boards/models/image.py

import hashlib
import os
from random import random
import time
from django.db import models
from boards import thumbs

__author__ = 'neko259'


IMAGE_THUMB_SIZE = (200, 150)
IMAGES_DIRECTORY = 'images/'
FILE_EXTENSION_DELIMITER = '.'


class PostImage(models.Model):
    class Meta:
        app_label = 'boards'
        ordering = ('id',)

    @staticmethod
    def _update_image_filename(filename):
        """
        Gets unique image filename
        """

        path = IMAGES_DIRECTORY
        new_name = str(int(time.mktime(time.gmtime())))
        new_name += str(int(random() * 1000))
        new_name += FILE_EXTENSION_DELIMITER
        new_name += filename.split(FILE_EXTENSION_DELIMITER)[-1:][0]

        return os.path.join(path, new_name)

    width = models.IntegerField(default=0)
    height = models.IntegerField(default=0)

    pre_width = models.IntegerField(default=0)
    pre_height = models.IntegerField(default=0)

    image = thumbs.ImageWithThumbsField(upload_to=_update_image_filename,
                                        blank=True, sizes=(IMAGE_THUMB_SIZE,),
                                        width_field='width',
                                        height_field='height',
                                        preview_width_field='pre_width',
                                        preview_height_field='pre_height')
    hash = models.CharField(max_length=36)

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

        if not self.pk and self.image:
            md5 = hashlib.md5()
            for chunk in self.image.chunks():
                md5.update(chunk)
            self.hash = md5.hexdigest()
        super(PostImage, self).save(*args, **kwargs)