grzanieplus.pl/plugins/stMailPlugin/lib/stHtml2Text.php

<?php

/* * ****************************************************************************
 * Copyright (c) 2010 Jevon Wright and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Jevon Wright - initial API and implementation
 * ************************************************************************** */

class stHtml2Text
{

   /**
    * Tries to convert the given HTML into a plain text format - best suited for
    * e-mail display, etc.
    *
    * <p>In particular, it tries to maintain the following features:
    * <ul>
    *   <li>Links are maintained, with the 'href' copied over
    *   <li>Information in the &lt;head&gt; is lost
    * </ul>
    *
    * @param html the input HTML
    * @return the HTML converted, as best as possible, to text
    */
   public static function convert($html)
   {
      $html = self::fixNewLines($html);

      $doc = new DOMDocument();

      $html = '<?xml encoding="UTF-8">'.$html;

      if (!$doc->loadHTML($html))
      {
         throw new sfException("Could not load HTML - badly formed?");
      }

      foreach ($doc->childNodes as $item)
      {
         if ($item->nodeType == XML_PI_NODE)
         {
            $doc->removeChild($item); // remove hack
         }
      }

      $output = self::iterateOverNode($doc);

      // remove leading and trailing spaces on each line
      $output = preg_replace("/[ \t]*\n[ \t]*/im", "\n", $output);

      // remove leading and trailing whitespace
      $output = trim($output);

      return $output;
   }

   /**
    * Unify newlines; in particular, \r\n becomes \n, and
    * then \r becomes \n. This means that all newlines (Unix, Windows, Mac)
    * all become \ns.
    *
    * @param text text with any number of \r, \r\n and \n combinations
    * @return the fixed text
    */
   protected static function fixNewLines($text)
   {
      // replace \r\n to \n
      $text = str_replace("\r\n", "\n", $text);
      // remove \rs
      $text = str_replace("\r", "\n", $text);

      return $text;
   }

   protected static function nextChildName($node)
   {
      // get the next child
      $nextNode = $node->nextSibling;
      while ($nextNode != null)
      {
         if ($nextNode instanceof DOMElement)
         {
            break;
         }
         $nextNode = $nextNode->nextSibling;
      }
      $nextName = null;
      if ($nextNode instanceof DOMElement && $nextNode != null)
      {
         $nextName = strtolower($nextNode->nodeName);
      }

      return $nextName;
   }

   protected static function getHasParentNodeName(DomElement $node, $name)
   {
      return $node->parentNode ? $node->parentNode->nodeName == $name : null;
   }

   protected static function getHasChildNodeName(DomElement $node, $name)
   {
      if ($node->childNodes)
      {
         foreach ($node->childNodes as $child_node)
         {
            if ($child_node->nodeName == $name)
            {
               return true;
            }
         }
      }

      return false;
   }

   protected static function prevChildName($node)
   {
      // get the previous child
      $nextNode = $node->previousSibling;
      while ($nextNode != null)
      {
         if ($nextNode instanceof DOMElement)
         {
            break;
         }
         $nextNode = $nextNode->previousSibling;
      }
      $nextName = null;
      if ($nextNode instanceof DOMElement && $nextNode != null)
      {
         $nextName = strtolower($nextNode->nodeName);
      }

      return $nextName;
   }

   protected static function iterateOverNode($node)
   {
      if ($node instanceof DOMText)
      {
         return preg_replace("/\\s+/im", " ", $node->wholeText);
      }
      if ($node instanceof DOMDocumentType)
      {
         // ignore
         return "";
      }

      $nextName = self::nextChildName($node);
      $prevName = self::prevChildName($node);

      $name = strtolower($node->nodeName);

      // start whitespace
      switch ($name)
      {
         case "hr":
            return "------\n";

         case "style":
         case "head":
         case "title":
         case "meta":
         case "script":
            // ignore these tags
            return "";

         case "h1":
         case "h2":
         case "h3":
         case "h4":
         case "h5":
         case "h6":
            // add two newlines
            $output = "\n";
            break;

         case "li":
            $output = "\n - ";
            break;

         case "p":
         case "div":
            // add one line
            $output = "\n";
            break;

         default:
            // print out contents of unknown tags
            $output = "";
            break;
      }

      // debug
      //$output .= "[$name,$nextName]";

      for ($i = 0; $i < $node->childNodes->length; $i++)
      {
         $n = $node->childNodes->item($i);

         $text = self::iterateOverNode($n);

         $output .= $text;
      }

      // end whitespace
      switch ($name)
      {
         case "style":
         case "head":
         case "title":
         case "meta":
         case "script":
            // ignore these tags
            return "";

         case "h1":
         case "h2":
         case "h3":
         case "h4":
         case "h5":
         case "h6":
         case "li":
            $output .= "\n";
            break;

         case "p":
         case "br":
            // add one line
            if ($nextName != "div")
               $output .= "\n";
            break;

         case "div":
            // add one line only if the next child isn't a div
            if ($nextName != "div" && $nextName != null)
               $output .= "\n";
            break;

         case "a":
            // links are returned in [text](link) format
            $href = $node->getAttribute("href");
            if ($href == null)
            {
               // it doesn't link anywhere
               if ($node->getAttribute("name") != null)
               {
                  $output = "[$output]";
               }
            }
            else
            {
               if ($href == $output)
               {
                  // link to the same address: just use link
                  $output;
               }
               else
               {
                  // replace it
                  $output = "[$output]($href)";
               }
            }

            // does the next node require additional whitespace?
            switch ($nextName)
            {
               case "h1": case "h2": case "h3": case "h4": case "h5": case "h6":
                  $output .= "\n";
                  break;
            }

         default:
         // do nothing
      }

      return $output;
   }

}