为什么 Asp.Net Core Kestrel 服务器向 Ngrok 返回 404 并且控制器永远不会被调用？答案

【问题标题】：Why is Asp.Net Core Kestrel server returns 404 to Ngrok and Controller is never gets called?为什么 Asp.Net Core Kestrel 服务器向 Ngrok 返回 404 并且控制器永远不会被调用？
【发布时间】：2021-03-07 16:57:00
【问题描述】：

几天来，我正在尝试运行一个简单的 asp.net 核心应用程序，并为 Telegram bot 设置 webhook。它在 Mac 上运行，带有 Kestrel 服务器，Ngrok 在其上用于将 https 代理到 webhook。目前它向 Ngrok 返回 404，我在控制台中也看到 404。任何帮助表示赞赏。我尝试了这条线的各种修改 ./ngrok http http://localhost:5000 -host-header=localhost:5000

我是 Asp.Net Core 的初学者。这是我应用的核心部分：

[Route("/")]
[ApiController]
public class UpdateController : ControllerBase
{
    [HttpPost]
    public async Task<OkResult> Post([FromBody]Update update)

这个永远不会被调用。这是我的 Program.cs

public class Program
{
    public static void Main(string[] args)
    {
        BuildWebHost(args).Run();
    }

    private static IWebHost BuildWebHost(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseKestrel()
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseStartup<Startup>()
            .Build();
}

Startup.cs

public class Startup
{
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        
        Bot.GetBotClientAsync().Wait();
    }
}

Bot.cs

public static class Bot
{
    private static TelegramBotClient botClient;
    private static List<Command> commandsList;

    public static IReadOnlyList<Command> Commands => commandsList.AsReadOnly();

    public static async Task<TelegramBotClient> GetBotClientAsync()
    {
        if (botClient != null)
        {
            return botClient;
        }

        commandsList = new List<Command>
        {
            new StartCommand()
        };

        botClient = new TelegramBotClient(AppSettings.Token);
        await botClient.SetWebhookAsync(AppSettings.NGrokUrl);
        return botClient;
    }
}

设置 webhook 工作正常，Ngrok 接收请求，但来自 Kestrel 的答案始终是 404，并且永远不会调用 Post 方法。

控制台输出示例：

dbug: Microsoft.AspNetCore.Hosting.Diagnostics[3]
      Hosting starting
dbug: Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServer[2]
      Failed to locate the development https certificate at '(null)'.
dbug: Microsoft.AspNetCore.Hosting.Diagnostics[4]
      Hosting started
dbug: Microsoft.AspNetCore.Hosting.Diagnostics[0]
      Loaded hosting startup assembly eBot
Hosting environment: Development
Content root path: /Users/yuriibabii/Projects/eBot/eBot
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.
dbug: Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets[6]
      Connection id "0HM4GMVPJLPSF" received FIN.
dbug: Microsoft.AspNetCore.Server.Kestrel[39]
      Connection id "0HM4GMVPJLPSF" accepted.
dbug: Microsoft.AspNetCore.Server.Kestrel[1]
      Connection id "0HM4GMVPJLPSF" started.
dbug: Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets[7]
      Connection id "0HM4GMVPJLPSF" sending FIN because: "The client closed the connection."
dbug: Microsoft.AspNetCore.Server.Kestrel[10]
      Connection id "0HM4GMVPJLPSF" disconnecting.
dbug: Microsoft.AspNetCore.Server.Kestrel[2]
      Connection id "0HM4GMVPJLPSF" stopped.
dbug: Microsoft.AspNetCore.Server.Kestrel[39]
      Connection id "0HM4GMVPJLPSG" accepted.
dbug: Microsoft.AspNetCore.Server.Kestrel[1]
      Connection id "0HM4GMVPJLPSG" started.
dbug: Microsoft.AspNetCore.Server.Kestrel[39]
      Connection id "0HM4GMVPJLPSH" accepted.
dbug: Microsoft.AspNetCore.Server.Kestrel[1]
      Connection id "0HM4GMVPJLPSH" started.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
dbug: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[0]
      Wildcard detected, all requests with hosts will be allowed.
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 45.4537ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000001": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000001": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 GET http://localhost:5000/  
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSG" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 9.3331ms 404 
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 10.7676ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000002": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000002": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 8.5738ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000003": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000003": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 8.8111ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000004": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000004": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 9.6591ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000005": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000005": done reading request body.

【问题讨论】：

标签： c# asp.net asp.net-core kestrel-http-server ngrok

【解决方案1】：

您是否发布了所有的 Startup 课程？我没有看到任何必须有 services.AddMvc().AddMvcOptions() 行的 ConfigureServices 方法，也没有在 Configure 方法中看到 app.UseMvc() 行。

我不太确定，但我一直认为您需要这两行来启用控制器。

尝试以这种方式更改您的 Startup 类：

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().AddMvcOptions();
        services.AddControllersWithViews();
    }


    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        
        app.UseRouting();
        app.UseMvc();

        Bot.GetBotClientAsync().Wait();
    }
}

【讨论】：

它确实奏效了！谢谢你。但是我不得不在代码中添加几行，因此我发布了一个新答案。

【解决方案2】：

对@PiGi78 的答案进行了一些修改，它确实有效。这是最终的解决方案：

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().AddMvcOptions(ApplyMvcOptions);
        services.AddControllersWithViews();
        services.AddControllers().AddNewtonsoftJson();
    }

    private void ApplyMvcOptions(MvcOptions options)
    {
        options.EnableEndpointRouting = false;
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        
        app.UseRouting();
        app.UseMvc();
        
        Bot.GetBotClientAsync().Wait();
    }
}

@PiGi78 非常感谢！

【讨论】：