global.asax 中的 Application_Error 未捕获 WebAPI 中的错误

Question

对于我正在处理的项目，我们正在实施的其中一件事是我们在我的一些团队中为一些较旧的 ASP.NET 和 MVC 项目提供了代码 - 一个 Application_Error 异常捕获器，可将电子邮件发送到具有异常经验和最相关细节的开发团队。

它的外观如下：

Global.asax：

protected void Application_Error(object sender, EventArgs e)
{
    Exception ex = Server.GetLastError();
    string path = "N/A";
    if (sender is HttpApplication)
        path = ((HttpApplication) sender).Request.Url.PathAndQuery;

    string args = string.Format("<b>Path:</b> {0}", path);

    // Custom code that generates an HTML-formatted exception dump
    string message = Email.GenerateExceptionMessage(ex, args);

    // Custom code that sends an email to the dev team.
    Email.SendUnexpectedErrorMessage("Some App", message);
}

不过，有一个“小”问题 - 当我故意让一部分代码抛出异常以测试此机制时...

public static void GetMuffinsByTopping(string topping)
{
    throw new Exception("Test Exception!", new Exception("Test Inner Exception!!!"));

    // Actual repository code is unreachable while this test code is there
}

前端 JavaScript 正在立即拦截 HTTP 500 请求，但没有到达上面提到的 global.asax.cs 代码（我在方法的第一行设置了断点。）

问题：我可以通过什么方式让“旧”Application_Error 处理程序发送错误电子邮件，以便我们团队的开发人员可以更轻松地调试我们的应用程序？

Answer 1

将您的错误处理逻辑从Application_Error 抽象到它自己的函数中。创建一个Web API exception filter。

//register your filter with Web API pipeline
//this belongs in the Application_Start event in Global Application Handler class (global.asax)
//or some other location that runs on startup
GlobalConfiguration.Configuration.Filters.Add(new LogExceptionFilterAttribute());

//Create filter
public class LogExceptionFilterAttribute : ExceptionFilterAttribute 
{
    public override void OnException(HttpActionExecutedContext context)
    {
        ErrorLogService.LogError(context.Exception);
    }
}

//in global.asax or global.asax.cs
protected void Application_Error(object sender, EventArgs e)
{
    Exception ex = Server.GetLastError();
    ErrorLogService.LogError(ex);
} 

//common service to be used for logging errors
public static class ErrorLogService
{
    public static void LogError(Exception ex)
    {
        //Email developers, call fire department, log to database etc.
    }
}

来自 Web API 的错误不会触发 Application_Error 事件。但是我们可以创建一个异常过滤器并注册它来处理错误。另见Global Error Handling in ASP.NET Web API 2。

Answer 2

就我而言，我不喜欢使用 Web.config。然后我在 Global.asax 文件中创建了上面的代码：

protected void Application_Error(object sender, EventArgs e)
    {
        Exception ex = Server.GetLastError();

        //Not Found (When user digit unexisting url)
        if(ex is HttpException && ((HttpException)ex).GetHttpCode() == 404)
        {
            HttpContextWrapper contextWrapper = new HttpContextWrapper(this.Context);

            RouteData routeData = new RouteData();
            routeData.Values.Add("controller", "Error");
            routeData.Values.Add("action", "NotFound");

            IController controller = new ErrorController();
            RequestContext requestContext = new RequestContext(contextWrapper, routeData);
            controller.Execute(requestContext);
            Response.End();
        }
        else //Unhandled Errors from aplication
        {
            ErrorLogService.LogError(ex);
            HttpContextWrapper contextWrapper = new HttpContextWrapper(this.Context);

            RouteData routeData = new RouteData();
            routeData.Values.Add("controller", "Error");
            routeData.Values.Add("action", "Index");

            IController controller = new ErrorController();
            RequestContext requestContext = new RequestContext(contextWrapper, routeData);
            controller.Execute(requestContext);
            Response.End();
        }
    }

这就是我的 ErrorController.cs

public class ErrorController : Controller
{
    // GET: Error
    public ViewResult Index()
    {
        Response.StatusCode = 500;
        Exception ex = Server.GetLastError();
        return View("~/Views/Shared/SAAS/Error.cshtml", ex);
    }

    public ViewResult NotFound()
    {
        Response.StatusCode = 404;
        return View("~/Views/Shared/SAAS/NotFound.cshtml");
    }
}

这是我从@mason 类复制的 ErrorLogService.cs

//common service to be used for logging errors
public static class ErrorLogService
{
    public static void LogError(Exception ex)
    {
        //Do what you want here, save log in database, send email to police station
    }
}