Creating multilingual not found page in MVC - asp.net-mvc

Question

We have a multilingual website that has content in four languages.Every language is understood by the language name that we add at the first of our url.
This is our routeConfig.cs:
routes.MapRoute(
name: "Default",
url: "{lang}/{controller}/{action}/{id}/{title}",
defaults: new { lang = "fa", controller = "Home", action = "Index", id = UrlParameter.Optional,title = UrlParameter.Optional }
and this is generated the url: /en/ContactUs/Index
Also, in our controllers we get the language name from url and change the currentCulture and currentUiCulture based on it.
Now, we want to have a not found page in all of the languages. Normally, to make it happen we add an error contoller and a NotFound action and view, then we add this section in our web.config:
<customErrors mode="On" defaultRedirect="error">
<error statusCode="404" redirect="error/notfound" />
<error statusCode="403" redirect="error/forbidden" />
</customErrors>
We have added a NotFound page that we use .resx files in it to make rtl/ltr and to show the messages in four languages.
But the problem here is that in a multilingual website we are not allowed to use this address "error/notfound" because there is no languagename in it and we don't know how to add the language name in redirect="error/notfound" in the web.config file to create something like "en/error/notfound" or "fa/error/notfound".
every help would be highly appreciated

Answer 1

First of all, have a look at this answer for info about localizing your site via URL.
Next, <customErrors> is a catch-all for ASP.NET error messages. But in general, you have control over a 404 (routing miss) within ASP.NET MVC by using a catch-all route. In this case, you can simply localize the catch-all route and get rid of this configuration in web.config.
public class RouteConfig
{
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute(
name: "Localized-Default",
url: "{lang}/{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
constraints: new { lang = new CultureConstraint(defaultCulture: "fa", pattern: "[a-z]{2}") }
);
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { lang = "fa", controller = "Home", action = "Index", id = UrlParameter.Optional }
);
// Catch-all route (for routing misses)
routes.MapRoute(
name: "Localized-404",
url: "{lang}/{*url}",
defaults: new { controller = "Error", action = "PageNotFound" },
constraints: new { lang = new CultureConstraint(defaultCulture: "fa", pattern: "[a-z]{2}") }
);
routes.MapRoute(
name: "Default-404",
url: "{*url}",
defaults: new { lang = "fa", controller = "Error", action = "PageNotFound" }
);
}
}
ErrorController
public class ErrorController : Controller
{
public ActionResult PageNotFound()
{
Response.CacheControl = "no-cache";
Response.StatusCode = (int)HttpStatusCode.NotFound;
return View();
}
}
That takes care of the route misses within ASP.NET. For those that don't hit ASP.NET (assuming you are hosting using IIS), you should use the <httpErrors> section of web.config rather than <customErrors>. <httpErrors> is localizable via the prefixLanguageFilePath setting.
Optional string attribute.
Specifies the initial path segment when generating the path for a custom error. This segment appears before the language-specific portion of the custom error path. For example, in the path C:\Inetpub\Custerr\en-us\404.htm, C:\Inetpub\Custerr is the prefixLanguageFilePath.
<configuration>
<system.webServer>
<httpErrors errorMode="DetailedLocalOnly" defaultResponseMode="File" >
<remove statusCode="404" />
<error statusCode="404"
prefixLanguageFilePath="C:\Contoso\Content\errors"
path="404.htm" />
</httpErrors>
</system.webServer>
</configuration>
Which means you would need to set up a file structure with language prefix, and use static files as targets.
C:\Contoso\Content\errors\fa\404.htm
C:\Contoso\Content\errors\en\404.htm
AFAIK, this unfortunately means you need to have physical files at these locations. However, you could have the content of these pages setup to do both a meta-refresh redirect and a JavaScript redirect to the correct controller action.
<html>
<head>
<title>404 Not Found</title>
<meta http-equiv="refresh" content="1;http://www.example.com/fa/Error/PageNotFound" />
</head>
<body>
<!-- Add localized message (for those browsers that don't redirect). -->
<script>
//<!--
setTimeout(function () {
window.location = "http://www.example.com/fa/Error/PageNotFound";
}, 1000);
//-->
</script>
</body>
</html>

Answer 2

The customErrors section in web.config is the static data about some status-code and how they will be handled. The responsibility of this section can be generated dynamically by the Application_EndRequest method in Global.asax.
protected void Application_EndRequest()
{
if (Context.Response.StatusCode == 404)
{
Response.Clear();
var routeData = new RouteData();
HttpContextBase currentContext = new HttpContextWrapper(HttpContext.Current);
var lang = RouteTable.Routes.GetRouteData(currentContext).Values["lang"];
routeData.Values["lang"] = lang;
routeData.Values["controller"] = "CustomError";
routeData.Values["action"] = "NotFound";
IController customErrorController = new CustomErrorController();
customErrorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
}
}

Answer 3

I believe you can use a session variable to hold current user's ui-culture data.
I don't see a point but, if you don't want to do that, you can follow this tutorial to generate your own routes for MVC custom error page handling.
http://setiabud.blogspot.com.tr/2013/04/handling-404-error-in-aspnet-mvc.html