UrlCssHelper: A helper extending ASP.NET MVC3 with simple ID and CSS class generators for page level elements, to make per-page or per-feature CSS includes/rules simpler

UrlCssHelper.cs

//-----------------------------------------------------------------------
// <copyright file="UriCssHelper.cs" company="The Swedish Post and Telecom Authority (PTS)">
//      Copyright (c) 2011, 2012 The Swedish Post and Telecom Authority (PTS)
//      Developed for PTS by Joel Purra <http://joelpurra.se/>
//      Released under the BSD license.
// </copyright>
//-----------------------------------------------------------------------
// https://gist.github.com/2253509

namespace JoelPurra.Web.Helpers
{
    using System;
    using System.Collections.Generic;
    using System.Diagnostics.Contracts;
    using System.Web;
    using System.Web.Mvc;

    public static class UrlCssHelper
    {
        #region Constants and Fields

        private const char UrlSegmentDelimiter = '/';

        private const string IdPrefix = "url-";

        #endregion

        #region Public Methods

        /// <example>
        ///     &lt;body id="@this.Html.GetPageId()"&gt;
        /// </example>
        public static MvcHtmlString GetPageId(this HtmlHelper htmlHelper)
        {
            Contract.Requires(htmlHelper != null);

            IEnumerable<string> parts = htmlHelper.GetUsableUrlParts();

            string id = IdPrefix + string.Join("-", parts);

            return new MvcHtmlString(id);
        }

        /// <example>
        ///     &lt;body class="page-type @this.Html.GetPageTypeClasses() any-other-class-you-like"&gt;
        /// </example>
        public static MvcHtmlString GetPageTypeClasses(this HtmlHelper htmlHelper)
        {
            Contract.Requires(htmlHelper != null);

            IEnumerable<string> parts = htmlHelper.GetUsableUrlParts();

            string classes = string.Join(" ", parts);

            return new MvcHtmlString(classes);
        }

        public static Uri GetUrl(this HtmlHelper htmlHelper)
        {
            Contract.Requires(htmlHelper != null);
            Contract.Requires(htmlHelper.ViewContext != null);
            Contract.Requires(htmlHelper.ViewContext.HttpContext != null);
            Contract.Requires(htmlHelper.ViewContext.HttpContext.Request != null);
            Contract.Requires(htmlHelper.ViewContext.HttpContext.Request.Url != null);

            Uri url = htmlHelper.ViewContext.HttpContext.Request.Url;
            return url;
        }

        public static Uri UrlOriginal(this HttpRequestBase request)
        {
            Contract.Requires(request != null);
            Contract.Requires(request.Url != null);

            string hostHeader = request.Headers["host"];

            return new Uri(string.Format("{0}://{1}{2}", request.Url.Scheme, hostHeader, request.RawUrl));
        }

        #endregion

        #region Methods

        private static IEnumerable<string> GetUsableUrlParts(this HtmlHelper htmlHelper)
        {
            Uri url = htmlHelper.GetUrl();

            return url.GetUsableUrlParts();
        }

        private static IEnumerable<string> GetUsableUrlParts(this Uri url)
        {
            IList<string> parts = new List<string>();

            foreach (string segment in url.Segments)
            {
                string clean = segment.Trim(UrlSegmentDelimiter).ToLowerInvariant();

                int routeId;

                if (int.TryParse(clean, out routeId))
                {
                    continue;
                }

                if (!string.IsNullOrWhiteSpace(clean))
                {
                    parts.Add(clean);
                }
            }

            return parts;
        }

        #endregion
    }
}