boards/models/attachment/__init__.py

import boards
from boards.models import STATUS_ARCHIVE
from django.core.files.images import get_image_dimensions
from django.db import models

from boards import utils
from boards.models.attachment.viewers import get_viewers, AbstractViewer, \
    FILE_TYPES_IMAGE
from boards.utils import get_upload_filename, get_extension, cached_result


class AttachmentManager(models.Manager):
    def create_with_hash(self, file):
        file_hash = utils.get_file_hash(file)
        existing = self.filter(hash=file_hash)
        if len(existing) > 0:
            attachment = existing[0]
        else:
            # FIXME Use full mimetype here, need to modify viewers too
            file_type = get_extension(file.name)
            attachment = self.create(file=file, mimetype=file_type,
                                     hash=file_hash)

        return attachment

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


class Attachment(models.Model):
    objects = AttachmentManager()

    file = models.FileField(upload_to=get_upload_filename)
    mimetype = models.CharField(max_length=50)
    hash = models.CharField(max_length=36)
    alias = models.TextField(unique=True, null=True, blank=True)

    def get_view(self):
        file_viewer = None
        for viewer in get_viewers():
            if viewer.supports(self.mimetype):
                file_viewer = viewer
                break
        if file_viewer is None:
            file_viewer = AbstractViewer

        return file_viewer(self.file, self.mimetype, self.hash).get_view()

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

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

    @cached_result()
    def get_size(self):
        if self.mimetype in FILE_TYPES_IMAGE:
            return get_image_dimensions(self.file)
        else:
            return 200, 150

    def get_thumb_url(self):
        split = self.file.url.rsplit('.', 1)
        w, h = 200, 150
        return '%s.%sx%s.%s' % (split[0], w, h, split[1])

    @cached_result()
    def get_preview_size(self):
        if self.mimetype in FILE_TYPES_IMAGE:
            preview_path = self.file.path.replace('.', '.200x150.')
            return get_image_dimensions(preview_path)
        else:
            return 200, 150