Handle errors and missing datasource in GlassViews

GetViewRendererWithItemValidation.cs

using Diversus.Core.Sitecore.ViewRenderers;
using Sitecore.Mvc.Extensions;
using Sitecore.Mvc.Pipelines.Response.GetRenderer;
using Sitecore.Mvc.Presentation;

namespace Diversus.Core.Sitecore.Pipeline
{
    public class GetViewRendererWithItemValidation : GetViewRenderer
    {
        /// <summary>
        /// Based on solution by Hedgehog, which gracefully outputs exception error messages in Experience Editor
        /// http://www.hhog.com/blog/robust-mvc-rendering-exception-handler/
        /// </summary>
        /// <param name="rendering"></param>
        /// <param name="args"></param>
        /// <returns></returns>
        protected override Renderer GetRenderer(Rendering rendering, GetRendererArgs args)
        {
            string viewPath = this.GetViewPath(rendering, args);
            if (viewPath.IsWhiteSpaceOrNull())
            {
                return null;
            }

            if (rendering.RenderingType != "Layout" && 
                rendering.RenderingItem != null &&
                string.IsNullOrEmpty(rendering.RenderingItem.DataSource))
            {
                return new NoDatasourceSafeViewRenderer
                {
                    ViewPath = viewPath,
                    Rendering = rendering
                };
            }

            //Return the default view renderer if rendering something from core or the page layout
            if (rendering.RenderingType == "Layout" ||
                rendering.RenderingItem == null ||
                rendering.RenderingItem.Database == null ||
                rendering.RenderingItem.Database.Name == "core")
            {
                return GetDefaultViewRenderer(rendering, viewPath);
            }

            //else safely handle the Exception for this View
            return new ExceptionSafeViewRenderer
            {
                ViewPath = viewPath,
                Rendering = rendering
            };
        }

        private static ViewRenderer GetDefaultViewRenderer(Rendering rendering, string viewPath)
        {
            //Handle the scenario where there is no Datasource but one is expected by the View
            if (rendering.RenderingItem != null && string.IsNullOrEmpty(rendering.RenderingItem.DataSource))
            {
                return new NoDatasourceSafeViewRenderer
                {
                    ViewPath = viewPath,
                    Rendering = rendering
                };
            }
            
            //else return default
            return new ViewRenderer
            {
                ViewPath = viewPath,
                Rendering = rendering
            };
        }
    }
}