PHP: Truncate string while preserving HTML tags and whole words

6 Comments on PHP: Truncate string while preserving HTML tags and whole words

1. Scott says:

   December 6, 2011 at 4:43 pm

   I written a Java version of truncateHTML. This version also preserves word boundaries.

   public static String truncateHTML(String text, int length, String suffix) {
   // if the plain text is shorter than the maximum length, return the whole text
   if (text.replaceAll(“”, “”).length() <= length) {
   return text;
   }
   String result = "";
   boolean trimmed = false;
   if (suffix == null) {
   suffix = "…";
   }

   /*
   * This pattern creates tokens, where each line starts with the tag.
   * For example, "One, Two, Three” produces the following:
   * One,
   * Two
   * , Three
   */
   Pattern tagPattern = Pattern.compile(“()?([^]*)”);

   /*
   * Checks for an empty tag, for example img, br, etc.
   */
   Pattern emptyTagPattern = Pattern.compile(“^$”);

   /*
   * Checks for closing tags, allowing leading and ending space inside the brackets
   */
   Pattern closingTagPattern = Pattern.compile(“^$”);

   /*
   * Checks for opening tags, allowing leading and ending space inside the brackets
   */
   Pattern openingTagPattern = Pattern.compile(“^$”);

   /*
   * Find   > …
   */
   Pattern entityPattern = Pattern.compile(“(&[0-9a-z]{2,8};|&#[0-9]{1,7};|[0-9a-f]{1,6};)”);

   // splits all html-tags to scanable lines
   Matcher tagMatcher = tagPattern.matcher(text);
   int numTags = tagMatcher.groupCount();

   int totalLength = suffix.length();
   List openTags = new ArrayList();

   boolean proposingChop = false;
   while (tagMatcher.find()) {
   String tagText = tagMatcher.group(1);
   String plainText = tagMatcher.group(2);

   if (proposingChop &&
   tagText != null && tagText.length() != 0 &&
   plainText != null && plainText.length() != 0) {
   trimmed = true;
   break;
   }

   // if there is any html-tag in this line, handle it and add it (uncounted) to the output
   if (tagText != null && tagText.length() > 0) {
   boolean foundMatch = false;

   // if it’s an “empty element” with or without xhtml-conform closing slash
   Matcher matcher = emptyTagPattern.matcher(tagText);
   if (matcher.find()) {
   foundMatch = true;
   // do nothing
   }

   // closing tag?
   if (!foundMatch) {
   matcher = closingTagPattern.matcher(tagText);
   if (matcher.find()) {
   foundMatch = true;
   // delete tag from openTags list
   String tagName = matcher.group(1);
   openTags.remove(tagName.toLowerCase());
   }
   }

   // opening tag?
   if (!foundMatch) {
   matcher = openingTagPattern.matcher(tagText);
   if (matcher.find()) {
   // add tag to the beginning of openTags list
   String tagName = matcher.group(1);
   openTags.add(0, tagName.toLowerCase());
   }
   }

   // add html-tag to result
   result += tagText;
   }

   // calculate the length of the plain text part of the line; handle entities (e.g.  ) as one character
   int contentLength = plainText.replaceAll(“&[0-9a-z]{2,8};|&#[0-9]{1,7};|[0-9a-f]{1,6};”, ” “).length();
   if (totalLength + contentLength > length) {
   // the number of characters which are left
   int numCharsRemaining = length – totalLength;
   int entitiesLength = 0;
   Matcher entityMatcher = entityPattern.matcher(plainText);
   while (entityMatcher.find()) {
   String entity = entityMatcher.group(1);
   if (numCharsRemaining > 0) {
   numCharsRemaining–;
   entitiesLength += entity.length();
   } else {
   // no more characters left
   break;
   }
   }

   // keep us from chopping words in half
   int proposedChopPosition = numCharsRemaining + entitiesLength;
   int endOfWordPosition = plainText.indexOf(” “, proposedChopPosition-1);
   if (endOfWordPosition == -1) {
   endOfWordPosition = plainText.length();
   }
   int endOfWordOffset = endOfWordPosition – proposedChopPosition;
   if (endOfWordOffset > 6) { // chop the word if it’s extra long
   endOfWordOffset = 0;
   }

   proposedChopPosition = numCharsRemaining + entitiesLength + endOfWordOffset;
   if (plainText.length() >= proposedChopPosition) {
   result += plainText.substring(0, proposedChopPosition);
   proposingChop = true;
   if (proposedChopPosition = length) {
   trimmed = true;
   break;
   }
   }

   for (String openTag : openTags) {
   result += “”;
   }
   if (trimmed) {
   result += suffix;
   }
   return result;
   }

   Reply
   • Jackson says:

     May 28, 2012 at 2:59 am

     Good job Alan Whipple !!!

     Reply
2. Jake says:

   July 15, 2012 at 9:42 am

   Wonderful work. Thank you!

   Reply
3. Cameron Barr says:

   December 12, 2012 at 9:36 am

   Great work! Works like a charm.

   Reply
4. enrmarc says:

   February 20, 2013 at 11:27 am

   Thanks man!

   Reply
5. Joe Corneli says:

   March 13, 2013 at 4:21 pm

   I found a slight modification to this code at http://www.gsdesign.ro/blog/cut-html-string-without-breaking-the-tags/#comment-487407314 (by Alex Prokop). It improves the code in the case $empty = false. I’ve tested it and it seems like a necessary fix for some complicated HTML. I thought I should mention it to, in case you want to add the fix into your version of the function.

   Reply