Rendering Markdown in .NET

29 May 2013 17:19

There are several options for rendering Markdown to HTML in .NET. If you bring up the NuGet Package Manager dialog and search for “markdown”, you get three pages of results, including MarkdownSharp, which is the renderer used by Stack Overflow, so it must be good.

More intriguingly, however, is Kiwi.Markdown which mentions support for GitHub-flavoured markdown and GitHub wiki pages. This sounds ideal, so we’ll quickly play with that.

At this point, we need is a simple web application that we can host in IIS Express. We need to be able to provide it with a path containing a file.

Spike: Rendering Markdown

I’m going to use Nancy for this, for two reasons:

  1. I think it’ll be lighter-weight than a full-blown ASP.NET MVC 4 application.
  2. I really like it.

So, the first thing we need is an “ASP.NET Empty Web Application”. I’ll call it “StartPage.WebApplication”. This gives us a C# web project that contains nothing more than a Web.config file.

To this, we add the Nancy.Hosting.Aspnet NuGet package, and add the home page:

public class HomeModule : NancyModule
    public HomeModule()
        Get["/"] = _ => "Hello World";

At this point, I double-check that it works in IIS Express if I run it as we’re planning to:

Start-Process $iisexpress `
    ('/path:"{0}"' -f 'C:\Usersoger\Source\vs-start-page\StartPage.WebApplication'), '/port:15510' `
    -WindowStyle Hidden

Yep. That’s all good.

Next up is actually rendering something, so we’ll add the Kiwi.Markdown package to the project, and add some code to use it:

Get["/"] = context =>
        var contentProvider = new FileContentProvider(@"C:\Usersoger\Source\vs-start-page");
        var converter = new MarkdownService(contentProvider);
        var document = converter.GetDocument("README");
        return document.Content;

Cool. That works. MarkdownService outputs an HTML snippet, rather than a full document, assuming that you’ll include it in something, but IE renders it fine, so we can call that a success.

Note: It turns out that Kiwi.Markdown uses MarkdownSharp anyway.