copy file from one model to another - django

Question

I have 2 simple models:
class UploadImage(models.Model):
Image = models.ImageField(upload_to="temp/")
class RealImage(models.Model):
Image = models.ImageField(upload_to="real/")
And one form
class RealImageForm(ModelForm):
class Meta:
model = RealImage
I need to save file from UploadImage into RealImage. How could i do this.
Below code doesn't work
realform.Image=UploadImage.objects.get(id=image_id).Image
realform.save()
Tnx for help.

Answer 1

Inspired by Gerard's solution I came up with the following code:
from django.core.files.base import ContentFile
#...
class Example(models.Model):
file = models.FileField()
def duplicate(self):
"""
Duplicating this object including copying the file
"""
new_example = Example()
new_file = ContentFile(self.file.read())
new_file.name = self.file.name
new_example.file = new_file
new_example.save()
This will actually go as far as renaming the file by adding a "_1" to the filename so that both the original file and this new copy of the file can exist on disk at the same time.

Answer 2

Although this is late, but I would tackle this problem thus,
class UploadImage(models.Model):
Image = models.ImageField(upload_to="temp/")
# i need to delete the temp uploaded file from the file system when i delete this model
# from the database
def delete(self, using=None):
name = self.Image.name
# i ensure that the database record is deleted first before deleting the uploaded
# file from the filesystem.
super(UploadImage, self).delete(using)
self.Image.storage.delete(name)
class RealImage(models.Model):
Image = models.ImageField(upload_to="real/")
# in my view or where ever I want to do the copying i'll do this
import os
from django.core.files import File
uploaded_image = UploadImage.objects.get(id=image_id).Image
real_image = RealImage()
real_image.Image = File(uploaded_image, uploaded_image.name)
real_image.save()
uploaded_image.close()
uploaded_image.delete()
If I were using a model form to handle the process, i'll just do
# django model forms provides a reference to the associated model via the instance property
form.instance.Image = File(uploaded_image, os.path.basename(uploaded_image.path))
form.save()
uploaded_image.close()
uploaded_image.delete()
note that I ensure the uploaded_image file is closed because calling real_image.save() will open the file and read its content. That is handled by what ever storage system is used by the ImageField instance

Answer 3

Try doing that without using a form. Without knowing the exact error that you are getting, I can only speculate that the form's clean() method is raising an error because of a mismatch in the upload_to parameter.
Which brings me to my next point, if you are trying to copy the image from 'temp/' to 'real/', you will have to do a some file handling to move the file yourself (easier if you have PIL):
import Image
from django.conf import settings
u = UploadImage.objects.get(id=image_id)
im = Image.open(settings.MEDIA_ROOT + str(u.Image))
newpath = 'real/' + str(u.Image).split('/', 1)[1]
im.save(settings.MEDIA_ROOT + newpath)
r = RealImage.objects.create(Image=newpath)
Hope that helped...

Answer 4

I had the same problem and solved it like this, hope it helps anybody:
# models.py
class A(models.Model):
# other fields...
attachment = FileField(upload_to='a')
class B(models.Model):
# other fields...
attachment = FileField(upload_to='b')
# views.py or any file you need the code in
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
from django.core.files.base import ContentFile
from main.models import A, B
obj1 = A.objects.get(pk=1)
# You and either copy the file to an existent object
obj2 = B.objects.get(pk=2)
# or create a new instance
obj2 = B(**some_params)
tmp_file = StringIO(obj1.attachment.read())
tmp_file = ContentFile(tmp_file.getvalue())
url = obj1.attachment.url.split('.')
ext = url.pop(-1)
name = url.pop(-1).split('/')[-1] # I have my files in a remote Storage, you can omit the split if it doesn't help you
tmp_file.name = '.'.join([name, ext])
obj2.attachment = tmp_file
# Remember to save you instance
obj2.save()

Answer 5

Update Gerard's Solution to handle it in a generic way:
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
from django.core.files.base import ContentFile
init_str = "src_obj." + src_field_name + ".read()"
file_name_str = "src_obj." + src_field_name + ".name"
try:
tmp_file = StringIO(eval(str(init_str)))
tmp_file = ContentFile(tmp_file.getvalue())
tmp_file.name = os.path.basename(eval(file_name_str))
except AttributeError:
tmp_file = None
if tmp_file:
try:
dest_obj.__dict__[dest_field_name] = tmp_file
dest_obj.save()
except KeyError:
pass
Variable's Used:
src_obj = source attachment object.
src_field_name = source attachment object's FileField Name.
dest_obj = destination attachment object.
dest_field_name = destination attachment object's FileField Name.