1、关系和超链接
0、文档
https://www.django-rest-framework.org/tutorial/5-relationships-and-hyperlinked-apis/
1、效果
2、name用法，配合reverse
第一，我们使用REST框架的reverse功能来返回完全限定的URL；
第二，URL模式是通过方便的名称来标识的，我们稍后将在snippets/urls.py中声明。
view
from rest_framework.reverse import reverse
urlpatterns = format_suffix_patterns([
path('', views.api_root), # 主index页面 path('snippets/', views.SnippetList.as_view(), name='snippet-list'), # name用法，配合reverse('snippet-list')
path('snippets/<int:pk>/', views.SnippetDetail.as_view(), name='snippet-detail'),
path('snippets/<int:pk>/highlight/', views.SnippetHighlight.as_view(), name='snippet-highlight'), path('users/', views.UserList.as_view(), name='user-list'),
path('users/<int:pk>', views.UserDetail.as_view(), name='user-detail'),
])
model
@api_view(['GET'])
def api_root(request, format=None): # 入口，首页
return Response({
'users': reverse('user-list', request=request, format=format), # reverse 反转
'snippets': reverse('snippet-list', request=request, format=format),
})
3、 超链接序列化：HyperlinkedModelSerializer
处理好实体之间的关系：希望在实体之间使用超链接方式
view视图不变
class UserList(generics.ListAPIView): # user/ get方式
queryset = User.objects.all().order_by('id')
serializer_class = UserSerializer
序列化：继承HyperModelSerilizer
class UserSerializer(serializers.HyperlinkedModelSerializer): # 实体之间使用超链接方式
# snippets = serializers.PrimaryKeyRelatedField(many=True, queryset=Snippet.objects.all()) # 添加一个显式字段 外键
# 关联关系，alex的snippet的详情
# many=True，多个字段，
snippets = serializers.HyperlinkedRelatedField(many=True, view_name='snippet-detail', read_only=True) class Meta:
model = User
fields = ['url', 'id', 'username', 'snippets'] class SnippetSerializer(serializers.ModelSerializer): owner = serializers.ReadOnlyField(source='owner.username') # source参数控制哪个属性用于填充字段
# # 它包含一个url字段 该snippet的highlight
# 单个字段，继承与HyperlinkedRelatedField
highlight = serializers.HyperlinkedIdentityField(view_name='snippet-highlight', format='html') class Meta:
model = Snippet
fields = ['url', 'id', 'title', 'code', 'linenos', 'language', 'style', 'owner', 'highlight']
4、HyperlinkedModelSerialize与ModelSerializer区别
HyperlinkedModelSerializer与ModelSerializer有以下区别：
- 默认情况下不包括
id字段。 - 它包含一个
url字段，使用HyperlinkedIdentityField。 - 关联关系使用
HyperlinkedRelatedField，而不是PrimaryKeyRelatedField。
5、高亮代码
model层
class Snippet(models.Model):
created = models.DateTimeField(auto_now_add=True) # 创建时间
title = models.CharField(max_length=100, blank=True, default='')
code = models.TextField()
linenos = models.BooleanField(default=False)
# choices = [(1,'java'),(2,'python'),(3,''golang')] # 下拉框选择，指代
language = models.CharField(choices=LANGUAGE_CHOICES, default='python', max_length=100)
style = models.CharField(choices=STYLE_CHOICES, default='friendly', max_length=100) # Tutorial 4: Authentication & Permissions
owner = models.ForeignKey('auth.User', related_name='snippets', on_delete=models.CASCADE)
# 设置related_name参数来覆盖原名称owner_id(ORM查询时)，实质，DB中还是owner_id
highlighted = models.TextField() class Meta:
ordering = ['created'] # def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
def save(self, *args, **kwargs):
"""
使用pygments库，创建一个高亮显示的HTML，表示代码段
"""
lexer = get_lexer_by_name(self.language)
linenos = self.linenos and 'table' or False
options = self.title and {'title': self.title} or {}
formatter = HtmlFormatter(style=self.style, linenos=linenos, full=True, **options)
self.highlighted = highlight(self.code, lexer, formatter)
super(Snippet, self).save(*args, **kwargs) # 继承父类Model的save
6、HTML渲染器
一个HTML渲染器类，简单地返回预渲染的HTML
data = '<html><body>example</body></html>'
return Response(data)
view层
from rest_framework import renderers
class SnippetHighlight(generics.GenericAPIView):
queryset = Snippet.objects.all()
renderer_classes = [renderers.StaticHTMLRenderer] def get(self, request, *args, **kwargs):
snippet = self.get_object() # 视图显示的对象。
return Response(snippet.highlighted) # 某个字段