boards/models/image.py

from django.core.files.images import get_image_dimensions
from django.db import models
from django.template.defaultfilters import filesizeformat

from boards import thumbs, utils
import boards
from boards.models.base import Viewable
from boards.models import STATUS_ARCHIVE
from boards.utils import get_upload_filename


__author__ = 'neko259'


IMAGE_THUMB_SIZE = (200, 150)
HASH_LENGTH = 36

CSS_CLASS_IMAGE = 'image'
CSS_CLASS_THUMB = 'thumb'


class PostImageManager(models.Manager):
    def create_with_hash(self, image):
        image_hash = utils.get_file_hash(image)
        existing = self.filter(hash=image_hash)
        if len(existing) > 0:
            post_image = existing[0]
        else:
            post_image = PostImage.objects.create(image=image)

        return post_image

    def get_random_images(self, count, tags=None):
        images = self.exclude(post_images__thread__status=STATUS_ARCHIVE)
        if tags is not None:
            images = images.filter(post_images__threads__tags__in=tags)
        return images.order_by('?')[:count]


class PostImage(models.Model, Viewable):
    objects = PostImageManager()

    class Meta:
        app_label = 'boards'
        ordering = ('id',)

    image = thumbs.ImageWithThumbsField(upload_to=get_upload_filename,
                                        blank=True, sizes=(IMAGE_THUMB_SIZE,))
    hash = models.CharField(max_length=HASH_LENGTH)
    alias = models.TextField(unique=True, null=True, blank=True)

    def save(self, *args, **kwargs):
        """
        Saves the model and computes the image hash for deduplication purposes.
        """

        if not self.pk and self.image:
            self.hash = utils.get_file_hash(self.image)
        super(PostImage, self).save(*args, **kwargs)

    def __str__(self):
        return self.image.url

    def get_view(self):
        metadata = '{}, {}'.format(self.image.name.split('.')[-1],
                                   filesizeformat(self.image.size))
        width, height = get_image_dimensions(self.image.file)
        preview_path = self.image.path.replace('.', '.200x150.')
        pre_width, pre_height = get_image_dimensions(preview_path)
        return '<div class="{}">' \
               '<a class="{}" href="{full}">' \
               '<img class="post-image-preview"' \
               ' src="{}"' \
               ' alt="{}"' \
               ' width="{}"' \
               ' height="{}"' \
               ' data-width="{}"' \
               ' data-height="{}" />' \
               '</a>' \
               '<div class="image-metadata">'\
               '<a href="{full}" download>{image_meta}</a>'\
               '</div>' \
               '</div>'\
            .format(CSS_CLASS_IMAGE, CSS_CLASS_THUMB,
                    self.image.url_200x150,
                    str(self.hash), str(pre_width),
                    str(pre_height), str(width), str(height),
                    full=self.image.url, image_meta=metadata)

    def get_random_associated_post(self):
        posts = boards.models.Post.objects.filter(images__in=[self])
        return posts.order_by('?').first()