Django rest_framework 实用技巧

前言:

　　最近工作中需要用到Django rest_framework框架做API, 边学边写,记录了一些实际工作中需要用到的功能,不是很全也不系统,以后需要什么功能可以在这查询. 后续还会更新其它的用法

####################################################################
########安装和简单使用
    ###### 准备工作
        pip install rest_framework  # 安装

        INSTALLED_APPS = (
            ...
            'rest_framework',   # 将其加入app列表内
        )


    ###### urls.py 
        from django.conf.urls import include, url  # 引入include二级路由, url
        from django.contrib import admin           # admin模块
        from rest_framework import routers         # 导入api路由 !
        import app1         # 导入app1

        router = routers.DefaultRouter()           # 获取api路由对象
        router.register(r'users', app1.SpecialGiftViewSet)# 注册路由到指定的ViewSet类

        urlpatterns = [
            url(r'^admin/', include(admin.site.urls)),  
            url(r'^', include(router.urls)),       # 设置api路由转发
        ]


    ###### app1/serializers.py
        from rest_framework import serializers  # api接口用于序列化 model 的类
        from app1.models import SpecialGift     # 自定义的要提供api的model类

        class UserSerializer(serializers.HyperlinkedModelSerializer):  # 序列化这个表的类
            class Meta:
                model = SpecialGift
                fields = ('url', 'username', 'email', 'is_staff')      # 验证字段可以省略!

        ---------参数扩展-----------
        # HyperlinkedModelSerializer 是建立超链接关系就是外健使用 "goods": "http://127.0.0.1:8080/goods/1/"
        # ModelSerializer  建立主健关系在json数据中表现为 'goods': 1
        # ReadOnlyModelViewSet  未知
     

    ####### app1/views.py 内容
        from rest_framework import routers, serializers, viewsets      # 分别为api的路由, 序列化, viewsets
        from app1.serializers import SpecialGiftSerializer           # 引入处理序列化的类
        from rest_framework.permissions import AllowAny, IsAuthenticated, IsAdminUser  # 用于指定权限, 所有人, 登录用户, 管理员
        from app01.models import SpecialGift                  # 引入models类
        from django.utils import timezone    # 按时区的,当前时间
        # from rest_framework import response

        class SpecialGiftViewSet(viewsets.ReadOnlyModelViewSet):
            queryset = SpecialGift.objects.all().order_by('-created')    # 指定默认查询方式, 按创建时间倒序
            serializer_class = SpecialGiftSerializer                  # 指定处理序列化的类
            permission_classes = [AllowAny]                        # 指定权限 AllowAny 为所有人

            def get_queryset(self):  # 过滤函数
                return self.queryset.filter(end_time__gt=timezone.now())  # 过滤当前时间以前的记录



    ###### app1/models.py 中写入模型定义
        from django.utils.translation import ugettext_lazy as _  # Django国际化翻译
        
        class SpecialGift(models.Model):
        title = models.CharField(max_length=64)
        image = VersatileImageField(_("gift_image"),
                                    max_length=255,
                                    upload_to=generate_upload_filename,
                                    )
        min_money = models.DecimalField(_("min_money"), max_digits=7, decimal_places=2, validators=[MinValueValidator(0)])
        price = models.DecimalField(_("price"), max_digits=7, decimal_places=2, validators=[MinValueValidator(0)],
                                    default=29.9)
        end_time = models.DateTimeField()

        def __unicode__(self):
            return self.title


    ###### app1/admin.py 中配置管理界面
        from django.contrib import admin
        from app1.models import SpecialGift

        admin.site.register(SpecialGift)  # 简单注册每行只显示对象名

        # 装饰器注册!
        @admin.register(SpecialGift)
        class SpecialGiftAdmin(admin.ModelAdmin):
            list_display = ('title', 'image', 'min_money', 'price', 'end_time')  # 显示为表结构包括所有的列
            search_fields = ['title']  # 出现搜索框, 指定搜索哪一列字段

        # 在django中我们没有创建对数据库的查询操作和页面返回，但是调用rest framework标准的api接口我们就可以直接从数据库中查询到数据，增删改查都是可以的！实现起来如此简单！


    ###### setting.py配置
    REST_FRAMEWORK = {
        'DEFAULT_PERMISSION_CLASSES': ('rest_framework.permissions.DjangoModelPermissionsOrAnonReadOnly',),
        'DEFAULT_FILTER_BACKENDS': ('rest_framework.filters.DjangoFilterBackend',),
        'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
        'DEFAULT_VERSIONING_CLASS': 'rest_framework.versioning.AcceptHeaderVersioning',
        'DEFAULT_VERSION': '160201',
        'PAGE_SIZE': 10,   # 每页10条数据
        'DEFAULT_AUTHENTICATION_CLASSES': (
            'rest_framework.authentication.SessionAuthentication',
            'rest_framework.authentication.TokenAuthentication',
        ),
    }




#######################################################################
# 为查询到的数据增加相关联的字段!! 正查!!
#######################################################################
    # models.py
    class Goods(models.Model):
        name = models.CharField(max_length=128)
        price = models.CharField(max_length=56, blank=True, null=True)


    class Index(models.Model):
        goods = models.ForeignKey(Goods, verbose_name="Goods")
        start_at = models.DateTimeField()
        end_at = models.DateTimeField()


    # serializers.py
    class GoodsSerializers(serializers.HyperlinkedModelSerializer):
        class Meta:
            model = Goods
            fields = ('name', 'price')


    class IndexSerializers(serializers.HyperlinkedModelSerializer):
        name = serializers.ReadOnlyField(source='goods.name')    # 增加外健的字段
        price = serializers.ReadOnlyField(source='goods.price')  # 添加外健的字段 

        class Meta:
            model = Index
            fields = ('goods', 'start_at', 'end_at', 'name', 'price')


    # views.py
    class IndexViewSet(viewsets.ReadOnlyModelViewSet):
        queryset = Index.objects.all()
        serializer_class = IndexSerializers


    class GoodsViewSet(viewsets.ReadOnlyModelViewSet):
        queryset = Goods.objects.all()
        serializer_class = GoodsSerializers

    # 结果! 商品本来只有一个url接口要起得到详细还得再查询一次.现在将详细直接加入数据中方便很多!
    {
        "count": 2,
        "next": null,
        "previous": null,
        "results": [
            {
                "goods": "http://127.0.0.1:8080/goods/1/",
                "start_at": "2017-01-03T14:22:55Z",
                "end_at": "2017-01-03T14:22:56Z",
                "name": "book",
                "price": "18.5"
            },
            {
                "goods": "http://127.0.0.1:8080/goods/2/",
                "start_at": "2017-01-03T14:23:04Z",
                "end_at": "2017-01-03T14:23:05Z",
                "name": "pen",
                "price": "34.5"
            }
        ]
    }




################################################################################
###### api嵌套查询, 查询外健对象的具具体内容, 而不是只显示iD
###### 正查例子
    class Column(models.Model):
        name = models.CharField(u'类型名称', max_length=256)
        slug = models.CharField(u'类型网址', max_length=256, db_index=True)
        intro = models.TextField(u'类型简介', default='')

    class Article(models.Model):
        column = models.ManyToManyField(Column, verbose_name=u'分类')
        genre = models.SmallIntegerField(u'文本<图片<视频', choices=ARTICLE_GENRE, default=ARTICLE_TXT,
                                         help_text=u'文章所属类型. 优先级别视频大于图片大于文本')

    # article的models里面有多对多的外健column字段
    class ColumnSerializer(serializers.ModelSerializer):
        class Meta:
            model = Column

    class ArticleSerializer(serializers.ModelSerializer):
        column = ColumnSerializer(many=True, read_only=False)  # 定义和外健字段重名的字段并为其指定序列化类
        class Meta:
            model = Article
            fields = ('title', 'column')   # 定义只操作这两列数据(如果不定义fields则默认为全部字段, 如果定义fields则
                                           # _必须包含本类中定义的column字段, 否则报错)

    class ArticleViewSet(viewsets.ReadOnlyModelViewSet):        # view.py
            queryset = Article.objects.all()                    # 查询
            serializer_class = ArticleSerializer                # 指定序列化类





###### 反查例子:
    # 还用上面的models为例再加个评论表, 外健分别为User, Article, 通过Article查询评论的内容如下
    class Comment(models.Model):
        owner = models.ForeignKey('auth.User')
        article = models.ForeignKey(Article, related_name='comments')  # 注意反查名
        content = models.CharField(u'评论内容', max_length=1024)
        flag = models.BooleanField(u'标记', default=True)
        updated = models.DateTimeField(auto_now=True)
        created = models.DateTimeField(auto_now_add=True)

    class CommentSerializer(serializers.ModelSerializer):   # 为此表定义序列化类
        class Meta:
            model = Comment

    class ArticleSerializer(serializers.ModelSerializer):
        column = ColumnSerializer(many=True, read_only=False)
        comments = CommentSerializer(many=True, read_only=False)  # 使用反查名指定序列化类
        class Meta:
            model = Article

    class ArticleViewSet(viewsets.ReadOnlyModelViewSet):    # view.py
        queryset = Article.objects.all()                    # 查询
        serializer_class = ArticleSerializer                # 指定序列化类
        def get_queryset(self):                        # 过滤函数
            return self.queryset.filter(end_time__gt=timezone.now())





################################################################################
######关于class Meta的其它功能
    class ArticleSerializer(serializers.ModelSerializer):
        column = ColumnSerializer(many=True, read_only=False)  # 定义和外健字段重名的字段并为其指定序列化类
        class Meta:
            model = Article          # 定义对应的model

            exclude = ('id', )        # 定义排除这几列数据

            fields = ('title', 'column')   # 定义只操作这两列数据(如果不定义,默认是全部数据)

            read_only_fields = ('id', 'user')  # 定义这几列数据是只读的