xmrauctions/items/models.py

from os import path as os_path
from secrets import token_urlsafe
from django.db import models
from django.core.files.uploadedfile import InMemoryUploadedFile
from django.contrib.auth.models import User
from monero.address import address
from PIL import Image, ExifTags
from io import BytesIO
from core.monero import AuctionDaemon
from core.validators import address_is_valid_monero


class Item(models.Model):
    owner = models.ForeignKey(User, related_name='owner', on_delete=models.CASCADE)
    name = models.CharField(max_length=100)
    list_date = models.DateTimeField(auto_now_add=True)
    last_updated = models.DateTimeField(auto_now=True)
    description = models.TextField(max_length=500)
    ask_price_xmr = models.FloatField()
    available = models.BooleanField(default=True)
    payout_address = models.CharField(max_length=100, validators=[address_is_valid_monero])
    whereabouts = models.CharField(max_length=100)

    def __str__(self):
        return f"{self.id} - {self.owner} - {self.name}"


class ItemImage(models.Model):
    item = models.ForeignKey(Item, related_name='images', on_delete=models.CASCADE)
    image = models.ImageField(upload_to='%Y/%m/%d')
    thumbnail = models.ImageField(upload_to='%Y/%m/%d')

    def save(self, *args, **kwargs):
        self.correct_image()
        super(ItemImage, self).save(*args, **kwargs)

    def correct_image(self):
        try:
            # Open image and set some variables
            img = Image.open(self.image)
            img_format = img.format
            max_size = (800, 800)
            thumb_size = (150, 150)
            file_ext = os_path.splitext(self.image.name)[1]
            random_str = token_urlsafe(12)
            img_name = f'{self.item.id}-{random_str}.%s{file_ext}'
            img_bytes = BytesIO()
            thumb_bytes = BytesIO()

            # If image contains exif check for orientation and rotate
            for orientation in ExifTags.TAGS.keys():
                if ExifTags.TAGS[orientation] == 'Orientation':
                    img_exif = img._getexif()
                    if img_exif:
                        if orientation in img_exif:
                            image_orientation = img_exif[orientation]
                            if image_orientation == 3:
                                img = img.rotate(180, expand=True)
                            if image_orientation == 6:
                                img = img.rotate(-90, expand=True)
                            if image_orientation == 8:
                                img = img.rotate(90, expand=True)

            # Store a copy of the image for thumbnail
            thumb = img.copy()

            # TODO - task this and just present page without until it's done

            # Correct the image size to safe maximums
            img.thumbnail(max_size, Image.ANTIALIAS)
            img.save(img_bytes, format=img_format, quality=80)
            self.image = InMemoryUploadedFile(
                img_bytes,
                'ImageField',
                img_name % 'full',
                self.image.file.content_type,
                img.size,
                self.image.file.charset
            )

            # Create thumbnail from image
            thumb.thumbnail(thumb_size, Image.ANTIALIAS)
            thumb.save(thumb_bytes, format=img_format, quality=80)
            self.thumbnail = InMemoryUploadedFile(
                thumb_bytes,
                'ImageField',
                img_name % 'thumbnail',
                self.image.file.content_type,
                img.size,
                self.image.file.charset
            )

            thumb.close()
            img.close()
        except:
            raise Exception('Unable to correct image size')

    def __str__(self):
        return f'{self.id} - {self.item.name} - {self.id}'