Question: sanitise HtmlNodeType.Text ie replace smart quotes with simple quote...

[mistyn8]

Question: sanitise HtmlNodeType.Text ie replace smart quotes with simple quote...
Is the following a reasonable way to do this? (though would like not to have to explicitly set on all the tags...)

public class CharReplacementSanitizer : IHtmlElementSanitizer
 {
     public SanitizerOperation SanitizeElement(HtmlNode element, HtmlSanitizerTagRule tagRule)
     {
         if (element.HasChildNodes)
         {
             for (int i = element.ChildNodes.Count - 1; i >= 0; i--)
             {
                 HtmlNode child = element.ChildNodes[i];
                 if (child.NodeType == HtmlNodeType.Text)
                 {
                     string updatedText = child.InnerText.Replace("’", "'");
                     HtmlNode newChild = HtmlNode.CreateNode(HtmlEntity.DeEntitize(updatedText));
                     element.ReplaceChild(newChild, child);
                 }
             }
         }
         else
         {
             element.InnerHtml = element.InnerHtml.Replace("’", "'");
         }

         return SanitizerOperation.DoNothing;
     }
 }

 var sanitizer = new HtmlSanitizer();
 
 sanitizer.EncodeHtmlEntities = true;
 sanitizer.Tag("div").NoAttributes(SanitizerOperation.FlattenTag);
 sanitizer.Tag("a").NoAttributes(SanitizerOperation.FlattenTag).Sanitize(new CharReplacementSanitizer());
 sanitizer.Tag("p").Sanitize(new CharReplacementSanitizer()).RemoveEmpty();
 sanitizer.Tag("br");
 sanitizer.Tag("ul");
 sanitizer.Tag("li").Sanitize(new CharReplacementSanitizer());
 sanitizer.Tag("strong").Sanitize(new CharReplacementSanitizer()).RemoveEmpty();
 sanitizer.Tag("em").Sanitize(new CharReplacementSanitizer()).RemoveEmpty();
 sanitizer.Tag("b").Rename("strong").Sanitize(new CharReplacementSanitizer()).RemoveEmpty();
 sanitizer.Tag("i").Rename("em").Sanitize(new CharReplacementSanitizer()).RemoveEmpty();

[cakkermans]

In general, I think you are in the right direction. In order to make sure I recommend adding a few unit tests to your code to prove this works the way you intended. Sorry for not getting back earlier.

Some remarks:

1. Isn't child.InnerText a property with a setter? If so, that would allow you to avoid having to replace the text nodes?
2. There is currently no method to set a global sanitizer, so you'll have to set the CharReplacementSanitizer for every individual rule. Add multiple tags fluent helper #40 is a PR proposed to make this easier.
3. Consider creating only a single CharReplacementSanitizer instance and reuse that. This avoids unnecessary memory allocations.