using System;
using System.Web;

/// <summary>Error 404 handler helper. 2008-10-20</summary>
/// <see cref="https://alexandre.alapetite.fr/doc-alex/redirection-404/"/>
public class Redirection404Helper : IHttpModule
{
	public void Dispose() {}

	public void Init(HttpApplication context)
	{
		context.Error += new EventHandler(On404Error);
	}

	void On404Error(object sender, EventArgs e)
	{
		HttpApplication httpApplication = sender as HttpApplication;
		if (httpApplication == null) return;
		HttpContext httpContext = httpApplication.Context;
		HttpException httpException = httpContext.Error as HttpException;
		if (httpException == null) return;
		if (httpException.GetHttpCode() == 404)
			httpContext.Server.Transfer(httpContext.Request.ApplicationPath +
			                            @"/errors/Redirection-404.aspx?aspxerrorpath=" + httpContext.Request.RawUrl);
	}
}