Allows multiple MVC sites to share the same Master Page, fetched from the server at compile time, instead of having to include it in each project.

VirtualPath.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Web.Caching;
using System.Web.Hosting;

namespace CWSToolkit {
    public enum CWSMasterPages { Default, OIT, Test, Bootstrap };

	public class PathProvider : VirtualPathProvider {
        public string remotePath = "https://cws.auburn.edu/shared/assets/masterpages/auburn.master.html";

		/// <summary>
        /// Intercepts requests for "site.master" and provides the default Auburn remote masterpage instead. 
		/// </summary>
		public PathProvider(): base(){
		}

		/// <summary>
		/// Intercepts requests for "site.master" and provides the specified remote masterpage instead.
		/// </summary>
		/// <param name="masterpage">The remote View Master Page (ASPX) to use. Specify from the CWSMasterPages enum (in the CWSToolkit namespace).</param>
		public PathProvider(CWSMasterPages masterpage) {
			if (masterpage == CWSMasterPages.OIT)
                this.remotePath = "https://cws.auburn.edu/shared/assets/masterpages/oit.master.html";
			else if (masterpage == CWSMasterPages.Test)
                this.remotePath = "https://auburn.edu/oit/includes/test.master";
			else if (masterpage == CWSMasterPages.Bootstrap)
				this.remotePath = "https://cws.auburn.edu/shared/assets/masterpages/bootstrap.master.html";
			else
                this.remotePath = "https://cws.auburn.edu/shared/assets/masterpages/auburn.master.html";
		}

        /// <summary>
        /// This usage is OBSOLETE. Please use the CWSMasterPages enum instead for the parameter.
        /// </summary>
        public PathProvider(string dud)
        {
            throw new System.ArgumentException("Specifying the shared masterpage in the global.asax no longer uses a string. Please use the CWSMasterPages enum type instead of a string. Ex: CWSMasterPages.OIT instead of \"oit\".");
        }

		public bool IsPathVirtual(string virtualPath) {
			virtualPath = virtualPath.ToLower();

			if (virtualPath.Contains("site.master"))
				return true;
			else if (virtualPath.Contains("shared-head.html"))
				return true;
			else
				return false;
			}

		public override bool FileExists(string virtualPath) {
			return IsPathVirtual(virtualPath) ? true : Previous.FileExists(virtualPath);
		}

		public override VirtualFile GetFile(string virtualPath) {
			if (virtualPath.ToLower().Contains("site.master"))
				return new RemoteFile(virtualPath, remotePath);
			else if (virtualPath.ToLower().Contains("shared-head.html"))
				return new RemoteFile(virtualPath, "http://auburn.edu/oit/includes/shared-head.html");
			else
				return Previous.GetFile(virtualPath);
		}

		public override CacheDependency GetCacheDependency(string virtualPath, IEnumerable virtualPathDependencies, DateTime utcStart) {
			if (IsPathVirtual(virtualPath)) {
				return null;
			} else {
				List<string> l = new List<string>();
				foreach (var v in virtualPathDependencies) {
					if (!(v.ToString().ToLower().Contains("includes")))
						l.Add(v.ToString());
			}
				IEnumerable safeDependencies = l;
				return Previous.GetCacheDependency(virtualPath, safeDependencies, utcStart);
			}
		}
	}

	public class RemoteFile : System.Web.Hosting.VirtualFile {
        public string remotePath = "https://cws.auburn.edu/shared/assets/masterpages/auburn.master.html";

		/// <summary>
		/// Accept remote files in addition to standard files.
		/// Specifically, use a remote View Master Page (ASPX).
		/// </summary>
		/// <param name="path">The default path.</param>
		public RemoteFile(string path): base(path) {
		}

		/// <summary>
		/// Accept remote files in addition to standard files.
		/// Specifically, use a remote View Master Page (ASPX).
		/// </summary>
		/// <param name="path">The default path.</param>
		/// <param name="remotePath">The remote View Master Page (ASPX) to use. Specify "default", "oit", or a custom url.</param>
		public RemoteFile(string path, string remotePath): base(path) {
				this.remotePath = remotePath;
		}

		public override System.IO.Stream Open() {
			MemoryStream stream = new MemoryStream();
			string path = remotePath;
			HttpWebRequest request = WebRequest.Create(path) as HttpWebRequest;
			using (HttpWebResponse response = request.GetResponse() as HttpWebResponse) {
				response.GetResponseStream().CopyTo(stream);
			}
			stream.Position = 0;
			return stream;
		}
	}
}