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()
render
(request, template_name, context=None, content_type=None, status=None, using=None)
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().
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. 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.
Optional arguments
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.
Example
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()
redirect
(to, \args, permanent=False, **kwargs*)
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 issues a temporary redirect; pass permanent=True
to issue a permanent redirect.
Examples
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)
get_object_or_404()
get_object_or_404
(klass, \args, **kwargs*)
Calls get() on a given model manager, but it raises Http404 instead of the model’s DoesNotExist exception.
Arguments
klass
A Model class, a Manager, or a QuerySet instance from which to get the object.
*args
**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):
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()
get_list_or_404
(klass, \args, **kwargs*)
Returns the result of filter() on a given model manager cast to a list, raising Http404 if the resulting list is empty.
Arguments
klass
A Model, Manager or QuerySet instance from which to get the list.
*args
**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("No MyModel matches the given query.")