Umbraco-CMS/src/Umbraco.Core/Models/ContentBaseExtensions.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Umbraco.Cms.Core.Models;
using Umbraco.Cms.Core.Strings;

namespace Umbraco.Extensions
{
    /// <summary>
    /// Provides extension methods to IContentBase to get URL segments.
    /// </summary>
    public static class ContentBaseExtensions
    {
        /// <summary>
        /// Gets the URL segment for a specified content and culture.
        /// </summary>
        /// <param name="content">The content.</param>
        /// <param name="shortStringHelper"></param>
        /// <param name="urlSegmentProviders"></param>
        /// <param name="culture">The culture.</param>
        /// <returns>The URL segment.</returns>
        public static string GetUrlSegment(this IContentBase content, IShortStringHelper shortStringHelper, IEnumerable<IUrlSegmentProvider> urlSegmentProviders, string culture = null)
        {
            if (content == null) throw new ArgumentNullException(nameof(content));
            if (urlSegmentProviders == null) throw new ArgumentNullException(nameof(urlSegmentProviders));

            var url = urlSegmentProviders.Select(p => p.GetUrlSegment(content, culture)).FirstOrDefault(u => u != null);
            if (url == null)
            {
                if (s_defaultUrlSegmentProvider == null)
                {
                    s_defaultUrlSegmentProvider = new DefaultUrlSegmentProvider(shortStringHelper);
                }

                url = s_defaultUrlSegmentProvider.GetUrlSegment(content, culture); // be safe
            }
            
            return url;
        }

        private static DefaultUrlSegmentProvider s_defaultUrlSegmentProvider;
    }
}