django1/docs/topics/http/shortcuts.txt

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.. _topics-http-shortcuts:
=========================
Django shortcut functions
=========================
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()``
========================
``django.shortcuts.render_to_response`` renders a given template with a given
context dictionary and returns an ``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
<subclassing-context-requestcontext>`, 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")
``get_object_or_404``
=====================
``django.shortcuts.get_object_or_404`` 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``
===================
``django.shortcuts.get_list_or_404`` 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 = MyModel.objects.filter(published=True)
if not my_objects:
raise Http404