Framework'ize html2text class

1 files changed, 691 insertions, 0 deletions

diff --git a/program/lib/Roundcube/rcube_html2text.php b/program/lib/Roundcube/rcube_html2text.php
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+++ b/program/lib/Roundcube/rcube_html2text.php
@@ -0,0 +1,691 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2008-2012, 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 (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.
+ */
+
+/**
+ * Converts HTML to formatted plain text
+ *
+ * @package    Framework
+ * @subpackage Utils
+ */
+class rcube_html2text
+{
+    /**
+     * 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 integer $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 $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>
+        '/<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 $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>
+        "\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 $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
+        '/&gt;/i',                               // Greater-than
+        '/&lt;/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 $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.
+     *
+     * @var array $callback_search
+     */
+    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.
+    *
+    * @var array $pre_search
+    * @see $pre_replace
+    */
+    protected $pre_search = array(
+        "/\n/",
+        "/\t/",
+        '/ /',
+        '/<pre[^>]*>/',
+        '/<\/pre>/'
+    );
+
+    /**
+     * List of pattern replacements corresponding to patterns searched for PRE body.
+     *
+     * @var array $pre_replace
+     * @see $pre_search
+     */
+    protected $pre_replace = array(
+        '<br>',
+        '&nbsp;&nbsp;&nbsp;&nbsp;',
+        '&nbsp;',
+        '',
+        ''
+    );
+
+    /**
+     * Contains a list of HTML tags to allow in the resulting text.
+     *
+     * @var string $allowed_tags
+     * @see 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 boolean $_converted
+     * @see $html, $text
+     */
+    protected $_converted = false;
+
+    /**
+     * Contains URL addresses from links to be rendered in plain text.
+     *
+     * @var array $_link_list
+     * @see _build_link_list()
+     */
+    protected $_link_list = array();
+
+    /**
+     * Boolean flag, true if a table of link URLs should be listed after the text.
+     *
+     * @var boolean $_do_links
+     * @see __construct()
+     */
+    protected $_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_links Indicate whether a table of link URLs is desired
+     * @param integer $width Maximum width of the formatted text, 0 for no limit
+     */
+    function __construct($source = '', $from_file = false, $do_links = true, $width = 75, $charset = 'UTF-8')
+    {
+        if (!empty($source)) {
+            $this->set_html($source, $from_file);
+        }
+
+        $this->set_base_url();
+
+        $this->_do_links = $do_links;
+        $this->width     = $width;
+        $this->charset   = $charset;
+    }
+
+    /**
+     * Loads source HTML into memory, either from $source string or a file.
+     *
+     * @param string $source HTML content
+     * @param boolean $from_file Indicates $source is a file to pull content from
+     */
+    function set_html($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 = 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
+     * $width characters.
+     *
+     * @param string Reference to HTML content string
+     */
+    protected function _converter(&$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, '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);
+
+        // 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 "&amp;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->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 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 _build_link_list( $link, $display )
+    {
+        if (!$this->_do_links || empty($link)) {
+            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 (($index = array_search($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 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, '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)
+            $text = preg_replace_callback('/<pre[^>]*>.*<\/pre>/ismU',
+                array($this, 'pre_preg_callback'), $text, 1);
+
+            // free memory
+            $this->pre_content = '';
+        }
+    }
+
+    /**
+     * Helper function for BLOCKQUOTE body conversion.
+     *
+     * @param string HTML content
+     */
+    protected function _convert_blockquotes(&$text)
+    {
+        if (preg_match_all('/<\/*blockquote[^>]*>/i', $text, $matches, PREG_OFFSET_CAPTURE)) {
+            $level = 0;
+            $diff = 0;
+            foreach ($matches[0] as $m) {
+                if ($m[0][0] == '<' && $m[0][1] == '/') {
+                    $level--;
+                    if ($level < 0) {
+                        $level = 0; // malformed HTML: go to next blockquote
+                    }
+                    else if ($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 = $this->width;
+                        if ($this->width > 0) $this->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->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]);
+                    }
+                    $level ++;
+                }
+            }
+        }
+    }
+
+    /**
+     * Callback function for preg_replace_callback use.
+     *
+     * @param  array PREG matches
+     * @return string
+     */
+    public function tags_preg_callback($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':
+            // Remove spaces in URL (#1487805)
+            $url = str_replace(' ', '', $matches[3]);
+            return $this->_build_link_list($url, $matches[4]);
+        }
+    }
+
+    /**
+     * Callback function for preg_replace_callback use in PRE content handler.
+     *
+     * @param array PREG matches
+     * @return string
+     */
+    public function pre_preg_callback($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 containg 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.
+     *
+     * @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;
+    }
+}