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<?php
/*************************************************************************
* *
* Converts HTML to formatted plain text *
* *
* Portions Copyright (c) 2005-2007 Jon Abernathy <jon@chuggnutt.com> *
* *
* This script is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* The GNU General Public License can be found at *
* http://www.gnu.org/copyleft/gpl.html. *
* *
* This script is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
*************************************************************************/
/**
* Converts HTML to formatted plain text
*/
class Html2Text
{
/**
* Contains the HTML content to convert.
*
* @type string
*/
protected $html;
/**
* Contains the converted, formatted text.
*
* @type string
*/
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.
*
* @type integer
*/
protected $width = 70;
/**
* List of preg* regular expression patterns to search for,
* used in conjunction with $replace.
*
* @type array
* @see $replace
*/
protected $search = array(
"/\r/", // Non-legal carriage return
"/[\n\t]+/", // Newlines and tabs
'/<head[^>]*>.*?<\/head>/i', // <head>
'/<script[^>]*>.*?<\/script>/i', // <script>s -- which strip_tags supposedly has problems with
'/<style[^>]*>.*?<\/style>/i', // <style>s -- which strip_tags supposedly has problems with
'/<p[^>]*>/i', // <P>
'/<br[^>]*>/i', // <br>
'/<i[^>]*>(.*?)<\/i>/i', // <i>
'/<em[^>]*>(.*?)<\/em>/i', // <em>
'/(<ul[^>]*>|<\/ul>)/i', // <ul> and </ul>
'/(<ol[^>]*>|<\/ol>)/i', // <ol> and </ol>
'/(<dl[^>]*>|<\/dl>)/i', // <dl> and </dl>
'/<li[^>]*>(.*?)<\/li>/i', // <li> and </li>
'/<dd[^>]*>(.*?)<\/dd>/i', // <dd> and </dd>
'/<dt[^>]*>(.*?)<\/dt>/i', // <dt> and </dt>
'/<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>
'/<span class="_html2text_ignore">.+?<\/span>/i' // <span class="_html2text_ignore">...</span>
);
/**
* List of pattern replacements corresponding to patterns searched.
*
* @type array
* @see $search
*/
protected $replace = array(
'', // Non-legal carriage return
' ', // Newlines and tabs
'', // <head>
'', // <script>s -- which strip_tags supposedly has problems with
'', // <style>s -- which strip_tags supposedly has problems with
"\n\n", // <P>
"\n", // <br>
'_\\1_', // <i>
'_\\1_', // <em>
"\n\n", // <ul> and </ul>
"\n\n", // <ol> and </ol>
"\n\n", // <dl> and </dl>
"\t* \\1\n", // <li> and </li>
" \\1\n", // <dd> and </dd>
"\t* \\1", // <dt> and </dt>
"\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>
"" // <span class="_html2text_ignore">...</span>
);
/**
* List of preg* regular expression patterns to search for,
* used in conjunction with $ent_replace.
*
* @type array
* @see $ent_replace
*/
protected $ent_search = array(
'/&(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.
*
* @type array
* @see $ent_search
*/
protected $ent_replace = array(
' ', // 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.
*
* @type array
*/
protected $callback_search = array(
'/<(a) [^>]*href=("|\')([^"\']+)\2([^>]*)>(.*?)<\/a>/i', // <a href="">
'/<(h)[123456]( [^>]*)?>(.*?)<\/h[123456]>/i', // h1 - h6
'/<(b)( [^>]*)?>(.*?)<\/b>/i', // <b>
'/<(strong)( [^>]*)?>(.*?)<\/strong>/i', // <strong>
'/<(th)( [^>]*)?>(.*?)<\/th>/i', // <th> and </th>
);
/**
* List of preg* regular expression patterns to search for in PRE body,
* used in conjunction with $pre_replace.
*
* @type array
* @see $pre_replace
*/
protected $pre_search = array(
"/\n/",
"/\t/",
'/ /',
'/<pre[^>]*>/',
'/<\/pre>/'
);
/**
* List of pattern replacements corresponding to patterns searched for PRE body.
*
* @type array
* @see $pre_search
*/
protected $pre_replace = array(
'<br>',
' ',
' ',
'',
''
);
/**
* Temporary workspace used during PRE processing.
*
* @type string
*/
protected $pre_content = '';
/**
* Contains a list of HTML tags to allow in the resulting text.
*
* @type string
* @see set_allowed_tags()
*/
protected $allowed_tags = '';
/**
* Contains the base URL that relative links should resolve to.
*
* @type string
*/
protected $url;
/**
* Indicates whether content in the $html variable has been converted yet.
*
* @type boolean
* @see $html, $text
*/
protected $_converted = false;
/**
* Contains URL addresses from links to be rendered in plain text.
*
* @type array
* @see _build_link_list()
*/
protected $_link_list = array();
/**
* Various configuration options (able to be set in the constructor)
*
* @type array
*/
protected $_options = array(
// 'none'
// 'inline' (show links inline)
// 'nextline' (show links on the next line)
// 'table' (if a table of link URLs should be listed after the text.
'do_links' => 'inline',
// 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.
'width' => 70,
);
/**
* 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 boolean $from_file Indicates $source is a file to pull content from
* @param array $options Set configuration options
*/
public function __construct($source = '', $from_file = false, $options = array())
{
$this->_options = array_merge($this->_options, $options);
if (!empty($source)) {
$this->set_html($source, $from_file);
}
$this->set_base_url();
}
/**
* Loads source HTML into memory, either from $source string or a file.
*
* @param string $source HTML content
* @param boolean $from_file Indicates $source is a file to pull content from
*/
public function set_html($source, $from_file = false)
{
if ($from_file && file_exists($source)) {
$this->html = file_get_contents($source);
} else {
$this->html = $source;
}
$this->_converted = false;
}
/**
* Returns the text, converted from HTML.
*
* @return string
*/
public function get_text()
{
if (!$this->_converted) {
$this->_convert();
}
return $this->text;
}
/**
* Prints the text, converted from HTML.
*/
public function print_text()
{
print $this->get_text();
}
/**
* Alias to print_text(), operates identically.
*
* @see print_text()
*/
public function p()
{
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.
* @param string $allowed_tags
*/
public function set_allowed_tags($allowed_tags = '')
{
if (!empty($allowed_tags)) {
$this->allowed_tags = $allowed_tags;
}
}
/**
* Sets a base URL to handle relative links.
*
* @param string $url
*/
public function set_base_url($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 = array();
$text = trim(stripslashes($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
* $this->_options['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);
// 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, array($this, '_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);
// 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 eg. 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->_options['width'] > 0) {
$text = wordwrap($text, $this->_options['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 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
* @param null $link_override
* @return string
*/
protected function _build_link_list($link, $display, $link_override = null)
{
$link_method = ($link_override) ? $link_override : $this->_options['do_links'];
if ($link_method == 'none') {
return $display;
}
// Ignored link types
if (preg_match('!^(javascript:|mailto:|#)!i', $link)) {
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 ($link_method == 'table') {
if (($index = array_search($url, $this->_link_list)) === false) {
$index = count($this->_link_list);
$this->_link_list[] = $url;
}
return $display . ' [' . ($index + 1) . ']';
} elseif ($link_method == 'nextline') {
return $display . "\n[" . $url . ']';
} else { // link_method defaults to inline
return $display . ' [' . $url . ']';
}
}
/**
* 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(
$this->callback_search,
array($this, '_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)
$text = preg_replace_callback(
'/<pre[^>]*>.*<\/pre>/ismU',
array($this, '_preg_pre_callback'),
$text,
1
);
// free memory
$this->pre_content = '';
}
}
/**
* Helper function for BLOCKQUOTE body conversion.
*
* @param string $text HTML content
*/
protected function _convert_blockquotes(&$text)
{
if (preg_match_all('/<\/*blockquote[^>]*>/i', $text, $matches, PREG_OFFSET_CAPTURE)) {
$start = 0;
$taglen = 0;
$level = 0;
$diff = 0;
foreach ($matches[0] as $m) {
if ($m[0][0] == '<' && $m[0][1] == '/') {
$level--;
if ($level < 0) {
$level = 0; // malformed HTML: go to next blockquote
} elseif ($level > 0) {
// skip inner blockquote
} else {
$end = $m[1];
$len = $end - $taglen - $start;
// Get blockquote content
$body = substr($text, $start + $taglen - $diff, $len);
// Set text width
$p_width = $this->_options['width'];
if ($this->_options['width'] > 0) $this->_options['width'] -= 2;
// Convert blockquote content
$body = trim($body);
$this->_converter($body);
// Add citation markers and create PRE block
$body = preg_replace('/((^|\n)>*)/', '\\1> ', trim($body));
$body = '<pre>' . htmlspecialchars($body) . '</pre>';
// Re-set text width
$this->_options['width'] = $p_width;
// Replace content
$text = substr($text, 0, $start - $diff)
. $body . substr($text, $end + strlen($m[0]) - $diff);
$diff = $len + $taglen + strlen($m[0]) - strlen($body);
unset($body);
}
} else {
if ($level == 0) {
$start = $m[1];
$taglen = strlen($m[0]);
}
$level++;
}
}
}
}
/**
* Callback function for preg_replace_callback use.
*
* @param array $matches PREG matches
* @return string
*/
protected function _preg_callback($matches)
{
switch (strtolower($matches[1])) {
case 'b':
case 'strong':
return $this->_toupper($matches[3]);
case 'th':
return $this->_toupper("\t\t" . $matches[3] . "\n");
case 'h':
return $this->_toupper("\n\n" . $matches[3] . "\n\n");
case 'a':
// override the link method
$link_override = null;
if (preg_match('/_html2text_link_(\w+)/', $matches[4], $link_override_match)) {
$link_override = $link_override_match[1];
}
// Remove spaces in URL (#1487805)
$url = str_replace(' ', '', $matches[3]);
return $this->_build_link_list($url, $matches[5], $link_override);
}
return '';
}
/**
* Callback function for preg_replace_callback use in PRE content handler.
*
* @param array $matches PREG matches
* @return string
*/
protected function _preg_pre_callback(
/** @noinspection PhpUnusedParameterInspection */
$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 contain HTML tags
$chunks = preg_split('/(<[^>]*>)/', $str, null, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
// convert toupper only the text between HTML tags
foreach ($chunks as $idx => $chunk) {
if ($chunk[0] != '<') {
$chunks[$idx] = $this->_strtoupper($chunk);
}
}
return implode($chunks);
}
/**
* Strtoupper multibyte wrapper function with HTML entities handling.
* Forces mb_strtoupper-call to UTF-8.
*
* @param string $str Text to convert
* @return string Converted text
*/
private function _strtoupper($str)
{
$str = html_entity_decode($str, ENT_COMPAT);
if (function_exists('mb_strtoupper'))
$str = mb_strtoupper($str, 'UTF-8');
else
$str = strtoupper($str);
$str = htmlspecialchars($str, ENT_COMPAT);
return $str;
}
}
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