如何在Django RestFramework中的外键中获取值

Question

I'm new in django restframework
I have a question about how to get the value in the Foreign key in django restframework

My code is below,when I want to use django restframework to get write the json.

models.py:

class Movie(models.Model):
    link = models.URLField()
    title = models.CharField(max_length=255, null=True)

class MovieImage(models.Model):
    movieimage = models.ForeignKey(Movie,null=True,blank=True)            
    img_link = models.URLField(max_length=255, null=True)   
    img_describe = models.URLField(max_length=255, null=True)   
    img_rank = models.URLField(max_length=255, null=True)   

serializers.py

class MovieSerializer(serializers.ModelSerializer):     
    images = serializers.RelatedField(many=True, read_only=True, source='movieimage_set')

    class Meta:
        model = Movie
        fields = ('link', 'title', 'images')

And I will get the results:

       {
            "link": "https://test.com/id=1", 
            "title": "TEST", 
            "images": [
                "MovieImage object"
            ]
        } 

I want to know how to display the variable in class images like:

       {
            "link": "https://test.com/id=1", 
            "title": "TEST",
            "images"[img_describe: "img_describe value",
                      img_link: "img_link vlaue" ]
        }           

Answer 1

If you only need images to be read-only, you can do this using a nested serializer. If it has to be writable, you may have some issues as nested serializers have problems with writing in DRF < 3.0, especially in many-to-many cases like this.

You would have to write a serializer for images, similar to this:

class MovieImageSerializer(serializers.ModelSerializer):
    img_link = serializers.URLField()
    img_describe = serializers.CharField()

    class Meta:
        model = MovieImage
        fields = ('img_link', 'img_describe', )

and add it to your current serializer as a replacement for the field, similar to this:

class MovieSerializer(serializers.ModelSerializer):     
    images = MovieImageSerializer(many=True, read_only=True, source='movieimage_set')

    class Meta:
        model = Movie
        fields = ('link', 'title', 'images')

This will give you output with nested objects, similiar to this:

{
    "link": "https://test.com/id=1", 
    "title": "TEST", 
    "images": [
        {
            "img_describe": "the value",
            "img_link": "a link"
        }
    ]
}

You can find more information on nested relationships in the Django REST Framework documentation .