Question

我正在构建简单的API，该API从url获取图像并将其存储在mongodb中。用户发送URL到API以提交新任务。然后，用户可以通过POST方法检查任务状态并获取获取的图像列表：

def get_image_task(self, task_id):
    try:
        return ImageTask.objects.get(task_id=task_id)
    except ImageTask.DoesNotExist:
        return None


def post(self):
    '''
    Get status of submitted task.
    '''
    json_data = api.payload
    task_id = json_data['task_id']
    image = self.get_image_task(task_id)
    if not image:
        abort(404, 'Task does not exist.')
    celery_task = AsyncResult(image.task_id)
    image.task_status = celery_task.state
    image.save()
    return ImagePOSTOutput.dump(image)

这是我的ImageTask和Image的模型：

from flask_mongoengine import Document
from mongoengine import (
    EmbeddedDocument,
    StringField,
    IntField,
    BinaryField,
    EmbeddedDocumentField,
    ListField,
)

class Image(EmbeddedDocument):
    id = IntField()
    img = BinaryField()


class ImageTask(Task):
    images = ListField(EmbeddedDocumentField(Image))

    @classmethod
    def pre_save(cls, sender, document, **kwargs):
        if not document.task_id:
            celery_task = get_images.apply_async((document.url, ))
            document.task_id = celery_task.id
            document.task_status = celery_task.state

这是我的序列化器：

from marshmallow_mongoengine import ModelSchema
from .models import ImageTask, Image


class ImageSchema(ModelSchema):
    '''
    Embedded image schema for Image model.
    '''

    class Meta:
        model = Image
        exclude = ('img', )


class ImageTaskSchema(ModelSchema):
    '''
    ImageTaskSchema schema for generating JSON response
    based on ImageTask model.
    '''

    images = ImageSchema(many=True)

    class Meta:
        model = ImageTask


# PUT /images endpoint request and response schemas
ImagePUTInput = ImageTaskSchema(only=('url', ))
ImagePUTOutput = ImageTaskSchema(only=(
    'task_id',
    'task_status',
))

# POST /images endpoint request and response schemas
ImagePOSTInput = ImageTaskSchema(only=('task_id', ))
ImagePOSTOutput = ImageTaskSchema(only=('task_id', 'task_status', 'images.id'))

现在，提交新任务后，我发送POST请求以获取图像列表并获得以下响应：

{
    "task_status": "SUCCESS",
    "task_id": "556f5b48-16fd-4775-aabf-a8fb14df0d08",
    "images": {
        "id": 0
    }
}

图像列表显示，只有一幅图像被提取并保存到数据库中，尽管MongoDb显示为该任务存储了多个图像：我正在关注官方Marshamallow docs，因此我的ImagePOSTOutput序列化程序仅在json结果中返回id，如schema = SiteSchema(only=['blog.author.email'])所示。我还尝试删除了only的{{1}}参数，但是随后响应不包含图像列表：

ImagePOSTOutput

问题：为什么棉花糖只序列化{ "task_status": "SUCCESS", "task_id": "556f5b48-16fd-4775-aabf-a8fb14df0d08" }中的一个嵌入式文档，而忽略所有剩余的嵌入式文档？我忘了做什么？

P.S：我正在使用Marshamllow-Mongoengine进行对象序列化。

棉花糖仅序列化MongoEngine ListField中的一个文档

0 个答案: