DRF:在“ImageField”上使用“ImageField”

Question

django模型如下：

class Post(models.Model):
    name = models.CharField()

class PostImage(models.Model):
    image = models.ImageField()
    post = models.ForeignKey(
        Post,
        related_name=images,
    )

序列化程序是：

class PostSerialiser(serializers.ModelSerializer):
    name = serializers.CharField()
    images = serializers.SlugRelatedField(
        slug_field='image',
        many=True,
        read_only=True,
    )

class Meta:
    model = PostModel
    fields = ('name' 'images',)

序列化程序数据输出如下：

[
    {
        "name": 'Name 1', 
        "images": [
            <ImageFieldFile: 1.jpg>,
            <ImageFieldFile: 2.jpg>,
        ],
    },
    {
        "name": 'Name 2', 
        "images": [
            <ImageFieldFile: 5.jpg>,
        ],
    }
]

但是，当试图获取相同数据的分页响应时，它会发生错误'ascii' codec can't decode byte 0xff in position 23: ordinal not in range(128)"崩溃。

这是因为存在ImageFieldFile而不是URL。

如何获得图像的绝对url (MEDIA_url+图像相对-url)，而不是ImageFieldFile？

Answer 1

能够找到to_representation实现FileField的方法。

class ImageUrlField(serializers.RelatedField):
    def to_representation(self, instance):
        url = instance.image.url
        request = self.context.get('request', None)
        if request is not None:
            return request.build_absolute_uri(url)
        return url

class PostSerialiser(serializers.ModelSerializer):
    name = serializers.CharField()
    images = serializers.ImageUrlField(many=True, read_only=True)

Answer 2

我对ImageFields没有太多的经验，所以可能会有另一种解决方案，但可以肯定地说，这是可行的：

class ImageUrlField(serializers.RelatedField):
    def to_representation(self, value):
        # Build absolute URL (next line is just sample code)
        str = settings.MEDIA_URL + str(value.image) 
        return str

class PostSerialiser(serializers.ModelSerializer):
    name = serializers.CharField()
    images = serializers.ImageUrlField(many=True, read_only=True)