Django 从 url 加载图像 - ImageField objected 没有属性 _committed

Question

I am using Django 3.2

I am trying to programatically create a model Foo that contains an ImageField object, when passed an image URL.

This is my code:

myproject/models.py

class ImageModel(models.Model):
    image = models.ImageField(_('image'),
                              max_length=IMAGE_FIELD_MAX_LENGTH,
                              upload_to=get_storage_path)
    # ...

class Foo(ImageModel):
    # ...

code attempting to create a Foo object from a passed in photo URL

# ...

image_content = ContentFile(requests.get(photo_url).content) # NOQA                          
image = ImageField() # empty image

data_dict = {
                'image': image,
                'date_taken': payload['date_taken'],
                'title': payload['title'],
                'caption': payload['caption'],
                'date_added': payload['date_added'],
                'is_public': False  
            }

foo = Foo.objects.create(**data_dict) # <- Barfs here
foo.image.save(str(uuid4()), image_content)
foo.save()  # <- not sure if this save is necessary ...

When the code snippet above is run, I get the following error:

ImageField object does attribute _committed

I know this question has been asked several times already - however, none of the accepted answers (from which my code is based) - actually works. I'm not sure if this is because the answers are old.

My question therefore is this - how do I fix this error, so that I can load an image from a URL and dynamically create an object that has an ImageField - using the fetched image?

Answer 1

The reason you are getting

ImageField object does attribute _committed

is because the ImageField returns varchar string, not the file instances.

FileField instances are created in your database as varchar columns with a default max length of 100 characters. As with other fields, you can change the maximum length using the max_length argument. doc

For generating an empty file/image instances you can use BytesIO

Give this a try

from django.core import files
from io import BytesIO

url = "https://homepages.cae.wisc.edu/~ece533/images/airplane.png"

io = BytesIO()
io.write(requests.get(url).content)

foo = Foo()
foo.caption = payload['caption']
foo.title = payload['title']
...

extention = url.split(".")[-1]
foo.image.save(f'{str(uuid4())}.{extention}', files.File(io))