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<?php
/*************************************************************************
* *
* class.html2text.inc *
* *
*************************************************************************
* *
* Converts HTML to formatted plain text *
* *
* Copyright (c) 2005-2007 Jon Abernathy <jon@chuggnutt.com> *
* All rights reserved. *
* *
* 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. *
* *
* Author(s): Jon Abernathy <jon@chuggnutt.com> *
* *
* Last modified: 08/08/07 *
* *
*************************************************************************/
/**
* Takes HTML and converts it to formatted, plain text.
*
* Thanks to Alexander Krug (http://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 (http://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 (http://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 (http://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 (http://www.synchromedia.co.uk/),
* Christian Basedau, Norbert Laposa (http://ln5.co.uk/),
* 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 (http://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.
*
* @author Jon Abernathy <jon@chuggnutt.com>
* @version 1.0.0
* @since PHP 4.0.2
*/
class html2text
{
/**
* Contains the HTML content to convert.
*
* @var string $html
* @access public
*/
var $html;
/**
* Contains the converted, formatted text.
*
* @var string $text
* @access public
*/
var $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 integer $width
* @access public
*/
var $width = 70;
/**
* List of preg* regular expression patterns to search for,
* used in conjunction with $replace.
*
* @var array $search
* @access public
* @see $replace
*/
var $search = array(
"/\r/", // Non-legal carriage return
"/[\n\t]+/", // Newlines and tabs
'/[ ]{2,}/', // Runs of spaces, pre-handling
'/<script[^>]*>.*?<\/script>/i', // <script>s -- which strip_tags supposedly has problems with
'/<style[^>]*>.*?<\/style>/i', // <style>s -- which strip_tags supposedly has problems with
//'/<!-- .* -->/', // Comments -- which strip_tags might have problem a with
'/<h[123][^>]*>(.*?)<\/h[123]>/ie', // H1 - H3
'/<h[456][^>]*>(.*?)<\/h[456]>/ie', // H4 - H6
'/<p[^>]*>/i', // <P>
'/<br[^>]*>/i', // <br>
'/<b[^>]*>(.*?)<\/b>/ie', // <b>
'/<strong[^>]*>(.*?)<\/strong>/ie', // <strong>
'/<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>
'/<a [^>]*href="([^"]+)"[^>]*>(.*?)<\/a>/ie',
// <a href="">
'/<hr[^>]*>/i', // <hr>
'/(<table[^>]*>|<\/table>)/i', // <table> and </table>
'/(<tr[^>]*>|<\/tr>)/i', // <tr> and </tr>
'/<td[^>]*>(.*?)<\/td>/i', // <td> and </td>
'/<th[^>]*>(.*?)<\/th>/ie', // <th> and </th>
'/&(nbsp|#160);/i', // Non-breaking space
'/&(quot|rdquo|ldquo|#8220|#8221|#147|#148);/i',
// Double quotes
'/&(apos|rsquo|lsquo|#8216|#8217);/i', // Single quotes
'/&gt;/i', // Greater-than
'/&lt;/i', // Less-than
'/&(amp|#38);/i', // Ampersand
'/&(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
'/&[^&;]+;/i', // Unknown/unhandled entities
'/[ ]{2,}/' // Runs of spaces, post-handling
);
/**
* List of pattern replacements corresponding to patterns searched.
*
* @var array $replace
* @access public
* @see $search
*/
var $replace = array(
'', // Non-legal carriage return
' ', // Newlines and tabs
' ', // Runs of spaces, pre-handling
'', // <script>s -- which strip_tags supposedly has problems with
'', // <style>s -- which strip_tags supposedly has problems with
//'', // Comments -- which strip_tags might have problem a with
"strtoupper(\"\n\n\\1\n\n\")", // H1 - H3
"ucwords(\"\n\n\\1\n\n\")", // H4 - H6
"\n\n\t", // <P>
"\n", // <br>
'strtoupper("\\1")', // <b>
'strtoupper("\\1")', // <strong>
'_\\1_', // <i>
'_\\1_', // <em>
"\n\n", // <ul> and </ul>
"\n\n", // <ol> and </ol>
"\t* \\1\n", // <li> and </li>
"\n\t* ", // <li>
'$this->_build_link_list("\\1", "\\2")',
// <a href="">
"\n-------------------------\n", // <hr>
"\n\n", // <table> and </table>
"\n", // <tr> and </tr>
"\t\t\\1\n", // <td> and </td>
"strtoupper(\"\t\t\\1\n\")", // <th> and </th>
' ', // Non-breaking space
'"', // Double quotes
"'", // Single quotes
'>',
'<',
'&',
'(c)',
'(tm)',
'(R)',
'--',
'-',
'*',
'£',
'EUR', // Euro sign. € ?
'', // Unknown/unhandled entities
' ' // Runs of spaces, post-handling
);
/**
* Contains a list of HTML tags to allow in the resulting text.
*
* @var string $allowed_tags
* @access public
* @see set_allowed_tags()
*/
var $allowed_tags = '';
/**
* Contains the base URL that relative links should resolve to.
*
* @var string $url
* @access public
*/
var $url;
/**
* Indicates whether content in the $html variable has been converted yet.
*
* @var boolean $_converted
* @access private
* @see $html, $text
*/
var $_converted = false;
/**
* Contains URL addresses from links to be rendered in plain text.
*
* @var string $_link_list
* @access private
* @see _build_link_list()
*/
var $_link_list = '';
/**
* Number of valid links detected in the text, used for plain text
* display (rendered similar to footnotes).
*
* @var integer $_link_count
* @access private
* @see _build_link_list()
*/
var $_link_count = 0;
/**
* 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
* @access public
* @return void
*/
function html2text( $source = '', $from_file = false )
{
if ( !empty($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
* @access public
* @return void
*/
function set_html( $source, $from_file = false )
{
$this->html = $source;
if ( $from_file && file_exists($source) ) {
$fp = fopen($source, 'r');
$this->html = fread($fp, filesize($source));
fclose($fp);
}
$this->_converted = false;
}
/**
* Returns the text, converted from HTML.
*
* @access public
* @return string
*/
function get_text()
{
if ( !$this->_converted ) {
$this->_convert();
}
return $this->text;
}
/**
* Prints the text, converted from HTML.
*
* @access public
* @return void
*/
function print_text()
{
print $this->get_text();
}
/**
* Alias to print_text(), operates identically.
*
* @access public
* @return void
* @see print_text()
*/
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.
*
* @access public
* @return void
*/
function set_allowed_tags( $allowed_tags = '' )
{
if ( !empty($allowed_tags) ) {
$this->allowed_tags = $allowed_tags;
}
}
/**
* Sets a base URL to handle relative links.
*
* @access public
* @return void
*/
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.
*
* 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.
*
* @access private
* @return void
*/
function _convert()
{
// Variables used for building the link list
$this->_link_count = 0;
$this->_link_list = '';
$text = trim(stripslashes($this->html));
// Run our defined search-and-replace
$text = preg_replace($this->search, $this->replace, $text);
// Strip any other HTML tags
$text = strip_tags($text, $this->allowed_tags);
// 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", $text);
// Add link list
if ( !empty($this->_link_list) ) {
$text .= "\n\nLinks:\n------\n" . $this->_link_list;
}
// 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);
}
$this->text = $text;
$this->_converted = true;
}
/**
* 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
* @access private
* @return string
*/
function _build_link_list( $link, $display )
{
if ( substr($link, 0, 7) == 'http://' || substr($link, 0, 8) == 'https://' ||
substr($link, 0, 7) == 'mailto:' ) {
$this->_link_count++;
$this->_link_list .= "[" . $this->_link_count . "] $link\n";
$additional = ' [' . $this->_link_count . ']';
} elseif ( substr($link, 0, 11) == 'javascript:' ) {
// Don't count the link; ignore it
$additional = '';
// what about href="#anchor" ?
} else {
$this->_link_count++;
$this->_link_list .= "[" . $this->_link_count . "] " . $this->url;
if ( substr($link, 0, 1) != '/' ) {
$this->_link_list .= '/';
}
$this->_link_list .= "$link\n";
$additional = ' [' . $this->_link_count . ']';
}
return $display . $additional;
}
}
?>
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