Handlebars.Net NancyFx View Engine

HandlebarViewEngine.cs

namespace Nancy.ViewEngines.Handlebars
{
    using System;
    using System.Collections.Generic;
    using System.IO;

    using global::HandlebarsDotNet;

    using Nancy.Responses;

    /// <summary>
    /// View engine for rendering nustache views.
    /// </summary>
    public class HandlebarsViewEngine : IViewEngine
    {
        /// <summary>
        /// Gets the extensions file extensions that are supported by the view engine.
        /// </summary>
        /// <value>An <see cref="IEnumerable{T}"/> instance containing the extensions.</value>
        /// <remarks>The extensions should not have a leading dot in the name.</remarks>
        public IEnumerable<string> Extensions
        {
            get { return new[] { "hbs" }; }
        }

        /// <summary>
        /// Initialise the view engine (if necessary)
        /// </summary>
        /// <param name="viewEngineStartupContext">Startup context</param>
        public void Initialize(ViewEngineStartupContext viewEngineStartupContext)
        {
            foreach (var view in viewEngineStartupContext.ViewLocator.GetAllCurrentlyDiscoveredViews())
            {
                if (view.Extension=="hbs" && view.Location.Contains("/partials"))
                {
                    using (var reader = File.OpenText(view.Location+"/"+view.Name+"."+view.Extension))
                    {
                        var partialTemplate = Handlebars.Compile(reader);
                        Handlebars.RegisterTemplate(view.Name, partialTemplate);
                    }
                }
            }
        }

        private Action<TextWriter, object> GetOrCompileTemplate(ViewLocationResult viewLocationResult, IRenderContext renderContext)
        {
            var viewFactory = renderContext.ViewCache.GetOrAdd(
                viewLocationResult,
                x =>
                {
                    using (var reader = x.Contents.Invoke())
                        return this.GetCompiledTemplate<dynamic>(reader);
                });

            var view = viewFactory.Invoke();

            return view;
        }

        private Func<Action<TextWriter, object>> GetCompiledTemplate<TModel>(TextReader reader)
        {
            var template = Handlebars.Compile(reader);
            return () =>
            {
                return template;
            };
        }

        /// <summary>
        /// Renders the view.
        /// </summary>
        /// <param name="viewLocationResult">A <see cref="ViewLocationResult"/> instance, containing information on how to get the view template.</param>
        /// <param name="model">The model that should be passed into the view</param>
        /// <param name="renderContext"></param>
        /// <returns>A response</returns>
        public Response RenderView(ViewLocationResult viewLocationResult, dynamic model, IRenderContext renderContext)
        {
            return new HtmlResponse
            {
                Contents = stream =>
                {
                    var template =
                        this.GetOrCompileTemplate(viewLocationResult, renderContext);

                    var writer =
                        new StreamWriter(stream);

                    template(writer, model);
                    writer.Flush();
                }
            };
        }
    }
}