I'm trying to create a breadcrumb based on the previously visited page (it won't work any other way in this case). My problem is that the HTTP Referer header does not exist.

I create the route like this:

public class RouteComposer : IComposer
{
    public void Compose(IUmbracoBuilder builder) =>
        builder.Services.Configure<UmbracoPipelineOptions>(options =>
        {
            AddEndpoint(
                options,
                nameof(TopicController),
                nameof(TopicController.Categories),
                “/topic/{topic}/{discipline}");
        });

    private void AddEndpoint(
        UmbracoPipelineOptions umbracoPipelineOptions,
        string controllerName,
        string actionName,
        string route)
        => umbracoPipelineOptions.AddFilter(new UmbracoPipelineFilter(controllerName)
        {
            Endpoints = app => app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute($“{controllerName} - {actionName} Endpoint”, route, new
                {
                    Controller = controllerName.Replace(“Controller”, “”),
                    Action = actionName
                }).ForUmbracoPage(FindContent);
            })
        });

    private IPublishedContent FindContent(ActionExecutingContext actionExecutingContext)
    {
        IServiceProvider services = actionExecutingContext.HttpContext.RequestServices;

        var defaultCultureAccessor = services.GetRequiredService<IDefaultCultureAccessor>();
        var umbracoContextAccessor = services.GetRequiredService<IUmbracoContextAccessor>();
        var variationContextAccessor = services.GetRequiredService<IVariationContextAccessor>();

        IUmbracoContext umbracoContext = umbracoContextAccessor.GetRequiredUmbracoContext();

        string culture = variationContextAccessor.VariationContext?.Culture ??
            defaultCultureAccessor.DefaultCulture;

        return umbracoContext.Content!.GetById(Guid.Parse(“f77e5883-5406-4b1a-9838-1ec9193c0cb3”));
    }
}

And currently display the referer in my master layout file:

Referer: @(string.Join(“,”, Context.Request.Headers[“Referer”].ToString()))

This also works so far. Until I open my route, then the referer is suddenly empty.

However, if I then go from my route to the start page, for example, the referer is displayed again (namely my custom route).

Can anyone tell me what's going on here?