类的继承
ListView处理的都是多个对象
DeleteView处理的都是单个对象
自定义类视图
NewsListView继承自
LoginRequiredMixin和ListView
自定义一些参数
# 网站的所有内容要求用户登录后才能看到 ==> LoginRequiredMixin
class NewsListView(LoginRequiredMixin, ListView):
"""首页动态"""
model = News
queryset = News.objects.all()
paginate_by = 20 # 分页：url中的?page=
page_kwarg = 'p'
ordering = 'created_at' # ("x", "y")
context_object_name = "news_list" # queryset在模板中的名字(默认: 模型类名_list / object_list)
template_name = "news/news_list.html" # 默认: '模型类名_list.html'
def get_ordering(self):
"""
自定义复杂的排序
:return:
"""
...
def get_paginate_by(self, queryset):
"""
处理分页
:param queryset: 要排序的查询集对象
:return:
"""
...
def get_queryset(self):
"""
获取视图的对象列表
:return: django查询集
"""
return News.objects.filter(reply=False)
def get_context_data(self, *, object_list=None, **kwargs):
"""
添加额外的上下文
:param object_list:
:param kwargs:
:return:
"""
context = super().get_context_data()
context["views"] = 100
return context
ListView的多继承
继承自
MultipleObjectTemplateResponseMixin和BaseListView
class ListView(MultipleObjectTemplateResponseMixin, BaseListView):
...
MultipleObjectTemplate…
继承自
TemplateResponseMixin
class MultipleObjectTemplateResponseMixin(TemplateResponseMixin):
"""Mixin for responding with a template and list of objects."""
template_name_suffix = '_list'
def get_template_names(self):
"""
获取模板的名字
"""
TemplateResponseMixin
class TemplateResponseMixin:
"""A mixin that can be used to render a template."""
template_name = None
template_engine = None
response_class = TemplateResponse
content_type = None
def render_to_response(self, context, **response_kwargs):
"""
将上下文(context)中的内容返回给前端
"""
BaseListView
继承自
MultipleObjectMixin和View
MultipleObjectMixin
class MultipleObjectMixin(ContextMixin):
"""A mixin for views manipulating multiple objects."""
allow_empty = True
# 这些参数都可以在自定义的时候重写
queryset = None
model = None
paginate_by = None
paginate_orphans = 0
context_object_name = None
paginator_class = Paginator
page_kwarg = 'page'
ordering = None
def get_queryset(self):
"""获取视图的列表"""
if self.queryset is not None:
# 如果自定义了queryset
queryset = self.queryset
if isinstance(queryset, QuerySet):
# 如果queryset是QuerySet类型，则返回queryset.all()--不是模型类的所有对象
queryset = queryset.all()
elif self.model is not None:
# 如果自定义了model，则返回整个模型类对象
queryset = self.model._default_manager.all()
else:
# 如果queryset和model都为空，则报错
raise ImproperlyConfigured(
"%(cls)s is missing a QuerySet. Define "
"%(cls)s.model, %(cls)s.queryset, or override "
"%(cls)s.get_queryset()." % {
'cls': self.__class__.__name__
}
)
# 对返回的queryset进行排序，直接获取ordring属性
ordering = self.get_ordering()
if ordering:
# 如果是字符串的话，自动变成元组的形式
if isinstance(ordering, str):
ordering = (ordering,)
# 如果是多个，就必须使用元组，然后使用*ordering解压赋值
queryset = queryset.order_by(*ordering)
return queryset
def get_ordering(self):
"""获取排序方式"""
return self.ordering
def get_context_object_name(self, object_list):
"""获取template中变量的名字"""
# 首先判断我们有没有自定义，有--返回自定义的值
if self.context_object_name:
return self.context_object_name
# 没有值的时候，则获取model_name + "_list"
elif hasattr(object_list, 'model'):
return '%s_list' % object_list.model._meta.model_name
else:
return None
def get_context_data(self, *, object_list=None, **kwargs):
"""
获取额外的上下文
使用方法:
class NewsListView(LoginRequiredMixin, ListView):
def get_context_data(self, *, object_list=None, **kwargs):
'''
添加额外的上下文
:param object_list:
:param kwargs:
:return:
'''
context = super().get_context_data()
context["views"] = 100 # 自定义要显示的上下文
return context
"""
# 先获取对象列表
queryset = object_list if object_list is not None else self.object_list
# 在这里获取一页中展示的内容条数，多少个，get_paginate_by获取到用户自定义的值
page_size = self.get_paginate_by(queryset)
# 在这里获取当前类，在模板文件中的名字
context_object_name = self.get_context_object_name(queryset)
# 如果分页存在，通过paginate_queryset对查询集进行分页
if page_size:
paginator,page,queryset,is_paginated = self.paginate_queryset(queryset,page_size)
# context--上下文，传递到前端的时候，在模板文件中可以直接获取并使用
context = {
'paginator': paginator, # 分页器
'page_obj': page, # 页码
'is_paginated': is_paginated, # 每一页的查询集
'object_list': queryset # 是否还有分页
}
else:
# 如果没有page_size，就直接返回queryset
context = {
'paginator': None,
'page_obj': None,
'is_paginated': False,
'object_list': queryset
}
# 如果用户自定义了context_object_name，则在这里重新赋值，并更新字典
if context_object_name is not None:
context[context_object_name] = queryset
context.update(kwargs)
# 最后重载父类方法返回，
return super().get_context_data(**context)
ContextMixin
class ContextMixin:
"""
A default context mixin that passes the keyword arguments received by
get_context_data() as the template context.
"""
extra_context = None
def get_context_data(self, **kwargs):
kwargs.setdefault('view', self)
if self.extra_context is not None:
kwargs.update(self.extra_context)
return kwargs
View
里面定义了八种常见请求方式
class View:
http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace']
...
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