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Editing: rcube_html2text.php
<?php /** +-----------------------------------------------------------------------+ | This file is part of the Roundcube Webmail client | | | | Copyright (C) The Roundcube Dev Team | | Copyright (c) 2005-2007, Jon Abernathy <jon@chuggnutt.com> | | | | Licensed under the GNU General Public License version 3 or | | any later version with exceptions for skins & plugins. | | See the README file for a full license statement. | | | | PURPOSE: | | Converts HTML to formatted plain text (based on html2text class) | +-----------------------------------------------------------------------+ | Author: Thomas Bruederli <roundcube@gmail.com> | | Author: Aleksander Machniak <alec@alec.pl> | | Author: Jon Abernathy <jon@chuggnutt.com> | +-----------------------------------------------------------------------+ */ /** * Takes HTML and converts it to formatted, plain text. * * Thanks to Alexander Krug (https://www.krugar.de/) to pointing out and * correcting an error in the regexp search array. Fixed 7/30/03. * * Updated set_html() function's file reading mechanism, 9/25/03. * * Thanks to Joss Sanglier (https://www.dancingbear.co.uk/) for adding * several more HTML entity codes to the $search and $replace arrays. * Updated 11/7/03. * * Thanks to Darius Kasperavicius (http://www.dar.dar.lt/) for * suggesting the addition of $allowed_tags and its supporting function * (which I slightly modified). Updated 3/12/04. * * Thanks to Justin Dearing for pointing out that a replacement for the * <TH> tag was missing, and suggesting an appropriate fix. * Updated 8/25/04. * * Thanks to Mathieu Collas (http://www.myefarm.com/) for finding a * display/formatting bug in the _build_link_list() function: email * readers would show the left bracket and number ("[1") as part of the * rendered email address. * Updated 12/16/04. * * Thanks to Wojciech Bajon (https://histeria.pl/) for submitting code * to handle relative links, which I hadn't considered. I modified his * code a bit to handle normal HTTP links and MAILTO links. Also for * suggesting three additional HTML entity codes to search for. * Updated 03/02/05. * * Thanks to Jacob Chandler for pointing out another link condition * for the _build_link_list() function: "https". * Updated 04/06/05. * * Thanks to Marc Bertrand (https://www.dresdensky.com/) for * suggesting a revision to the word wrapping functionality; if you * specify a $width of 0 or less, word wrapping will be ignored. * Updated 11/02/06. * * *** Big housecleaning updates below: * * Thanks to Colin Brown (http://www.sparkdriver.co.uk/) for * suggesting the fix to handle </li> and blank lines (whitespace). * Christian Basedau (http://www.movetheweb.de/) also suggested the * blank lines fix. * * Special thanks to Marcus Bointon (https://www.synchromedia.co.uk/), * Christian Basedau, Norbert Laposa (https://norbertlaposa.com/), * Bas van de Weijer, and Marijn van Butselaar * for pointing out my glaring error in the <th> handling. Marcus also * supplied a host of fixes. * * Thanks to Jeffrey Silverman (http://www.newtnotes.com/) for pointing * out that extra spaces should be compressed--a problem addressed with * Marcus Bointon's fixes but that I had not yet incorporated. * * Thanks to Daniel Schledermann (https://www.typoconsult.dk/) for * suggesting a valuable fix with <a> tag handling. * * Thanks to Wojciech Bajon (again!) for suggesting fixes and additions, * including the <a> tag handling that Daniel Schledermann pointed * out but that I had not yet incorporated. I haven't (yet) * incorporated all of Wojciech's changes, though I may at some * future time. * * *** End of the housecleaning updates. Updated 08/08/07. */ /** * Converts HTML to formatted plain text * * @package Framework * @subpackage Utils */ class rcube_html2text { const LINKS_NONE = 0; const LINKS_END = 1; const LINKS_INLINE = 2; const LINKS_DEFAULT = self::LINKS_END; /** * Contains the HTML content to convert. * * @var string $html */ protected $html; /** * Contains the converted, formatted text. * * @var string $text */ protected $text; /** * Maximum width of the formatted text, in columns. * * Set this value to 0 (or less) to ignore word wrapping * and not constrain text to a fixed-width column. * * @var int $width */ protected $width = 70; /** * Target character encoding for output text * * @var string $charset */ protected $charset = 'UTF-8'; /** * List of preg* regular expression patterns to search for, * used in conjunction with $replace. * * @var array $search * @see self::$replace */ protected $search = [ '/\r/', // Non-legal carriage return '/\n*<\/?html>\n*/is', // <html> '/\n*<head[^>]*>.*?<\/head>\n*/is', // <head> '/\n*<script[^>]*>.*?<\/script>\n*/is', // <script> '/\n*<style[^>]*>.*?<\/style>\n*/is', // <style> '/[\n\t]+/', // Newlines and tabs '/<p[^>]*>/i', // <p> '/<\/p>[\s\n\t]*<div[^>]*>/i', // </p> before <div> '/<br[^>]*>[\s\n\t]*<div[^>]*>/i', // <br> before <div> '/<br[^>]*>\s*/i', // <br> '/<i[^>]*>(.*?)<\/i>/i', // <i> '/<em[^>]*>(.*?)<\/em>/i', // <em> '/(<ul[^>]*>|<\/ul>)/i', // <ul> and </ul> '/(<ol[^>]*>|<\/ol>)/i', // <ol> and </ol> '/<li[^>]*>(.*?)<\/li>/i', // <li> and </li> '/<li[^>]*>/i', // <li> '/<hr[^>]*>/i', // <hr> '/<div[^>]*>/i', // <div> '/(<table[^>]*>|<\/table>)/i', // <table> and </table> '/(<tr[^>]*>|<\/tr>)/i', // <tr> and </tr> '/<td[^>]*>(.*?)<\/td>/i', // <td> and </td> ]; /** * List of pattern replacements corresponding to patterns searched. * * @var array $replace * @see self::$search */ protected $replace = [ '', // Non-legal carriage return '', // <html>|</html> '', // <head> '', // <script> '', // <style> ' ', // Newlines and tabs "\n\n", // <p> "\n<div>", // </p> before <div> '<div>', // <br> before <div> "\n", // <br> '_\\1_', // <i> '_\\1_', // <em> "\n\n", // <ul> and </ul> "\n\n", // <ol> and </ol> "\t* \\1\n", // <li> and </li> "\n\t* ", // <li> "\n-------------------------\n", // <hr> "<div>\n", // <div> "\n\n", // <table> and </table> "\n", // <tr> and </tr> "\t\t\\1\n", // <td> and </td> ]; /** * List of preg* regular expression patterns to search for, * used in conjunction with $ent_replace. * * @var array $ent_search * @see self::$ent_replace */ protected $ent_search = [ '/&(nbsp|#160);/i', // Non-breaking space '/&(quot|rdquo|ldquo|#8220|#8221|#147|#148);/i', // Double quotes '/&(apos|rsquo|lsquo|#8216|#8217);/i', // Single quotes '/>/i', // Greater-than '/</i', // Less-than '/&(copy|#169);/i', // Copyright '/&(trade|#8482|#153);/i', // Trademark '/&(reg|#174);/i', // Registered '/&(mdash|#151|#8212);/i', // mdash '/&(ndash|minus|#8211|#8722);/i', // ndash '/&(bull|#149|#8226);/i', // Bullet '/&(pound|#163);/i', // Pound sign '/&(euro|#8364);/i', // Euro sign '/&(amp|#38);/i', // Ampersand: see _converter() '/[ ]{2,}/', // Runs of spaces, post-handling ]; /** * List of pattern replacements corresponding to patterns searched. * * @var array $ent_replace * @see self::$ent_search */ protected $ent_replace = [ "\xC2\xA0", // Non-breaking space '"', // Double quotes "'", // Single quotes '>', '<', '(c)', '(tm)', '(R)', '--', '-', '*', '£', 'EUR', // Euro sign. € '|+|amp|+|', // Ampersand: see _converter() ' ', // Runs of spaces, post-handling ]; /** * List of preg* regular expression patterns to search for * and replace using callback function. * * @var array $callback_search */ protected $callback_search = [ '/<(a) [^>]*href=("|\')([^"\']+)\2[^>]*>(.*?)<\/a>/i', // <a href=""> '/<(h)[123456]( [^>]*)?>(.*?)<\/h[123456]>/i', // h1 - h6 '/<(th)( [^>]*)?>(.*?)<\/th>/i', // <th> and </th> ]; /** * List of preg* regular expression patterns to search for in PRE body, * used in conjunction with $pre_replace. * * @var array $pre_search * @see self::$pre_replace */ protected $pre_search = [ "/\n/", "/\t/", '/ /', '/<pre[^>]*>/', '/<\/pre>/' ]; /** * List of pattern replacements corresponding to patterns searched for PRE body. * * @var array $pre_replace * @see self::$pre_search */ protected $pre_replace = [ '<br>', ' ', ' ', '', '' ]; /** * Temp. PRE content * * @var string $pre_content */ protected $pre_content = ''; /** * Contains a list of HTML tags to allow in the resulting text. * * @var string $allowed_tags * @see self::set_allowed_tags() */ protected $allowed_tags = ''; /** * Contains the base URL that relative links should resolve to. * * @var string $url */ protected $url; /** * Indicates whether content in the $html variable has been converted yet. * * @var bool $_converted * @see self::$html * @see self::$text */ protected $_converted = false; /** * Contains URL addresses from links to be rendered in plain text. * * @var array $_link_list * @see self::_build_link_list() */ protected $_link_list = []; /** * Links handling. * - 0 if links should be removed * - 1 if a table of link URLs should be listed after the text * - 2 if the link should be displayed to the original point in the text they appeared * * @var int $_links_mode */ protected $_links_mode = 1; /** * Constructor. * * If the HTML source string (or file) is supplied, the class * will instantiate with that source propagated, all that has * to be done it to call get_text(). * * @param string $source HTML content * @param bool $from_file Indicates $source is a file to pull content from * @param bool|int $links_mode Links handling mode * @param int $width Maximum width of the formatted text, 0 for no limit */ function __construct($source = '', $from_file = false, $links_mode = self::LINKS_DEFAULT, $width = 75, $charset = 'UTF-8') { if (!empty($source)) { $this->set_html($source, $from_file); } $this->set_base_url(); $this->set_links_mode($links_mode); $this->width = $width; $this->charset = $charset; } /** * Sets the links behavior mode * * @param bool|int $mode */ private function set_links_mode($mode) { $allowed = [ self::LINKS_NONE, self::LINKS_END, self::LINKS_INLINE ]; if (!in_array((int) $mode, $allowed)) { $this->_links_mode = self::LINKS_DEFAULT; return; } $this->_links_mode = (int) $mode; } /** * Loads source HTML into memory, either from $source string or a file. * * @param string $source HTML content * @param bool $from_file Indicates $source is a file to pull content from */ function set_html($source, $from_file = false) { if ($from_file && file_exists($source)) { $this->html = file_get_contents($source); } else { $this->html = $source; } $this->_converted = false; } /** * Returns the text, converted from HTML. * * @return string Plain text */ function get_text() { if (!$this->_converted) { $this->_convert(); } return $this->text; } /** * Prints the text, converted from HTML. */ function print_text() { print $this->get_text(); } /** * Sets the allowed HTML tags to pass through to the resulting text. * * Tags should be in the form "<p>", with no corresponding closing tag. */ function set_allowed_tags($allowed_tags = '') { if (!empty($allowed_tags)) { $this->allowed_tags = $allowed_tags; } } /** * Sets a base URL to handle relative links. */ function set_base_url($url = '') { if (empty($url)) { if (!empty($_SERVER['HTTP_HOST'])) { $this->url = 'http://' . $_SERVER['HTTP_HOST']; } else { $this->url = ''; } } else { // Strip any trailing slashes for consistency (relative // URLs may already start with a slash like "/file.html") if (substr($url, -1) == '/') { $url = substr($url, 0, -1); } $this->url = $url; } } /** * Workhorse function that does actual conversion (calls _converter() method). */ protected function _convert() { // Variables used for building the link list $this->_link_list = []; $text = $this->html; // Convert HTML to TXT $this->_converter($text); // Add link list if (!empty($this->_link_list)) { $text .= "\n\nLinks:\n------\n"; foreach ($this->_link_list as $idx => $url) { $text .= '[' . ($idx+1) . '] ' . $url . "\n"; } } $this->text = $text; $this->_converted = true; } /** * Workhorse function that does actual conversion. * * First performs custom tag replacement specified by $search and * $replace arrays. Then strips any remaining HTML tags, reduces whitespace * and newlines to a readable format, and word wraps the text to * $width characters. * * @param string &$text Reference to HTML content string */ protected function _converter(&$text) { // Convert <BLOCKQUOTE> (before PRE!) $this->_convert_blockquotes($text); // Convert <PRE> $this->_convert_pre($text); // Remove body tag and anything before // We used to have '/^.*<body[^>]*>\n*/is' in $this->search, but this requires // high pcre.backtrack_limit setting when converting long HTML strings (#8137) if (($pos = stripos($text, '<body')) !== false) { $pos = strpos($text, '>', $pos); $text = substr($text, $pos + 1); $text = ltrim($text); } // Run our defined tags search-and-replace $text = preg_replace($this->search, $this->replace, $text); // Run our defined tags search-and-replace with callback $text = preg_replace_callback($this->callback_search, [$this, 'tags_preg_callback'], $text); // Strip any other HTML tags $text = strip_tags($text, $this->allowed_tags); // Run our defined entities/characters search-and-replace $text = preg_replace($this->ent_search, $this->ent_replace, $text); // Replace known html entities $text = html_entity_decode($text, ENT_QUOTES, $this->charset); // Replace unicode nbsp to regular spaces $text = preg_replace('/\xC2\xA0/', ' ', $text); // Remove unknown/unhandled entities (this cannot be done in search-and-replace block) $text = preg_replace('/&([a-zA-Z0-9]{2,6}|#[0-9]{2,4});/', '', $text); // Convert "|+|amp|+|" into "&", need to be done after handling of unknown entities // This properly handles situation of "&quot;" in input string $text = str_replace('|+|amp|+|', '&', $text); // Bring down number of empty lines to 2 max $text = preg_replace("/\n\s+\n/", "\n\n", $text); $text = preg_replace("/[\n]{3,}/", "\n\n", $text); // remove leading empty lines (can be produced by e.g. P tag on the beginning) $text = ltrim($text, "\n"); // Wrap the text to a readable format // for PHP versions >= 4.0.2. Default width is 75 // If width is 0 or less, don't wrap the text. if ($this->width > 0) { $text = wordwrap($text, $this->width); } } /** * Helper function called by preg_replace() on link replacement. * * Maintains an internal list of links to be displayed at the end of the * text, with numeric indices or simply the link to the original point in the text they * appeared. Also makes an effort at identifying and handling absolute * and relative links. * * @param string $link URL of the link * @param string $display Part of the text to associate number with */ protected function _handle_link($link, $display) { if (empty($link)) { return $display; } // Ignored link types if (preg_match('!^(javascript:|mailto:|#)!i', $link)) { return $display; } // skip links with href == content (#1490434) if ($link === $display) { return $display; } if (preg_match('!^([a-z][a-z0-9.+-]+:)!i', $link)) { $url = $link; } else { $url = $this->url; if (substr($link, 0, 1) != '/') { $url .= '/'; } $url .= "$link"; } if (self::LINKS_NONE === $this->_links_mode) { // When not using link list use URL if there's no content (#5795) // The content here is HTML, convert it to text first $h2t = new rcube_html2text($display, false, false, 1024, $this->charset); $display = $h2t->get_text(); if (empty($display) && preg_match('!^([a-z][a-z0-9.+-]+://)!i', $link)) { return $link; } return $display; } if (self::LINKS_INLINE === $this->_links_mode) { return $this->_build_link_inline($url, $display); } return $this->_build_link_list($url, $display); } /** * Helper function called by _handle_link() on link replacement. * * Displays the link next to the original point in the text they * appeared. * * @param string $url URL of the link * @param string $display linktext */ protected function _build_link_inline($url, $display) { return $display . ' <' . $url . '>'; } /** * Helper function called by _handle_link() on link replacement. * * Maintains an internal list of links to be displayed at the end of the * text, with numeric indices to the original point in the text they * appeared. * * @param string $url URL of the link * @param string $display Part of the text to associate number with */ protected function _build_link_list($url, $display) { if (($index = array_search($url, $this->_link_list)) === false) { $index = count($this->_link_list); $this->_link_list[] = $url; } return $display . ' [' . ($index+1) . ']'; } /** * Helper function for PRE body conversion. * * @param string &$text HTML content */ protected function _convert_pre(&$text) { // get the content of PRE element while (preg_match('/<pre[^>]*>(.*)<\/pre>/ismU', $text, $matches)) { $this->pre_content = $matches[1]; // Run our defined tags search-and-replace with callback $this->pre_content = preg_replace_callback($this->callback_search, [$this, 'tags_preg_callback'], $this->pre_content); // convert the content $this->pre_content = sprintf('<div><br>%s<br></div>', preg_replace($this->pre_search, $this->pre_replace, $this->pre_content)); // replace the content (use callback because content can contain $0 variable) $text = preg_replace_callback('/<pre[^>]*>.*<\/pre>/ismU', [$this, 'pre_preg_callback'], $text, 1); // free memory $this->pre_content = ''; } } /** * Helper function for BLOCKQUOTE body conversion. * * @param string &$text HTML content */ protected function _convert_blockquotes(&$text) { $level = 0; $offset = 0; while (($start = stripos($text, '<blockquote', $offset)) !== false) { $offset = $start + 12; do { $end = stripos($text, '</blockquote>', $offset); $next = stripos($text, '<blockquote', $offset); // nested <blockquote>, skip if ($next !== false && $next < $end) { $offset = $next + 12; $level++; } // nested </blockquote> tag if ($end !== false && $level > 0) { $offset = $end + 12; $level--; } // found matching end tag else if ($end !== false && $level == 0) { $taglen = strpos($text, '>', $start) - $start; $startpos = $start + $taglen + 1; // get blockquote content $body = trim(substr($text, $startpos, $end - $startpos)); // adjust text wrapping width $p_width = $this->width; if ($this->width > 0) $this->width -= 2; // replace content with inner blockquotes $this->_converter($body); // restore text width $this->width = $p_width; // Add citation markers and create <pre> block $body = preg_replace_callback('/((?:^|\n)>*)([^\n]*)/', [$this, 'blockquote_citation_callback'], trim($body)); $body = '<pre>' . htmlspecialchars($body, ENT_COMPAT | ENT_HTML401 | ENT_SUBSTITUTE, $this->charset) . '</pre>'; $text = substr_replace($text, $body . "\n", $start, $end + 13 - $start); $offset = 0; break; } // abort on invalid tag structure (e.g. no closing tag found) else { break; } } while ($end || $next); } } /** * Callback function to correctly add citation markers for blockquote contents */ public function blockquote_citation_callback($m) { $line = ltrim($m[2]); $space = isset($line[0]) && $line[0] == '>' ? '' : ' '; return $m[1] . '>' . $space . $line; } /** * Callback function for preg_replace_callback use. * * @param array $matches PREG matches * * @return string Element content */ public function tags_preg_callback($matches) { switch (strtolower($matches[1])) { case 'th': return $this->_toupper("\t\t". $matches[3] ."\n"); case 'h': return $this->_toupper("\n\n". $matches[3] ."\n\n"); case 'a': // Remove spaces in URL (#1487805) $url = str_replace(' ', '', $matches[3]); $url = html_entity_decode($url, \ENT_HTML5, RCUBE_CHARSET); return $this->_handle_link($url, $matches[4]); } } /** * Callback function for preg_replace_callback use in PRE content handler. * * @param array $matches PREG matches * * @return string PRE content */ public function pre_preg_callback($matches) { return $this->pre_content; } /** * Strtoupper function with HTML tags and entities handling. * * @param string $str Text to convert * * @return string Converted text */ private function _toupper($str) { // string can containing HTML tags $chunks = preg_split('/(<[^>]*>)/', $str, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE); // convert toupper only the text between HTML tags foreach ($chunks as $idx => $chunk) { if ($chunk[0] != '<') { $chunks[$idx] = $this->_strtoupper($chunk); } } return implode($chunks); } /** * Strtoupper multibyte wrapper function with HTML entities handling. * * @param string $str Text to convert * * @return string Converted text */ private function _strtoupper($str) { $str = html_entity_decode($str, ENT_COMPAT, $this->charset); $str = mb_strtoupper($str); $str = htmlspecialchars($str, ENT_COMPAT, $this->charset); return $str; } }
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