Intercepting Rendered HTML using the Commander Addin

Markdown Monster supports intercepting the Markdown and generated HTML and making modifications using full featured .NET Addins or - for simple things - using the Commander or Snippets addins. Full addins take a bit of effort, but using the Commander add in can be very easy.

Here's a use case somebody asked about recently:

I use HTML comments in my markdown to break up my Markdown text, but I don't want to render the comments into the output. Is there a way to strip the comments?

Yes it's possible to intercept the rendering process using a couple of events on the MarkdownDocument object in Markdown monster.

Using the Command add in you can create a commander script that looks like this:

To do this:

  • Use the Addin Manager to install the Commander Addin
  • Use Add Command to create a new Command Script
  • Enter the code shown below
  • Run Command to test and make sure there are no compilation errors

To get the addin to work you need to run the command or you can create a hot key to activate it. It will not automatically run and the command is effectively bound to the document you run it on.

Here's the code that hooks up the event:

using System.Text.RegularExpressions

var doc = Model.ActiveDocument as MarkdownDocument;
doc.DocumentRendered += (html,markdown) =>
{
    if (string.IsNullOrEmpty(html))
        return html;
        
        
    return Regex.Replace(html, 
                 "<!--.*?-->", "",
                 RegexOptions.IgnoreCase | RegexOptions.Multiline);
};

Creating an Addin

If you want a more permanent solution that fires without explicit interaction you can create a full addin.

Addins have a dedicated method for modifying the rendered HTML (or Markdown) OnModifyPreviewHtml() and you can override the HTML in this method using the same Regex logic used in the Commander script above.

public class StripCommentsAddin : MarkdownMonster.AddIns.MarkdownMonsterAddin
{
    public override void OnApplicationStart()
    {
        Id = "StripCommentsAddin";
        Name = "Strip Comments From HTML";            
    }

    public override OnModifyPreviewHtml(html, markdown)
    {
        return Regex.Replace(html, 
                    "<!--.*?-->", "",
                    RegexOptions.IgnoreCase | RegexOptions.Multiline);
    }
}

© West Wind Technologies, 2019 • Updated: 09/02/18
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