I'm looking for a way to split a string containing HTML in to two halves. Requirements:
- Split a string by a number of chars
- Must not split in the middle of a word
- Must not include HTML chars when calculating where to split the string
For example take the following string:
<p>This is a test string that contains <strong>HTML</strong> tags and text content. This string needs to be split without slicing through the <em>middle</em> of a word and must preserve the validity of the HTML, i.e. not split in the middle of a tag, and make sure closing tags are respected correctly.</p>
Say I want to split at char position 39, middle of word HTML (not counting html), I would want the function to split the string in to the following two parts:
<p>This is a test string that contains <strong>HTML</strong></p>
and
<p>tags and text content. This string needs to be split without slicing through the <em>middle</em> of a word and must preserve the validity of the HTML, i.e. not split in the middle of a tag, and make sure closing tags are respected correctly.</p>
Notice in the above two example results I would require the the HTML validity be respected, so the closing </strong> and </p> tags were added. Also a starting <p> tag was added to second half as one it closed at the end of the string.
I found this function on StackOverflow to truncate a string by a number of text chars and preserve HTML, but it only goes halfway to want I need, as I need to split in to two halves.
function printTruncated($maxLength, $html)
{
$printedLength = 0;
$position = 0;
$tags = array();
while ($printedLength < $maxLength && preg_match('{</?([a-z]+)[^>]*>|&#?[a-zA-Z0-9]+;}', $html, $match, PREG_OFFSET_CAPTURE, $position))
{
list($tag, $tagPosition) = $match[0];
// Print text leading up to the tag.
$str = substr($html, $position, $tagPosition - $position);
if ($printedLength + strlen($str) > $maxLength)
{
print(substr($str, 0, $maxLength - $printedLength));
$printedLength = $maxLength;
break;
}
print($str);
$printedLength += strlen($str);
if ($tag[0] == '&')
{
// Handle the entity.
print($tag);
$printedLength++;
}
else
{
// Handle the tag.
$tagName = $match[1][0];
if ($tag[1] == '/')
{
// This is a closing tag.
$openingTag = array_pop($tags);
assert($openingTag == $tagName); // check that tags are properly nested.
print($tag);
}
else if ($tag[strlen($tag) - 2] == '/')
{
// Self-closing tag.
print($tag);
}
else
{
// Opening tag.
print($tag);
$tags[] = $tagName;
}
}
// Continue after the tag.
$position = $tagPosition + strlen($tag);
}
// Print any remaining text.
if ($printedLength < $maxLength && $position < strlen($html))
print(substr($html, $position, $maxLength - $printedLength));
// Close any open tags.
while (!empty($tags))
printf('</%s>', array_pop($tags));
}
