404 Redirect loop Issue (Web.config)

Question

User-195907812 posted

I have the following in my (webforms) web.config:

<system.web>
     <customErrors mode="On" defaultRedirect="/errors/404">
          <error statusCode="500" redirect="/errors/500" />
     </customErrors>
</system.web>

<system.webServer>
     <httpErrors errorMode="Custom" existingResponse="Replace">
          <clear />
          <error statusCode="404" path="/errors/404" responseMode="Redirect"/>
     </httpErrors>
</system.webServer>

When a 404 occurs, I want to redirect the user to /errors/404 (and log the 404 in a database).

However, I still need /errors/404 to set the 404 header, but when I do this, it's causing a loop.

protected override void Render(HtmlTextWriter writer)
{
     base.Render(writer);
     Response.StatusCode = 404;
}

protected override void OnInit(EventArgs e)
{
     base.OnInit(e);
     Response.Buffer = true;
     Response.StatusCode = 404;
     Response.Status = "404 Not Found";
     Response.TrySkipIisCustomErrors = true;
}

How would I stop the loop? 

Thanks

Answer 1

User-893317190 posted

Hi RageRiot,

If you only want to  when 404 occurs ,record log,I suggest you could use the  Application_EndRequest event, it will fire on every request ends.

Your configuration will not stop redirecting until the response's status code is not 404, which in your case will cause  a loop.

You could register the Application_EndRequest in Global.asax.

My code:

 protected void Application_EndRequest(object sender, EventArgs e)
        {
          HttpResponse response=     HttpContext.Current.Response;
            if (response.StatusCode == 404)
            {
                Response.Write(HttpContext.Current.Request.Path);
            }

        
        }

After I enter the path "my404".

Best regards,

Ackerly Xu

Answer 2

User-195907812 posted

Unfortunately, this still loops.

I'm trying to implement a solution where:

- I can write the 404 URL to the database

- I can display (redirect?) a friendly 404 error page

- A 404 response header is sent

Answer 3

User-893317190 posted

Hi RageRiot,

Not sure whether this will meet your requirement.

Below is my code in endRequest,

     protected void Application_EndRequest(object sender, EventArgs e)
        {
          HttpResponse response=     HttpContext.Current.Response;
            if (response.StatusCode == 404 && HttpContext.Current.Request.Path !="/404.aspx")
            {
                Response.Redirect("/404.aspx");
            }
            if(HttpContext.Current.Request.Path == "/404.aspx")
            {
                response.StatusCode = 404;
            }

        
        }

This will make all the pages that are not found  redirected to 404.aspx and 404.aspx will return 404 header.

But all the pages that are not found themselves will return a 302 status code because of redirecting.

Best regards,

Ackerly Xu