Django shortcut functions

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.

Required arguments

klass

A Model class, a Manager, or a 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):
    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.

Required arguments

klass

A Model, Manager or 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("No MyModel matches the given query.")