Startup.cs 中的错误路由不会在 404 或 500 错误 ASP.NET Core MVC 时重定向到 controller

Question

I want my startup.cs class to redirect to my Error controller when a 404 or 500 error occurs.

Startup.cs

public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IHttpContextAccessor accessor)
  {
     if (env.IsDevelopment())
     {
        app.UseDeveloperExceptionPage();
        app.UseExceptionHandler("/ErrorPages/500");
     }
     app.UseRouting();
     app.UseAuthentication();
     app.UseAuthorization();
     app.UseIPRestrictionService();
     app.Use(async (content, next) =>
     {
        await next();
        if (content.Response.StatusCode == 404 && !content.Response.HasStarted)
        {
            content.Request.Path = "/ErrorPages/404";
            await next();
        }
        if (content.Response.StatusCode == 500)
        {
            content.Request.Path = "/500";
            await next();
        }
     });
     app.UseHttpsRedirection();
     app.UseStaticFiles();
     app.UseEndpoints(endpoints =>
     {
        endpoints.MapContent();
        endpoints.MapControllers();
     });


     ContentExtensions.SetHttpContextAccessor(accessor);
     VisitorGroupManager.SetHttpContextAccessor(accessor);
     PageExtensions.SetHttpContextAccessor(accessor);
     //IsAuthenticatedCriterion.SetHttpContextAccessor(accessor);
  }

But when the content.Request.Path is set when a 404 or 500 status code is detected, the path does not change in the URL. How to I get this to redirect to my controller so I can then apply my logic.

ErrorController.cs

    [Route("ErrorPages")]
class ErrorController : Controller
{        
    [Route("500")]
    public IActionResult AppError()
    {
        return View();
    }

    [Route("404")]
    public IActionResult PageNotFound()
    {
        return View("~/Views/404.cshtml");
    }
}

Answer 1

For that you need an error controller

in your ErrorController.cs file

public class ErrorController : Controller
{
    private readonly ILogger<ErrorController> logger;

    public ErrorController(ILogger<ErrorController> logger)
    {
        this.logger = logger;
    }

    [Route("Error/{statusCode}")]
    public IActionResult HttpStatusCodeHandler(int statusCode)
    {
        var viewToReturn = string.empty;
        var statusCodeResult = HttpContext.Features.Get<IStatusCodeReExecuteFeature>();
        switch (statusCode)
        {
            case 404:
                ViewBag.ErrorMessage = "Sorry the resource you requested could not be found";
                logger.LogWarning($"404 Error Occured. Path = {statusCodeResult.OriginalPath}" + $"and QueryString = {statusCodeResult.OriginalQueryString}");
                viewToReturn = nameof(Notfound);
                break;
        }

        return View(viewToReturn ?? "defaultUnInterceptedErrorView");
    }

    [Route("Error")]
    [AllowAnonymous]
    public IActionResult Error()
    {
        var exceptionDetails = HttpContext.Features.Get<IExceptionHandlerPathFeature>();
        logger.LogError($"The Path {exceptionDetails.Path} threw an exception" + $"{exceptionDetails.Error}");
        return View("Error");
    }
}

In your startup.cs file

if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseStatusCodePagesWithReExecute("/Error/{0}");
        }

you can also have your NotFound.cshtml view, which you can be listening for the value of ViewBag.ErrorMessage ( Note: ASP.NET Core always searches for the Notfound action in AccountController.cs but you can change that in your startup.cs )

and then you can also continue the case switch statement to suit all the status code errors you're planning to intercept