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ASP.Net Core例外処理ミドルウェア

ASP.Net Core 3.0 Web APIプロジェクトで例外処理にミドルウェアを使用しようとしています。

public class ErrorHandlingMiddleware
{
    private readonly RequestDelegate next;

    public ErrorHandlingMiddleware(RequestDelegate next)
    {
        this.next = next;
    }

    public async Task Invoke(HttpContext context)
    {
        try
        {
            await next(context);
        }
        catch (Exception ex)
        {
            await HandleException(context, ex);
        }
    }

    private static Task HandleException(HttpContext context, Exception ex)
    {
        HttpStatusCode code = HttpStatusCode.InternalServerError; // 500 if unexpected

        // Specify different custom exceptions here
        if (ex is CustomException) code = HttpStatusCode.BadRequest;

        string result = JsonConvert.SerializeObject(new { error = ex.Message });

        context.Response.ContentType = "application/json";
        context.Response.StatusCode = (int)code;

        return context.Response.WriteAsync(result);
    }
}

startup.cs

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        // Add controllers with a route prefix
        services.AddControllers(x => { x.UseGeneralRoutePrefix($"api/v{Configuration["APIVersion"]}"); });
        services.AddSwaggerGen(c =>
        {
            c.SwaggerDoc("v0.1", new OpenApiInfo { Title = "My API", Version = "v0.1" });
        });
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseHttpsRedirection();

        app.UseSwagger();
        app.UseSwaggerUI(c =>
        {
            c.SwaggerEndpoint("/swagger/v0.1/swagger.json", "My API V1");
        });

        app.UseMiddleware(typeof(ErrorHandlingMiddleware));

        app.UseRouting();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
    }
}

コントローラ

[HttpPost]
public ActionResult Method()
{
    if (condition)
        throw new CustomException();
    else
        return Ok();
}

しかし、コントローラーでスローされた例外はミドルウェアによって処理されません。ミドルウェアを使用する正しい方法は何でしょうか？

c#asp.net-coreasp.net-core-webapiasp.net-core-middleware
2
Eutherpy

のようだ

app.UseDeveloperExceptionPage();

例外処理ミドルウェアが例外をキャッチするのを妨げていました。それを取り除くと問題が解決します。

2
Eutherpy
app.UseMiddleware<ErrorHandlingMiddleware>();

このように使うべきだと思います。この行をConfigureメソッドに追加します

0
Muhammed Zayif
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseCors(ApiConstantVars.Azure_POLICY);
        app.UseCors(ApiConstantVars.CORS_POLICY_NAME);
        app.UseAuthentication();
        app.UseMvc();

        app.Run(
               async context =>
               {
                   var handler = context.Features.Get<Microsoft.AspNetCore.Diagnostics.IExceptionHandlerFeature>();
                   if (handler != null && handler.Error != null)
                   {
                       var errorModel = new OperationResult
                       {
                           IsSuccess = false,
                       };
                        //Handle the JSON request to respond in its Origin format
                       if (context.Request.ContentType.ToUpper().IndexOf("JSON") != -1)
                       {
                           context.Response.ContentType = "application/json";
                           context.Response.StatusCode = 400; //Set the Status Code to responde JSON Failed requests
                           await context.Response
                           .WriteAsync(Newtonsoft.Json.JsonConvert.SerializeObject(new { error = "Unhandled internal error", success = false, Origin = context.Request.Path }))
                           .ConfigureAwait(false);
                       }
                       else
                       {
                           context.Response.StatusCode = (int)System.Net.HttpStatusCode.InternalServerError;
                           await context.Response.WriteAsync(Newtonsoft.Json.JsonConvert.SerializeObject(handler.Error.Message))
                               .ConfigureAwait(false);
                       }
                   }
                   else
                   {
                       context.Response.StatusCode = (int)System.Net.HttpStatusCode.InternalServerError;
                       await context.Response
                           .WriteAsync(Newtonsoft.Json.JsonConvert.SerializeObject(new { message = "Unhandled internal error" }))
                           .ConfigureAwait(false);
                   }
               });
    }
0
4d875752c6a784cb21d90a2818c6e0