Django快捷函数

发布时间:2019-08-11 12:09--阅读:270--评论:0条

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()
render(request, template_name, context=None, content_type=None, status=None, using=None)

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没有提供返回:class:~django.template.response.TemplateResponse 的快捷函数,因为:class:~django.template.response.TemplateResponse 的构造函数提供了与:func:`render()`相同的方便程度。

必选参数
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 template loading documentation 。

可选参数
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类型默认为:设置:setting:DEFAULT_CONTENT_TYPE 设置的值。

status

响应的状态代码默认为“200”。

using

用于加载模板的模板引擎的 :setting:`NAME ` 。

例如
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')


render_to_response()
render_to_response(template_name, context=None, content_type=None, status=None, using=None)[源代码]¶

2.0 版后已移除.

该函数之前引入了:func:render ,并类似地工作,只是它不使响应中的 request 可用。

redirect()
redirect(to, permanent=False, *args, **kwargs)[源代码]¶

将一个 HttpResponseRedirect 返回到传递的参数的适当URL。

论点可以是:

  • A model: the model's get_absolute_url() function will be called.
  • A view name, possibly with arguments: reverse() will be used to reverse-resolve the name.
  • An absolute or relative URL, which will be used as-is for the redirect location.

By default issues a temporary redirect; pass permanent=True to issue a permanent redirect.

示例
You can use the redirect() function in a number of ways.

1.By passing some object; that object's get_absolute_url() method will be called to figure out the redirect URL:

from django.shortcuts import redirect
 
def my_view(request):
    ...
    obj = MyModel.objects.get(...)
    return redirect(obj)


2.By passing the name of a view and optionally some positional or keyword arguments; the URL will be reverse resolved using the reverse() method:

def my_view(request):
    ...
    return redirect('some-view-name', foo='bar')


By passing a hardcoded URL to redirect to:

def my_view(request):
    ...
    return redirect('/some/url/')


This also works with full URLs:

def my_view(request):
    ...
    return redirect('https://example.com/')


By default, redirect() returns a temporary redirect. All of the above forms accept a permanent argument; if set to True a permanent redirect will be returned:

def my_view(request):
    ...
    obj = MyModel.objects.get(...)
    return redirect(obj, permanent=True)


get_object_or_404()
get_object_or_404(klass, *args, **kwargs)[源代码]¶

Calls get() on a given model manager, but it raises Http404 instead of the model's DoesNotExist exception.

必选参数
klass

A Model class, a Manager, or a QuerySet instance from which to get the object.

**kwargs

Lookup parameters, which should be in the format accepted by get() and filter().

例如
The following example gets the object with the primary key of 1 from MyModel:

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.")


The most common use case is to pass a Model, as shown above. However, you can also pass a QuerySet instance:

queryset = Book.objects.filter(title__startswith='M')
get_object_or_404(queryset, pk=1)


The above example is a bit contrived since it's equivalent to doing:

get_object_or_404(Book, title__startswith='M', pk=1)


but it can be useful if you are passed the queryset variable from somewhere else.

Finally, you can also use a Manager. This is useful for example if you have a custom manager:

get_object_or_404(Book.dahl_objects, title='Matilda')


You can also use related managers:

author = Author.objects.get(name='Roald Dahl')
get_object_or_404(author.book_set, title='Matilda')


Note: As with get(), a MultipleObjectsReturned exception will be raised if more than one object is found.

get_list_or_404()
get_list_or_404(klass, *args, **kwargs)[源代码]¶

Returns the result of filter() on a given model manager cast to a list, raising Http404 if the resulting list is empty.

必选参数
klass

A Model, Manager or QuerySet instance from which to get the list.

**kwargs

Lookup parameters, which should be in the format accepted by get() and filter().

例如
The following example gets all published objects from MyModel:

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.")
 

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