AcumaticaHTMLClean/HTMLUtility.cs

using HtmlAgilityPack;
using System;
using System.IO;

namespace PX.Data
{
  //Source: https://github.com/ceee/ReadSharp/blob/master/ReadSharp/HtmlUtilities.cs
  public class HtmlUtilities
  {
    /// <summary>
    /// Converts HTML to plain text / strips tags.
    /// </summary>
    /// <param name="html">The HTML.</param>
    /// <returns></returns>
    public static string ConvertToPlainText(string html)
    {
      HtmlDocument doc = new HtmlDocument();
      doc.LoadHtml(html);

      StringWriter sw = new StringWriter();
      ConvertTo(doc.DocumentNode, sw);
      sw.Flush();
      return sw.ToString();
    }

    /// <summary>
    /// Count the words.
    /// The content has to be converted to plain text before (using ConvertToPlainText).
    /// </summary>
    /// <param name="plainText">The plain text.</param>
    /// <returns></returns>
    public static int CountWords(string plainText)
    {
      return !String.IsNullOrEmpty(plainText) ? plainText.Split(' ', '\n').Length : 0;
    }


    public static string Cut(string text, int length)
    {
      if (!String.IsNullOrEmpty(text) && text.Length > length)
      {
        text = text.Substring(0, length - 4) + " ...";
      }
      return text;
    }


    private static void ConvertContentTo(HtmlNode node, TextWriter outText)
    {
      foreach (HtmlNode subnode in node.ChildNodes)
      {
        ConvertTo(subnode, outText);
      }
    }


    private static void ConvertTo(HtmlNode node, TextWriter outText)
    {
      string html;
      switch (node.NodeType)
      {
        case HtmlNodeType.Comment:
          // don't output comments
          break;

        case HtmlNodeType.Document:
          ConvertContentTo(node, outText);
          break;

        case HtmlNodeType.Text:
          // script and style must not be output
          string parentName = node.ParentNode.Name;
          if ((parentName == "script") || (parentName == "style"))
            break;

          // get text
          html = ((HtmlTextNode)node).Text;

          // is it in fact a special closing node output as text?
          if (HtmlNode.IsOverlappedClosingElement(html))
            break;

          // check the text is meaningful and not a bunch of whitespaces
          if (html.Trim().Length > 0)
          {
            outText.Write(HtmlEntity.DeEntitize(html));
          }
          break;

        case HtmlNodeType.Element:
          switch (node.Name)
          {
            case "p":
              // treat paragraphs as crlf
              outText.Write("\r\n");
              break;
            case "br":
              outText.Write("\r\n");
              break;
          }

          if (node.HasChildNodes)
          {
            ConvertContentTo(node, outText);
          }
          break;
      }
    }
  }
}