关于python：Django REST：上传和序列化多个图像

Django REST: Uploading and serializing multiple images

我有两个模型Task和TaskImage，这是属于Task对象的图像集合。

我想要的是能够向我的Task对象添加多个图像，但是我只能使用2个模型。目前，当我添加图像时，它不允许我上传和保存新对象。

设置.py

1 2	MEDIA_ROOT = os.path.join(BASE_DIR, 'media') MEDIA_URL = '/media/'

序列化程序.py

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class TaskImageSerializer(serializers.ModelSerializer):
class Meta:
model = TaskImage
fields = ('image',)

class TaskSerializer(serializers.HyperlinkedModelSerializer):
user = serializers.ReadOnlyField(source='user.username')
images = TaskImageSerializer(source='image_set', many=True, read_only=True)

class Meta:
model = Task
fields = '__all__'

def create(self, validated_data):
images_data = validated_data.pop('images')
task = Task.objects.create(**validated_data)
for image_data in images_data:
TaskImage.objects.create(task=task, **image_data)
return task

号

型号.py

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class Task(models.Model):
title = models.CharField(max_length=100, blank=False)
user = models.ForeignKey(User)

def save(self, *args, **kwargs):
super(Task, self).save(*args, **kwargs)

class TaskImage(models.Model):
task = models.ForeignKey(Task, on_delete=models.CASCADE)
image = models.FileField(blank=True)

但是，当我执行post请求时：

enter image description here 。

我得到了以下回溯：

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/django/core/handlers/exception.py"
in inner
41. response = get_response(request)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/django/core/handlers/base.py"
in _get_response
187. response = self.process_exception_by_middleware(e, request)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/django/core/handlers/base.py"
in _get_response
185. response = wrapped_callback(request, *callback_args, **callback_kwargs)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/django/views/decorators/csrf.py"
in wrapped_view
58. return view_func(*args, **kwargs)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/rest_framework/viewsets.py"
in view
95. return self.dispatch(request, *args, **kwargs)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/rest_framework/views.py"
in dispatch
494. response = self.handle_exception(exc)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/rest_framework/views.py"
in handle_exception
454. self.raise_uncaught_exception(exc)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/rest_framework/views.py"
in dispatch
491. response = handler(request, *args, **kwargs)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/rest_framework/mixins.py"
in create
21. self.perform_create(serializer)

File"/Users/gr/Desktop/PycharmProjects/godo/api/views.py" in
perform_create
152. serializer.save(user=self.request.user)

File
"/Applications/Anaconda/anaconda/envs/godo/lib/python3.6/site-packages/rest_framework/serializers.py"
in save
214. self.instance = self.create(validated_data)

File"/Users/gr/Desktop/PycharmProjects/godo/api/serializers.py" in
create
67. images_data = validated_data.pop('images')

Exception Type: KeyError at /api/tasks/ Exception Value: 'images'

号

问题描述例外的起源是一个KeyError，因为这个声明images_data = validated_data.pop('images')。这是因为验证的数据没有密钥images。这意味着图像输入不会验证来自邮递员的图像输入。Django Post请求将InMemmoryUpload存储在request.FILES中，因此我们使用它来获取文件。另外，您希望一次上载多个图像。所以，在上传图片时，你必须使用不同的图片名(邮差)。把你的serializer改成这样，

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class TaskSerializer(serializers.HyperlinkedModelSerializer):
user = serializers.ReadOnlyField(source='user.username')
images = TaskImageSerializer(source='taskimage_set', many=True, read_only=True)

class Meta:
model = Task
fields = ('id', 'title', 'user', 'images')

def create(self, validated_data):
images_data = self.context.get('view').request.FILES
task = Task.objects.create(title=validated_data.get('title', 'no-title'),
user_id=1)
for image_data in images_data.values():
TaskImage.objects.create(task=task, image=image_data)
return task

我不知道你的观点，但我想用ModelViewSet预科课程

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class Upload(ModelViewSet):
serializer_class = TaskSerializer
queryset = Task.objects.all()

号

邮差控制台 enter image description here 。DRF结果

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{
"id": 12,
"title":"This Is Task Title",
"user":"admin",
"images": [
{
"image":"http://127.0.0.1:8000/media/Screenshot_from_2017-12-20_07-18-43_tNIbUXV.png"
},
{
"image":"http://127.0.0.1:8000/media/game-of-thrones-season-valar-morghulis-wallpaper-1366x768_3bkMk78.jpg"
},
{
"image":"http://127.0.0.1:8000/media/IMG_212433_lZ2Mijj.jpg"
}
]
}

更新这是你评论的答案。在Django，reverse foreignKey使用_set捕获。见官方文件。这里，Task和TaskImage是OneToMany关系，所以如果你有一个Task实例，你可以通过这个reverse look-up特性得到所有相关的TaskImage实例。下面是例子

1 2	task_instance = Task.objects.get(id=1) task_img_set_all = task_instance.taskimage_set.all()

。

在这里，这个task_img_set_all等于TaskImage.objects.filter(task_id=1)。