1. *

   ---

   * * @param string $string * The string to be transformed. * @param array $allowed_tags * (optional) If supplied, a list of tags that will be transformed. If * omitted, all supported tags are transformed. * * @return string * The transformed string. */ public static function htmlToText($string, $allowed_tags = NULL) { // Cache list of supported tags. if (empty(static::$supportedTags)) { static::$supportedTags = ['a', 'em', 'i', 'strong', 'b', 'br', 'p', 'blockquote', 'ul', 'ol', 'li', 'dl', 'dt', 'dd', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', ]; } // Make sure only supported tags are kept. $allowed_tags = isset($allowed_tags) ? array_intersect(static::$supportedTags, $allowed_tags) : static::$supportedTags; // Make sure tags, entities and attributes are well-formed and properly // nested. $string = Html::normalize(Xss::filter($string, $allowed_tags)); // Apply inline styles. $string = preg_replace('! +)[^>]*)?>!i', '/', $string); $string = preg_replace('! +)[^>]*)?>!i', '*', $string); // Replace inline tags with the text of link and a footnote. // 'See the Drupal site' becomes // 'See the Drupal site [1]' with the URL included as a footnote. static::htmlToMailUrls(NULL, TRUE); $pattern = '@(]+?href="([^"]*)"[^>]*?>(.+?))@i'; $string = preg_replace_callback($pattern, [static::class, 'htmlToMailUrls'], $string); $urls = static::htmlToMailUrls(); $footnotes = ''; if (count($urls)) { $footnotes .= "\n"; for ($i = 0, $max = count($urls); $i < $max; $i++) { $footnotes .= '[' . ($i + 1) . '] ' . $urls[$i] . "\n"; } } // Split tags from text. $split = preg_split('/<([^>]+?)>/', $string, -1, PREG_SPLIT_DELIM_CAPTURE); // Note: PHP ensures the array consists of alternating delimiters and // literals and begins and ends with a literal (inserting $null as // required). // Odd/even counter (tag or no tag). $tag = FALSE; $output = ''; // All current indentation string chunks. $indent = []; // Array of counters for opened lists. $lists = []; foreach ($split as $value) { // Holds a string ready to be formatted and output. $chunk = NULL; // Process HTML tags (but don't output any literally). if ($tag) { [$tagname] = explode(' ', strtolower($value), 2); switch ($tagname) { // List counters. case 'ul': array_unshift($lists, '*'); break; case 'ol': array_unshift($lists, 1); break; case '/ul': case '/ol': array_shift($lists); // Ensure blank new-line. $chunk = ''; break; // Quotation/list markers, non-fancy headers. case 'blockquote': // Format=flowed indentation cannot be mixed with lists. $indent[] = count($lists) ? ' "' : '>'; break; case 'li': $indent[] = isset($lists[0]) && is_numeric($lists[0]) ? ' ' . $lists[0]++ . ') ' : ' * '; break; case 'dd': $indent[] = ' '; break; case 'h3': $indent[] = '.... '; break; case 'h4': $indent[] = '.. '; break; case '/blockquote': if (count($lists)) { // Append closing quote for inline quotes (immediately). $output = rtrim($output, "> \n") . "\"\n"; // Ensure blank new-line. $chunk = ''; } // Intentional fall-through to the processing for '/li' and '/dd'. case '/li': case '/dd': array_pop($indent); break; case '/h3': case '/h4': array_pop($indent); // Intentional fall-through to the processing for '/h5' and '/h6'. case '/h5': case '/h6': // Ensure blank new-line. $chunk = ''; break; // Fancy headers. case 'h1': $indent[] = '======== '; break; case 'h2': $indent[] = '-------- '; break; case '/h1': case '/h2': // Pad the line with dashes. $output = static::htmlToTextPad($output, ($tagname == '/h1') ? '=' : '-', ' '); array_pop($indent); // Ensure blank new-line. $chunk = ''; break; // Horizontal rulers. case 'hr': // Insert immediately. $output .= static::wrapMail('', implode('', $indent)) . "\n"; $output = static::htmlToTextPad($output, '-'); break; // Paragraphs and definition lists. case '/p': case '/dl': // Ensure blank new-line. $chunk = ''; break; } } // Process blocks of text. else { // Convert inline HTML text to plain text; not removing line-breaks or // white-space, since that breaks newlines when sanitizing plain-text. $value = trim(Html::decodeEntities($value)); if (mb_strlen($value)) { $chunk = $value; } } // See if there is something waiting to be output. if (isset($chunk)) { $line_endings = Settings::get('mail_line_endings', PHP_EOL); // Format it and apply the current indentation. $output .= static::wrapMail($chunk, implode('', $indent)) . $line_endings; // Remove non-quotation markers from indentation. $indent = array_map('\Drupal\Core\Mail\MailFormatHelper::htmlToTextClean', $indent); } $tag = !$tag; } return $output . $footnotes; } /** * Wraps words on a single line. * * Callback for array_walk() within * \Drupal\Core\Mail\MailFormatHelper::wrapMail(). * * Note that we are skipping MIME content header lines, because attached * files, especially applications, could have long MIME types or long * filenames which result in line length longer than the 77 characters limit * and wrapping that line will break the email format. For instance, the * attached file hello_drupal.docx will produce the following Content-Type: * @code * Content-Type: * application/vnd.openxmlformats-officedocument.wordprocessingml.document; * name="hello_drupal.docx" * @endcode */ protected static function wrapMailLine(&$line, $key, $values) { $line_is_mime_header = FALSE; $mime_headers = [ 'Content-Type', 'Content-Transfer-Encoding', 'Content-Disposition', 'Content-Description', ]; // Do not break MIME headers which could be longer than 77 characters. foreach ($mime_headers as $header) { if (str_starts_with($line, $header . ': ')) { $line_is_mime_header = TRUE; break; } } if (!$line_is_mime_header) { // Use soft-breaks only for purely quoted or un-indented text. $line = wordwrap($line, 77 - $values['length'], $values['soft'] ? " \n" : "\n"); } // Break really long words at the maximum width allowed. $line = wordwrap($line, 996 - $values['length'], $values['soft'] ? " \n" : "\n", TRUE); } /** * Keeps track of URLs and replaces them with placeholder tokens. * * Callback for preg_replace_callback() within * \Drupal\Core\Mail\MailFormatHelper::htmlToText(). */ protected static function htmlToMailUrls($match = NULL, $reset = FALSE) { // @todo Use request context instead. global $base_url, $base_path; if ($reset) { // Reset internal URL list. static::$urls = []; } else { if (empty(static::$regexp)) { static::$regexp = '@^' . preg_quote($base_path, '@') . '@'; } if ($match) { [, , $url, $label] = $match; // Ensure all URLs are absolute. static::$urls[] = strpos($url, '://') ? $url : preg_replace(static::$regexp, $base_url . '/', $url); return $label . ' [' . count(static::$urls) . ']'; } } return static::$urls; } /** * Replaces non-quotation markers from a piece of indentation with spaces. * * Callback for array_map() within * \Drupal\Core\Mail\MailFormatHelper::htmlToText(). */ protected static function htmlToTextClean($indent) { return preg_replace('/[^>]/', ' ', $indent); } /** * Pads the last line with the given character. * * @param string $text * The text to pad. * @param string $pad * The character to pad the end of the string with. * @param string $prefix * (optional) Prefix to add to the string. * * @return string * The padded string. * * @see \Drupal\Core\Mail\MailFormatHelper::htmlToText() */ protected static function htmlToTextPad($text, $pad, $prefix = '') { // Remove last line break. $text = substr($text, 0, -1); // Calculate needed padding space and add it. if (($p = strrpos($text, "\n")) === FALSE) { $p = -1; } $n = max(0, 79 - (strlen($text) - $p) - strlen($prefix)); // Add prefix and padding, and restore linebreak. return $text . $prefix . str_repeat($pad, $n) . "\n"; } }