Several of Django's built-in views are documented in\n编写视图 as well as elsewhere in the documentation.
\nThere may be files other than your project's static assets that, for\nconvenience, you'd like to have Django serve for you in local development.\nThe serve() view can be used to serve any directory\nyou give it. (This view is not hardened for production use and should be\nused only as a development aid; you should serve these files in production\nusing a real front-end web server).
The most likely example is user-uploaded content in MEDIA_ROOT.\ndjango.contrib.staticfiles is intended for static assets and has no\nbuilt-in handling for user-uploaded files, but you can have Django serve your\nMEDIA_ROOT by appending something like this to your URLconf:
from django.conf import settings\nfrom django.urls import re_path\nfrom django.views.static import serve\n\n# ... the rest of your URLconf goes here ...\n\nif settings.DEBUG:\n urlpatterns += [\n re_path(r'^media/(?P<path>.*)$', serve, {\n 'document_root': settings.MEDIA_ROOT,\n }),\n ]\nNote, the snippet assumes your MEDIA_URL has a value of\n'/media/'. This will call the serve() view,\npassing in the path from the URLconf and the (required) document_root\nparameter.
Since it can become a bit cumbersome to define this URL pattern, Django\nships with a small URL helper function static()\nthat takes as parameters the prefix such as MEDIA_URL and a dotted\npath to a view, such as 'django.views.static.serve'. Any other function\nparameter will be transparently passed to the view.
Django comes with a few views by default for handling HTTP errors. To override\nthese with your own custom views, see 自定义报错视图.
\nWhen you raise Http404 from within a view, Django loads a\nspecial view devoted to handling 404 errors. By default, it's the view\ndjango.views.defaults.page_not_found(), which either produces a "Not\nFound" message or loads and renders the template 404.html if you created it\nin your root template directory.
The default 404 view will pass two variables to the template: request_path,\nwhich is the URL that resulted in the error, and exception, which is a\nuseful representation of the exception that triggered the view (e.g. containing\nany message passed to a specific Http404 instance).
关于404视图需要注意的三个要点：
\nThe 404 view is also called if Django doesn't find a match after\nchecking every regular expression in the URLconf.
The 404 view is passed a RequestContext and\nwill have access to variables supplied by your template context\nprocessors (e.g. MEDIA_URL).
如果 DEBUG 设置为``True``（在您的配置模块中），那么您的404视图将永远不会被使用，作为替代，你的URL配置与一些调试信息将会被显示。
Similarly, Django executes special-case behavior in the case of runtime errors\nin view code. If a view results in an exception, Django will, by default, call\nthe view django.views.defaults.server_error, which either produces a\n"Server Error" message or loads and renders the template 500.html if you\ncreated it in your root template directory.
默认的500视图不会将变量传递给``500.html``模板，并使用空的``Context``渲染以减少出现附加错误的可能性。
\n如果 DEBUG 设置为``True``（在您的配置模块中），那么您的500视图将永远不会被使用，作为替代，调用回溯与一些调试信息将会被显示。
与404和500视图一样，Django有处理403 Forbidden错误的视图。如果视图导致403异常，那么Django默认会调用视图``django.views.defaults.permission_denied``。
\n这个视图从你的根模板目录加载和渲染 403.html 模板，如果这个文件不存在将会显示“403 Forbidden”，按照 RFC 7231 Section 6.5.3 （HTTP 1.1 规范）。 模板上下文包含 exception，它是触发视图的异常的字符串表示形式。
django.views.defaults.permission_denied is triggered by a\nPermissionDenied exception. To deny access in a\nview you can use code like this:
from django.core.exceptions import PermissionDenied\n\ndef edit(request, pk):\n if not request.user.is_staff:\n raise PermissionDenied\n # ...\nWhen a SuspiciousOperation is raised in Django,\nit may be handled by a component of Django (for example resetting the session\ndata). If not specifically handled, Django will consider the current request a\n'bad request' instead of a server error.
django.views.defaults.bad_request, is otherwise very similar to the\nserver_error view, but returns with the status code 400 indicating that\nthe error condition was the result of a client operation. By default, nothing\nrelated to the exception that triggered the view is passed to the template\ncontext, as the exception message might contain sensitive information like\nfilesystem paths.
bad_request``视图也仅在以下情况下使用 :setting:`DEBUG` 为 ``False。