lostplaces-backend/lostplaces/lostplaces_app/models.py

116 lines
3.0 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
''' (Data)models which describe the structure of data to be saved into database. '''
import os
import uuid
from django.db import models
from django.dispatch import receiver
from django.contrib.auth.models import AbstractUser
from django_thumbs.fields import ImageThumbsField
# Create your models here.
class Explorer(AbstractUser):
"""
Custom user model
Addtional fields wbd
"""
def __str__(self):
return self.username
class Place (models.Model):
"""
Place defines a lost place (location, name, description etc.).
"""
name = models.CharField(max_length=50)
submitted_by = models.ForeignKey(
Explorer,
on_delete=models.SET_NULL,
null=True,
blank=True,
related_name='places'
)
location = models.CharField(max_length=50)
latitude = models.FloatField()
longitude = models.FloatField()
description = models.TextField()
def __str__(self):
return self.name
def generate_image_upload_path(instance, filename):
"""
Callback for generating path for uploaded images
"""
return 'places/' + str(uuid.uuid4())+'.'+filename.split('.')[-1]
class PlaceImage (models.Model):
SIZES=(
{'code': 'thumbnail', 'wxh': '390x390'},
{'code': 'hero', 'wxh': '700x700'},
{'code': 'large', 'wxh': '1920x1920'}
)
description = models.TextField(blank=True)
filename = ImageThumbsField(
upload_to=generate_image_upload_path,
max_length=50,
sizes=SIZES
)
place = models.ForeignKey(
Place,
on_delete=models.CASCADE,
related_name='images'
)
submitted_by = models.ForeignKey(
Explorer,
on_delete=models.SET_NULL,
null=True,
blank=True,
related_name='images'
)
def __str__(self):
"""
Returning the name of the corresponding place + id
of this image as textual represntation of this instance
"""
return ' '.join([self.place.name, str(self.pk)])
# These two auto-delete files from filesystem when they are unneeded:
@receiver(models.signals.post_delete, sender=PlaceImage)
def auto_delete_file_on_delete(sender, instance, **kwargs):
"""
Deletes file from filesystem
when corresponding `PlaceImage` object is deleted.
"""
if instance.filename:
if os.path.isfile(instance.filename.path):
os.remove(instance.filename.path)
@receiver(models.signals.pre_save, sender=PlaceImage)
def auto_delete_file_on_change(sender, instance, **kwargs):
"""
Deletes old file from filesystem
when corresponding `PlaceImage` object is updated
with new file.
"""
if not instance.pk:
return False
try:
old_file = PlaceImage.objects.get(pk=instance.pk).filename
except PlaceImage.DoesNotExist:
return False
new_file = instance.filename
if not old_file == new_file:
if os.path.isfile(old_file.path):
os.remove(old_file.path)