django rest

djangorest框架是今天看的一个文档。
比较简单的是入门篇，
https://github.com/moocstudent/django-proj
这个呢就是根据入门篇来的代码，
其中比django原教程多的就是关于深入的rest框架的关键点使用。

from django.shortcuts import render

from django.contrib.auth.models import User, Group
from rest_framework import viewsets
from rest_framework import permissions
from tutorial.quickstart.serializers import UserSerializer, GroupSerializer

# Rather than write multiple views we're grouping together all the common behavior into classes called ViewSets.
class UserViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows users to be viewed or edited.
    """
    queryset = User.objects.all().order_by('-date_joined')
    serializer_class = UserSerializer
    permission_classes = [permissions.IsAuthenticated]


class GroupViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows groups to be viewed or edited.
    """
    queryset = Group.objects.all()
    serializer_class = GroupSerializer
    permission_classes = [permissions.IsAuthenticated]

比如下面这里的ModelViewSet就是一个通用的restful接口组件，

from django.contrib.auth.models import User, Group
from rest_framework import serializers

# Notice that we're using hyperlinked relations in this case with HyperlinkedModelSerializer.
# You can also use primary key and various other relationships, but hyperlinking is good RESTful design.
class UserSerializer(serializers.HyperlinkedModelSerializer):
    # meta data set
    class Meta:
        model = User
        # custom fields
        fields = ['url', 'username', 'email', 'groups']


class GroupSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Group
        fields = ['url', 'name']

再比如serializer序列化，这个序列化类在view层进行了指定。
最后接口的路由是通过urls配置的：

from django.urls import include, path
from rest_framework import routers
from tutorial.quickstart import views

router = routers.DefaultRouter()
router.register(r'users', views.UserViewSet)
router.register(r'groups', views.GroupViewSet)

# Wire up our API using automatic URL routing.
# Additionally, we include login URLs for the browsable API.
urlpatterns = [
    path('', include(router.urls)),
    path('api-auth/', include('rest_framework.urls', namespace='rest_framework'))
]

整理也就是说前端请求过来之后通过urls找到相应接口路由，
再找到视图views，然后处理相关逻辑，而serializer类似一个处理单元。
在serializer中，原本配置比较多

from rest_framework import serializers
import snippets.models


class SnippetSerializer(serializers.ModelSerializer):
    # 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')

    class Meta:
        model = Snippet
        fields = ['id','title','code','linenos','language','style']

   #  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

如果上面第一行是class SnippetSerializer(serializers.Serializer)的话对应注释代码也是
配合serializers.Serializer的，而ModelSerializer则提供了通用的方法。