AliasUrlProvider.cs

public class AliasUrlProvider : DefaultUrlProvider
{
	public AliasUrlProvider(IRequestHandlerSection requestSettings, ILogger logger, IGlobalSettings globalSettings, ISiteDomainHelper siteDomainHelper)
		: base(requestSettings, logger, globalSettings, siteDomainHelper)
	{
	}

	public override UrlInfo GetUrl(UmbracoContext umbracoContext, IPublishedContent content, UrlMode mode, string culture, Uri current)
	{
		var defaultUrlInfo = base.GetUrl(umbracoContext, content, mode, culture, current);
		if (content == null || defaultUrlInfo == null)
		{
			return defaultUrlInfo;
		}

		var uri = new Uri(defaultUrlInfo.Text, UriKind.RelativeOrAbsolute);
		string url = null;

		if (!string.IsNullOrEmpty(content.GetPropertyValue(Constants.Conventions.Content.UrlAlias)))
		{
			url = $"{(uri.IsAbsoluteUri ? uri.GetLeftPart(UriPartial.Authority) : string.Empty)}/{content.GetPropertyValue(Constants.Conventions.Content.UrlAlias)}{(Current.Configs.Settings().RequestHandler.AddTrailingSlash ? "/" : string.Empty)}";
		}

		return !string.IsNullOrEmpty(url) ? new UrlInfo(url, true, defaultUrlInfo.Culture) : defaultUrlInfo;
	}
}