ASP.NET MVC HandleError

Question

How do I go about the [HandleError] filter in asp.net MVC Preview 5?
I set the customErrors in my Web.config file

<customErrors mode="On" defaultRedirect="Error.aspx">
  <error statusCode="403" redirect="NoAccess.htm"/>
  <error statusCode="404" redirect="FileNotFound.htm"/>
</customErrors>

and put [HandleError] above my Controller Class like this:

[HandleError]
public class DSWebsiteController: Controller
{
    [snip]
    public ActionResult CrashTest()
    {
        throw new Exception("Oh Noes!");
    }
}

Then I let my controllers inherit from this class and call CrashTest() on them. Visual studio halts at the error and after pressing f5 to continue, I get rerouted to Error.aspx?aspxerrorpath=/sxi.mvc/CrashTest (where sxi is the name of the used controller. Off course the path cannot be found and I get "Server Error in '/' Application." 404.

This site was ported from preview 3 to 5. Everything runs (wasn't that much work to port) except the error handling. When I create a complete new project the error handling seems to work.

Ideas?

--Note--
Since this question has over 3K views now, I thought it would be beneficial to put in what I'm currently (ASP.NET MVC 1.0) using. In the mvc contrib project there is a brilliant attribute called "RescueAttribute" You should probably check it out too ;)

Scaphoid

Link to the RescueAttribute source: mvccontrib.codeplex.com/SourceControl/changeset/view/… – Consortium

Answer 1

[HandleError]

When you provide only the HandleError attribute to your class (or to your action method for that matter), then when an unhandled exception occurs MVC will look for a corresponding View named "Error" first in the Controller's View folder. If it can't find it there then it will proceed to look in the Shared View folder (which should have an Error.aspx file in it by default)

[HandleError(ExceptionType = typeof(SqlException), View = "DatabaseError")]
[HandleError(ExceptionType = typeof(NullReferenceException), View = "LameErrorHandling")]

You can also stack up additional attributes with specific information about the type of exception you are looking for. At that point, you can direct the Error to a specific view other than the default "Error" view.

For more information, take a look at Scott Guthrie's blog post about it.

Multidisciplinary

Thanks for the extended information. I don't know what I did wrong, but I created a new project, ported all the existing views, controllers and models in it and now it works. Didn't know about the selective views though. – Scaphoid

If logging of these exceptions is desired, would this be an acceptable place to add a codebehind to the view? – Cherimoya

Iconic, here's my "better late than never" reply to your comment: You can instead subclass the HandleErrorAttribute and override its "OnException" method: Then, insert whatever logging or custom actions that you desire. You can then either fully handle the exception (setting context.ExceptionHandled to true), or defer back to the base class's own OnException method for this. Here's an excellent article that may help with this: blog.dantup.me.uk/2009/04/… – Presumably

I have lot of controllers so can i handle this inside global.asax like this to show a message to users ? – Travax

@What about using the same error page as PartialView and render it on the modal dialog after exception occurs? Could you please provide an example in your answer? What I want to achieve was explained on Global Error handling using PartialView in MVC. – Estancia

Answer 2

It should also be noted that errors that don't set the http error code to 500

(e.g. UnauthorizedAccessException)

will not be handled by the HandleError filter.

Battaglia

True, but check out the RescueAttribute in MVC contrib (link in OP) – Scaphoid

Answer 3

Solution for http error code to 500 this is an attribute called [ERROR] put it on an action

public class Error: System.Web.Mvc.HandleErrorAttribute
{
    public override void OnException(System.Web.Mvc.ExceptionContext filterContext)
    {

            if (filterContext.HttpContext.IsCustomErrorEnabled)
            {
                filterContext.ExceptionHandled = true;

            }
            base.OnException(filterContext);
            //OVERRIDE THE 500 ERROR  
           filterContext.HttpContext.Response.StatusCode = 200;
    }

    private static void RaiseErrorSignal(Exception e)
    {
        var context = HttpContext.Current;
      // using.Elmah.ErrorSignal.FromContext(context).Raise(e, context);
    } 

}

//EXAMPLE:

[Error]
[HandleError]
[PopulateSiteMap(SiteMapName="Mifel1", ViewDataKey="Mifel1")]
public class ApplicationController : Controller
{
}

Resect

Answer 4

Attributes in MVC is very useful in error handling at get and post method, it also track for ajax call.

Create a base controller in your application and inherit it in your main controller(EmployeeController).

public class EmployeeController : BaseController

Add below code in base controller.

/// <summary>
/// Base Controller
/// </summary>
public class BaseController : Controller
{       
    protected override void OnException(ExceptionContext filterContext)
    {
        Exception ex = filterContext.Exception;

        //Save error log in file
        if (ConfigurationManager.AppSettings["SaveErrorLog"].ToString().Trim().ToUpper() == "TRUE")
        {
            SaveErrorLog(ex, filterContext);
        }

        // if the request is AJAX return JSON else view.
        if (IsAjax(filterContext))
        {
            //Because its a exception raised after ajax invocation
            //Lets return Json
            filterContext.Result = new JsonResult()
            {
                Data = Convert.ToString(filterContext.Exception),
                JsonRequestBehavior = JsonRequestBehavior.AllowGet
            };
        }
        else
        {
            filterContext.ExceptionHandled = true;
            filterContext.HttpContext.Response.Clear();

            filterContext.Result = new ViewResult()
            {
                //Error page to load
                ViewName = "Error",
                ViewData = new ViewDataDictionary()
            };

            base.OnException(filterContext);
        }
    }

    /// <summary>
    /// Determines whether the specified filter context is ajax.
    /// </summary>
    /// <param name="filterContext">The filter context.</param>
    private bool IsAjax(ExceptionContext filterContext)
    {
        return filterContext.HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest";
    }

    /// <summary>
    /// Saves the error log.
    /// </summary>
    /// <param name="ex">The ex.</param>
    /// <param name="filterContext">The filter context.</param>
    void SaveErrorLog(Exception ex, ExceptionContext filterContext)
    {
        string logMessage = ex.ToString();

        string logDirectory = Server.MapPath(Url.Content("~/ErrorLog/"));

        DateTime currentDateTime = DateTime.Now;
        string currentDateTimeString = currentDateTime.ToString();
        CheckCreateLogDirectory(logDirectory);
        string logLine = BuildLogLine(currentDateTime, logMessage, filterContext);
        logDirectory = (logDirectory + "\\Log_" + LogFileName(DateTime.Now) + ".txt");

        StreamWriter streamWriter = null;
        try
        {
            streamWriter = new StreamWriter(logDirectory, true);
            streamWriter.WriteLine(logLine);
        }
        catch
        {
        }
        finally
        {
            if (streamWriter != null)
            {
                streamWriter.Close();
            }
        }
    }

    /// <summary>
    /// Checks the create log directory.
    /// </summary>
    /// <param name="logPath">The log path.</param>
    bool CheckCreateLogDirectory(string logPath)
    {
        bool loggingDirectoryExists = false;
        DirectoryInfo directoryInfo = new DirectoryInfo(logPath);
        if (directoryInfo.Exists)
        {
            loggingDirectoryExists = true;
        }
        else
        {
            try
            {
                Directory.CreateDirectory(logPath);
                loggingDirectoryExists = true;
            }
            catch
            {
            }
        }

        return loggingDirectoryExists;
    }

    /// <summary>
    /// Builds the log line.
    /// </summary>
    /// <param name="currentDateTime">The current date time.</param>
    /// <param name="logMessage">The log message.</param>
    /// <param name="filterContext">The filter context.</param>       
    string BuildLogLine(DateTime currentDateTime, string logMessage, ExceptionContext filterContext)
    {
        string controllerName = filterContext.RouteData.Values["Controller"].ToString();
        string actionName = filterContext.RouteData.Values["Action"].ToString();

        RouteValueDictionary paramList = ((System.Web.Routing.Route)(filterContext.RouteData.Route)).Defaults;
        if (paramList != null)
        {
            paramList.Remove("Controller");
            paramList.Remove("Action");
        }

        StringBuilder loglineStringBuilder = new StringBuilder();

        loglineStringBuilder.Append("Log Time : ");
        loglineStringBuilder.Append(LogFileEntryDateTime(currentDateTime));
        loglineStringBuilder.Append(System.Environment.NewLine);

        loglineStringBuilder.Append("Username : ");
        loglineStringBuilder.Append(Session["LogedInUserName"]);
        loglineStringBuilder.Append(System.Environment.NewLine);

        loglineStringBuilder.Append("ControllerName : ");
        loglineStringBuilder.Append(controllerName);
        loglineStringBuilder.Append(System.Environment.NewLine);

        loglineStringBuilder.Append("ActionName : ");
        loglineStringBuilder.Append(actionName);
        loglineStringBuilder.Append(System.Environment.NewLine);

        loglineStringBuilder.Append("----------------------------------------------------------------------------------------------------------");
        loglineStringBuilder.Append(System.Environment.NewLine);

        loglineStringBuilder.Append(logMessage);
        loglineStringBuilder.Append(System.Environment.NewLine);
        loglineStringBuilder.Append("==========================================================================================================");

        return loglineStringBuilder.ToString();
    }

    /// <summary>
    /// Logs the file entry date time.
    /// </summary>
    /// <param name="currentDateTime">The current date time.</param>
    string LogFileEntryDateTime(DateTime currentDateTime)
    {
        return currentDateTime.ToString("dd-MMM-yyyy HH:mm:ss");
    }

    /// <summary>
    /// Logs the name of the file.
    /// </summary>
    /// <param name="currentDateTime">The current date time.</param>
    string LogFileName(DateTime currentDateTime)
    {
        return currentDateTime.ToString("dd_MMM_yyyy");
    }

}

================================================

Finds the Directory : Root/App_Start/FilterConfig.cs

Add below code:

/// <summary>
/// Filter Config
/// </summary>
public class FilterConfig
{
    /// <summary>
    /// Registers the global filters.
    /// </summary>
    /// <param name="filters">The filters.</param>
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        filters.Add(new HandleErrorAttribute());
    }
}

Track AJAX Error:

Call CheckAJAXError function in layout page load.

function CheckAJAXError() {
    $(document).ajaxError(function (event, jqXHR, ajaxSettings, thrownError) {

        var ex;
        if (String(thrownError).toUpperCase() == "LOGIN") {
            var url = '@Url.Action("Login", "Login")';
            window.location = url;
        }
        else if (String(jqXHR.responseText).toUpperCase().indexOf("THE DELETE STATEMENT CONFLICTED WITH THE REFERENCE CONSTRAINT") >= 0) {

            toastr.error('ReferanceExistMessage');
        }
        else if (String(thrownError).toUpperCase() == "INTERNAL SERVER ERROR") {
            ex = ajaxSettings.url;
            //var url = '@Url.Action("ErrorLog", "Home")?exurl=' + ex;
            var url = '@Url.Action("ErrorLog", "Home")';
            window.location = url;
        }
    });
};

Mitrailleuse

You're leaking exception details on AJAX requests, you don't always want that. Your logging code isn't thread safe. You're assuming there's an Error view and returning that, without altering the response code. Then you go check for certain error strings in JavaScript (what about localization?). Basically you're repeating what an existing answer already says: "Override OnException to handle exceptions", but showing a pretty bad implementation of it. – Plowshare

What is the @School.Resource.Messages.ReferanceExist parameter? – Estancia

@Plowshare Do you know any better way for using such a kind of error handling method with AJAX in ASP.NET MVC? Any help please? – Estancia

Return a 400 or 500, as HTTP is intended. Don't go digging for specific strings in the response body. – Plowshare

@Plowshare Could you please have a look at Global Error handling using PartialView in MVC regarding to this problem? – Estancia

@SandipPatel Thanks a lot. I tried this method but when exception occurs in Controller I return JSON to the related AJAX call and then call your CheckAJAXError() method. But when I debug using Firebug, it returns after the first line of this Javascript method. Is there any implementation that I have in my Controller method (I inherited from BaseController already). Any idea? – Estancia

Answer 5

You are missing Error.aspx :) In preview 5, this is located in your Views/Shared folder. Just copy it over from a new Preview 5 project.

Microanalysis

Thanks for the reply, but I already copied the Error.aspx page. Could indeed have been something I would normally forget, but not this time. :P – Scaphoid

Answer 6

    [HandleError]
    public class ErrorController : Controller
    {        
        [AcceptVerbs(HttpVerbs.Get)]
        public ViewResult NotAuthorized()
        {
            //401
            Response.StatusCode = (int)HttpStatusCode.Unauthorized;

        return View();
    }

    [AcceptVerbs(HttpVerbs.Get)]
    public ViewResult Forbidden()
    {
        //403
        Response.StatusCode = (int)HttpStatusCode.Forbidden;

        return View();
    }

    [AcceptVerbs(HttpVerbs.Get)]
    public ViewResult NotFound()
    {
        //404
        Response.StatusCode = (int)HttpStatusCode.NotFound;
        return View();
    }

    public ViewResult ServerError()
    {
        //500
        Response.StatusCode = (int)HttpStatusCode.NotFound;
        return View();
    }

}

Estancia