django-categories/categories/models.py

"""Category models."""

from functools import reduce

from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType
from django.core.files.images import get_image_dimensions
from django.db import models
from django.urls import reverse
from django.utils.encoding import force_str
from django.utils.translation import gettext_lazy as _

from .base import CategoryBase
from .settings import (
    RELATION_MODELS,
    RELATIONS,
    THUMBNAIL_STORAGE_ALIAS,
    THUMBNAIL_UPLOAD_PATH,
)

# Determine storage method based on Django version
try:  # Django 4.2+
    from django.core.files.storage import storages

    STORAGE = storages[THUMBNAIL_STORAGE_ALIAS]
except ImportError:
    from django.core.files.storage import get_storage_class

    from .settings import THUMBNAIL_STORAGE

    STORAGE = get_storage_class(THUMBNAIL_STORAGE)()


class Category(CategoryBase):
    """A basic category model."""

    thumbnail = models.FileField(
        upload_to=THUMBNAIL_UPLOAD_PATH,
        null=True,
        blank=True,
        storage=STORAGE,
    )
    thumbnail_width = models.IntegerField(blank=True, null=True)
    thumbnail_height = models.IntegerField(blank=True, null=True)
    order = models.IntegerField(default=0)
    alternate_title = models.CharField(
        blank=True, default="", max_length=100, help_text="An alternative title to use on pages with this category."
    )
    alternate_url = models.CharField(
        blank=True,
        max_length=200,
        help_text="An alternative URL to use instead of the one derived from " "the category hierarchy.",
    )
    description = models.TextField(blank=True, null=True)
    meta_keywords = models.CharField(
        blank=True, default="", max_length=255, help_text="Comma-separated keywords for search engines."
    )
    meta_extra = models.TextField(
        blank=True, default="", help_text="(Advanced) Any additional HTML to be placed verbatim " "in the &lt;head&gt;"
    )

    @property
    def short_title(self):
        """Return the name."""
        return self.name

    def get_absolute_url(self):
        """Return a path."""
        from django.urls import NoReverseMatch

        if self.alternate_url:
            return self.alternate_url
        try:
            prefix = reverse("categories_tree_list")
        except NoReverseMatch:
            prefix = "/"
        ancestors = list(self.get_ancestors()) + [
            self,
        ]
        return prefix + "/".join([force_str(i.slug) for i in ancestors]) + "/"

    if RELATION_MODELS:

        def get_related_content_type(self, content_type):
            """
            Get all related items of the specified content type.
            """
            return self.categoryrelation_set.filter(content_type__name=content_type)

        def get_relation_type(self, relation_type):
            """
            Get all relations of the specified relation type.
            """
            return self.categoryrelation_set.filter(relation_type=relation_type)

    def save(self, *args, **kwargs):
        """Save the category."""
        if self.thumbnail:
            width, height = get_image_dimensions(self.thumbnail.file)
        else:
            width, height = None, None

        self.thumbnail_width = width
        self.thumbnail_height = height

        super(Category, self).save(*args, **kwargs)

    class Meta(CategoryBase.Meta):
        verbose_name = _("category")
        verbose_name_plural = _("categories")

    class MPTTMeta:
        order_insertion_by = ("order", "name")


if RELATIONS:
    CATEGORY_RELATION_LIMITS = reduce(lambda x, y: x | y, RELATIONS)
else:
    CATEGORY_RELATION_LIMITS = []


class CategoryRelationManager(models.Manager):
    """Custom access functions for category relations."""

    def get_content_type(self, content_type):
        """
        Get all the items of the given content type related to this item.
        """
        qs = self.get_queryset()
        return qs.filter(content_type__name=content_type)

    def get_relation_type(self, relation_type):
        """
        Get all the items of the given relationship type related to this item.
        """
        qs = self.get_queryset()
        return qs.filter(relation_type=relation_type)


class CategoryRelation(models.Model):
    """Related category item."""

    category = models.ForeignKey(Category, verbose_name=_("category"), on_delete=models.CASCADE)
    content_type = models.ForeignKey(
        ContentType,
        on_delete=models.CASCADE,
        limit_choices_to=CATEGORY_RELATION_LIMITS,
        verbose_name=_("content type"),
    )
    object_id = models.PositiveIntegerField(verbose_name=_("object id"))
    content_object = GenericForeignKey("content_type", "object_id")
    relation_type = models.CharField(
        verbose_name=_("relation type"),
        max_length=200,
        blank=True,
        null=True,
        help_text=_("A generic text field to tag a relation, like 'leadphoto'."),
    )

    objects = CategoryRelationManager()

    def __unicode__(self):
        return "CategoryRelation"