174 lines
6.6 KiB
Plaintext
174 lines
6.6 KiB
Plaintext
==============
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Built-in Views
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==============
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.. module:: django.views
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:synopsis: Django's built-in views.
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Several of Django's built-in views are documented in
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:doc:`/topics/http/views` as well as elsewhere in the documentation.
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Serving files in development
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============================
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.. function:: static.serve(request, path, document_root, show_indexes=False)
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There may be files other than your project's static assets that, for
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convenience, you'd like to have Django serve for you in local development.
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The :func:`~django.views.static.serve` view can be used to serve any directory
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you give it. (This view is **not** hardened for production use and should be
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used only as a development aid; you should serve these files in production
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using a real front-end web server).
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The most likely example is user-uploaded content in :setting:`MEDIA_ROOT`.
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``django.contrib.staticfiles`` is intended for static assets and has no
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built-in handling for user-uploaded files, but you can have Django serve your
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:setting:`MEDIA_ROOT` by appending something like this to your URLconf::
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from django.conf import settings
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from django.views.static import serve
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# ... the rest of your URLconf goes here ...
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if settings.DEBUG:
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urlpatterns += [
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url(r'^media/(?P<path>.*)$', serve, {
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'document_root': settings.MEDIA_ROOT,
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}),
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]
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Note, the snippet assumes your :setting:`MEDIA_URL` has a value of
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``'/media/'``. This will call the :func:`~django.views.static.serve` view,
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passing in the path from the URLconf and the (required) ``document_root``
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parameter.
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Since it can become a bit cumbersome to define this URL pattern, Django
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ships with a small URL helper function :func:`~django.conf.urls.static.static`
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that takes as parameters the prefix such as :setting:`MEDIA_URL` and a dotted
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path to a view, such as ``'django.views.static.serve'``. Any other function
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parameter will be transparently passed to the view.
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.. _error-views:
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Error views
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===========
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Django comes with a few views by default for handling HTTP errors. To override
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these with your own custom views, see :ref:`customizing-error-views`.
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.. _http_not_found_view:
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The 404 (page not found) view
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-----------------------------
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.. function:: defaults.page_not_found(request, exception, template_name='404.html')
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When you raise :exc:`~django.http.Http404` from within a view, Django loads a
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special view devoted to handling 404 errors. By default, it's the view
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:func:`django.views.defaults.page_not_found`, which either produces a very
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simple "Not Found" message or loads and renders the template ``404.html`` if
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you created it in your root template directory.
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The default 404 view will pass two variables to the template: ``request_path``,
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which is the URL that resulted in the error, and ``exception``, which is a
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useful representation of the exception that triggered the view (e.g. containing
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any message passed to a specific ``Http404`` instance).
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Three things to note about 404 views:
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* The 404 view is also called if Django doesn't find a match after
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checking every regular expression in the URLconf.
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* The 404 view is passed a :class:`~django.template.RequestContext` and
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will have access to variables supplied by your template context
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processors (e.g. ``MEDIA_URL``).
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* If :setting:`DEBUG` is set to ``True`` (in your settings module), then
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your 404 view will never be used, and your URLconf will be displayed
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instead, with some debug information.
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.. versionchanged:: 1.10
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Passing a nonexistent ``template_name`` will raise ``TemplateDoesNotExist``.
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.. _http_internal_server_error_view:
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The 500 (server error) view
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---------------------------
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.. function:: defaults.server_error(request, template_name='500.html')
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Similarly, Django executes special-case behavior in the case of runtime errors
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in view code. If a view results in an exception, Django will, by default, call
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the view ``django.views.defaults.server_error``, which either produces a very
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simple "Server Error" message or loads and renders the template ``500.html`` if
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you created it in your root template directory.
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The default 500 view passes no variables to the ``500.html`` template and is
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rendered with an empty ``Context`` to lessen the chance of additional errors.
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If :setting:`DEBUG` is set to ``True`` (in your settings module), then
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your 500 view will never be used, and the traceback will be displayed
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instead, with some debug information.
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.. versionchanged:: 1.10
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Passing a nonexistent ``template_name`` will raise ``TemplateDoesNotExist``.
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.. _http_forbidden_view:
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The 403 (HTTP Forbidden) view
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-----------------------------
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.. function:: defaults.permission_denied(request, exception, template_name='403.html')
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In the same vein as the 404 and 500 views, Django has a view to handle 403
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Forbidden errors. If a view results in a 403 exception then Django will, by
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default, call the view ``django.views.defaults.permission_denied``.
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This view loads and renders the template ``403.html`` in your root template
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directory, or if this file does not exist, instead serves the text
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"403 Forbidden", as per :rfc:`7231#section-6.5.3` (the HTTP 1.1 Specification).
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The template context contains ``exception``, which is the unicode
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representation of the exception that triggered the view.
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``django.views.defaults.permission_denied`` is triggered by a
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:exc:`~django.core.exceptions.PermissionDenied` exception. To deny access in a
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view you can use code like this::
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from django.core.exceptions import PermissionDenied
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def edit(request, pk):
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if not request.user.is_staff:
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raise PermissionDenied
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# ...
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.. versionchanged:: 1.10
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Passing a nonexistent ``template_name`` will raise ``TemplateDoesNotExist``.
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.. _http_bad_request_view:
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The 400 (bad request) view
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--------------------------
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.. function:: defaults.bad_request(request, exception, template_name='400.html')
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When a :exc:`~django.core.exceptions.SuspiciousOperation` is raised in Django,
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it may be handled by a component of Django (for example resetting the session
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data). If not specifically handled, Django will consider the current request a
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'bad request' instead of a server error.
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``django.views.defaults.bad_request``, is otherwise very similar to the
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``server_error`` view, but returns with the status code 400 indicating that
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the error condition was the result of a client operation. By default, nothing
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related to the exception that triggered the view is passed to the template
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context, as the exception message might contain sensitive information like
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filesystem paths.
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``bad_request`` views are also only used when :setting:`DEBUG` is ``False``.
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.. versionchanged:: 1.10
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Passing a nonexistent ``template_name`` will raise ``TemplateDoesNotExist``.
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