Umbraco 7 - Global.asax - Application_Error - umbraco

Question

I am trying to write my own "Application_Error" for my site.
I need to catch 404's (to see what mistakes users are making) & 500's to catch my programming errors. I did this succesfully in my site before I started using Umbraco in the global.asax.
I have tried the following method.
1: I created a class MyGlobal (file MyGlobal.vb in the App_Code directory:
Public Class MyGlobal
Inherits umbraco.Web.UmbracoApplication
Protected Overloads Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)
Dim ctx As HttpContext = HttpContext.Current
ctx.Response.Redirect("http://wwww.google.com")
End Sub
End Class
Obivously, this is only to test.
In addition, I editeted my Global.asax file and now it looks like this:
<%# Application Language="VB" Inherits="MyGlobal" %>
<script runat="server">
</script>
I already have:
<customErrors mode="Off" />
&
<httpErrors existingResponse="PassThrough"/>
in my web.config.
1: When I try to enter a non-existent page, i get the Umbraco 404 error page.
2: When I purposely create a 500 error, the system shows me the error page and does not redirect to Google.
Please help as I can not go live without this.
Thanks.
Yoni
Edit:
As I am working in VB, I have used this:
Imports Microsoft.VisualBasic
Imports Umbraco.Core
Public Class MyCustomEvent1
Inherits ApplicationEventHandler
Protected Overrides Sub ApplicationStarted(umbracoApplication As UmbracoApplicationBase, applicationContext As ApplicationContext)
AddHandler umbracoApplication.[Error], AddressOf umbracoApplication_Error
End Sub
Private Sub umbracoApplication_Error(sender As Object, e As EventArgs)
Dim x As HttpContext = HttpContext.Current
x.Response.Redirect("http://www.espn.com")
' Do your stuff
End Sub
End Class
It is not firing when I try either a 404 or a 500 error.
(If I put a redirect in the upper section, i get an error that "System.Web.HttpException: Response is not available in this context.")
Can you help?
Thanks

Answer 1

Concerning 404's, you should look at the package 301 URL Tracker. This is an amazing free package tracking all 404's. While doing that it also tracks all renames of nodes, when a node has been renamed, it also creates a redirect to the new url. Of cource you can also create your own redirects using urls from a previous site or using regex.
Writing your own global asax is not best practice when you use Umbraco, because umbraco uses a lot of things at startup itself. Instead you can hook into the ApplicationEventHandler events to register your custom code at startup. The only thing to activate the handlers is implementing the ApplicationEventHandler class. All classes derived from this class will be called at the umbraco boot-up.
The UmbracoApplicationBase class is derived from the HttpApplication. You can hook into the Error event of this class to implement your own error handler logic.
public class MyCustomEvent1 : ApplicationEventHandler
{
protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
{
umbracoApplication.Error += umbracoApplication_Error;
// very bad example
// Response.Redirect("http://google.com")
}
void umbracoApplication_Error(object sender, EventArgs e)
{
// Do your stuff
}
}
EDIT
If you need to create your own "404 not found" pipeline you should create an IContentFinder (see documentation). The example below comes from this PDF: http://www.zpqrtbnk.net/CoreInternalsForWebsiteDevelopment.pdf and this session from Stéphane Gay presented at Codegarden.
public class My404ContentFinder : IContentFinder
{
public bool TryFindContent(PublishedContentRequest contentRequest)
{
if (!contentRequest.HasDomain)
return false;
var contentCache = contentRequest.RoutingContext.UmbracoContext.ContentCache;
var domainRoot = contentCache.GetById(contentRequest.Domain.RootNodeId);
var firstSegment = contentRequest.Uri.AbsolutePath.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries).First();
var root = domainRoot.Children.FirstOrDefault(x => x.UrlName == firstSegment);
root = root ?? domainRoot.Children.First();
var page = root.Descendants().FirstOrDefault(x => x.Name == "404");
if (page == null) return false;
contentRequest.PublishedContent = page;
var wcd = Domain.GetDomainsById(root.Id, true).SingleOrDefault(x => x.IsWildcard);
if (wcd != null) contentRequest.Culture = new CultureInfo(wcd.Language.CultureAlias);
return true;
}
}