Updating the response headers on your 404 Page in Sitecore

A few weeks ago I blogged about how to create a custom 404 Page in Sitecore. Following on from that, one thing you may notice in the response header of your 404 Page is the status code is 200 Ok, rather than 404 Page not found.

When Sitecore can’t find a page what actually happens is a 302 redirect is issued to the page not found page, which as its an ordinary page will return a 200 Ok. Thankfully Google is actually quite good at detecting pages a being 404’s even when they return the wrong status code, but it would be better if our sites issues the correct headers.

Method 1

The simplest solution is to create a view rendering with the following logic and place it somewhere on your page not found page. This will update the response headers with the correct values.

@{
      Response.TrySkipIisCustomErrors = true;
      Response.StatusCode = 404;
      Response.StatusDescription = "Page not found";
}

However personally I don’t think this a particularly neat solution. The contents of a view should really be left for what’s going in a page rather than interfering with its headers, even if it does have access to the Response object.

Method 2

Rather than using a view my solution is to add some code to the httpRequestEnd pipeline that will check the context items Id against a setting where we will store the Id of the 404 page item in Sitecore and if the two match then update the response header.

The solution will look like this

Pipeline logic

using Sitecore.Configuration;
using Sitecore.Data;
using Sitecore.Pipelines.HttpRequest;

namespace Pipelines.HttpRequest
{
    public class PageNotFoundResponseHeader : HttpRequestProcessor
    {
        private static readonly string PageNotFoundID = Settings.GetSetting("PageNotFound");

        public override void Process(HttpRequestArgs args)
        {
            if (Sitecore.Context.Item != null && Sitecore.Context.Item.ID == new ID(PageNotFoundID))
            {
                args.Context.Response.TrySkipIisCustomErrors = true;
                args.Context.Response.StatusCode = 404;
                args.Context.Response.StatusDescription = "Page not found";
            }
        }
    }
}

Patch config file

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>    
    <pipelines>
      <httpRequestEnd>
        <processor
          patch:after="processor[@type='Sitecore.Pipelines.PreprocessRequest.CheckIgnoreFlag, Sitecore.Kernel']"
          type="Pipelines.HttpRequest.PageNotFoundResponseHeader, MyProjectName"  />
      </httpRequestEnd> 
    </pipelines>
    <settings>
      <!-- Page Not Found Item Id -->
      <setting name="PageNotFound" value="ID of 404 Page" />
    </settings>
  </sitecore>   
</configuration>

What’s the TrySkipIisCustomErrors property

Quite simply this stops a scenario where you end up on IIS’s 404 page rather than your own. If you don’t set this, when you update the header status code to 404, IIS likes to return the page from it’s settings rather than continuing with your own.

Creating a custom 404 Page in Sitecore

Nobody wants to see the standard Sitecore 404 page. Thankfully it’s really easy to change the error pages a user is redirected to through some config settings.

Your error pages can be pages in Sitecore or static HTML files. For 404 pages I would normally use a Sitecore page, that way content authors can still manage its content. For an Error Page I would recommend a static html file to avoid issues with the Error page potentially error-ing.

Add these to a patch file and update the urls accordingly:

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <settings>
      <!--  ITEM NOT FOUND HANDLER
            Url of page handling 'Item not found' errors
      -->
      <setting name="ItemNotFoundUrl">
        <patch:attribute name="value">/ErrorPages/404.html</patch:attribute>
      </setting>
      <!--  LINK ITEM NOT FOUND HANDLER
            Url of page handling 'Link item not found' errors
      -->
      <setting name="LinkItemNotFoundUrl">
        <patch:attribute name="value">/ErrorPages/404.html</patch:attribute>
      </setting>
      <!--  LAYOUT NOT FOUND HANDLER
            Url of page handling 'Layout not found' errors
      -->
      <setting name="LayoutNotFoundUrl">
        <patch:attribute name="value">/ErrorPages/404.html</patch:attribute>
      </setting>
      <!--  ERROR HANDLER
            Url of page handling generic errors
      -->
       <setting name="ErrorPage">
        <patch:attribute name="value">/ErrorPages/Error.html</patch:attribute>
      </setting>
    </settings>
  </sitecore>
</configuration>


These settings are already defined in the web.config file and changing them here will have the same effect, but I recommend adding patch config files as it will make your solution easier to update in the future.