简介
特点
- 请求你所要的数据，不多不少
- 获取多个资源，只用一个请求
- 描述所有的可能，类型系统
- 几乎所有语言支持
文档
Graphene-Python
GraphQL | A query language for your API
背景
- 传统restful的接口定义类型多，试图简化接口定义
- django中使用restframework定义restful资源接口时，可能会出现深度查询，造成有时候查询过度
- 例如前端用户需要查询接口用于展示在下拉框时，用户仅需要id与value值时，造成无用字段冗余，影响接口返回性能
- 当一张表字段较多时，例如接口1一共有40个字段，A页面需要5个字段做展示，B页面需要另外10个字段展示，这时我们需要根据用户需求定义返回接口提升性能，且数据不会被暴露
实际问题
问题
- 请求数据量40kB可以根据用户缩减，也就是返回数据量可以做到<40KB
- 后端数据实际耗时783ms,但是数据传输一共耗时5s
Django中如何使用呢
安装
安装
pip install graphene-djangodjango配置
INSTALLED_APPS = [
"django.contrib.staticfiles",
"graphene_django"
]
GRAPHENE = {
"SCHEMA": "test_api.schema.schema" # 下文中需要定义schema.py文件
}Demo
定义数据库模型
from django.db import models
class Category(models.Model):
name = models.CharField(max_length=100, help_text="名称")
id = models.BigAutoField(primary_key=True)
class Ingredient(models.Model):
id = models.BigAutoField(primary_key=True)
name = models.CharField(max_length=100, help_text="名称")
notes = models.TextField(help_text="笔记")
category = models.ForeignKey(
Category, related_name="category", on_delete=models.CASCADE
)
def __str__(self):
return self.name定义serializer
from graphene_django.rest_framework.mutation import SerializerMutation
from rest_framework.serializers import ModelSerializer
from ..models import Category, Ingredient
class CategorySerializer(ModelSerializer):
class Meta:
model = Category
fields = "__all__"
class IngredientSerializer(ModelSerializer):
class Meta:
model = Ingredient
fields = "__all__"定义接口
import graphene
from graphene import relay
from graphene_django import DjangoObjectType
from graphene_django.filter import DjangoFilterConnectionField
from graphene_django.rest_framework.mutation import SerializerMutation
from ..models import Category, Ingredient
from ..serializer import CategorySerializer, IngredientSerializer
# 为查询添加查询总数
class CountableConnectionBase(relay.Connection):
class Meta:
abstract = True
total_count = graphene.Int()
def resolve_total_count(self, info, **kwargs):
return self.iterable.count()
# Ingredient 查看过滤
class IngredientFilter(DjangoObjectType):
class Meta:
model = Ingredient
fields = "__all__"
filter_fields = {
"name": ['exact', "contains", "istartswith"],
"category": ["exact"],
'category__name': ['exact'],
}
interfaces = (relay.Node,)
connection_class = CountableConnectionBase
extra_field = graphene.String()
def resolve_extra_field(self: Ingredient, info):
return "hello!" + str(self.id)
# CategoryFilter 查询过滤
class CategoryFilter(DjangoObjectType):
class Meta:
model = Category
fields = "__all__"
filter_fields = {
"name": ['exact', "contains", "istartswith"],
}
interfaces = (relay.Node,)
connection_class = CountableConnectionBase
# CategoryMutation 修改或新增
class CategoryMutation(SerializerMutation):
class Meta:
serializer_class = CategorySerializer
# IngredientMutation 修改或新增
class IngredientMutation(SerializerMutation):
class Meta:
serializer_class = IngredientSerializer
# 汇总query接口
class ApiQuery(graphene.ObjectType):
search_category = DjangoFilterConnectionField(CategoryFilter)
search_ingredient = DjangoFilterConnectionField(IngredientFilter)
# 汇总操作类接口
class ApiMutation(graphene.ObjectType):
update_category = CategoryMutation.Field()
update_ingredient = IngredientMutation.Field()
汇总所有接口
import graphene
from .api import ApiQuery, ApiMutation
class Query(ApiQuery):
# 新增时提供多继承即可
pass
class Mutation(ApiMutation):
# 新增时提供多继承即可
pass
schema = graphene.Schema(query=Query, mutation=Mutation)启动
python manage.py runserver 0.0.0.0:8080接口文档
总结
- 查询时，可以使用django_filter , 快速查询
- 用法基本和drf框架基本类似
- 接口面涉及的深度查询，通过connection实现，如果返回字段中没有改要求，将不会深度查询
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