GraphQL:来来来,Union_查询接口

  Union就是把不相干的一些数据实体,合并起来,一起供外部查询。不用像webapi,完成查询不同的数据,需要多次请求。一次请求,获取多样数据,减少请求次数,这也是GraphQL的优势之一。怎么弄,来来来,代码看过来:

using HotChocolate;
using HotChocolate.Execution;
using HotChocolate.Types;
using System;

namespace GraphQLBase006
{
class Program
{
static void Main(string[] args)
{
UnionDemo.Run();
}
}
public class UnionDemo
{
public static void Run()
{
var schema = SchemaBuilder.New()
.AddQueryType<Query>()
.AddType<Car>()
.AddType<Cabbage>()
.AddType<Earth>()
.AddProjections()
.Create();

var executor = schema.MakeExecutable();
Console.WriteLine(executor.Execute(@"
{
formats
{
__typename,
... on Car{
brand,
price
},
... on Cabbage{
name,
nutrition
}
... on Earth{
diameter
}
}
}").ToJson());
}
}

public class Query
{
public IUnion[] GetFormats()
{
return new IUnion[]
{
new Car{
Brand="Benz",
Price=1000000
},
new Cabbage{
Name="灰子白",
Nutrition="纤维"
},
new Earth{
Diameter=12742
}
};
}
}

[UnionType("Unio")]
public interface IUnion
{
}
public class Car : IUnion
{
public string Brand { get; set; }
public decimal Price { get; set; }
}

public class Cabbage : IUnion
{
public string Name { get; set; }
public string Nutrition { get; set; }
}
public class Earth : IUnion
{
public double Diameter { get; set; }
}
}

  案例中就是把不相干的Car,Cabbage,Earth,通过继承一个空接口合并起来,供外部访问,通过自定义查询接口语句,达到灵活取想要的数据,比如一些数据字典的查询就很有用,不相干的一些配置,同时获取到,以备后用。

  结果:

{
"data": {
"formats": [
{
"__typename": "Car",
"brand": "Benz",
"price": 1000000
},
{
"__typename": "Cabbage",
"name": "\u7070\u5B50\u767D",
"nutrition": "\u7EA4\u7EF4"
},
{
"__typename": "Earth",
"diameter": 12742
}
]
}
}


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