Fake an UmbracoContext for use when doing published scheduling or other scenarios where UmbracoContext is normally null.

ContextHelpers.cs

public class ContextHelpers
{
    public static UmbracoContext EnsureUmbracoContext() {
        if (UmbracoContext.Current != null)
        {
            return UmbracoContext.Current;
        }
        
        var httpContext = new HttpContextWrapper(HttpContext.Current ?? new HttpContext(new SimpleWorkerRequest("temp.aspx", "", new StringWriter())));
        
        /* v7.3+ */
        return UmbracoContext.EnsureContext(
            httpContext,
            ApplicationContext.Current,
            new WebSecurity(httpContext, ApplicationContext.Current),
            UmbracoConfig.For.UmbracoSettings(),
            UrlProviderResolver.Current.Providers,
            false);
        
        /* v6.1.4 - v7.2.8 */
       return UmbracoContext.EnsureContext(httpContext, ApplicationContext.Current, new WebSecurity(httpContext, ApplicationContext.Current), false);
        
        /* v6.1.3 and earlier (I think) */
        return (typeof(UmbracoContext)
            .GetMethods(BindingFlags.Static | BindingFlags.NonPublic)
            .First(x => x.GetParameters().Count() == 3)
            .Invoke(null, new object[] { httpContext, ApplicationContext.Current, false })) as UmbracoContext;
    }
}

EventHooks.cs

public class EventHooks : ApplicationEventHandler
{
    protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
    {
        base.ApplicationStarted(umbracoApplication, applicationContext);
 
        Umbraco.Core.Services.ContentService.Published += (sender, args) =>
        {
            using (var umbracoContext = SiteHelpers.EnsureUmbracoContext()) 
            {
                var helper = new UmbracoHelper(umbracoContext);

                foreach (var content in args.PublishedEntities)
                {
                    var publishedContent = helper.TypedContent(content.Id);
                    var url = publishedContent.Url;
                    // do something with that url
                    ...
                }
            }
        };
    }
}