如何在 Django 中序列化 ImageField？

Question

I'm trying to serialize one of my models which has an ImageField . The inbuilt serializer can't seem to serialize this and therefore I thought of writing a custom serializer. Could you tell me how I could serialize an image and use this with the default JSON serializer in Django?

Thanks

Answer 1

you can't serialize the object, because it's an Image. You have to serialize the string representation of it's path.

The easiest way of achiving it is to call it's str() method when you what to serialize it.

json.dumps(unicode(my_imagefield)) # py2
json.dumps(str(my_imagefield)) # py3

should work.

Answer 2

I wrote an extension to the simplejson encoder. Instead to serializing the image to base643, it returns the path of the image. Here's a snippet:

def encode_datetime(obj):
    """
    Extended encoder function that helps to serialize dates and images
    """
    if isinstance(obj, datetime.date):
        try:
            return obj.strftime('%Y-%m-%d')
        except ValueError, e:
            return ''

    if isinstance(obj, ImageFieldFile):
        try:
            return obj.path
        except ValueError, e:
            return ''

    raise TypeError(repr(obj) + " is not JSON serializable")

Answer 3

您可以尝试使用base64 编码来序列化要在 JSON 中使用的图像

Answer 4

Use another encoder such that:

import json
from django.core.serializers.json import DjangoJSONEncoder
from django.db.models.fields.files import ImageFieldFile


class ExtendedEncoder(DjangoJSONEncoder):
    def default(self, o):
        if isinstance(o, ImageFieldFile):
            return str(o)
        else:
            return super().default(o)


result = json.dumps(your_object, cls=ExtendedEncoder)