django使用graphql的实例
一、开发环境
1、python3.6
2、django2.0
3、window10
二、项目搭建
1、创建一个虚拟空间mkvirtualenv 空间名
2、创建一个django项目
3、安装graphql的依赖包
pip install graphene-django
4、创建一个组件blog
5、把组件blog及graphene_django注入到app中
6、在settings.py中配置mysql数据库连接
三、书写blog的内容
1、在models.py中写上数据模型
from django.db import models
# Create your models here.
class User(models.Model):
name = models.CharField(max_length=100, verbose_name="博主名字")
gender = models.CharField(max_length=6, choices=(('male', u'男'), ('female', '女')), default='female',
verbose_name='性别')
create_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')
class Blog(models.Model):
title = models.CharField(max_length=100, verbose_name='标题')
user = models.ForeignKey(User, null=True, blank=True, on_delete=models.SET_NULL, verbose_name='博主名字')
content = models.TextField(verbose_name='博客内容')
create_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')
update_at = models.DateTimeField(auto_now=True, verbose_name='更新时间')
2、新建一个schema.py文件
#!/usr/bin/env python
# encoding: utf-8
import graphene
from graphene_django.types import DjangoObjectType
from .models import User, Blog
class UserType(DjangoObjectType):
class Meta:
model = User
class BlogType(DjangoObjectType):
class Meta:
model = Blog
# 定义动作约素输入类型
class UserInput(graphene.InputObjectType):
name = graphene.String(required=True)
gender = graphene.String(required=True)
class BlogInput(graphene.InputObjectType):
title = graphene.String(required=True)
user = graphene.Int(required=True)
content = graphene.String(required=True)
# 定义一个创建user的mutation
class CreateUser(graphene.Mutation):
# api的输入参数
class Arguments:
user_data = UserInput(required=True)
# api的响应参数
ok = graphene.Boolean()
user = graphene.Field(UserType)
# api的相应操作，这里是create
def mutate(self, info, user_data):
user = User.objects.create(name=user_data['name'], gender=user_data['gender'])
ok = True
return CreateUser(user=user, ok=ok)
# 定义一个创建博客的mutation
class CreateBlog(graphene.Mutation):
class Arguments:
blog_data = BlogInput(required=True)
blog = graphene.Field(BlogType)
def mutate(self, info, blog_data):
# 插入到数据库中
blog = Blog.objects.create(title=blog_data['title'], user_id=blog_data['user'], content=blog_data['content'])
return CreateBlog(blog=blog)
# 定义一个查询语句
class Query(object):
all_user = graphene.List(UserType)
all_blog = graphene.List(BlogType)
def resolve_all_user(self, info, **kwargs):
# 查询所有book的逻辑
return User.objects.all()
def resolve_all_blog(self, info, **kwargs):
# 查询所有title的逻辑
return Blog.objects.all()
3、在跟目录(和settings.py同级)创建一个项目的总schema.py
import graphene
import book.schema, blog.schema
class Query(blog.schema.Query, graphene.ObjectType):
# 总的Schema的query入口
pass
class Mutations(graphene.ObjectType):
# 总的Schema的mutations入口
create_user = blog.schema.CreateUser.Field()
create_blog = blog.schema.CreateBlog.Field()
schema = graphene.Schema(query=Query, mutation=Mutations)
4、配置url地址
from django.contrib import admin
from django.urls import path
from graphene_django.views import GraphQLView
from .schema import schema
urlpatterns = [
path('admin/', admin.site.urls),
path('graphql/', GraphQLView.as_view(graphiql=True, schema=schema)),
]
5、生成数据库映射及启动项目,直接在浏览器上访问
四、可以对上面的代码调整
1、把Mutations也单独定义在各自的schema.py中
# 定义一个总的mutation出口
class Mutation(graphene.AbstractType):
create_user = CreateUser.Field()
create_blog = CreateBlog.Field()
2、在总的schema.py中引入类型Query一样的操作
class Mutations(blog.schema.Mutation, graphene.ObjectType):
# 总的Schema的mutations入口
pass
3、输入数据类型可以直接定义在mutation里面
class CreateUser(graphene.Mutation):
# api的输入参数(类名可以随便定义)
class Arguments:
name = graphene.String(required=True)
gender = graphene.String(required=True)
# api的响应参数
ok = graphene.Boolean()
user = graphene.Field(UserType)
# api的相应操作，这里是create
def mutate(self, info, name, gender):
user = User.objects.create(name=name, gender=gender)
ok = True
return CreateUser(user=user, ok=ok)
五、Query语句中使用条件查询
1、app的schema(官方案例)
import graphene
from graphene_django.types import DjangoObjectType
from .models import Category, Ingredient
class CategoryType(DjangoObjectType):
class Meta:
model = Category
class IngredientType(DjangoObjectType):
class Meta:
model = Ingredient
# 定义一个查询
class Query(object):
# 定义一个根据id或者name查询的
category = graphene.Field(CategoryType,
id=graphene.Int(),
name=graphene.String())
# 查询全部的
all_categories = graphene.List(CategoryType)
# 根据条件查询
ingredient = graphene.Field(IngredientType,
id=graphene.Int(),
name=graphene.String())
# 查询全部的
all_ingredients = graphene.List(IngredientType)
def resolve_all_categories(self, info, **kwargs):
return Category.objects.all()
def resolve_all_ingredients(self, info, **kwargs):
# We can easily optimize query count in the resolve method
return Ingredient.objects.select_related('category').all()
# 定义查询语句
def resolve_category(self, info, **kwargs):
id = kwargs.get('id')
name = kwargs.get('name')
if id is not None:
return Category.objects.get(pk=id)
if name is not None:
return Category.objects.get(name=name)
return None
def resolve_ingredient(self, info, **kwargs):
id = kwargs.get('id')
name = kwargs.get('name')
if id is not None:
return Ingredient.objects.get(pk=id)
if name is not None:
return Ingredient.objects.get(name=name)
return None
官网地址
补充知识：记录下python中使用定时器的几种方法
方式一、直接使用while循环的方式
from datetime import datetime
import time
# 每n秒执行一次
def timer(n):
while True:
print(datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
time.sleep(n)
timer(5)
方式二、使用threading模块中的Timer
from datetime import datetime
from threading import Timer
# 打印时间函数
def print_time(inc):
print(datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
"""
Timer的参数说明
inc:表示时间间隔
print_time:执行的函数
(inc,):传递给执行函数的参数
"""
t = Timer(inc, print_time, (inc,))
t.start()
print_time(2)
方式三、使用sched模块
import time
import sched
from datetime import datetime
# 初始化 sched 模块的 scheduler 类
# 第一个参数是一个可以返回时间戳的函数，第二个参数可以在定时未到达之前阻塞。
schedule = sched.scheduler(time.time, time.sleep)
# 被周期性调度触发的函数
def print_time(inc):
print(datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
schedule.enter(inc, 0, print_time, (inc,))
# 默认参数 60 s
def start(inc=60):
# enter四个参数分别为：间隔事件、优先级（用于同时间到达的两个事件同时执行时定序）、被调用触发的函数、给触发函数的参数（tuple形式）
schedule.enter(0, 0, print_time, (inc,))
schedule.run()
if __name__ == "__main__":
start(10)
方式四、使用apscheduler
from apscheduler.schedulers.blocking import BlockingScheduler
from datetime import datetime
def job():
print(datetime.now().strftime('%Y-%m-%d %H:%M:%S'))
if __name__ == "__main__":
scheduler = BlockingScheduler()
scheduler.add_job(job, 'interval', seconds=5)
scheduler.start()
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