Html Agility Pack: make code look neat

html-agility-pack

Question

Can I use Html Agility Pack to make the output look nicely indented, unnecessary white space stripped?

Accepted Answer

HAP is not going to give you the results you are after.

Try using a .net wrapper for HtmlTidy such as the one found here

using System;
using System.IO;
using System.Net;
using Mark.Tidy;

namespace CleanupHtml
{
    /// <summary>
    /// http://markbeaton.com/SoftwareInfo.aspx?ID=81a0ecd0-c41c-48da-8a39-f10c8aa3f931
    /// </summary>
    internal class Program
    {
        private static void Main(string[] args)
        {
            string html =
                new WebClient().DownloadString(
                    "http://stackoverflow.com/questions/2593147/html-agility-pack-make-code-look-neat/2610903#2610903");

            using (Document doc = new Document(html))
            {
                doc.ShowWarnings = false;
                doc.Quiet = true;
                doc.OutputXhtml = true;
                doc.OutputXml = true;
                doc.IndentBlockElements = AutoBool.Yes;
                doc.IndentAttributes = false;
                doc.IndentCdata = true;
                doc.AddVerticalSpace = false;
                doc.WrapAt = 120;

                doc.CleanAndRepair();

                string output = doc.Save();
                Console.WriteLine(output);
                File.WriteAllText("output.htm", output);
            }
        }
    }
}

Results:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta name="generator" content="HTML Tidy for Windows (vers 14 October 2008), see www.w3.org" />
    <title>
      Html Agility Pack: make code look neat - Stack Overflow
    </title>
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                        Can I use Html Agility Pack to make the output look nicely indented, unnecessary white space
                        stripped?
                      </p>
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                        <td class="post-signature owner">
                          <div class="user-info">
                            <div class="user-action-time">
                              asked <span title="2010-04-07 14:13:47Z" class="relativetime">2 days ago</span>
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                            <div>
                              what output? From where? some more details perhaps? &ndash;&nbsp;<a href=
                              "/users/97614/sam-holder" title="1868" class="comment-user">Sam Holder</a> <span class=
                              "comment-date"><span title="2010-04-07 14:16:41Z">2 days ago</span></span>
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                          <td class="comment-text">
                            <div>
                              <i>(reference)</i> <a href="http://htmlagilitypack.codeplex.com/Wikipage" rel=
                              "nofollow">htmlagilitypack.codeplex.com/Wikipage</a> &ndash;&nbsp;<a href=
                              "/users/208809/gordon" title="16497" class="comment-user">Gordon</a> <span class=
                              "comment-date"><span title="2010-04-07 14:16:55Z">2 days ago</span></span>
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                          </td>
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                          <td class="comment-text">
                            <div>
                              output = html code output &ndash;&nbsp;<a href="/users/51795/illdev" title="53" class=
                              "comment-user owner">illdev</a> <span class="comment-date"><span title=
                              "2010-04-10 13:14:42Z">12 secs ago</span></span>
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                      <p>
                        A variation of this question has been answered recently
                      </p>
                      <ul>
                        <li>
                          <a href=
                          "http://stackoverflow.com/questions/2490765/which-is-the-best-html-tidy-pack-is-there-any-option-in-html-agility-pack-to-mak/2507673#2507673">
                          http://stackoverflow.com/questions/2490765/which-is-the-best-html-tidy-pack-is-there-any-option-in-html-agility-pack-to-mak/2507673#2507673</a>
                        </li>
                      </ul>
                      <p>
                        Basically the outcome of this was that while you <strong>can</strong> use HtmlAgilityPack to
                        clean it up a bit by using the fix nested tags.
                      </p>
                      <p>
                        The best solution is to use something called Tidy which is an application that was originally
                        created by some developers at w3c and then made open source. Its the engine that powers the w3c
                        validator as well.
                      </p>
                      <p>
                        This article covers how to use it but you had to sign up (free) to view it:
                      </p>
                      <ul>
                        <li>
                          <a href="http://www.devx.com/dotnet/Article/20505/1763/" rel=
                          "nofollow">http://www.devx.com/dotnet/Article/20505/1763/</a>
                        </li>
                      </ul>
                      <p>
                        It seems like a legit article but its funny because nobody else seems to have covered this
                        topic in the last six years...
                      </p>
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                          <div class="user-info">
                            <div class="user-action-time">
                              answered <span title="2010-04-09 20:55:18Z" class="relativetime">16 hours ago</span>
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                      <p>
                        Output as XHTML and run that through an <a href=
                        "http://msdn.microsoft.com/en-us/library/system.xml.xmltextwriter.indentation.aspx" rel=
                        "nofollow">XmlTextWriter</a>
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                              answered <span title="2010-04-09 21:02:34Z" class="relativetime">16 hours ago</span>
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Popular Answer

See a similar question here: HtmlAgilityPack: how to create indented HTML? and my answer:

No, and it's a "by design" choice. There is a big difference between XML (or XHTML, which is XML, not HTML) where - most of the times - whitespaces are no specific meaning, and HTML.

This is not a so minor improvement, as changing whitespaces can change the way some browsers render a given HTML chunk, especially malformed HTML (that is in general well handled by the library). And The Html Agility Pack was designed to minimize the way the HTML is rendered, not the way the markup is written.

I'm not saying it's not feasible or plain impossible. Obviously you can convert to XML and voilà (and you could write an extension method to make this easier) but the rendered output may be different, in the general case.




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