icontentfinder to handle 404s doc types with no template - Extending Umbraco and using the API

Tom 34 posts 154 karma points

Dec 29, 2017 @ 10:21

IContentFinder to handle 404's doc types with no template

Hi all, I've made an implementation of the IContentFinder to pick up on 404's and redirect them to a desired node. Everything work's fine when I set the contentRequest.PublishedContent to the node I want to display when a 404 occurs However if the path of a URL is set a node of which the document type has no template then I get to see the standard 404 notification (No template exists to render the document at url '/submitted-contact-forms/').

I've tried using contentRequest.SetIsInitialPublishedContent() after I assigned my 404 node to contentRequest.PublishedContent but no luck.

Here's the simplified version of my code;

public class _404iLastChanceFinder : IContentFinder {
    public bool TryFindContent(PublishedContentRequest contentRequest) {
        if (contentRequest.Is404) {
            var home = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetByRoute("/");
            var notFoundNode =  home.Children.FirstOrDefault(x => x.DocumentTypeAlias == "error_404");

            if (notFoundNode != null) {
                contentRequest.SetResponseStatus(404, notFoundNode.HasProperty("title") ? notFoundNode.GetPropertyValue("title").ToString() : "404");
                contentRequest.PublishedContent = notFoundNode;
            }

             return contentRequest.PublishedContent != null;
        } else {
            return false;
        }
    }
}

Hooked it up via the ApplicationEventHandler

public class UmbracoApplication : ApplicationEventHandler {
    protected override void ApplicationStarting(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext) {
        ContentLastChanceFinderResolver.Current.SetFinder(new _404iLastChanceFinder());
    }
}

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Dave Woestenborghs 3504 posts 12135 karma points MVP 9x admin c-trib

Dec 29, 2017 @ 11:25

Hi Tom,

This is the code we have for serving a page for 404 requests.

Contentfinder :

using Umbraco.Core.Configuration;
    using Umbraco.Web;
    using Umbraco.Web.Routing;

    /// <summary>
    /// The four oh four content finder.
    /// </summary>
    internal class FourOhFourContentFinder : IContentFinder
    {
        /// <summary>
        /// Tries to find and assign an Umbraco document to a <c>PublishedContentRequest</c>.
        /// </summary>
        /// <param name="contentRequest">The <c>PublishedContentRequest</c>.</param>
        /// <returns>A value indicating whether an Umbraco document was found and assigned.</returns>
        /// <remarks>Optionally, can also assign the template or anything else on the document request, although that is not required.</remarks>
        public bool TryFindContent(PublishedContentRequest contentRequest)
        {
            // Check request is a 404
            if (contentRequest.Is404)
            {
                return contentRequest.PublishedContent != null;
            }

            var errorPage =
                UmbracoContext.Current.ContentCache.GetSingleByXPath($"//error_404[@isDoc]");

            if (errorPage != null)
            {
                // set content for the 404 page
                contentRequest.PublishedContent = errorPage;

                // Set Response Status to be HTTP 404
                contentRequest.SetIs404();
            }

            return false;
        }
    }

Application start

public class UmbracoApplication : ApplicationEventHandler {
    protected override void ApplicationStarting(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext) {
       ContentFinderResolver.Current.InsertTypeBefore<ContentFinderByNotFoundHandlers, FourOhFourContentFinder>();
    }
}

This works perfectly for us.

Dave

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Tom 34 posts 154 karma points

Dec 29, 2017 @ 12:20

Hi Dave,

Thanks for the reply. In the code you provided there is a return contentRequest.PublishedContent != null; before assigning the errorpage node thus you still get redirected to the default 404 page. Remove the return but the problem remains unfortunately.

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Dave Woestenborghs 3504 posts 12135 karma points MVP 9x admin c-trib

Dec 29, 2017 @ 12:25

Hi Tom,

Does your 404 page have a template assigned ? It needs a template to be rendered.

Dave

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Tom 34 posts 154 karma points

Dec 29, 2017 @ 12:36

I overlooked something; I've hooked my implementation of the IContentFinder to the ContentLastChanceFinderResolver on application_start where your solution does so on the ContentFinderResolver.

Tried your solution again but unfortunately, if a page that's based on a document type without a template get's requested the FourOhFourContentFinder doesn't even get called and I still get to see the default 404 page.

My 404 page does have a template. Request to non-existent pages like example.com/foobartest123 get to see this custom 404 page

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Tom 34 posts 154 karma points

Dec 29, 2017 @ 12:42

I've noticed another subtle difference between how the implementation of the IContentFinder is hooked up inside the application_start. I did so by using the ContentLastChanceFinderResolver while yours used the ContentFinderResolver.

Tried it again but unfortunately a page request that has it's document type based on one without a template get's redirected to the default 404 page. Whereas e.g. the non-existent page example.com/foobar get's to see my custom 404 page (it does have a template). Whilst debugging i've noticed that the FourOhFourContentFinder doesn't even get called.

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Dave Woestenborghs 3504 posts 12135 karma points MVP 9x admin c-trib

Dec 29, 2017 @ 12:55

Hi Tom,

Maybe it's related to some config :

I notice that we have removed this from config/404handlers.config

<notFound assembly="umbraco" type="SearchForTemplate"/>

In config/umbracoSettings.config we have the following set trySkipIisCustomErrors to true in the web.routing section

In our web.config we have the following tag in our system.webServer section

<httpErrors existingResponse="PassThrough" errorMode="DetailedLocalOnly" />

Can you check your configuration ?

Dave

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Tom 34 posts 154 karma points

Dec 29, 2017 @ 13:23

Hi Dave,

I've changed the 404handlers.config and set the trySkipIisCustomErrors to true. PassThrough value was already there. Still no luck. I'm going to try this out on a clean umbraco installation to see if I've missed something.

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Dave Woestenborghs 3504 posts 12135 karma points MVP 9x admin c-trib

Dec 29, 2017 @ 12:25

Hi Tom,

This is for when the request is already marked as 404. So there is no need to set the 404 page again.

Dave

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IContentFinder to handle 404's doc types with no template