Django with PIL - '_io.BytesIO' object has no attribute 'name' - django

Question

I'm using PIL to resize an uploaded photo before saving. Note that I'm using formsets to upload the pictures. I'm using BytesIO to open the file. At the last step, I get the error - '_io.BytesIO' object has no attribute 'name'. Why is this?
def fsbo_create_listing(request):
PhotoFormSet = formset_factory(OwnerListingPhotoForm, extra=15)
if request.method == 'POST':
form = OwnerListingForm(request.POST)
photo_formset = PhotoFormSet(request.POST, request.FILES)
if form.is_valid() and photo_formset.is_valid():
form.instance.user = request.user
form.save()
for i in photo_formset:
if i.instance.pk and i.instance.photo == '':
i.instance.delete()
elif i.cleaned_data:
temp = i.save(commit=False)
temp.listing = form.instance
temp.save() # Where the error happens
def clean_photo(self):
picture = self.cleaned_data.get('photo')
# I had to import ImageFieldFile. If picture is already uploaded, picture would still be retrieved as ImageFieldFile. The following line checks the variable type of `picture` to determine whether the cleaning should proceed.
if type(picture) != ImageFieldFile:
image_field = self.cleaned_data.get('photo')
image_file = BytesIO(image_field.read())
image = Image.open(image_file)
image = ImageOps.fit(image, (512,512,), Image.ANTIALIAS)
image_file = BytesIO()
image.save(image_file, 'JPEG', quality=90)
image_field.file = image_file
#if picture._size > 2*1024*1024:
#raise ValidationError("Image file too large. Max size is 2MB.")
return picture
class OwnerListingPhoto(models.Model):
listing = models.ForeignKey(OwnerListing, on_delete=models.CASCADE, related_name='owner_listing_photo')
photo = models.ImageField(upload_to=owner_listing_folder_name)

Answer 1

The issue is that new versions of Django default to using MemoryFileUploadHandler, which doesn't create a temporary file, and therefore there is no file "name." See related Django ticket.
You'll probably have to modify your code a bit to make this work, but you can at least start getting the name property by setting:
FILE_UPLOAD_HANDLERS = [
'django.core.files.uploadhandler.TemporaryFileUploadHandler',
]
In your settings.py file.
You may find the code I've used to solve almost the exact same issue as helpful.
def clean_logo_file(self):
logo_file_field = self.cleaned_data.get('logo_file')
if logo_file_field:
try:
logo_file = logo_file_field.file
with Image.open(logo_file_field.file.name) as image:
image.thumbnail((512, 512), Image.ANTIALIAS)
image.save(logo_file, format=image.format)
logo_file_field.file = logo_file
return logo_file_field
except IOError:
logger.exception("Error during image resize.")
Additional information on upload handlers.

Answer 2

If file is bigger than 2.5mb (2621440 bytes) - Django will
use TemporaryFileUploadHandler.
Otherwise Django will use MemoryFileUploadHandler.
You can change FILE_UPLOAD_MAX_MEMORY_SIZE (doc) in settings.py
Or change FILE_UPLOAD_HANDLERS (doc) as Nostalg.io mentioned above.
My example with Django Rest Framework serializers:
Broken code:
# models.py
class ImageModel(Model):
image = models.ImageField(upload_to='images/', null=False, blank=False)
# serializers.py
class ImageSerializer(serializers.ModelSerializer):
class Meta:
model = ImageModel
fields = ["id", "image"]
read_only_fields = ["id"]
def validate_image(self, user_img):
img = Image.open(user_img)
... # process image here
img_io = io.BytesIO()
img.save(img_io, format='JPEG', quality=100)
filename = "%s.jpg" % user_img.name.split('.')[0]
user_img.name = "%s.jpg" % user_img.name.split('.')[0]
user_img.file = img_io # BAD IDEA!!!
# This overrides django's tempfile._TemporaryFileWrapper() with _io.BytesIO() !!!
...
return user_img # if picture bigger than 2.5mb -> gives an error!
Fixed code:
#settings.py
FILE_UPLOAD_HANDLERS = [
'django.core.files.uploadhandler.TemporaryFileUploadHandler',
]
# serializers.py
class ImageSerializer(serializers.ModelSerializer):
class Meta:
model = ImageModel
fields = ["id", "image"]
read_only_fields = ["id"]
def validate_image(self, user_img):
img = Image.open(user_img)
... # process image here
# override old TemporaryFile image with edited image
path_to_tmp = user_img.file.name
new_filename = "%s.jpeg" % user_img.name.split('.')[0]
# set new image name
img.save(path_to_tmp, format='JPEG', quality=100)
user_img.name = new_filename
...
return user_img # no errors more :)
It might be more rational to process image by rewriting save() method in models.py, but I convert images in serializers.py because of handly ValidationError() :)