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roundcubemail/program/lib/html2text.inc

451 lines
14 KiB
PHP

<?php
/*************************************************************************
* *
* class.html2text.inc *
* *
*************************************************************************
* *
* Converts HTML to formatted plain text *
* *
* Copyright (c) 2005 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: 04/06/05 *
* Modified: 2004/05/19 (tbr) *
* *
*************************************************************************/
/**
* 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.
*
* @author Jon Abernathy <jon@chuggnutt.com>
* @version 0.6.1
* @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.
*
* @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
'/<script[^>]*>.*?<\/script>/i', // <script>s -- which strip_tags supposedly has problems with
//'/<!-- .* -->/', // Comments -- which strip_tags might have problem a with
'/<a [^>]*href=("|\')([^"\']+)\1[^>]*>(.+?)<\/a>/ie', // <a href="">
'/<h[123][^>]*>(.+?)<\/h[123]>/ie', // H1 - H3
'/<h[456][^>]*>(.+?)<\/h[456]>/ie', // H4 - H6
'/<p[^>]*>/i', // <P>
'/<br[^>]*>/i', // <br>
'/<b[^>]*>(.+?)<\/b>/ie', // <b>
'/<i[^>]*>(.+?)<\/i>/i', // <i>
'/(<ul[^>]*>|<\/ul>)/i', // <ul> and </ul>
'/(<ol[^>]*>|<\/ol>)/i', // <ol> and </ol>
'/<li[^>]*>/i', // <li>
'/<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;/i',
'/&quot;/i',
'/&gt;/i',
'/&lt;/i',
'/&(amp|#38);/i',
'/&copy;/i',
'/&trade;/i',
'/&#8220;/',
'/&#8221;/',
'/&#8211;/',
'/&#(8217|39);/',
'/&#169;/',
'/&#8482;/',
'/&#151;/',
'/&#147;/',
'/&#148;/',
'/&#149;/',
'/&reg;/i',
'/&bull;/i',
'/&[&;]+;/i'
);
/**
* List of pattern replacements corresponding to patterns searched.
*
* @var array $replace
* @access public
* @see $search
*/
var $replace = array(
'', // Non-legal carriage return
' ', // Newlines and tabs
'', // <script>s -- which strip_tags supposedly has problems with
//'', // Comments -- which strip_tags might have problem a with
'$this->_build_link_list("\\2", "\\3")', // <a href="">
"strtoupper(\"\n\n\\1\n\n\")", // H1 - H3
"ucwords(\"\n\n\\1\n\")", // H4 - H6
"\n\n", // <P>
"\n", // <br>
'strtoupper("\\1")', // <b>
'_\\1_', // <i>
"\n\n", // <ul> and </ul>
"\n\n", // <ol> and </ol>
"\t*", // <li>
"\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>
' ',
'"',
'>',
'<',
'&',
'(c)',
'(tm)',
'"',
'"',
'-',
"'",
'(c)',
'(tm)',
'--',
'"',
'"',
'*',
'(R)',
'*',
''
);
/**
* 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 = array();
/**
* Boolean flag, true if a table of link URLs should be listed after the text.
*
* @var boolean $_do_links
* @access private
* @see html2text()
*/
var $_do_links = true;
/**
* 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 boolean $do_link_table indicate whether a table of link URLs is desired
* @access public
* @return void
*/
function html2text( $source = '', $from_file = false, $produce_link_table = true )
{
if ( !empty($source) ) {
$this->set_html($source, $from_file);
}
$this->set_base_url();
$this->_do_links = $produce_link_table;
}
/**
* 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) ) {
$this->url = 'http://' . $_SERVER['HTTP_HOST'];
} else {
// Strip any trailing slashes for consistency (relative
// URLs may already start with a slash like "/file.html")
if ( substr($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
* $width characters.
*
* @access private
* @return void
*/
function _convert()
{
// Variables used for building the link list
//$link_count = 1;
//$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", $text);
$text = preg_replace("/[\n]{3,}/", "\n\n", $text);
// Add link list
if ( sizeof($this->_link_list) ) {
$text .= "\n\nLinks:\n------\n";
foreach ($this->_link_list as $id => $link) {
$text .= '[' . ($id+1) . '] ' . $link . "\n";
}
}
// Wrap the text to a readable format
// for PHP versions >= 4.0.2. Default width is 75
$text = wordwrap($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 integer $link_count Counter tracking current link number
* @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 (! $this->_do_links) return $display;
$link_lc = strtolower($link);
if (substr($link_lc, 0, 7) == 'http://' || substr($link_lc, 0, 8) == 'https://' || substr($link_lc, 0, 7) == 'mailto:')
{
$url = $link;
}
else
{
$url = $this->url;
if ($link{0} != '/') {
$url .= '/';
}
$url .= $link;
}
$index = array_search($url, $this->_link_list);
if ($index===FALSE)
{
$index = sizeof($this->_link_list);
$this->_link_list[$index] = $url;
}
return $display . ' [' . ($index+1) . ']';
}
}
?>