Python-сообщество

# model.py
.....
from sorl.thumbnail import delete
from sorl.thumbnail.fields import ImageField
......

class Book(models.Model):
    .....
    cover = ImageField(......)
    ......

    def is_empty_cover(self):
        return True if self.cover else False

    def save(self):
        try:
            old_book = Book.objects.get(id=self.id)
        except Book.DoesNotExist:
            pass
        else:
            if old_book.is_empty_cover() and old_book.cover != self.cover:
                path_cover = os.path.join(settings.MEDIA_ROOT, '%s') % old_book.cover
                if os.path.exists(path_cover):
                    delete(old_book.cover)
        super(Book, self).save()
        
    def delete(self):
        try:
            old_book = Book.objects.get(id=self.id)
        except Book.DoesNotExist:
            pass
        else:
            if old_book.is_empty_cover():
                path_cover = os.path.join(settings.MEDIA_ROOT, '%s') % old_book.cover
                if os.path.exists(path_cover):
                    delete(old_book.cover)
        super(Book, self).delete()

# admin.py
....
class BookAdmin(admin.ModelAdmin):
.......
    actions=['really_delete_selected']
    
    def get_actions(self, request): 
        actions = super(BookAdmin, self).get_actions(request) 
        del actions['delete_selected']    
        return actions 
        
    def really_delete_selected(self, request, queryset): 
        for book in queryset: 
            book.delete()
        self.message_user(request, u'успешно удалено книг: %s' % queryset.count()) 
    really_delete_selected.short_description = u'удалить выбранные книги'
.....

# coding: utf-8
from django.db import models
from django.db.models import Model 
from django.conf import settings
import os
import shutil

class Project(Model):        
    img = ImageField(verbose_name=u'Изображение') 
    
    def save(self,*args, **kwargs):
        #типы полей, даные которых удаляем при сохранении
        fild_type = ['ImageField',]
        class_child = self.__class__
        fild_list = []
        for i in self.__dict__:
            if str(self.__dict__[i].__class__).replace('<class ', '').replace('>', '').replace("'", '').split('.')[-1] in fild_type:
                fild_list.append(i) 
        try:
            old_obj = class_child.objects.get(id=self.id)
        except class_child.DoesNotExist:
            pass
        else:
            for f in fild_list: 
                new = eval('self.' + f) 
                old = eval('old_obj.' + f)              
                if (old != new) and old:                
                    path_del = (str(settings.MEDIA_ROOT) + str(old)).replace('\\','/')
                    if os.path.exists(path_del):
                        os.unlink(path_del)  
                    else:
                        pass       
        super(Project, self).save(*args, **kwargs)

   
class Cottage(Project): 
	pass