Source code for mezzanine.core.models

from __future__ import unicode_literals
from future.builtins import str
from future.utils import with_metaclass

from json import loads
try:
    from urllib.request import urlopen
    from urllib.parse import urlencode
except ImportError:
    from urllib import urlopen, urlencode

from django.contrib.contenttypes.fields import GenericForeignKey
from django.db import models
from django.db.models.base import ModelBase
from django.template.defaultfilters import truncatewords_html
from django.utils.encoding import python_2_unicode_compatible
from django.utils.html import strip_tags
from django.utils.timesince import timesince
from django.utils.timezone import now
from django.utils.translation import ugettext, ugettext_lazy as _

from mezzanine.conf import settings
from mezzanine.core.fields import RichTextField, OrderField
from mezzanine.core.managers import DisplayableManager, CurrentSiteManager
from mezzanine.generic.fields import KeywordsField
from mezzanine.utils.html import TagCloser
from mezzanine.utils.models import base_concrete_model, get_user_model_name
from mezzanine.utils.sites import current_site_id, current_request
from mezzanine.utils.urls import admin_url, slugify, unique_slug


user_model_name = get_user_model_name()


[docs]class SiteRelated(models.Model): """ Abstract model for all things site-related. Adds a foreignkey to Django's ``Site`` model, and filters by site with all querysets. See ``mezzanine.utils.sites.current_site_id`` for implementation details. """ objects = CurrentSiteManager() class Meta: abstract = True site = models.ForeignKey("sites.Site", editable=False)
[docs] def save(self, update_site=False, *args, **kwargs): """ Set the site to the current site when the record is first created, or the ``update_site`` argument is explicitly set to ``True``. """ if update_site or (self.id is None and self.site_id is None): self.site_id = current_site_id() super(SiteRelated, self).save(*args, **kwargs)
@python_2_unicode_compatible
[docs]class Slugged(SiteRelated): """ Abstract model that handles auto-generating slugs. Each slugged object is also affiliated with a specific site object. """ title = models.CharField(_("Title"), max_length=500) slug = models.CharField(_("URL"), max_length=2000, blank=True, null=True, help_text=_("Leave blank to have the URL auto-generated from " "the title.")) class Meta: abstract = True def __str__(self): return self.title
[docs] def save(self, *args, **kwargs): """ If no slug is provided, generates one before saving. """ if not self.slug: self.slug = self.generate_unique_slug() super(Slugged, self).save(*args, **kwargs)
[docs] def generate_unique_slug(self): """ Create a unique slug by passing the result of get_slug() to utils.urls.unique_slug, which appends an index if necessary. """ # For custom content types, use the ``Page`` instance for # slug lookup. concrete_model = base_concrete_model(Slugged, self) slug_qs = concrete_model.objects.exclude(id=self.id) return unique_slug(slug_qs, "slug", self.get_slug())
[docs] def get_slug(self): """ Allows subclasses to implement their own slug creation logic. """ attr = "title" if settings.USE_MODELTRANSLATION: from modeltranslation.utils import build_localized_fieldname attr = build_localized_fieldname(attr, settings.LANGUAGE_CODE) # Get self.title_xx where xx is the default language, if any. # Get self.title otherwise. return slugify(getattr(self, attr, None) or self.title)
def admin_link(self): return "<a href='%s'>%s</a>" % (self.get_absolute_url(), ugettext("View on site")) admin_link.allow_tags = True admin_link.short_description = ""
[docs]class MetaData(models.Model): """ Abstract model that provides meta data for content. """ _meta_title = models.CharField(_("Title"), null=True, blank=True, max_length=500, help_text=_("Optional title to be used in the HTML title tag. " "If left blank, the main title field will be used.")) description = models.TextField(_("Description"), blank=True) gen_description = models.BooleanField(_("Generate description"), help_text=_("If checked, the description will be automatically " "generated from content. Uncheck if you want to manually " "set a custom description."), default=True) keywords = KeywordsField(verbose_name=_("Keywords")) class Meta: abstract = True
[docs] def save(self, *args, **kwargs): """ Set the description field on save. """ if self.gen_description: self.description = strip_tags(self.description_from_content()) super(MetaData, self).save(*args, **kwargs)
[docs] def meta_title(self): """ Accessor for the optional ``_meta_title`` field, which returns the string version of the instance if not provided. """ return self._meta_title or str(self)
[docs] def description_from_content(self): """ Returns the first block or sentence of the first content-like field. """ description = "" # Use the first RichTextField, or TextField if none found. for field_type in (RichTextField, models.TextField): if not description: for field in self._meta.fields: if (isinstance(field, field_type) and field.name != "description"): description = getattr(self, field.name) if description: from mezzanine.core.templatetags.mezzanine_tags \ import richtext_filters description = richtext_filters(description) break # Fall back to the title if description couldn't be determined. if not description: description = str(self) # Strip everything after the first block or sentence. ends = ("</p>", "<br />", "<br/>", "<br>", "</ul>", "\n", ". ", "! ", "? ") for end in ends: pos = description.lower().find(end) if pos > -1: description = TagCloser(description[:pos]).html break else: description = truncatewords_html(description, 100) try: description = unicode(description) except NameError: pass # Python 3. return description
[docs]class TimeStamped(models.Model): """ Provides created and updated timestamps on models. """ class Meta: abstract = True created = models.DateTimeField(null=True, editable=False) updated = models.DateTimeField(null=True, editable=False) def save(self, *args, **kwargs): _now = now() self.updated = _now if not self.id: self.created = _now super(TimeStamped, self).save(*args, **kwargs)
CONTENT_STATUS_DRAFT = 1 CONTENT_STATUS_PUBLISHED = 2 CONTENT_STATUS_CHOICES = ( (CONTENT_STATUS_DRAFT, _("Draft")), (CONTENT_STATUS_PUBLISHED, _("Published")), ) SHORT_URL_UNSET = "unset"
[docs]class Displayable(Slugged, MetaData, TimeStamped): """ Abstract model that provides features of a visible page on the website such as publishing fields. Basis of Mezzanine pages, blog posts, and Cartridge products. """ status = models.IntegerField(_("Status"), choices=CONTENT_STATUS_CHOICES, default=CONTENT_STATUS_PUBLISHED, help_text=_("With Draft chosen, will only be shown for admin users " "on the site.")) publish_date = models.DateTimeField(_("Published from"), help_text=_("With Published chosen, won't be shown until this time"), blank=True, null=True, db_index=True) expiry_date = models.DateTimeField(_("Expires on"), help_text=_("With Published chosen, won't be shown after this time"), blank=True, null=True) short_url = models.URLField(blank=True, null=True) in_sitemap = models.BooleanField(_("Show in sitemap"), default=True) objects = DisplayableManager() search_fields = {"keywords": 10, "title": 5} class Meta: abstract = True
[docs] def save(self, *args, **kwargs): """ Set default for ``publish_date``. We can't use ``auto_now_add`` on the field as it will be blank when a blog post is created from the quick blog form in the admin dashboard. """ if self.publish_date is None: self.publish_date = now() super(Displayable, self).save(*args, **kwargs)
def get_admin_url(self): return admin_url(self, "change", self.id)
[docs] def publish_date_since(self): """ Returns the time since ``publish_date``. """ return timesince(self.publish_date)
publish_date_since.short_description = _("Published from")
[docs] def get_absolute_url(self): """ Raise an error if called on a subclass without ``get_absolute_url`` defined, to ensure all search results contains a URL. """ name = self.__class__.__name__ raise NotImplementedError("The model %s does not have " "get_absolute_url defined" % name)
[docs] def get_absolute_url_with_host(self): """ Returns host + ``get_absolute_url`` - used by the various ``short_url`` mechanics below. Technically we should use ``self.site.domain``, here, however if we were to invoke the ``short_url`` mechanics on a list of data (eg blog post list view), we'd trigger a db query per item. Using ``current_request`` should provide the same result, since site related data should only be loaded based on the current host anyway. """ return current_request().build_absolute_uri(self.get_absolute_url())
[docs] def set_short_url(self): """ Generates the ``short_url`` attribute if the model does not already have one. Used by the ``set_short_url_for`` template tag and ``TweetableAdmin``. If no sharing service is defined (bitly is the one implemented, but others could be by overriding ``generate_short_url``), the ``SHORT_URL_UNSET`` marker gets stored in the DB. In this case, ``short_url`` is temporarily (eg not persisted) set to host + ``get_absolute_url`` - this is so that we don't permanently store ``get_absolute_url``, since it may change over time. """ if self.short_url == SHORT_URL_UNSET: self.short_url = self.get_absolute_url_with_host() elif not self.short_url: self.short_url = self.generate_short_url() self.save()
[docs] def generate_short_url(self): """ Returns a new short URL generated using bit.ly if credentials for the service have been specified. """ from mezzanine.conf import settings if settings.BITLY_ACCESS_TOKEN: url = "https://api-ssl.bit.ly/v3/shorten?%s" % urlencode({ "access_token": settings.BITLY_ACCESS_TOKEN, "uri": self.get_absolute_url_with_host(), }) response = loads(urlopen(url).read().decode("utf-8")) if response["status_code"] == 200: return response["data"]["url"] return SHORT_URL_UNSET
def _get_next_or_previous_by_publish_date(self, is_next, **kwargs): """ Retrieves next or previous object by publish date. We implement our own version instead of Django's so we can hook into the published manager and concrete subclasses. """ arg = "publish_date__gt" if is_next else "publish_date__lt" order = "publish_date" if is_next else "-publish_date" lookup = {arg: self.publish_date} concrete_model = base_concrete_model(Displayable, self) try: queryset = concrete_model.objects.published except AttributeError: queryset = concrete_model.objects.all try: return queryset(**kwargs).filter(**lookup).order_by(order)[0] except IndexError: pass
[docs] def get_next_by_publish_date(self, **kwargs): """ Retrieves next object by publish date. """ return self._get_next_or_previous_by_publish_date(True, **kwargs)
[docs] def get_previous_by_publish_date(self, **kwargs): """ Retrieves previous object by publish date. """ return self._get_next_or_previous_by_publish_date(False, **kwargs)
[docs]class RichText(models.Model): """ Provides a Rich Text field for managing general content and making it searchable. """ content = RichTextField(_("Content")) search_fields = ("content",) class Meta: abstract = True
[docs]class OrderableBase(ModelBase): """ Checks for ``order_with_respect_to`` on the model's inner ``Meta`` class and if found, copies it to a custom attribute and deletes it since it will cause errors when used with ``ForeignKey("self")``. Also creates the ``ordering`` attribute on the ``Meta`` class if not yet provided. """ def __new__(cls, name, bases, attrs): if "Meta" not in attrs: class Meta: pass attrs["Meta"] = Meta if hasattr(attrs["Meta"], "order_with_respect_to"): order_field = attrs["Meta"].order_with_respect_to attrs["order_with_respect_to"] = order_field del attrs["Meta"].order_with_respect_to if not hasattr(attrs["Meta"], "ordering"): setattr(attrs["Meta"], "ordering", ("_order",)) return super(OrderableBase, cls).__new__(cls, name, bases, attrs)
[docs]class Orderable(with_metaclass(OrderableBase, models.Model)): """ Abstract model that provides a custom ordering integer field similar to using Meta's ``order_with_respect_to``, since to date (Django 1.2) this doesn't work with ``ForeignKey("self")``, or with Generic Relations. We may also want this feature for models that aren't ordered with respect to a particular field. """ _order = OrderField(_("Order"), null=True) class Meta: abstract = True
[docs] def with_respect_to(self): """ Returns a dict to use as a filter for ordering operations containing the original ``Meta.order_with_respect_to`` value if provided. If the field is a Generic Relation, the dict returned contains names and values for looking up the relation's ``ct_field`` and ``fk_field`` attributes. """ try: name = self.order_with_respect_to value = getattr(self, name) except AttributeError: # No ``order_with_respect_to`` specified on the model. return {} # Support for generic relations. field = getattr(self.__class__, name) if isinstance(field, GenericForeignKey): names = (field.ct_field, field.fk_field) return dict([(n, getattr(self, n)) for n in names]) return {name: value}
[docs] def save(self, *args, **kwargs): """ Set the initial ordering value. """ if self._order is None: lookup = self.with_respect_to() lookup["_order__isnull"] = False concrete_model = base_concrete_model(Orderable, self) self._order = concrete_model.objects.filter(**lookup).count() super(Orderable, self).save(*args, **kwargs)
[docs] def delete(self, *args, **kwargs): """ Update the ordering values for siblings. """ lookup = self.with_respect_to() lookup["_order__gte"] = self._order concrete_model = base_concrete_model(Orderable, self) after = concrete_model.objects.filter(**lookup) after.update(_order=models.F("_order") - 1) super(Orderable, self).delete(*args, **kwargs)
def _get_next_or_previous_by_order(self, is_next, **kwargs): """ Retrieves next or previous object by order. We implement our own version instead of Django's so we can hook into the published manager, concrete subclasses and our custom ``with_respect_to`` method. """ lookup = self.with_respect_to() lookup["_order"] = self._order + (1 if is_next else -1) concrete_model = base_concrete_model(Orderable, self) try: queryset = concrete_model.objects.published except AttributeError: queryset = concrete_model.objects.filter try: return queryset(**kwargs).get(**lookup) except concrete_model.DoesNotExist: pass
[docs] def get_next_by_order(self, **kwargs): """ Retrieves next object by order. """ return self._get_next_or_previous_by_order(True, **kwargs)
[docs] def get_previous_by_order(self, **kwargs): """ Retrieves previous object by order. """ return self._get_next_or_previous_by_order(False, **kwargs)
[docs]class Ownable(models.Model): """ Abstract model that provides ownership of an object for a user. """ user = models.ForeignKey(user_model_name, verbose_name=_("Author"), related_name="%(class)ss") class Meta: abstract = True
[docs] def is_editable(self, request): """ Restrict in-line editing to the objects's owner and superusers. """ return request.user.is_superuser or request.user.id == self.user_id
[docs]class SitePermission(models.Model): """ Permission relationship between a user and a site that's used instead of ``User.is_staff``, for admin and inline-editing access. """ user = models.OneToOneField(user_model_name, verbose_name=_("Author"), related_name="%(class)ss") sites = models.ManyToManyField("sites.Site", blank=True, verbose_name=_("Sites")) class Meta: verbose_name = _("Site permission") verbose_name_plural = _("Site permissions")