Hi,

I would like to know what people usually do to handle "unhandled exceptions". Right now I'm trying to create a http module which listens on the OnError event. When the event is triggered I try to lookup a Umbraco content node with document type PageInternalError and that goes fine but when I try to do an internal redirect to that page "it just blows up".

I'm using Umbraco 6.1.4. I know this has been possible in earlier verions (think it was 4.7.x).

The code which when an error occur:

private void OnError(object sender, EventArgs e)
{
    var lastException = UmbracoContext.Current.HttpContext.Server.GetLastError();

    if (lastException != null)
    {
        var umbracoContext = UmbracoContext.Current;
        var websiteNode = umbracoContext.ContentCache.GetAtRoot().SingleOrDefault();

        if (websiteNode == null)
            throw new InvalidOperationException("Could not find website node.");

        var language = umbracoContext.PublishedContentRequest.Culture;
        var languageNode = websiteNode.Descendants("Language")
                    .SingleOrDefault(x => x.Name.Equals(language.Name, StringComparison.OrdinalIgnoreCase));

        if (languageNode == null)
        {
            languageNode = websiteNode.Descendants("Language")
                .FirstOrDefault();
        }

        if (languageNode == null)
            throw new InvalidOperationException(
                string.Format("Could not find language node with name '{0}'", language.Name));

        var pageInternalError = languageNode.Descendants("PageInternalError")
            .SingleOrDefault();

        if (pageInternalError == null)
            throw new InvalidOperationException(
                string.Format("Could not find PageInternalError page for language '{0}'", language.Name));

        var url = new Uri(pageInternalError.Url, UriKind.Absolute);

        umbracoContext.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
        umbracoContext.HttpContext.Response.TrySkipIisCustomErrors = true;
        umbracoContext.HttpContext.Server.ClearError();
        umbracoContext.HttpContext.Server.Transfer(url.LocalPath);
    }
}

When Server.Transfer() occurs another error is thrown by asp.net saying that the path is not a virtual path. I have as well tried to use PublishedContentRequest (I think it's called that?) and using the methods SetInternalRedirectPublishedContent and parsing my page. When I do that it throws an exception "Cannot modify a PublishedContentRequest once it is read-only.".

Soo... What posibilities do I have?

Well, I know it works when I use Response.Redirect() but then I don't keep my Url where the error happened which I think is important otherwise the user might not be able to report which page failed.

Anyone having an idea or perhaps the Umbraco Core needs a new extension point to make this easier.

Note: This ErrorModule is only thought to catch unhandled exceptions which occur in custom code and not within Umbraco itself.

Best regards Martin