+1 for SEO checker.

Thanks Richard, that blog post looks like it's exactly what I'm looking for, I'll get that in my solution, will be useful forall my projects! Thanks! I'll post back if it worked!

Hey Richard, 

Ok I think I have the basics in, but my problem is this, I have a Manage Hostnames set to my FR node. basically like this:

MySite
    - FR (Hostname: mysite.local)

My english node for this version of the website is not ready yet so I default to the french site and this way I don't see mysite.local/fr/[...].

Problem is that in my code, I run this:

    var node = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetByRoute(pathToNextNode);

I'm running this test with this "mysite.local/pageThatDoesNotExist", my pathToNextNode is then set to "/". Basically, I'm using the path to move up the content tree to find a node that will have a property "404Page" set, so that I can use that. My problem is that this GetByRoute, does not give me my FR node, but rather my Site node... It's like it's bypassing my hostname settings.

Ever seen this?

Bellow is the full code I'm running!

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Umbraco.Core;
using Umbraco.Web;
using Umbraco.Web.Routing;

// Needs interfaces and cms references

namespace PrixModeMtlCms.Code
{
    public class Umbraco404Handler : IContentFinder
    {

        public bool TryFindContent(PublishedContentRequest contentRequest)
        {

            // Safety check, this should never occur
            if (contentRequest != null)
            {

                // Check request is a 404
                if (contentRequest.Is404)
                {

                    var path = contentRequest.Uri.GetAbsolutePathDecoded();

                    // Reversed parts of the path
                    var parts = path.Split(new[] { '/' }, System.StringSplitOptions.RemoveEmptyEntries).Reverse();

                    // Loop up the parts, until you find a node
                    foreach (var part in parts)
                    {

                        // Remove the last part since it's not found
                        parts = parts.Where(x => x != part).ToArray();

                        var pathToNextNode = "/" + String.Join("/", parts);

                        // Try to find that node
                        var node = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetByRoute(pathToNextNode);

                        // If we can't find that node either we'll let the loop continue
                        if (node == null)
                        {
                            continue;
                        }

                        // We've found a node, let's find our root nodes to find our 404 page
                        var site = node.AncestorOrSelf("Site");
                        var lang = node.AncestorOrSelf("AccueilLangage");

                        // Use lang or site
                        var nodeToUse = lang;
                        if (lang == null)
                        {
                            nodeToUse = site;
                        }

                        int notFoundNodeId = 0;
                        if (nodeToUse != null)
                        {
                            notFoundNodeId = nodeToUse.AsDynamic().page404; // Unset content picker, cast to int, will be 0
                            if (notFoundNodeId == 0)
                            {
                                notFoundNodeId = site.AsDynamic().page404;
                            }
                        }

                        // Get the 404 node
                        if (notFoundNodeId != 0)
                        {

                            var notFoundNode = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetById(notFoundNodeId);
                            if (notFoundNode == null)
                            {
                                // The specified 404 node can't be found, break here and let resolve normally
                                break;
                            }

                            // Set Response Status to be HTTP 404
                            contentRequest.SetResponseStatus(404, "404 Page Not Found");

                            // Set the node to be the not found node
                            contentRequest.PublishedContent = notFoundNode;

                        }

                    }

                }

            }

            // Finally, we return weather we have found a node to use for this request
            return contentRequest.PublishedContent != null;
        }

    }
}

 Edit: Fixed a bug that was in there. This runs good, but does not give me multilingual support, coming from the hostnames.

Ok! Strike that! I guess I had towrite the long version to figure out the short version. This works the way I want! (Well the minimum, I can scope creep later on :))

Turns out using contentRequest.Domain.RootNodeId was really smooth!

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Umbraco.Core;
using Umbraco.Web;
using Umbraco.Web.Routing;

// Needs interfaces and cms references

namespace MyNamespace.Code
{
    public class Umbraco404Handler : IContentFinder
    {

        public bool TryFindContent(PublishedContentRequest contentRequest)
        {

            // Safety check, this should never occur
            if (contentRequest != null)
            {

                // Check request is a 404
                if (contentRequest.Is404)
                {
                    var domainNode = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetById(contentRequest.Domain.RootNodeId);
                    if (domainNode != null)
                    {
                        int notFoundNodeId = domainNode.AsDynamic().page404; // Unset content picker, cast to int, will be 0
                        if (notFoundNodeId != 0)
                        {
                            // Get the 404 node
                            var notFoundNode = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetById(notFoundNodeId);
                            if (notFoundNode != null)
                            {

                                // Set Response Status to be HTTP 404
                                contentRequest.SetResponseStatus(404, "404 Page Not Found");

                                // Set the node to be the not found node
                                contentRequest.PublishedContent = notFoundNode;

                            }
                        }
                    }
                }

            }

            // Finally, we return weather we have found a node to use for this request
            return contentRequest.PublishedContent != null;
        }

    }
}

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