Several of Django’s built-in views are documented in Writing views as well as elsewhere in the documentation.
There may be files other than your project’s static assets that, for
convenience, you’d like to have Django serve for you in local development.
The serve() view can be used to serve any directory
you give it. (This view is not hardened for production use and should be
used only as a development aid; you should serve these files in production
using a real front-end web server).
The most likely example is user-uploaded content in MEDIA_ROOT.
django.contrib.staticfiles is intended for static assets and has no
built-in handling for user-uploaded files, but you can have Django serve your
MEDIA_ROOT by appending something like this to your URLconf:
from django.conf import settings
from django.urls import re_path
from django.views.static import serve
# ... the rest of your URLconf goes here ...
if settings.DEBUG:
urlpatterns += [
re_path(r'^media/(?P<path>.*)$', serve, {
'document_root': settings.MEDIA_ROOT,
}),
]
Note, the snippet assumes your MEDIA_URL has a value of
'/media/'. This will call the serve() view,
passing in the path from the URLconf and the (required) document_root
parameter.
Since it can become a bit cumbersome to define this URL pattern, Django
ships with a small URL helper function static()
that takes as parameters the prefix such as MEDIA_URL and a dotted
path to a view, such as 'django.views.static.serve'. Any other function
parameter will be transparently passed to the view.
Django comes with a few views by default for handling HTTP errors. To override these with your own custom views, see Customizing error views.
When you raise Http404 from within a view, Django loads a
special view devoted to handling 404 errors. By default, it’s the view
django.views.defaults.page_not_found(), which either produces a very
simple “Not Found” message or loads and renders the template 404.html if
you created it in your root template directory.
The default 404 view will pass two variables to the template: request_path,
which is the URL that resulted in the error, and exception, which is a
useful representation of the exception that triggered the view (e.g. containing
any message passed to a specific Http404 instance).
Three things to note about 404 views:
The 404 view is also called if Django doesn’t find a match after checking every regular expression in the URLconf.
The 404 view is passed a RequestContext and
will have access to variables supplied by your template context
processors (e.g. MEDIA_URL).
If DEBUG is set to True (in your settings module), then
your 404 view will never be used, and your URLconf will be displayed
instead, with some debug information.
Similarly, Django executes special-case behavior in the case of runtime errors
in view code. If a view results in an exception, Django will, by default, call
the view django.views.defaults.server_error, which either produces a very
simple “Server Error” message or loads and renders the template 500.html if
you created it in your root template directory.
The default 500 view passes no variables to the 500.html template and is
rendered with an empty Context to lessen the chance of additional errors.
If DEBUG is set to True (in your settings module), then
your 500 view will never be used, and the traceback will be displayed
instead, with some debug information.
In the same vein as the 404 and 500 views, Django has a view to handle 403
Forbidden errors. If a view results in a 403 exception then Django will, by
default, call the view django.views.defaults.permission_denied.
This view loads and renders the template 403.html in your root template
directory, or if this file does not exist, instead serves the text
“403 Forbidden”, as per RFC 7231#section-6.5.3 (the HTTP 1.1 Specification).
The template context contains exception, which is the string
representation of the exception that triggered the view.
django.views.defaults.permission_denied is triggered by a
PermissionDenied exception. To deny access in a
view you can use code like this:
from django.core.exceptions import PermissionDenied
def edit(request, pk):
if not request.user.is_staff:
raise PermissionDenied
# ...
When a SuspiciousOperation is raised in Django,
it may be handled by a component of Django (for example resetting the session
data). If not specifically handled, Django will consider the current request a
‘bad request’ instead of a server error.
django.views.defaults.bad_request, is otherwise very similar to the
server_error view, but returns with the status code 400 indicating that
the error condition was the result of a client operation. By default, nothing
related to the exception that triggered the view is passed to the template
context, as the exception message might contain sensitive information like
filesystem paths.
bad_request views are also only used when DEBUG is False.
Dec 25, 2023