---
title: "Built-in Views"
version: 3.0
locale: zh-hans
source: https://docs.djangoproject.com/zh-hans/3.0/ref/views/
canonical: https://djangodocs.dev/zh-hans/3.0/ref/views/
---
# Built-in Views

Several of Django's built-in views are documented in
[编写视图](/zh-hans/3.0/topics/http/views/) as well as elsewhere in the documentation.

## Serving files in development

#### `static.serve(request, path, document_root, show_indexes=False)`

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()`](#django.views.static.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`](/zh-hans/3.0/ref/settings/#std-setting-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`](/zh-hans/3.0/ref/settings/#std-setting-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`](/zh-hans/3.0/ref/settings/#std-setting-MEDIA_URL) has a value of
`'/media/'`. This will call the [`serve()`](#django.views.static.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()`](/zh-hans/3.0/ref/urls/#django.conf.urls.static.static)
that takes as parameters the prefix such as [`MEDIA_URL`](/zh-hans/3.0/ref/settings/#std-setting-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.

## 错误的视图

Django comes with a few views by default for handling HTTP errors. To override
these with your own custom views, see [自定义报错视图](/zh-hans/3.0/topics/http/views/#customizing-error-views).

### 404 (page not found) 视图

#### `defaults.page_not_found(request, exception, template_name='404.html')`

When you raise [`Http404`](/zh-hans/3.0/topics/http/views/#django.http.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()`](#django.views.defaults.page_not_found), which either produces a "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).

关于404视图需要注意的三个要点：

- 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`](/zh-hans/3.0/ref/templates/api/#django.template.RequestContext) and
  will have access to variables supplied by your template context
  processors (e.g. `MEDIA_URL`).
- 如果 [`DEBUG`](/zh-hans/3.0/ref/settings/#std-setting-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。

### The 500 (server error) view

#### `defaults.server_error(request, template_name='500.html')`

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
"Server Error" message or loads and renders the template `500.html` if you
created 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。

如果 [`DEBUG`](/zh-hans/3.0/ref/settings/#std-setting-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。

### 403 (HTTP Forbidden) 视图

#### `defaults.permission_denied(request, exception, template_name='403.html')`

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\`\`。

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**](https://datatracker.ietf.org/doc/html/rfc7231.html#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
[`PermissionDenied`](/zh-hans/3.0/ref/exceptions/#django.core.exceptions.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
    # ...
```

### 400 (bad request) 视图

#### `defaults.bad_request(request, exception, template_name='400.html')`

When a [`SuspiciousOperation`](/zh-hans/3.0/ref/exceptions/#django.core.exceptions.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``视图也仅在以下情况下使用 :setting:`DEBUG` 为 ``False```。