.NET 6.0配置Ocelot网关重定向至同应用控制器的404问题排查

环境与问题 #

目标框架：.NET 6.0，Ocelot版本：18.0.0

现有代码如下：

Program.cs

using Ocelot.DependencyInjection;
using Ocelot.Middleware;

var builder = WebApplication.CreateBuilder(args);

var ocelotConfig = builder.Configuration.AddJsonFile(Path.Combine(builder.Environment.ContentRootPath, "ocelot.json"), optional: false, reloadOnChange: true);
builder.Services.AddOcelot(builder.Configuration);
builder.Services.AddControllers();

var app = builder.Build();

app.UseOcelot();
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();

app.Run();

ocelot.json

{
  "GlobalConfiguration": {
    "BaseAddress": "https://localhost:7249"
  },
  "Routes": [
    {
      "DownstreamPathTemplate": "/api/WeatherForecast",
      "DownstreamScheme": "https",
      "DownstreamHostAndPorts": [
        {
          "Host": "localhost",
          "Port": 7249
        }
      ],
      "UpstreamPathTemplate": "/gtw/WeatherForecast",
      "UpstreamHttpMethod": [ "Get" ]
    }
  ]
}

WeatherForecastController.cs

using Microsoft.AspNetCore.Mvc;

namespace DemoApiGateway.Controllers;

[ApiController]
[Route("api/[controller]")]
public class WeatherForecastController : ControllerBase
{
    private static readonly string[] Summaries = new[]
    {
        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

    private readonly ILogger<WeatherForecastController> _logger;

    public WeatherForecastController(ILogger<WeatherForecastController> logger)
    {
        _logger = logger;
    }

    [HttpGet(Name = "GetWeatherForecast")]
    public IEnumerable<WeatherForecast> Get()
    {
        return Enumerable.Range(1, 5).Select(index => new WeatherForecast
        {
            Date = DateTime.Now.AddDays(index),
            TemperatureC = Random.Shared.Next(-20, 55),
            Summary = Summaries[Random.Shared.Next(Summaries.Length)]
        })
        .ToArray();
    }
}

调用https://localhost:7249/gtw/WeatherForecast或直接调用https://localhost:7249/api/WeatherForecast均返回HTTP 404错误，此前在.NET Core 2.2版本中可正常运行。

解决步骤 #

1. 修复Ocelot中间件的异步调用 #

Ocelot 18.x在.NET 6+环境中，UseOcelot()是异步方法，必须使用await等待初始化完成，否则网关路由无法正确加载。

2. 调整中间件顺序 #

中间件执行顺序直接影响请求处理逻辑，正确顺序应为：

• 先处理HTTPS重定向
• 再处理授权逻辑
• 启动Ocelot网关中间件
• 最后映射本地控制器路由

这样既保证网关能处理转发请求，也能让本地API路由正常生效。

3. 简化Ocelot配置加载方式 #

无需手动拼接路径，builder.Configuration默认会从项目根目录读取配置文件，可简化代码。

修正后的代码 #

Program.cs

using Ocelot.DependencyInjection;
using Ocelot.Middleware;

var builder = WebApplication.CreateBuilder(args);

// 简化配置文件加载
builder.Configuration.AddJsonFile("ocelot.json", optional: false, reloadOnChange: true);
builder.Services.AddOcelot(builder.Configuration);
builder.Services.AddControllers();

var app = builder.Build();

// 调整中间件顺序并异步启动Ocelot
app.UseHttpsRedirection();
app.UseAuthorization();
await app.UseOcelotAsync();
app.MapControllers();

app.Run();

验证 #

修改后重新启动项目：

• 直接访问https://localhost:7249/api/WeatherForecast，应正常返回天气数据
• 访问网关路径https://localhost:7249/gtw/WeatherForecast，Ocelot会转发请求到本地API，同样返回数据

内容的提问来源于stack exchange，提问作者Vladimer Bagoshvili