Spark View Engine

This week I am continuing my exploration of view engines by taking a closer look at the Spark view engine. I wanted to find at least one third party view engine that I could play around with and Spark seemed like potentially the best candidate. Spark was released before Razor, and it appears that it was last updated in June 2015. The good news is that there is a NuGet Package that allows you to use Spark with MVC 5. This helps to make it at least usable with current versions of Visual Studio.

One of the primary goals with Spark is that HTML comes to the forefront in the markup with less intermixed code than was seen with the ASPX view engine. Part of the driving force behind this implementation was that ASPX pages would be more and more difficult to maintain and read as time went by and they grew in size. The view engine was authored by Louis Dejardin and based on comments and search results, I’m going to guess that it was at one time the most popular third party view engine.

In my most recent post, I mentioned refreshing a classic ASP.NET tutorial web application, the Movie App. I had brought this project up to speed using MVC 5, so that I could use it as a basis for other experiments. I figured that a perfect usage for this would be to convert my previously created version of the Movie App to leverage the Spark view engine.

Getting up and running with Spark was not too tough. I started out by referencing the previously mentioned Spark.Web.Mvc5 NuGet package. After that, I updated my Global.asax.cs, removing all other view engines from usage and adding the Spark view engine. This would be the approach that you would want to take if you were wanting to using only Spark. If you wanted to also use Razor or ASPX, you would not bother to clear out the existing view engines.

As an optional step, you can add a spark section to your Web.config. Take a look at the configuration documentation for more details on what you can do there. I did read that setting the debug setting to true can be helpful in troubleshooting view compilation errors, so you may want to consider using that setting.

After modifying the configuration, I needed to make a few changes to the file structure under the Views folder. First, I had to rename all the views to *.spark, so that they would be recognized by the Spark view engine. Second, I deleted _ViewStart.cshtml, as it is not used by Spark. Third, I renamed _Layout.cshtml to Application.spark. Spark automatically looks for a layout file by that name. Finally, I had to add a reference to System.Web.Optimization in the _global.spark file that was added when I referenced the NuGet package. This enabled me to reference Styles.Render and Scripts.Render.

The next step, and the most involved step, was to replace the existing Razor syntax in all of the views with Spark syntax. One of the things that pops out at you right away is that several of the C# constructs, such as if and for are replaced by markup that looks like HTML. This does contribute to the readability of the document. Below is one example of a view that I updated, the movie creation view.

The Form tag in the above example leverages another important feature of Spark, bindings. You can create a binding that will replace HTML-like markup with C# code. In this case, I created a binding that could wrap some HTML with the appropriate code needed to render a form. This binding is defined within Bindings.xml, which sits in the Views folder. Below is the example binding that I created.

After setting up the binding and replacing the existing Razor syntax in the views, I was pretty much set to go. With a minimal amount of effort, I once again had the Movie App running, but this time using Spark syntax. Despite the fact that Spark hasn’t been updated in several years, it is still a fairly painless experience to get started.

Would I choose to use Spark over Razor? Probably not. I’ve already got some amount of Razor experience and I didn’t see anything compelling enough to persuade me to change. However, it is nice to know that you have options, and I can see how Spark was an attractive alternative to ASPX. The HTML-like markup does make it easier to read than a complex ASPX view.

Updating a Classic

This week I went searching for a classic ASP.NET MVC example that I could use as a basis for making further modifications in future articles. I found an old example Movie Database Application from 2009 that I decided to use. Its features include listing movies from a database, creating new movie entries, and editing existing movie entries. Admittedly, it is not a full-featured application, but it does at least give one a starting point to try to understand how to accomplish some simple goals quickly using ASP.NET MVC.

As I mentioned, the article was written in 2009, so there have been a lot of changes since then. The screenshots were taken using Visual Studio 2008. I decided to refresh the example, using Visual Studio 2015 and ASP.NET MVC 5. Given the release date of the article, it appears that the article was written using ASP.NET MVC 1.0.

The purpose of this article is to share my updated version of this classic example and to discuss a few of the differences that I encountered in recreating it with ASP.NET MVC 5. Although the differences were not extensive, they would be enough to trip up a novice trying to follow along at this point. Granted, there are likely plenty of other newer examples, but I felt like this simple example was a good fit for my planned usage in future articles.

First, you would now use one of the Visual Studio Community versions. 2017 is the newest, but I already had 2015 installed, so I went with that. The feature set of these free versions is quite impressive given the bargain price tag. Given that you would be using a different version of Visual Studio, many of the dialogs are slightly different. However, the differences are quite minor considering that nearly ten years has passed.

Second, creating an Entity Framework (EF) data model has changed slightly, but again the change is very minor. The thing that stood out to me was the fact that EF6 is now trying to come up with appropriate singular names for the objects based upon the plural naming of the database table. In my case, it tried to rename the Movies table to Movy. This update would probably work for a number of different nouns, so it’s understandable why they took that approach.

Third, the generated views now use Razor instead of ASPX. I am of a similar opinion to a lot of developers that Razor is easier to work with, so this is a bonus. Razor became the default view engine with ASP.NET MVC 3, so it makes sense that this would now be the case. Although these views like a fair amount different from those given in the example, they are all generated, so the impact on creating the project is virtually none.

Finally, the biggest difference that I found in this example was that the EF editing code needed to be updated to work with EF6. Some of the methods called in the example, such as ObjectContext.ApplyPropertyChanges, are no longer available. I had to end up replacing the code for adding records to the database and updating records in the database.

Below is the controller method that I used to handle creating a movie record in the database. This includes the updated EF methods necessary to make this work with EF6.

The following is the controller method that I used to handle updating a movie record in the database. Again, this includes updated EF methods needed to make this work with EF6.

All in all, the process of getting this classic example running with ASP.NET MVC5 in Visual Studio 2015 was accomplished with little difficulties. I consider this to be somewhat impressive, given that the example is nearly ten years old. I will be using this refreshed version of the example in some future articles to demonstrate various features of ASP.NET MVC.

 

Third Party View Engines R.I.P?

After finishing my recent overview of ASP.NET MVC view engines, I thought that I would take a deeper look at a specific third party view engine implementation. The users of Stack Overflow have provided a good list of available view engines. I took a brief look at the web sites for all of the view engines, and one thing that really stuck out at me was the fact that none of them had been updated for quite some time.

Despite this, I decided that I would experiment one of them, and chose NHaml. Based on the Rails Haml view engine, NHaml sounds intriguing to me. It takes a different approach than most by abstracting away the HTML markup language.

I saw that a NuGet package was available for NHaml, so i figured that chances for getting it running were promising. Unfortunately, after fiddling around with it for a while, I did not have good luck getting it running under MVC5. I managed to get around the initial error with the NuGet package (Derived types must either match the security accessibility of the base type or be less accessible) by downloading the source code and removing the “AllowPartiallyTrustedCallers” attribute from the SharedAssemblyInfo.cs in the System.Web.NHaml project. However, I then found myself running into access denied errors as NHaml apparently tries to delete temp files from disk.

Considering that NHaml has not been updated for quite some time, I decided that it wasn’t worth investing anymore time into getting it up and running. I may still take a look at one of the other view engines, just to get a sense for how different it is from Razor.

I do still wonder why there has been no recent action on the third party view engine front. I don’t have any complaints about Razor, but is it really that good that it deserves no well maintained competition other than the ASPX view engine? Apparently, Microsoft has done a good job of meeting the desires of developers with the feature set that they have provided in Razor.