A script for a one-time formatting of blog posts, which were originally turned into HTML by copy-pasting from MS Word into a wysiwyg editor, along with a bunch of weird stylings and formatting oddities.

FormatArticles.php

Article::all()
  ->each(function (Article $article) {

      // Mark "width" inline styles for keeping
      $article->content = Str::replaceMatches(
          '/style=(\"[^\"]*width:[^\"]*\")/',
          fn($matches) => 'keepwidth_123=' . $matches[1],
          $article->old_content
      );

      // Remove inline styles, except image widths
      $article->content = Str::replaceMatches(
          '/style=\"[^\"]*\"/',
          '',
          $article->content
      );

      // put widths back
      $article->content = Str::replaceMatches(
          '/keepwidth_123=(\"[^\"]*width:[^\"]*\")/',
          fn($matches) => 'style=' . $matches[1],
          $article->content,
      );

      // Remove inline classes
      $article->content = Str::replaceMatches(
          '/class=\"[^\"]*\"/',
          '',
          $article->content
      );

      // Remove inline font declarations (!)
      $article->content = Str::replaceMatches(
          '/<font [^>]*>/',
          '',
          $article->content
      );

      // remove errant spaces before the end of html tags <>
      $article->content = Str::replaceMatches(
          '/\s+>/',
          '>',
          $article->content
      );

      // remove no-brake-spaces (hidden characters)
      $article->content = Str::replaceMatches(
          [
              '/&nbsp;/',
              '/<o:p>/',
              '/<\/o:p>/',
              '/<\/font>/',
              '/<span[^>]*>/',
              '/<\/span>/',
          ],
          '',
          $article->content
      );

      // remove newlines (line-breaks are all over the place in many of the articles)
      $article->content = Str::replaceMatches(
          '/[\n\r]+/',
          ' ',
          $article->content
      );

      // Add in linebreaks to match paragraph tags
      $article->content = Str::replaceMatches(
          '/<\/p>?[\s]*</',
          '</p>
  <',
          $article->content
      );

      // Add in linebreaks after header tags
      $article->content = Str::replaceMatches(
          '/<\/h(\d)>?[\s]*</',
          fn($matches) => '</h' . $matches[1] . '>
  <',
          $article->content
      );

      // and after <br/> tags
      $article->content = Str::replaceMatches(
          '/<br\/>?[\s]*</',
          '<br\/>
  <',
          $article->content
      );


      // Remove empty tags
      $article->content = Str::replaceMatches(
          '/[\r\n]<p>\s*<\/p>/',
          '',
          $article->content
      );

      // Remove empty space before the end of a <p> tag.
      $article->content = Str::replaceMatches(
          '/[\s\n\r]*<\/p>/',
          '</p>',
          $article->content
      );

      // Remove span tags, as they're only used for inline formatting
      $article->content = Str::replaceMatches(
          [
              '/<span>/',
              '/<\/span>/',
          ],
          '',
          $article->content
      );

   //  $article->content = $article->old_content;

      $article->save();

  });