Trackback.php

Go to the documentation of this file.

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package             CodeIgniter
 * @author              ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2006, EllisLab, Inc.
 * @license             http://codeigniter.com/user_guide/license.html
 * @link                http://codeigniter.com
 * @since               Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * Trackback Class
 *
 * Trackback Sending/Receiving Class
 *
 * @package             CodeIgniter
 * @subpackage  Libraries
 * @category    Trackbacks
 * @author              ExpressionEngine Dev Team
 * @link                http://codeigniter.com/user_guide/libraries/trackback.html
 */
class CI_Trackback {
                
        var $time_format        = 'local';
        var $charset            = 'UTF-8';
        var $data                       = array('url' => '', 'title' => '', 'excerpt' => '', 'blog_name' => '', 'charset' => '');
        var $convert_ascii      = TRUE;
        var $response           = '';
        var $error_msg          = array();

        /**
         * Constructor
         *
         * @access      public
         */
        function CI_Trackback()
        {
                log_message('debug', "Trackback Class Initialized");
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Send Trackback
         *
         * @access      public
         * @param       array
         * @return      bool
         */     
        function send($tb_data)
        {               
                if ( ! is_array($tb_data))
                {
                        $this->set_error('The send() method must be passed an array');
                        return FALSE;
                }
                
                // Pre-process the Trackback Data
                foreach (array('url', 'title', 'excerpt', 'blog_name', 'ping_url') as $item)
                {
                        if ( ! isset($tb_data[$item]))
                        {
                                $this->set_error('Required item missing: '.$item);
                                return FALSE;
                        }
                        
                        switch ($item)
                        {
                                case 'ping_url' : $$item = $this->extract_urls($tb_data[$item]);
                                        break;
                                case 'excerpt'  : $$item = $this->limit_characters($this->convert_xml(strip_tags(stripslashes($tb_data[$item]))));
                                        break;
                                case 'url'              : $$item = str_replace('&#45;', '-', $this->convert_xml(strip_tags(stripslashes($tb_data[$item]))));
                                        break;
                                default                 : $$item = $this->convert_xml(strip_tags(stripslashes($tb_data[$item])));
                                        break;
                        }

                        // Convert High ASCII Characters
                        if ($this->convert_ascii == TRUE)
                        {
                                if ($item == 'excerpt')
                                {
                                        $$item = $this->convert_ascii($$item);
                                }
                                elseif ($item == 'title')
                                {
                                        $$item = $this->convert_ascii($$item);
                                }
                                elseif($item == 'blog_name')
                                {
                                        $$item = $this->convert_ascii($$item);
                                }
                        }
                }

                // Build the Trackback data string
                $charset = ( ! isset($tb_data['charset'])) ? $this->charset : $tb_data['charset'];
                
                $data = "url=".rawurlencode($url)."&title=".rawurlencode($title)."&blog_name=".rawurlencode($blog_name)."&excerpt=".rawurlencode($excerpt)."&charset=".rawurlencode($charset);
                                
                // Send Trackback(s)
                $return = TRUE;
                if (count($ping_url) > 0)
                {
                        foreach ($ping_url as $url)
                        {
                                if ($this->process($url, $data) == FALSE)
                                {
                                        $return = FALSE;
                                }
                        }       
                }

                return $return;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Receive Trackback  Data
         *
         * This function simply validates the incoming TB data.
         * It returns false on failure and true on success.
         * If the data is valid it is set to the $this->data array
         * so that it can be inserted into a database.
         *
         * @access      public
         * @return      bool
         */     
        function receive()
        {                                       
                foreach (array('url', 'title', 'blog_name', 'excerpt') as $val)
                {
                        if ( ! isset($_POST[$val]) OR $_POST[$val] == '')
                        {
                                $this->set_error('The following required POST variable is missing: '.$val);
                                return FALSE;
                        }
                        
                        $this->data['charset'] = ( ! isset($_POST['charset'])) ? 'auto' : strtoupper(trim($_POST['charset']));
        
                        if ($val != 'url' && function_exists('mb_convert_encoding'))
                        {
                                $_POST[$val] = mb_convert_encoding($_POST[$val], $this->charset, $this->data['charset']);
                        }
                        
                        $_POST[$val] = ($val != 'url') ? $this->convert_xml(strip_tags($_POST[$val])) : strip_tags($_POST[$val]);
                        
                        if ($val == 'excerpt')
                        {
                                $_POST['excerpt'] = $this->limit_characters($_POST['excerpt']);
                        }
                        
                        $this->data[$val] = $_POST[$val];
                }

                return TRUE;
        }       
        
        // --------------------------------------------------------------------
        
        /**
         * Send Trackback Error Message
         *
         * Allows custom errors to be set.  By default it
         * sends the "incomplete information" error, as that's
         * the most common one.
         *
         * @access      public
         * @param       string
         * @return      void
         */     
        function send_error($message = 'Incomplete Information')
        {
                echo "<?xml version=\"1.0\" encoding=\"utf-8\"?".">\n<response>\n<error>1</error>\n<message>".$message."</message>\n</response>";
                exit;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Send Trackback Success Message
         *
         * This should be called when a trackback has been
         * successfully received and inserted.
         *
         * @access      public
         * @return      void
         */             
        function send_success()
        {
                echo "<?xml version=\"1.0\" encoding=\"utf-8\"?".">\n<response>\n<error>0</error>\n</response>";
                exit;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Fetch a particular item
         *
         * @access      public
         * @param       string
         * @return      string
         */     
        function data($item)
        {
                return ( ! isset($this->data[$item])) ? '' : $this->data[$item];
        }

        // --------------------------------------------------------------------
        
        /**
         * Process Trackback
         *
         * Opens a socket connection and passes the data to
         * the server.  Returns true on success, false on failure
         *
         * @access      public
         * @param       string
         * @param       string
         * @return      bool
         */     
        function process($url, $data)
        {
                $target = parse_url($url);
        
                // Open the socket
                if ( ! $fp = @fsockopen($target['host'], 80))
                {
                        $this->set_error('Invalid Connection: '.$url);
                        return FALSE;
                }

                // Build the path
                $ppath = ( ! isset($target['path'])) ? $url : $target['path'];
                
                $path = (isset($target['query']) && $target['query'] != "") ? $ppath.'?'.$target['query'] : $ppath;

                // Add the Trackback ID to the data string
                if ($id = $this->get_id($url))
                {
                        $data = "tb_id=".$id."&".$data;
                }

                // Transfer the data
                fputs ($fp, "POST " . $path . " HTTP/1.0\r\n" );
                fputs ($fp, "Host: " . $target['host'] . "\r\n" );
                fputs ($fp, "Content-type: application/x-www-form-urlencoded\r\n" );
                fputs ($fp, "Content-length: " . strlen($data) . "\r\n" );
                fputs ($fp, "Connection: close\r\n\r\n" );
                fputs ($fp, $data);

                // Was it successful?
                $this->response = "";
                
                while( ! feof($fp))
                {
                        $this->response .= fgets($fp, 128);
                }
                @fclose($fp);
                
                if ( ! eregi("<error>0</error>", $this->response))
                {
                        $message = 'An unknown error was encountered';
                        
                        if (preg_match("/<message>(.*?)<\/message>/is", $this->response, $match))
                        {
                                $message = trim($match['1']);
                        }
                        
                        $this->set_error($message);
                        return FALSE;
                }

                return TRUE;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Extract Trackback URLs
         *
         * This function lets multiple trackbacks be sent.
         * It takes a string of URLs (separated by comma or
         * space) and puts each URL into an array
         *
         * @access      public
         * @param       string
         * @return      string
         */     
        function extract_urls($urls)
        {               
                // Remove the pesky white space and replace with a comma.
                $urls = preg_replace("/\s*(\S+)\s*/", "\\1,", $urls);
                
                // If they use commas get rid of the doubles.
                $urls = str_replace(",,", ",", $urls);
                
                // Remove any comma that might be at the end
                if (substr($urls, -1) == ",")
                {
                        $urls = substr($urls, 0, -1);
                }
                                
                // Break into an array via commas
                $urls = preg_split('/[,]/', $urls);
                
                // Removes duplicates
                $urls = array_unique($urls);
                
                array_walk($urls, array($this, 'validate_url'));
                
                return $urls;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Validate URL
         *
         * Simply adds "http://" if missing
         *
         * @access      public
         * @param       string
         * @return      string
         */     
        function validate_url($url)
        {
                $url = trim($url);

                if (substr($url, 0, 4) != "http")
                {
                        $url = "http://".$url;
                }
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Find the Trackback URL's ID
         *
         * @access      public
         * @param       string
         * @return      string
         */     
        function get_id($url)
        {       
                $tb_id = "";
                
                if (strstr($url, '?'))
                {
                        $tb_array = explode('/', $url);
                        $tb_end   = $tb_array[count($tb_array)-1];
                        
                        if ( ! is_numeric($tb_end))
                        {
                                $tb_end  = $tb_array[count($tb_array)-2];
                        }
                        
                        $tb_array = explode('=', $tb_end);
                        $tb_id  = $tb_array[count($tb_array)-1];
                }
                else
                {
                        if (ereg("/$", $url))
                        {
                                $url = substr($url, 0, -1);
                        }
                                
                        $tb_array = explode('/', $url);
                        $tb_id  = $tb_array[count($tb_array)-1];
                        
                        if ( ! is_numeric($tb_id))
                        {
                                $tb_id  = $tb_array[count($tb_array)-2];
                        }
                }       
                                
                if ( ! preg_match ("/^([0-9]+)$/", $tb_id))
                {
                        return false;
                }
                else
                {
                        return $tb_id;
                }               
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Convert Reserved XML characters to Entities
         *
         * @access      public
         * @param       string
         * @return      string
         */
        function convert_xml($str)
        {
                $temp = '__TEMP_AMPERSANDS__';
                
                $str = preg_replace("/&#(\d+);/", "$temp\\1;", $str);
                $str = preg_replace("/&(\w+);/",  "$temp\\1;", $str);
                
                $str = str_replace(array("&","<",">","\"", "'", "-"),
                                                   array("&amp;", "&lt;", "&gt;", "&quot;", "&#39;", "&#45;"),
                                                   $str);
                        
                $str = preg_replace("/$temp(\d+);/","&#\\1;",$str);
                $str = preg_replace("/$temp(\w+);/","&\\1;", $str);
                        
                return $str;
        }       
        
        // --------------------------------------------------------------------
        
        /**
         * Character limiter
         *
         * Limits the string based on the character count. Will preserve complete words.
         *
         * @access      public
         * @param       string
         * @param       integer
         * @param       string
         * @return      string
         */
        function limit_characters($str, $n = 500, $end_char = '&#8230;')
        {
                if (strlen($str) < $n)
                {
                        return $str;
                }

                $str = preg_replace("/\s+/", ' ', str_replace(array("\r\n", "\r", "\n"), ' ', $str));
        
                if (strlen($str) <= $n)
                {
                        return $str;
                }
                                                                                
                $out = "";
                foreach (explode(' ', trim($str)) as $val)
                {
                        $out .= $val.' ';                       
                        if (strlen($out) >= $n)
                        {
                                return trim($out).$end_char;
                        }               
                }
        }
        
        // --------------------------------------------------------------------
        
        /**
         * High ASCII to Entities
         *
         * Converts Hight ascii text and MS Word special chars
         * to character entities
         *
         * @access      public
         * @param       string
         * @return      string
         */
        function convert_ascii($str)
        {
           $count       = 1;
           $out = '';
           $temp        = array();
                
           for ($i = 0, $s = strlen($str); $i < $s; $i++)
           {
                   $ordinal = ord($str[$i]);
                
                   if ($ordinal < 128)
                   {
                           $out .= $str[$i];                    
                   }
                   else
                   {
                           if (count($temp) == 0)
                           {
                                   $count = ($ordinal < 224) ? 2 : 3;
                           }
                        
                           $temp[] = $ordinal;
                        
                           if (count($temp) == $count)
                           {
                                   $number = ($count == 3) ? (($temp['0'] % 16) * 4096) + (($temp['1'] % 64) * 64) + ($temp['2'] % 64) : (($temp['0'] % 32) * 64) + ($temp['1'] % 64);
        
                                   $out .= '&#'.$number.';';
                                   $count = 1;
                                   $temp = array();
                           }
                   }
           }
        
           return $out;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Set error message
         *
         * @access      public
         * @param       string
         * @return      void
         */     
        function set_error($msg)
        {
                log_message('error', $msg);
                $this->error_msg[] = $msg;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Show error messages
         *
         * @access      public
         * @param       string
         * @param       string
         * @return      string
         */     
        function display_errors($open = '<p>', $close = '</p>')
        {       
                $str = '';
                foreach ($this->error_msg as $val)
                {
                        $str .= $open.$val.$close;
                }
        
                return $str;
        }

}
// END Trackback Class

/* End of file Trackback.php */
/* Location: ./system/libraries/Trackback.php */