ASP.NET Core 3.1中的Ocelot API Gateway自定义聚合器问题

如何解决ASP.NET Core 3.1中的Ocelot API Gateway自定义聚合器问题

我正在使用ASP.NET中的Ocelot实现自定义聚合器，它在Startup.cs Ocelot中间件中引发了错误。但是，两个微服务都可以正常工作，并且可以独立获取数据。

当我从我的API网关调用它们时，它抛出以下错误。

Startup.cs

public class Startup

{
    // This method gets called by the runtime. Use this method to add services to the container.
    // For more information on how to configure your application,visit https://go.microsoft.com/fwlink/?LinkID=398940
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddOcelot()
            .AddSingletonDefinedAggregator<MyAggregator>();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public async void Configure(IApplicationBuilder app,IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
        await app.USEOcelot();
    }
}

这是我的用于不同微服务路由的ocelot.json文件。

ocelot.json

{
  "ReRoutes": [
    {
      "DownstreamPathTemplate": "/user/getUser","DownstreamScheme": "https","DownstreamHostAndPorts": [
        {
          "Host": "localhost","Port": "44378"
        }
      ],"UpstreamPathTemplate": "/getUser","Key": "User"
    },{
      "DownstreamPathTemplate": "/product/getProduct","Port": "44357"
        }
      ],"UpstreamPathTemplate": "/getProduct","Key": "Product"
    }
  ],"Aggregates": [
    {
      "ReRouteKeys": [
        "User","Product"
      ],"UpstreamPathTemplate": "/UserAndProduct"
    }
  ],"GlobalConfiguration": {
    "BaseUrl": "http://localhost:5000/"
  }
}

我的自定义聚合器类

MyAggregator.cs

public class MyAggregator : IDefinedAggregator
    {
      
        public async Task<DownstreamResponse> Aggregate(List<HttpContext> responses)
        {
            var one = await responses[0].Items.DownstreamResponse().Content.ReadAsstringAsync();
            var two = await responses[1].Items.DownstreamResponse().Content.ReadAsstringAsync();

            var contentBuilder = new StringBuilder();
            contentBuilder.Append(one);
            contentBuilder.Append(two);

            var stringContent = new StringContent(contentBuilder.ToString())
            {
                Headers = { ContentType = new MediaTypeHeaderValue("application/json") }
            };

            return new DownstreamResponse(stringContent,HttpStatusCode.OK,new List<keyvaluePair<string,IEnumerable<string>>>(),"OK");
        }
    }

解决方法

您忘记在ocelot.json文件中提及您的自定义聚合器。每当您点击/UserAndProduct时，Ocelot都需要了解您的自定义聚合器。

“集合”：[ { “ ReRouteKeys”：[ “用户”， “产品” ]， “ UpstreamPathTemplate”：“ / UserAndProduct” } ]

ocelot的最新版本发生了重大变化。使用钥匙 Routes，而不是ReRoutes。您可以使用以下json文件。

{
  "Routes": [
    {
      "DownstreamPathTemplate": "/user/getUser","DownstreamScheme": "https","DownstreamHostAndPorts": [
        {
          "Host": "localhost","Port": "44378"
        }
      ],"UpstreamPathTemplate": "/getUser","Key": "User"
    },{
      "DownstreamPathTemplate": "/product/getProduct","Port": "44357"
        }
      ],"UpstreamPathTemplate": "/getProduct","Key": "Product"
    }
  ],"Aggregates": [
    {
      "RouteKeys": [
        "User","Product"
      ],"UpstreamPathTemplate": "/UserAndProduct","Aggregator": "MyAggregator"
    }
  ],"GlobalConfiguration": {
    "BaseUrl": "http://localhost:5000/"
  }
}