class Author(models.Model):
    photo_url = models.URLField(null=True, blank=True, max_length=1024,verbose_name = _('Original photo url'))
    photo_copy = models.ImageField(upload_to='photos/%Y/%m/%d/authors',null=True, blank=True, verbose_name = _('Thumbnail'))
    def save(self, *args, **kwargs):
        if not self.photo_copy and self.photo_url:
            img_temp = NamedTemporaryFile(delete=True)
            img_temp.write(urllib2.urlopen(self.photo_url).read())
            img_temp.flush()
            self.photo_copy.save('filename.jpg', File(img_temp),save=False)
        super(Author, self).save(*args, **kwargs)
Results in:

ValueError: I/O operation on closed file

django.db.models.fileds.files.py line 93

self._size = content.size
More info could be find here ​https://groups.google.com/forum/#!topic/django-users/SXMDKFFnoSc

This bug occured just after migration from dajngo 1.6 to django 1.7.

My traceback:

Traceback (most recent call last):
  File "/home/hodza/projects/pinstream/pins/management/commands/import.py", line 85, in handle
    author.save()
  File "/home/hodza/projects/pinstream/pins/models.py", line 199, in save
    self.photo_copy.save(img_filename, File(img_temp),save=False)
  File "/home/hodza/projects/pinstream/venv/src/django/django/db/models/fields/files.py", line 93, in save
    self._size = content.size
  File "/home/hodza/projects/pinstream/venv/src/django/django/core/files/base.py", line 46, in _get_size
    pos = self.file.tell()
ValueError: I/O operation on closed file
    Last edited 10 years ago
        by Aymeric Augustin
      (previous)
      (diff)
from django.db import models
from django.db.models.fields.files import FieldFile
from django.core.files.temp import NamedTemporaryFile
from django.core.files import File
from django.core.files.storage import FileSystemStorage
fs = FileSystemStorage(location='.')
field = models.FileField(storage=fs, name="field")
class Model(object):
    field = ""
instance = Model()
temp = NamedTemporaryFile(delete=True)
field_file = FieldFile(instance,field,"field")
field_file.save('file', File(temp),save=False)
How about instead of setting the cached file size from the intermediate content, we just ask the newly-saved file in the underlying storage? I think that's a simple fix that doesn't require callers to know about and clean up framework debris. The test script above, and of course the test suite, look OK with it.

​https://github.com/django/django/pull/2712

This patch is two-fold; first it ensure that Django does close everything in

request.FILES at the end of the request and secondly the storage system should

no longer close any files during save, it's up to the caller to handle that --

or let Django close the files at the end of the request.

This patch is two-fold; first it ensure that Django does close everything in

request.FILES at the end of the request and secondly the storage system should

no longer close any files during save, it's up to the caller to handle that --

or let Django close the files at the end of the request.

Backport of e2efc8965edf684aaf48621680ef54b84e116576 from master.