가. 지금까지 완료 된 것
– 1부 링크 : http://wp.me/p7xrpI-9h
– Anaconda 설치
– TensorFlow 설치
– Pycharm 설치
– postgresql 설치
– Django 설치
– Django Service 생성
– snippets APP 생성 완료
– Snippet Model 생성
– postgresql 동기화 완료
나. Serializer
우리가 위에서 정의한 Snippet 데이터 클레스를 받아서 JSON 데이터로 변환하거나 ,
그 반대를 수행하는 클래스라고 생각하면 된다. 아래와 같이 프로젝트에 파일을 추가하고
콘솔을 실행하여 몇 가지 예를 테스트해보면 더 이해가 용이할 것이이다.
[Serializer 생성]
from rest_framework import serializers from snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICES class SnippetSerializer(serializers.Serializer): pk = 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
[테스트 결과]
[디장고 쉘 실행]
python manage.py shell
[디비에 데이터 두건 삽입]
from snippets.models importSnippetfrom snippets.serializers importSnippetSerializerfrom rest_framework.renderers importJSONRendererfrom rest_framework.parsers importJSONParser snippet =Snippet(code='foo = "bar"\n') snippet.save() snippet =Snippet(code='print "hello, world"\n') snippet.save()
[정렬된 파이선 기본 데이터 타입]
serializer =SnippetSerializer(snippet) serializer.data
ReturnDict([('pk', None), ('title', u''), ('code', u'foo = "bar"\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')])
[정렬된 파이선 데이터를 JSON으로 변환]
content =JSONRenderer().render(serializer.data) content
'[{"pk":1,"title":"","code":"foo = \\"bar\\"\\n","linenos":false,"language":"python","style":"friendly"},{"pk":2,"title":"","code":"print \\"hello, world\\"\\n","linenos":false,"language":"python","style":"friendly"}]'
[JSON 파싱]
from django.utils.six importBytesIO stream =BytesIO(content) data =JSONParser().parse(stream)
[역정렬 – 데이터 객체로 만들고 다시 저장까지]
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>
[현재 디비에 저장된 모든 항목 출력]
serializer =SnippetSerializer(Snippet.objects.all(), many=True) serializer.data
Out[34]: [OrderedDict([('pk', 1), ('title', u''), ('code', u'foo = "bar"\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')]), OrderedDict([('pk', 2), ('title', u''), ('code', u'print "hello, world"\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')])]
다. ModelSerializer 사용
위에서 정의한 꽤나 긴 Serialzier Code 를 아래와 같이 단순화 할 수 있다
class SnippetSerializer(serializers.ModelSerializer): class Meta: model = Snippet fields = ('id', 'title', 'code', 'linenos', 'language', 'style')
라. views.py
실제로 서비스를 제공할 로직을 구현한다. 아래의 예제는 snippet_list 와 snippet_detail
두 가지 서비스에 대한 코드로 호출 주소에 대한 규칙은 urls.py 에 정의한다.
그리고 해당 메서드를 rest 로 정의하는 코드는 @api_view 로 처리하고자 하는 CRUD
를 정의하고 분기하여 처리한다.
from rest_framework import status from rest_framework.decorators import api_view from rest_framework.response import Response from snippets.models import Snippet from snippets.serializers import SnippetSerializer @api_view(['GET', 'POST']) def snippet_list(request, format=None): """ List all snippets, or create a new snippet. """ if request.method == 'GET': snippets = Snippet.objects.all() serializer = SnippetSerializer(snippets, many=True) return Response(serializer.data) elif request.method == 'POST': serializer = SnippetSerializer(data=request.data) if serializer.is_valid(): serializer.save() return Response(serializer.data, status=status.HTTP_201_CREATED) return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST) @api_view(['GET', 'PUT', 'DELETE']) def snippet_detail(request, pk, format=None): """ Retrieve, update or delete a snippet instance. """ try: snippet = Snippet.objects.get(pk=pk) except Snippet.DoesNotExist: return Response(status=status.HTTP_404_NOT_FOUND) if request.method == 'GET': serializer = SnippetSerializer(snippet) return Response(serializer.data) elif request.method == 'PUT': serializer = SnippetSerializer(snippet, data=request.data) if serializer.is_valid(): serializer.save() return Response(serializer.data) return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST) elif request.method == 'DELETE': snippet.delete() return Response(status=status.HTTP_204_NO_CONTENT)
마. urls.py
from django.conf.urls import url from django.contrib import admin from rest_framework.urlpatterns import format_suffix_patterns from snippets import views urlpatterns = [ url(r'^admin/', admin.site.urls), url(r'^snippets/$', views.snippet_list), url(r'^snippets/(?P<pk>[0-9]+)$', views.snippet_detail), ] urlpatterns = format_suffix_patterns(urlpatterns)
바. TEST
[snippet_list]
http http://127.0.0.1:8000/snippets/ Accept:application/json
[snippet_detail]
http —form POST http://127.0.0.1:8000/snippets/ code=”print 123″
사. Class Based View
위 의 예제는 annotation 을 지정하여 사용하는 전형적인 REST 서버의 모습이었다고 하면, 클래스 형태로 REST 서비스를 구성하는 패턴도 있다
[views.py]
from snippets.models import Snippet from snippets.serializers import SnippetSerializer from django.http import Http404 from rest_framework.views import APIView from rest_framework.response import Response from rest_framework import status class SnippetList(APIView): """ List all snippets, or create a new snippet. """ def get(self, request, format=None): snippets = Snippet.objects.all() serializer = SnippetSerializer(snippets, many=True) return Response(serializer.data) def post(self, request, format=None): serializer = SnippetSerializer(data=request.data) if serializer.is_valid(): serializer.save() return Response(serializer.data, status=status.HTTP_201_CREATED) return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
class SnippetDetail(APIView): """ Retrieve, update or delete a snippet instance. """ def get_object(self, pk): try: return Snippet.objects.get(pk=pk) except Snippet.DoesNotExist: raise Http404 def get(self, request, pk, format=None): snippet = self.get_object(pk) serializer = SnippetSerializer(snippet) return Response(serializer.data) def put(self, request, pk, format=None): snippet = self.get_object(pk) serializer = SnippetSerializer(snippet, data=request.data) if serializer.is_valid(): serializer.save() return Response(serializer.data) return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST) def delete(self, request, pk, format=None): snippet = self.get_object(pk) snippet.delete() return Response(status=status.HTTP_204_NO_CONTENT)
[urls.py]
from django.conf.urls import url from django.contrib import admin from rest_framework.urlpatterns import format_suffix_patterns from snippets import views urlpatterns = [ url(r'^admin/', admin.site.urls), url(r'^snippets/$', views.SnippetList.as_view()), url(r'^snippets/(?P<pk>[0-9]+)/$', views.SnippetDetail.as_view()), ] urlpatterns = format_suffix_patterns(urlpatterns)