Saving a decoded temporary image to Django Imagefield - django

Question

I'm trying to save images which have been passed to me as Base64 encoded text into a Django Imagefield.
But it seems to not be saving correctly. The database reports all my images are stored as "" when it should report them as a filename for example:
"template_images/template_folders/myImage.png"
The code that's trying to save my images is as follows:
elif model_field.get_internal_type() == "ImageField" or model_field.get_internal_type() == "FileField": # Convert files from base64 back to a file.
if field_elt.text is not None:
setattr(instance, model_field.name, File(b64decode(field_elt.text)))

Answer 1

After reading this answer, I got this to work:
from base64 import b64decode
from django.core.files.base import ContentFile
image_data = b64decode(b64_text)
my_model_instance.cool_image_field = ContentFile(image_data, 'whatup.png')
my_model_instance.save()
Therefore, I suggest you change your code to:
from django.core.files.base import ContentFile
# Your other code...
elif model_field.get_internal_type() == "ImageField" or model_field.get_internal_type() == "FileField": # Convert files from base64 back to a file.
if field_elt.text is not None:
image_data = b64decode(field_elt.text)
setattr(instance, model_field.name, ContentFile(image_data, 'myImage.png'))
Then, assuming your ImageField is defined with the upload_to argument set to template_images/template_folders/, you should see the file save down to YOUR_MEDIA_URL/template_images/template_folders/myImage.png

Answer 2

Another good approach based on this SO answer: https://stackoverflow.com/a/28036805/6143656 tried it and tested in django 1.10
I made a function for decoded base64 file.
def decode_base64_file(data):
def get_file_extension(file_name, decoded_file):
import imghdr
extension = imghdr.what(file_name, decoded_file)
extension = "jpg" if extension == "jpeg" else extension
return extension
from django.core.files.base import ContentFile
import base64
import six
import uuid
# Check if this is a base64 string
if isinstance(data, six.string_types):
# Check if the base64 string is in the "data:" format
if 'data:' in data and ';base64,' in data:
# Break out the header from the base64 content
header, data = data.split(';base64,')
# Try to decode the file. Return validation error if it fails.
try:
decoded_file = base64.b64decode(data)
except TypeError:
TypeError('invalid_image')
# Generate file name:
file_name = str(uuid.uuid4())[:12] # 12 characters are more than enough.
# Get the file name extension:
file_extension = get_file_extension(file_name, decoded_file)
complete_file_name = "%s.%s" % (file_name, file_extension, )
return ContentFile(decoded_file, name=complete_file_name)
Then you can call the function
import decode_base64_file
p = Post(content='My Picture', image=decode_based64_file(your_base64_file))
p.save()

Answer 3

I guess this is the cleanest and shortest way to do this.
Here is how you can handle a Base64 encoded image file in a post request at the Django-based (drf also) API end which saves it as an ImageField.
Let say you have a Model as follows:
Class MyImageModel(models.Model):
image = models.ImageField(upload_to = 'geo_entity_pic')
data=model.CharField()
So the Corresponding Serializer would be as follows:
from drf_extra_fields.fields import Base64ImageField
Class MyImageModelSerializer(serializers.ModelSerializers):
image=Base64ImageField()
class meta:
model=MyImageModel
fields= ('data','image')
def create(self, validated_data):
image=validated_data.pop('image')
data=validated_data.pop('data')
return MyImageModel.objects.create(data=data,image=image)
The corresponding View can be as follows:
elif request.method == 'POST':
serializer = MyImageModelSerializer(data=request.data)
if serializer.is_valid():
serializer.save()
return Response(serializer.data, status=201)
return Response(serializer.errors, status=400)
Notice In the Serializer I have used Implementation of Base64ImageField provided in the module django-extra-field
To install this module run the command
pip install pip install django-extra-fields
Import the same and Done!
Send (via post method) your image as an Base64 encoded String in JSON object along with any other data you have.