drf-serializer.md

Serializers

기본 시리얼라이저는 Model에 정의한 코드를 거의 그대로 반복한다.

from rest_framework import serializers
from snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICES


class SnippetSerializer(serializers.Serializer):
    id = serializers.IntegerField(read_only=True)
    title = serializers.CharField(required=False, allow_blank=True, max_length=100)
    code = serializers.CharField(style={'base_template': 'textarea.html'})
    linenos = serializers.BooleanField(required=False)
    language = serializers.ChoiceField(choices=LANGUAGE_CHOICES, default='python')
    style = serializers.ChoiceField(choices=STYLE_CHOICES, default='friendly')

    def create(self, validated_data):
        """
        Create and return a new `Snippet` instance, given the validated data.
        """
        return Snippet.objects.create(**validated_data)

    def update(self, instance, validated_data):
        """
        Update and return an existing `Snippet` instance, given the validated data.
        """
        instance.title = validated_data.get('title', instance.title)
        instance.code = validated_data.get('code', instance.code)
        instance.linenos = validated_data.get('linenos', instance.linenos)
        instance.language = validated_data.get('language', instance.language)
        instance.style = validated_data.get('style', instance.style)
        instance.save()
        return instance

Using ModelSerializers

class SnippetSerializer(serializers.ModelSerializer):
    class Meta:
        model = Snippet
        fields = ['id', 'title', 'code', 'linenos', 'language', 'style']

• An automatically determined set of fields.
• Simple default implementations for the create() and update() methods.

Serializer 사용법

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework.renderers import JSONRenderer
from rest_framework.parsers import JSONParser

snippet = Snippet(code='foo = "bar"\n')
snippet.save()

snippet = Snippet(code='print("hello, world")\n')
snippet.save()

Serialization

## model object to python native datatype ## 
serializer = SnippetSerializer(snippet)
serializer.data
# {'id': 2, 'title': '', 'code': 'print("hello, world")\n', 'linenos': False, 'language': 'python', 'style': 'friendly'}


## python native datatype to json ##
content = JSONRenderer().render(serializer.data)
content
# b'{"id": 2, "title": "", "code": "print(\\"hello, world\\")\\n", "linenos": false, "language": "python", "style": "friendly"}'

Deserialization

import io

## json to python native datatype ##
stream = io.BytesIO(content)
data = JSONParser().parse(stream)

## python native datatype to model object ## 
serializer = SnippetSerializer(data=data)
serializer.is_valid()
# True
serializer.validated_data
# OrderedDict([('title', ''), ('code', 'print("hello, world")\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')])
serializer.save()
# <Snippet: Snippet object>