Django 便捷函数Link to this heading
包 django.shortcuts 收集助手函数和“跨”多级mvc的类,换句话说,为了方便起见,这些函数/类引入受控耦合。
render()Link to this heading
- render(request, template_name, context=None, content_type=None, status=None, using=None)Link to this definition
将给定的模板与给定的上下文字典组合在一起,并以渲染的文本返回一个
HttpResponse对象。Django does not provide a shortcut function which returns a
TemplateResponsebecause the constructor ofTemplateResponseoffers the same level of convenience asrender().
必选参数Link to this heading
request用于生成此响应的请求对象。
template_name要使用的模板的全名或模板名称的序列。如果给定一个序列,则将使用存在的第一个模板。有关如何查找模板的更多信息,请参见 模板加载文档 。
可选参数Link to this heading
context要添加到模板上下文的值的字典。 默认情况下,这是一个空的字典。 如果字典中的值是可调用的,则视图将在渲染模板之前调用它。
content_type用于结果文档的 MIME 类型。默认
'text/html'。status响应的状态码默认为
200。using用于加载模板的模板引擎的
NAME。
例如Link to this heading
下面的示例使用 MIME 类型呈现模板 myapp/index.html 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",
)
此示例相当于:
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()Link to this heading
- redirect(to, *args, permanent=False, preserve_request=False, **kwargs)Link to this definition
返回一个
HttpResponseRedirect,指向传递参数的适当 URL。参数可以是:
A model: the model's
get_absolute_url()function will be called.视图名,可能带有的参数:
reverse()将被用于反向解析名称。一个绝对或相对 URL,将按原样用作重定向位置。
By default, a temporary redirect is issued with a 302 status code. If
permanent=True, a permanent redirect is issued with a 301 status code.If
preserve_request=True, the response instructs the user agent to preserve the method and body of the original request when issuing the redirect. In this case, temporary redirects use a 307 status code, and permanent redirects use a 308 status code. This is better illustrated in the following table:permanent
preserve_request
HTTP status code
TrueFalse301
FalseFalse302
FalseTrue307
TrueTrue308
示例Link to this heading
你可以通过多种方法使用 redirect() 函数。
传递对象,对象的
get_absolute_url()方法将被调用来指向重定向地址:from django.shortcuts import redirect def my_view(request): ... obj = MyModel.objects.get(...) return redirect(obj)传递视图名和一些可选的位置或关键字参数;URL 将使用
reverse()方法来反向解析:def my_view(request): ... return redirect("some-view-name", foo="bar")通过传递一个硬编码的 URL 来进行重定向:
def my_view(request): ... return redirect("/some/url/")这也适用于完整的 URL:
def my_view(request): ... return redirect("https://example.com/")
默认情况下,redirect() 返回临时重定向。所有以上形式都接受 permanent 参数;如果设置为 True 会返回一个永久重定向:
def my_view(request):
...
obj = MyModel.objects.get(...)
return redirect(obj, permanent=True)
Additionally, the preserve_request argument can be used to preserve the
original HTTP method:
def my_view(request):
# ...
obj = MyModel.objects.get(...)
if request.method in ("POST", "PUT"):
# Redirection preserves the original request method.
return redirect(obj, preserve_request=True)
# ...
resolve_url()Link to this heading
- resolve_url(to, *args, **kwargs)Link to this definition
Returns a URL string by resolving and normalizing the given
toargument into a concrete URL. The parametertomay be:An object implementing
get_absolute_url(), in which case the method will be called and its result returned.A view name, view function, or view class, possibly with arguments passed as
*argsand**kwargs, in which casereverse()will be used to reverse-resolve the view.A URL string, which will be returned unchanged.
This function is used internally by the
redirect()shortcut to determine the target URL for the redirect location.
示例Link to this heading
Resolving a URL for a model that defines
get_absolute_url():models.pyfrom django.db import models from django.urls import reverse class Article(models.Model): title = models.CharField(max_length=100) def get_absolute_url(self): return reverse("article-detail", args=[self.pk])views.pyfrom django.http import JsonResponse from django.shortcuts import get_object_or_404, resolve_url from .models import Article def article_api_view(request, pk): """Return metadata about an article, including its canonical URL.""" article = get_object_or_404(Article, pk=pk) return JsonResponse( { "id": article.pk, "title": article.title, "url": resolve_url(article), } )Resolving a target URL for use outside of a redirect, such as in an HTTP response header:
from django.conf import settings from django.http import HttpResponse from django.shortcuts import resolve_url def login_success(request): response = HttpResponse("Login successful") response["X-Next-URL"] = resolve_url(settings.LOGIN_REDIRECT_URL) return response
get_object_or_404()Link to this heading
- get_object_or_404(klass, *args, **kwargs)Link to this definition
- aget_object_or_404(klass, *args, **kwargs)Link to this definition
异步版本:
aget_object_or_404()Calls
get()on a given model manager, but it raisesHttp404instead of the model'sDoesNotExistexception.
参数Link to this heading
例如Link to this heading
下面的例子是展示从 MyModel 中获取主键为1的对象:
from django.shortcuts import get_object_or_404
def my_view(request):
obj = get_object_or_404(MyModel, pk=1)
此示例相当于:
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.")
如上所示,最常用的使用案例是传递 Model 。但是,你也可以传递一个 QuerySet 实例:
queryset = Book.objects.filter(title__startswith="M")
get_object_or_404(queryset, pk=1)
以上例子有点冗长,因为它等同于:
get_object_or_404(Book, title__startswith="M", pk=1)
但如果你是从其他地方传递的 queryset 变量,那它会很有用。
最后,你也可以使用 Manager 。如果你有自定义管理器( custom manager )会很有用:
get_object_or_404(Book.dahl_objects, title="Matilda")
你也可以使用关联管理器( related managers ):
author = Author.objects.get(name="Roald Dahl")
get_object_or_404(author.book_set, title="Matilda")
注意:与 get() 一样,如果查询结果有多个对象,那么会引发 MultipleObjectsReturned 异常。
get_list_or_404()Link to this heading
- get_list_or_404(klass, *args, **kwargs)Link to this definition
- aget_list_or_404(klass, *args, **kwargs)Link to this definition
异步版本:
aget_list_or_404()Returns the result of
filter()on a given model manager cast to a list, raisingHttp404if the resulting list is empty.
参数Link to this heading
例如Link to this heading
下面的例子展示从 MyModel 中获取所有 published=True 的对象:
from django.shortcuts import get_list_or_404
def my_view(request):
my_objects = get_list_or_404(MyModel, published=True)
此示例相当于:
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.")