model manager, raising ``django.http.Http404`` if the resulting list is empty. Required arguments ------------------ ``klass`` A ``Model``, ``Manager`` or ``QuerySet`` instance from which to get the object. ``**kwargs`` Lookup parameters, which should be in the format accepted by ``get()`` and ``filter()``. Example ------- The following example gets all published objects from ``MyModel``:: from django.shortcuts import get_list_or_404 def my_view(request): my_objects = get_list_or_404(MyModel, published=True) This example is equivalent to:: from django.http import Http404 def my_view(request): my_objects = list(MyModel.objects.filter(published=True)) if not my_objects: raise Http404