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()
¶Combines a given template with a given context dictionary and returns an
HttpResponse
object with that rendered text.
Django does not provide a shortcut function which returns a
TemplateResponse
because the constructor
of TemplateResponse
offers the same level
of convenience as render()
.
request
The request object used to generate this response.
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 template loading documentation for more information on how templates are found.
context
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.
content_type
The MIME type to use for the resulting document. Defaults to
'text/html'
.
status
The status code for the response. Defaults to 200
.
using
The NAME
of a template engine to use for
loading the template.
The following example renders the template myapp/index.html
with the
MIME type 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 loader
def my_view(request):
# View code here...
t = loader.get_template("myapp/index.html")
c = {"foo": "bar"}
return HttpResponse(t.render(c, request), content_type="application/xhtml+xml")
redirect()
¶Returns an HttpResponseRedirect
to the appropriate 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: 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, a temporary redirect is issued with a 302 status code. If
permanent=True
, a permanent redirect is issued with a 301 status code.
If preserve_request=True
, the response instructs the user agent to
preserve the method and body of the original request when issuing the
redirect. In this case, temporary redirects use a 307 status code, and
permanent redirects use a 308 status code. This is better illustrated in the
following table:
permanent |
preserve_request |
HTTP status code |
---|---|---|
|
|
301 |
|
|
302 |
|
|
307 |
|
|
308 |
The argument preserve_request
was added.
You can use the redirect()
function in a number of ways.
By passing some object; that object’s
get_absolute_url()
method will be called
to figure out the redirect URL:
from django.shortcuts import redirect
def my_view(request):
...
obj = MyModel.objects.get(...)
return redirect(obj)
By passing the name of a view and optionally some positional or
keyword arguments; the URL will be reverse resolved using the
reverse()
method:
def my_view(request):
...
return redirect("some-view-name", foo="bar")
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("https://example.com/")
By default, 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):
...
obj = MyModel.objects.get(...)
return redirect(obj, permanent=True)
Additionally, the preserve_request
argument can be used to preserve the
original HTTP method:
def my_view(request):
# ...
obj = MyModel.objects.get(...)
if request.method in ("POST", "PUT"):
# Redirection preserves the original request method.
return redirect(obj, preserve_request=True)
# ...
get_object_or_404()
¶Asynchronous version: aget_object_or_404()
Calls get()
on a given model
manager, but it raises Http404
instead of the model’s
DoesNotExist
exception.
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):
obj = get_object_or_404(MyModel, pk=1)
This example is equivalent to:
from django.http import Http404
def my_view(request):
try:
obj = MyModel.objects.get(pk=1)
except MyModel.DoesNotExist:
raise Http404("No MyModel matches the given query.")
The most common use case is to pass a Model
, as
shown above. However, you can also pass a
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 Manager
. This is useful
for example if you have a
custom manager:
get_object_or_404(Book.dahl_objects, title="Matilda")
You can also use
related managers
:
author = Author.objects.get(name="Roald Dahl")
get_object_or_404(author.book_set, title="Matilda")
Note: As with get()
, a
MultipleObjectsReturned
exception
will be raised if more than one object is found.
get_list_or_404()
¶Asynchronous version: aget_list_or_404()
Returns the result of filter()
on
a given model manager cast to a list, raising Http404
if the resulting list is empty.
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("No MyModel matches the given query.")
Nov 27, 2024