text_summary

text_summary($text, $format = NULL, $size = NULL)

function text_summary($text, $format = NULL, $size = NULL) {

  if (!isset($size)) {
    $size = \Drupal::config('text.settings')->get('default_summary_length');
  }

  // Find where the delimiter is in the body
  $delimiter = strpos($text, '<!--break-->');

  // If the size is zero, and there is no delimiter, the entire body is the summary.
  if ($size == 0 && $delimiter === FALSE) {
    return $text;
  }

  // If a valid delimiter has been specified, use it to chop off the summary.
  if ($delimiter !== FALSE) {
    return substr($text, 0, $delimiter);
  }

  // Retrieve the filters of the specified text format, if any.
  if (isset($format)) {
    $filters = FilterFormat::load($format)->filters();
    // If the specified format does not exist, return nothing. $text is already
    // filtered text, but the remainder of this function will not be able to
    // ensure a sane and secure summary.
    if (!$filters) {
      return '';
    }
  }

  // If we have a short body, the entire body is the summary.
  if (Unicode::strlen($text) <= $size) {
    return $text;
  }

  // If the delimiter has not been specified, try to split at paragraph or
  // sentence boundaries.

  // The summary may not be longer than maximum length specified. Initial slice.
  $summary = Unicode::truncate($text, $size);

  // Store the actual length of the UTF8 string -- which might not be the same
  // as $size.
  $max_rpos = strlen($summary);

  // How much to cut off the end of the summary so that it doesn't end in the
  // middle of a paragraph, sentence, or word.
  // Initialize it to maximum in order to find the minimum.
  $min_rpos = $max_rpos;

  // Store the reverse of the summary. We use strpos on the reversed needle and
  // haystack for speed and convenience.
  $reversed = strrev($summary);

  // Build an array of arrays of break points grouped by preference.
  $break_points = array();

  // A paragraph near the end of sliced summary is most preferable.
  $break_points[] = array('</p>' => 0);

  // If no complete paragraph then treat line breaks as paragraphs.
  $line_breaks = array('<br />' => 6, '<br>' => 4);
  // Newline only indicates a line break if line break converter
  // filter is present.
  if (isset($format) && $filters->has('filter_autop') && $filters->get('filter_autop')->status) {
    $line_breaks["\n"] = 1;
  }
  $break_points[] = $line_breaks;

  // If the first paragraph is too long, split at the end of a sentence.
  $break_points[] = array('. ' => 1, '! ' => 1, '? ' => 1, '。' => 0, '؟ ' => 1);

  // Iterate over the groups of break points until a break point is found.
  foreach ($break_points as $points) {
    // Look for each break point, starting at the end of the summary.
    foreach ($points as $point => $offset) {
      // The summary is already reversed, but the break point isn't.
      $rpos = strpos($reversed, strrev($point));
      if ($rpos !== FALSE) {
        $min_rpos = min($rpos + $offset, $min_rpos);
      }
    }

    // If a break point was found in this group, slice and stop searching.
    if ($min_rpos !== $max_rpos) {
      // Don't slice with length 0. Length must be <0 to slice from RHS.
      $summary = ($min_rpos === 0) ? $summary : substr($summary, 0, 0 - $min_rpos);
      break;
    }
  }

  // If the htmlcorrector filter is present, apply it to the generated summary.
  if (isset($format) && $filters->has('filter_htmlcorrector') && $filters->get('filter_htmlcorrector')->status) {
    $summary = Html::normalize($summary);
  }

  return $summary;
}