========================= Django shortcut functions ========================= .. module:: django.shortcuts :synopsis: Convenience shortcuts that span 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`` ========== .. function:: render(request, template_name[, dictionary][, context_instance][, content_type][, status][, current_app][, dirs]) Combines a given template with a given context dictionary and returns an :class:`~django.http.HttpResponse` object with that rendered text. :func:`render()` is the same as a call to :func:`render_to_response()` with a ``context_instance`` argument that forces the use of a :class:`~django.template.RequestContext`. Django does not provide a shortcut function which returns a :class:`~django.template.response.TemplateResponse` because the constructor of :class:`~django.template.response.TemplateResponse` offers the same level of convenience as :func:`render()`. Required arguments ------------------ ``request`` The request object used to generate this response. ``template_name`` The full name of a template to use or sequence of template names. 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 ``RequestContext`` instance (filled with values from ``request`` and ``dictionary``). ``content_type`` The MIME type to use for the resulting document. Defaults to the value of the :setting:`DEFAULT_CONTENT_TYPE` setting. ``status`` The status code for the response. Defaults to ``200``. ``current_app`` A hint indicating which application contains the current view. See the :ref:`namespaced URL resolution strategy ` for more information. .. versionchanged:: 1.7 The ``dirs`` parameter was added. .. versionchanged:: 1.8 The ``dirs`` parameter was deprecated. Example ------- The following example renders the template ``myapp/index.html`` with the MIME type :mimetype:`application/xhtml+xml`:: from django.shortcuts import render def my_view(request): # View code here... return render(request, 'myapp/index.html', {"foo": "bar"}, content_type="application/xhtml+xml") This example is equivalent to:: from django.http import HttpResponse from django.template import RequestContext, loader def my_view(request): # View code here... t = loader.get_template('myapp/index.html') c = RequestContext(request, {'foo': 'bar'}) return HttpResponse(t.render(c), content_type="application/xhtml+xml") ``render_to_response`` ====================== .. function:: render_to_response(template_name[, dictionary][, context_instance][, content_type][, dirs]) Renders a given template with a given context dictionary and returns an :class:`~django.http.HttpResponse` object with that rendered text. Required arguments ------------------ ``template_name`` The full name of a template to use or sequence of template names. If a sequence is given, the first template that exists will be used. See the :ref:`template loader documentation ` for more information on how templates are found. 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 :class:`~django.template.Context` instance (filled with values from ``dictionary``). If you need to use :ref:`context processors `, render the template with a :class:`~django.template.RequestContext` instance instead. Your code might look something like this:: return render_to_response('my_template.html', my_data_dictionary, context_instance=RequestContext(request)) ``content_type`` The MIME type to use for the resulting document. Defaults to the value of the :setting:`DEFAULT_CONTENT_TYPE` setting. .. versionchanged:: 1.7 The ``dirs`` parameter was added. .. versionchanged:: 1.8 The ``dirs`` parameter was deprecated. Example ------- The following example renders the template ``myapp/index.html`` with the MIME type :mimetype:`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"}, content_type="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/index.html') c = Context({'foo': 'bar'}) return HttpResponse(t.render(c), content_type="application/xhtml+xml") ``redirect`` ============ .. function:: redirect(to[, permanent=False], *args, **kwargs) Returns an :class:`~django.http.HttpResponseRedirect` to the appropriate URL for the arguments passed. The arguments could be: * A model: the model's :meth:`~django.db.models.Model.get_absolute_url()` function will be called. * A view name, possibly with arguments: :func:`urlresolvers.reverse ` will be used to reverse-resolve the name. * An absolute or relative 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. .. versionchanged:: 1.7 The ability to use relative URLs was added. 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:: from django.shortcuts import redirect 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(klass, *args, **kwargs) Calls :meth:`~django.db.models.query.QuerySet.get()` on a given model manager, but it raises :class:`~django.http.Http404` instead of the model's :class:`~django.core.exceptions.DoesNotExist` exception. Required arguments ------------------ ``klass`` A :class:`~django.db.models.Model` class, a :class:`~django.db.models.Manager`, or a :class:`~django.db.models.query.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 The most common use case is to pass a :class:`~django.db.models.Model`, as shown above. However, you can also pass a :class:`~django.db.models.query.QuerySet` instance:: queryset = Book.objects.filter(title__startswith='M') get_object_or_404(queryset, pk=1) The above example is a bit contrived since it's equivalent to doing:: get_object_or_404(Book, title__startswith='M', pk=1) but it can be useful if you are passed the ``queryset`` variable from somewhere else. Finally, you can also use a :class:`~django.db.models.Manager`. This is useful for example if you have a :ref:`custom manager`:: get_object_or_404(Book.dahl_objects, title='Matilda') You can also use :class:`related managers`:: author = Author.objects.get(name='Roald Dahl') get_object_or_404(author.book_set, title='Matilda') Note: As with ``get()``, a :class:`~django.core.exceptions.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.query.QuerySet.filter()` on a given model manager cast to a list, raising :class:`~django.http.Http404` if the resulting list is empty. Required arguments ------------------ ``klass`` A :class:`~django.db.models.Model`, :class:`~django.db.models.Manager` or :class:`~django.db.models.query.QuerySet` instance from which to get the list. ``**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