django中如何实现model对象加入装饰器-创新互联
这篇文章将为大家详细讲解有关django中如何实现model对象加入装饰器，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。
＃在现有的对象加入日期修改Mixin
class Person(CreationModificationDateMixin):
多出字段：
| created | datetime(6) | NO | | NULL | | | modified | datetime(6) | YES | | NULL | | |
＃加入url MinIn
class Person(UrlMixin):
＃加入原数据MInxIn
class Person(MetaTagsMixin):
多出字段：
| meta_keywords | varchar(255) | NO | | NULL | | | meta_description | varchar(255) | NO | | NULL | | | meta_author | varchar(255) | NO | | NULL | | | meta_copyright | varchar(255) | NO | | NULL | | |
# -*- coding: UTF-8 -*-
from __future__ import unicode_literals
import urlparse
from django.conf import settings
from django.utils.timezone import now as timezone_now
from django.utils.safestring import mark_safe
from django.template.defaultfilters import escape
from django.db import models
from django.utils.translation import ugettext_lazy as _
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes.fields import GenericForeignKey
from django.core.exceptions import FieldError
### See recipe "Model mixin with URL-related methods"
class UrlMixin(models.Model):
"""
A replacement for get_absolute_url()
Models extending this mixin should have either get_url or get_url_path implemented.
http://code.djangoproject.com/wiki/ReplacingGetAbsoluteUrl
"""
class Meta:
abstract = True
def get_url(self):
if hasattr(self.get_url_path, "dont_recurse"):
raise NotImplementedError
try:
path = self.get_url_path()
except NotImplementedError:
raise
website_url = getattr(settings, "DEFAULT_WEBSITE_URL", "http://127.0.0.1:8000")
return website_url + path
get_url.dont_recurse = True
def get_url_path(self):
if hasattr(self.get_url, "dont_recurse"):
raise NotImplementedError
try:
url = self.get_url()
except NotImplementedError:
raise
bits = urlparse.urlparse(url)
return urlparse.urlunparse(("", "") + bits[2:])
get_url_path.dont_recurse = True
def get_absolute_url(self):
return self.get_url_path()
### See recipe "Model mixin handling creation and modification dates"
class CreationModificationDateMixin(models.Model):
"""
Abstract base class with a creation and modification date and time
"""
created = models.DateTimeField(
_("creation date and time"),
editable=False,
)
modified = models.DateTimeField(
_("modification date and time"),
null=True,
editable=False,
)
def save(self, *args, **kwargs):
if not self.pk:
self.created = timezone_now()
else:
# To ensure that we have a creation data always, we add this one
if not self.created:
self.created = timezone_now()
self.modified = timezone_now()
super(CreationModificationDateMixin, self).save(*args, **kwargs)
save.alters_data = True
class Meta:
abstract = True
### See recipe "Model mixin taking care of meta tags"
class MetaTagsMixin(models.Model):
"""
Abstract base class for meta tags in the <head> section
"""
meta_keywords = models.CharField(
_("Keywords"),
max_length=255,
blank=True,
help_text=_("Separate keywords by comma."),
)
meta_description = models.CharField(
_("Description"),
max_length=255,
blank=True,
)
meta_author = models.CharField(
_("Author"),
max_length=255,
blank=True,
)
meta_copyright = models.CharField(
_("Copyright"),
max_length=255,
blank=True,
)
class Meta:
abstract = True
def get_meta_keywords(self):
meta_tag = ""
if self.meta_keywords:
meta_tag = """<meta name="keywords" content="%s" />\n""" % escape(self.meta_keywords)
return mark_safe(meta_tag)
def get_meta_description(self):
meta_tag = ""
if self.meta_description:
meta_tag = """<meta name="description" content="%s" />\n""" % escape(self.meta_description)
return mark_safe(meta_tag)
def get_meta_author(self):
meta_tag = ""
if self.meta_author:
meta_tag = """<meta name="author" content="%s" />\n""" % escape(self.meta_author)
return mark_safe(meta_tag)
def get_meta_copyright(self):
meta_tag = ""
if self.meta_copyright:
meta_tag = """<meta name="copyright" content="%s" />\n""" % escape(self.meta_copyright)
return mark_safe(meta_tag)
def get_meta_tags(self):
return mark_safe("".join((
self.get_meta_keywords(),
self.get_meta_description(),
self.get_meta_author(),
self.get_meta_copyright(),
)))
### See recipe "Model mixin handling generic relations"
def object_relation_mixin_factory(
prefix=None,
prefix_verbose=None,
add_related_name=False,
limit_content_type_choices_to={},
limit_object_choices_to={},
is_required=False,
):
"""
returns a mixin class for generic foreign keys using
"Content type - object Id" with dynamic field names.
This function is just a class generator
Parameters:
prefix : a prefix, which is added in front of the fields
prefix_verbose : a verbose name of the prefix, used to
generate a title for the field column
of the content object in the Admin.
add_related_name : a boolean value indicating, that a
related name for the generated content
type foreign key should be added. This
value should be true, if you use more
than one ObjectRelationMixin in your model.
The model fields are created like this:
<<prefix>>_content_type : Field name for the "content type"
<<prefix>>_object_id : Field name for the "object Id"
<<prefix>>_content_object : Field name for the "content object"
"""
p = ""
if prefix:
p = "%s_" % prefix
content_type_field = "%scontent_type" % p
object_id_field = "%sobject_id" % p
content_object_field = "%scontent_object" % p
class TheClass(models.Model):
class Meta:
abstract = True
if add_related_name:
if not prefix:
raise FieldError("if add_related_name is set to True, a prefix must be given")
related_name = prefix
else:
related_name = None
optional = not is_required
ct_verbose_name = (
_("%s's type (model)") % prefix_verbose
if prefix_verbose
else _("Related object's type (model)")
)
content_type = models.ForeignKey(
ContentType,
verbose_name=ct_verbose_name,
related_name=related_name,
blank=optional,
null=optional,
help_text=_("Please select the type (model) for the relation, you want to build."),
limit_choices_to=limit_content_type_choices_to,
)
fk_verbose_name = (prefix_verbose or _("Related object"))
object_id = models.CharField(
fk_verbose_name,
blank=optional,
null=False,
help_text=_("Please enter the ID of the related object."),
max_length=255,
default="", # for south migrations
)
object_id.limit_choices_to = limit_object_choices_to
# can be retrieved by MyModel._meta.get_field("object_id").limit_choices_to
content_object = GenericForeignKey(
ct_field=content_type_field,
fk_field=object_id_field,
)
TheClass.add_to_class(content_type_field, content_type)
TheClass.add_to_class(object_id_field, object_id)
TheClass.add_to_class(content_object_field, content_object)
return TheClass关于“django中如何实现model对象加入装饰器”这篇文章就分享到这里了，希望以上内容可以对大家有一定的帮助，使各位可以学到更多知识，如果觉得文章不错，请把它分享出去让更多的人看到。
另外有需要云服务器可以了解下创新互联scvps.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。
分享标题：django中如何实现model对象加入装饰器-创新互联
新闻来源：https://www.cdcxhl.com/article34/esope.html
成都网站建设公司_创新互联，为您提供定制开发、企业网站制作、全网营销推广、做网站、定制网站、网站改版
声明：本网站发布的内容（图片、视频和文字）以用户投稿、用户转载内容为主，如果涉及侵权请尽快告知，我们将会在第一时间删除。文章观点不代表本网站立场，如需处理请联系客服。电话：028-86922220；邮箱：631063699@qq.com。内容未经允许不得转载，或转载时需注明来源： 创新互联
- 成都响应式网站建设那么火的原因在哪？ 2023-02-17
- 为何选择响应式网站制作 2022-08-06
- H5响应式网站建设越来越流行了 2021-01-24
- 建设响应式网站时应注意什么 2022-12-27
- 让你不得不选择响应式网站制作的理由 2016-03-28
- 手机端做响应式网站建设还是独立手机网站好 2013-12-19
- 成都响应式网站设计：网站建设方式有哪些？ 2023-03-11
- 成都网站建设：一个好的H5响应式网站有哪些标准？ 2017-01-05
- 成都企业网站HTML5响应式网站建设 2022-05-30
- 网络营销如何从响应式网站设计中获益 2023-02-13
- 制作响应式网站设计优势有哪些？ 2023-01-06
- 云城响应式网站建设怎么做才更受欢迎？ 2021-01-05