Custom NancyFX IViewLocationProvider implementation to allow for loading views from a RavenDB server instance. Views loaded from RavenDB will override views which exist on the File System.

CustomBootstraper.cs

        protected override NancyInternalConfiguration InternalConfiguration
        {
            get
            {
  		return NancyInternalConfiguration
			.WithOverrides(x => x.ViewLocationProvider = typeof (RavenViewLocationProvider))
                	.WithIgnoredAssembly(asm => asm.FullName.StartsWith("RavenDB", StringComparison.InvariantCulture)); // or override ConfigureApplicationContainer to set AutoRegister to false
            }
        }

RavenViewLocationProvider.cs

using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using NSemble.Core.Models;
using Nancy;
using Nancy.ViewEngines;

namespace NSemble.Core.Nancy
{
	public class RavenViewLocationProvider : IViewLocationProvider
	{
		private readonly IViewLocationProvider defaultViewLocationProvider;

		public RavenViewLocationProvider(IRootPathProvider rootPathProvider)
		{
			defaultViewLocationProvider = new FileSystemViewLocationProvider(rootPathProvider);
		}

		public RavenViewLocationProvider(IRootPathProvider rootPathProvider, IFileSystemReader fileSystemReader)
		{
			defaultViewLocationProvider = new FileSystemViewLocationProvider(rootPathProvider, fileSystemReader);
		}

		public IEnumerable<ViewLocationResult> GetLocatedViews(IEnumerable<string> supportedViewExtensions)
		{
			var sb = new StringBuilder();

			// Make sure to only load saved views with supported extensions
			foreach (var s in supportedViewExtensions)
			{
				if (sb.Length > 0)
					sb.Append("|");
				sb.Append("*.");
				sb.Append(s);
			}
			
			ViewTemplate[] views = null;
			using (var session = NSembleModule.DocumentStore.OpenSession())
			{
				// It's probably safe to assume we will have no more than 1024 views, so no reason to bother with paging
				views = session.Advanced.LoadStartingWith<ViewTemplate>(Constants.RavenViewDocumentPrefix, sb.ToString(), 0, 1024);
			}

			// Read the views from the default location
			IEnumerable<ViewLocationResult> defaultViews = defaultViewLocationProvider.GetLocatedViews(supportedViewExtensions);
			if (views.Length == 0)
				return defaultViews;

			var ret = new HashSet<ViewLocationResult>(from v in views
								  where supportedViewExtensions.Contains(v.Extension)
			                                          select new ViewLocationResult(
				                                          v.Location,
				                                          v.Name,
				                                          v.Extension,
				                                          () => new StringReader(v.Contents)));

			foreach (var v in defaultViews)
				ret.Add(v);

			return ret;
		}
	}
}