bounce_driver.class.php

<?php
/* BOUNCE HANDLER Class, Version 7.3
 * Description: "chops up the bounce into associative arrays"
 *     ~ http://www.anti-spam-man.com/php_bouncehandler/v7.3/
 *     ~ https://github.com/cfortune/PHP-Bounce-Handler/
 *     ~ http://www.phpclasses.org/browse/file/11665.html
 */

/* Debugging / Contributers:
    * "Kanon"
    * Jamie McClelland http://mayfirst.org
    * Michael Cooper
    * Thomas Seifert
    * Tim Petrowsky http://neuecouch.de
    * Willy T. Koch http://apeland.no
    * ganeshaspeaks.com - FBL development
    * Richard Catto - FBL development
    * Scott Brynen - FBL development  http://visioncritical.com
*/


/*
 The BSD License
 Copyright (c) 2006-forever, Chris Fortune http://cfortune.kics.bc.ca
 All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
    * Neither the name of the BounceHandler nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
class BounceHandler{
    
    /**** VARS ****************************************************************/
    public $head_hash = array();
    public $fbl_hash = array();
    public $body_hash = array(); // not necessary
    public $bouncelist = array(); // from bounce_responses.txt
    public $autorespondlist = array(); // from bounce_responses.txt

    public $looks_like_a_bounce = false;
    public $looks_like_an_FBL = false;
    public $looks_like_an_autoresponse = false;
    public $is_hotmail_fbl = false;
    
    // these are for feedback reports, so you can extract uids from the emails
    // eg X-my-custom-header: userId12345
    // eg <img src="http://mysite.com/track.php?u=userId12345">
    public $web_beacon_preg_1 = "";
    public $web_beacon_preg_2 = "";
    public $x_header_search_1 = "";
    public $x_header_search_2 = "";

    // accessors
    public $type = "";
    public $web_beacon_1 = "";
    public $web_beacon_2 = "";
    public $feedback_type = "";
    public $x_header_beacon_1 = "";
    public $x_header_beacon_2 = "";
    
    // these accessors are useful only for FBL's
    // or if the output array has only one index
    public $action = "";
    public $status = "";
    public $subject = "";
    public $recipient = "";

    // the raw data set, a multiArray
    public $output = array();

    public $first_body_hash = array();

    
    /**** INSTANTIATION *******************************************************/

    /**
     * Construct
     */
    public function __construct(){
        $this->output[0]['action']  = "";
        $this->output[0]['status']  = "";
        $this->output[0]['recipient'] = "";
        include_once('bounce_responses.php');
        $this->bouncelist = $bouncelist;
        $this->autorespondlist = $autorespondlist;
    }
    

    /**** METHODS *************************************************************/
    /**
     * Pareses a single email
     *
     * @see self::get_the_facts
     * @param $eml
     * @return array
     */
    public function parse_email($eml){
        return $this->get_the_facts($eml);
    }

    /**
     * Returns all Information for a single email
     *
     * @param $eml
     * @return array
     */
    public function get_the_facts($eml){
        // fluff up the email
        $bounce = $this->init_bouncehandler($eml);
        list($head, $body) = preg_split("/\r\n\r\n/", $bounce, 2);
        $this->head_hash = $this->parse_head($head);

        // parse the email into data structures
        $boundary = @$this->head_hash['Content-type']['boundary'];
        $mime_sections = $this->parse_body_into_mime_sections($body, $boundary);
        $this->body_hash = preg_split("/\r\n/", $body);
        $this->first_body_hash = $this->parse_head(@$mime_sections['first_body_part']);

        $this->looks_like_a_bounce = $this->is_a_bounce();
        $this->looks_like_an_FBL = $this->is_an_ARF();
        $this->looks_like_an_autoresponse = $this->is_an_autoresponse();
        

        /* If you are trying to save processing power, and don't care much
         * about accuracy then uncomment this statement in order to skip the
         * heroic text parsing below. 
         */
        //if(!$this->looks_like_a_bounce && !$this->looks_like_an_FBL && !$this->looks_like_an_autoresponse){
        //    return "unknown";
        //}


        /*** now we try all our weird text parsing methods (E-mail is weird!) ******************************/

        // is it a Feedback Loop, in Abuse Feedback Reporting Format (ARF)?
        // http://en.wikipedia.org/wiki/Abuse_Reporting_Format#Abuse_Feedback_Reporting_Format_.28ARF.29
        if($this->looks_like_an_FBL){
            $this->output[0]['action'] = 'failed';
            $this->output[0]['status'] = "5.7.1";
            $this->subject = trim(str_ireplace("Fw:", "", $this->head_hash['Subject']));
            if($this->is_hotmail_fbl === true){
                // fill in the fbl_hash with sensible values
                $this->fbl_hash['Content-disposition'] = 'inline';
                $this->fbl_hash['Content-type'] = 'message/feedback-report';
                $this->fbl_hash['Feedback-type'] = 'abuse';
                $this->fbl_hash['User-agent'] = 'Hotmail FBL';
                if (isset($this->first_body_hash['Date'])) {
                    $this->fbl_hash['Received-date'] = $this->first_body_hash['Date'];
                }
                if (!empty($this->recipient)){
                    $this->fbl_hash['Original-rcpt-to'] = $this->recipient;
                }
                if(isset($this->first_body_hash['X-sid-pra'])){
                    $this->fbl_hash['Original-mail-from'] = $this->first_body_hash['X-sid-pra'];
                }
            }
            else{
                $this->fbl_hash = $this->standard_parser($mime_sections['machine_parsable_body_part']);
                $returnedhash = $this->standard_parser($mime_sections['returned_message_body_part']);
                if (empty($this->fbl_hash['Original-mail-from']) && !empty($returnedhash['From'])) {
                    $this->fbl_hash['Original-mail-from'] = $returnedhash['From'];
                }
                if (empty($this->fbl_hash['Original-rcpt-to']) && !empty($this->fbl_hash['Removal-recipient']) ) {
                    $this->fbl_hash['Original-rcpt-to'] = $this->fbl_hash['Removal-recipient'];
                }
                elseif (!empty($returnedhash['To'])) {
                    $this->fbl_hash['Original-rcpt-to'] = $returnedhash['To'];
                }
            }
            // warning, some servers will remove the name of the original intended recipient from the FBL report,
            // replacing it with redacted@rcpt-hostname.com, making it utterly useless, of course (unless you used a web-beacon).
            // here we try our best to give you the actual intended recipient, if possible.
            if (preg_match('/Undisclosed|redacted/i', $this->fbl_hash['Original-rcpt-to']) && isset($this->fbl_hash['Removal-recipient']) ) {
                $this->fbl_hash['Original-rcpt-to'] = @$this->fbl_hash['Removal-recipient'];
            }
            if (empty($this->fbl_hash['Received-date']) && !empty($this->fbl_hash[@'Arrival-date']) ) {
                $this->fbl_hash['Received-date'] = @$this->fbl_hash['Arrival-date'];
            }
            $this->fbl_hash['Original-mail-from'] = $this->strip_angle_brackets(@$this->fbl_hash['Original-mail-from']);
            $this->fbl_hash['Original-rcpt-to']   = $this->strip_angle_brackets(@$this->fbl_hash['Original-rcpt-to']);
            $this->output[0]['recipient'] = $this->fbl_hash['Original-rcpt-to'];
        }

        else if (preg_match("/auto.{0,20}reply|vacation|(out|away|on holiday).*office/i", $this->head_hash['Subject'])){
            // looks like a vacation autoreply, ignoring
            $this->output[0]['action'] = 'autoreply';
        } 

        // is this an autoresponse ?
        else if ($this->looks_like_an_autoresponse) {
            $this->output[0]['action'] = 'transient';
            $this->output[0]['status'] = '4.3.2';
            // grab the first recipient and break
            $this->output[0]['recipient'] = isset($this->head_hash['Return-path']) ? $this->strip_angle_brackets($this->head_hash['Return-path']) : '';
            if(empty($this->output[0]['recipient'])){
                $arrFailed = $this->find_email_addresses($body);
                for($j=0; $j<count($arrFailed); $j++){
                    $this->output[$j]['recipient'] = trim($arrFailed[$j]);
                    break; 
                }
            }
        }

        else if ($this->is_RFC1892_multipart_report() === TRUE){
            $rpt_hash = $this->parse_machine_parsable_body_part($mime_sections['machine_parsable_body_part']);
            for($i=0; $i<count($rpt_hash['per_recipient']); $i++){
                $this->output[$i]['recipient'] = $this->find_recipient($rpt_hash['per_recipient'][$i]);
                $mycode = @$this->format_status_code($rpt_hash['per_recipient'][$i]['Status']);
                $this->output[$i]['status'] = @$mycode['code'];
                $this->output[$i]['action'] = @$rpt_hash['per_recipient'][$i]['Action'];
            }
        }

        else if(isset($this->head_hash['X-failed-recipients'])) {
            //  Busted Exim MTA
            //  Up to 50 email addresses can be listed on each header.
            //  There can be multiple X-Failed-Recipients: headers. - (not supported)
            $arrFailed = preg_split("/\,/", $this->head_hash['X-failed-recipients']);
            for($j=0; $j<count($arrFailed); $j++){
                $this->output[$j]['recipient'] = trim($arrFailed[$j]);
                $this->output[$j]['status'] = $this->get_status_code_from_text($this->output[$j]['recipient'],0);
                $this->output[$j]['action'] = $this->get_action_from_status_code($this->output[$j]['status']);
            }
        }

        else if(!empty($boundary) && $this->looks_like_a_bounce){
            // oh god it could be anything, but at least it has mime parts, so let's try anyway
            $arrFailed = $this->find_email_addresses($mime_sections['first_body_part']);
            for($j=0; $j<count($arrFailed); $j++){
                $this->output[$j]['recipient'] = trim($arrFailed[$j]);
                $this->output[$j]['status'] = $this->get_status_code_from_text($this->output[$j]['recipient'],0);
                $this->output[$j]['action'] = $this->get_action_from_status_code($this->output[$j]['status']);
            }
        }

        else if($this->looks_like_a_bounce){
            // last ditch attempt
            // could possibly produce erroneous output, or be very resource consuming,
            // so be careful.  You should comment out this section if you are very concerned
            // about 100% accuracy or if you want very fast performance.
            // Leave it turned on if you know that all messages to be analyzed are bounces.
            $arrFailed = $this->find_email_addresses($body);
            for($j=0; $j<count($arrFailed); $j++){
                $this->output[$j]['recipient'] = trim($arrFailed[$j]);
                $this->output[$j]['status'] = $this->get_status_code_from_text($this->output[$j]['recipient'],0);
                $this->output[$j]['action'] = $this->get_action_from_status_code($this->output[$j]['status']);
            }
        }
        // else if()..... add a parser for your busted-ass MTA here
        
        // remove empty array indices
        $tmp = array();
        foreach($this->output as $arr){
            if(empty($arr['recipient']) && empty($arr['status']) && empty($arr['action']) ){
                continue;
            }
            $tmp[] = $arr;
        }
        $this->output = $tmp;

        // accessors
        /*if it is an FBL, you could use the class variables to access the
        data (Unlike Multipart-reports, FBL's report only one bounce)
        */
        $this->type = $this->find_type();
        $this->action = $this->output[0]['action'];
        $this->status = $this->output[0]['status'];
        $this->subject = ($this->subject) ? $this->subject : $this->head_hash['Subject'];
        $this->recipient = $this->output[0]['recipient'];
        $this->feedback_type = @($this->fbl_hash['Feedback-type']) ? $this->fbl_hash['Feedback-type'] : "";

        // sniff out any web beacons
        if($this->web_beacon_preg_1) {
            $this->web_beacon_1 = $this->find_web_beacon($body, $this->web_beacon_preg_1);
        }
        if($this->web_beacon_preg_2) {
            $this->web_beacon_2 = $this->find_web_beacon($body, $this->web_beacon_preg_2);
        }
        if($this->x_header_search_1) {
            $this->x_header_beacon_1 = $this->find_x_header  ($this->x_header_search_1);
        }
        if($this->x_header_search_2) {
            $this->x_header_beacon_2 = $this->find_x_header  ($this->x_header_search_2);
        }

        return $this->output;
    }


    /**
     * Initialisation of the bouncehandler
     *
     * @param $blob
     * @param string $format
     * @return mixed
     */
    private function init_bouncehandler($blob, $format='string'){
        $this->head_hash = array();
        $this->fbl_hash = array();
        $this->body_hash = array(); 
        $this->looks_like_a_bounce = false;
        $this->looks_like_an_FBL = false;
        $this->is_hotmail_fbl = false;
        $this->type = "";
        $this->feedback_type = "";
        $this->action = "";
        $this->status = "";
        $this->subject = "";
        $this->recipient = "";
        $this->output = array();

        // TODO: accept several formats (XML, string, array)
        // currently accepts only string
        //if($format=='xml_array'){
        //    $strEmail = "";
        //    $out = "";
        //    for($i=0; $i<$blob; $i++){
        //        $out = preg_replace("/<HEADER>/i", "", $blob[$i]);
        //        $out = preg_replace("/</HEADER>/i", "", $out);
        //        $out = preg_replace("/<MESSAGE>/i", "", $out);
        //        $out = preg_replace("/</MESSAGE>/i", "", $out);
        //        $out = rtrim($out) . "\r\n";
        //        $strEmail .= $out;
        //    }
        //}
        //else if($format=='string'){

            $strEmail = str_replace("\r\n", "\n", $blob);    // line returns 1
            $strEmail = str_replace("\n", "\r\n", $strEmail);// line returns 2
            $strEmail = str_replace("=\r\n", "", $strEmail); // remove MIME line breaks
            $strEmail = str_replace("=3D", "=", $strEmail);  // equals sign =
            $strEmail = str_replace("=09", "  ", $strEmail); // tabs

        //}
        //else if($format=='array'){
        //    $strEmail = "";
        //    for($i=0; $i<$blob; $i++){
        //        $strEmail .= rtrim($blob[$i]) . "\r\n";
        //    }
        //}

        return $strEmail;
    }

    // general purpose recursive heuristic function
    // to try to extract useful info from the bounces produced by busted MTAs

    /**
     * Tries to get the status code from Mailtext
     *
     * @param $recipient
     * @param $index
     * @return string
     */
    public function get_status_code_from_text($recipient, $index){
        for($i=$index; $i<count($this->body_hash); $i++){
            $line = trim($this->body_hash[$i]);

            /******** recurse into the email if you find the recipient ********/
            if(stristr($line, $recipient)!==FALSE){
                // the status code MIGHT be in the next few lines after the recipient line,
                // depending on the message from the foreign host... What a laugh riot!
                $status_code = $this->get_status_code_from_text($recipient, $i+1);
                if($status_code){
                    return $status_code;
                }

            }

            /******** exit conditions ********/
            // if it's the end of the human readable part in this stupid bounce
            if(stristr($line, '------ This is a copy of the message')!==FALSE){
                return '';
            }
            //if we see an email address other than our current recipient's,
            if(count($this->find_email_addresses($line))>=1
               && stristr($line, $recipient)===FALSE
               && strstr($line, 'FROM:<')===FALSE){ // Kanon added this line because Hotmail puts the e-mail address too soon and there actually is error message stuff after it.
                return '';
            }
            /******** pattern matching ********/
            foreach ($this->bouncelist as $bouncetext => $bouncecode) {
              if (preg_match("/$bouncetext/i", $line, $matches)) {
                return (isset($matches[1])) ? $matches[1] : $bouncecode;
              }
            }

            // rfc1893 return code
            if(preg_match('/\W([245]\.[01234567]\.[012345678])\W/', $line, $matches)){
                if(stripos($line, 'Message-ID')!==FALSE){
                    break;
                }
                $mycode = str_replace('.', '', $matches[1]);
                $mycode = $this->format_status_code($mycode);
                return implode('.', $mycode['code']);
            }

            // search for RFC821 return code
            // thanks to mark.tolman@gmail.com
            // Maybe at some point it should have it's own place within the main parsing scheme (at line 88)
            if(preg_match('/\]?: ([45][01257][012345]) /', $line, $matches)
               || preg_match('/^([45][01257][012345]) (?:.*?)(?:denied|inactive|deactivated|rejected|disabled|unknown|no such|not (?:our|activated|a valid))+/i', $line, $matches))
            {
                $mycode = $matches[1];
                // map common codes to new rfc values
                if($mycode == '450' || $mycode == '550' || $mycode == '551' || $mycode == '554'){
                    $mycode = '511';
                } else if($mycode == '452' || $mycode == '552'){
                    $mycode = '422';
                } else if ($mycode == '421'){
                    $mycode = '432';
                }
                $mycode = $this->format_status_code($mycode);
                return implode('.', $mycode['code']);
            }

        }
        return '';
    }

    /**
     * Checks if the format of the email is formated as RFC1892
     *
     * @return bool
     */
    private function is_RFC1892_multipart_report(){
        return @$this->head_hash['Content-type']['type']=='multipart/report'
           &&  @$this->head_hash['Content-type']['report-type']=='delivery-status'
           &&  @$this->head_hash['Content-type'][boundary]!=='';
    }

    /**
     * Parses the header of the email
     *
     * @param $headers
     * @return array
     */
    private function parse_head($headers){
        if(!is_array($headers)) $headers = explode("\r\n", $headers);
        $hash = $this->standard_parser($headers);
        if(!empty($hash['Content-type'])){//preg_match('/Multipart\/Report/i', $hash['Content-type'])){
            $multipart_report = explode (';', $hash['Content-type']);
            $hash['Content-type']='';
            $hash['Content-type']['type'] = strtolower($multipart_report[0]);
            foreach($multipart_report as $mr){
                if(preg_match('/([^=.]*?)=(.*)/i', $mr, $matches)){
                // didn't work when the content-type boundary ID contained an equal sign,
                // that exists in bounces from many Exchange servers
                //if(preg_match('/([a-z]*)=(.*)?/i', $mr, $matches)){
                    $hash['Content-type'][strtolower(trim($matches[1]))]= str_replace('"','',$matches[2]);
                }
            }
        }
        return $hash;
    }

    /**
     * Splits body in single parts
     *
     * @param $body
     * @param $boundary
     * @return array
     */
    private function parse_body_into_mime_sections($body, $boundary){
        if(!$boundary) return array();
        if(is_array($body)) $body = implode("\r\n", $body);
        $body = explode($boundary, $body);
        $mime_sections['first_body_part']            = @$body[1];
        $mime_sections['machine_parsable_body_part'] = @$body[2];
        $mime_sections['returned_message_body_part'] = @$body[3];
        return $mime_sections;
    }

    /**
     * Standard Parser for several parts of the mail
     *
     * @param $content
     * @return array
     */
    private function standard_parser($content){ // associative array orstr
        // receives email head as array of lines
        // simple parse (Entity: value\n)
        $hash = array('Received'=>'');
        if(!is_array($content)) $content = explode("\r\n", $content);
        foreach($content as $line){
            if(preg_match('/^([^\s.]*):\s*(.*)\s*/', $line, $array)){
                $entity = ucfirst(strtolower($array[1]));
                if(empty($hash[$entity])){
                    $hash[$entity] = trim($array[2]);
                }
                else if($hash['Received']){
                    // grab extra Received headers :(
                    // pile it on with pipe delimiters,
                    // oh well, SMTP is broken in this way
                    if ($entity and $array[2] and $array[2] != $hash[$entity]){
                        $hash[$entity] .= "|" . trim($array[2]);
                    }
                }
            }
            elseif (preg_match('/^\s+(.+)\s*/', $line) && !empty($entity)) {
                $hash[$entity] .= ' '. $line;
            }
        }
        // special formatting
        $hash['Received']= @explode('|', $hash['Received']);
        $hash['Subject'] = iconv_mime_decode($hash['Subject'], 0, "ISO-8859-1");

        return $hash;
    }

    /**
     * Parse some part of the body
     *
     * @param $str
     * @return mixed
     */
    private function parse_machine_parsable_body_part($str){
        //Per-Message DSN fields
        $hash = $this->parse_dsn_fields($str);
        $hash['mime_header'] = $this->standard_parser($hash['mime_header']);
        $hash['per_message'] = $this->standard_parser($hash['per_message']);
        if(!empty($hash['per_message']['X-postfix-sender'])){
            $arr = explode (';', $hash['per_message']['X-postfix-sender']);
            $hash['per_message']['X-postfix-sender']='';
            $hash['per_message']['X-postfix-sender']['type'] = @trim($arr[0]);
            $hash['per_message']['X-postfix-sender']['addr'] = @trim($arr[1]);
        }
        if(!empty($hash['per_message']['Reporting-mta'])){
            $arr = explode (';', $hash['per_message']['Reporting-mta']);
            $hash['per_message']['Reporting-mta']='';
            $hash['per_message']['Reporting-mta']['type'] = @trim($arr[0]);
            $hash['per_message']['Reporting-mta']['addr'] = @trim($arr[1]);
        }
        //Per-Recipient DSN fields
        for($i=0; $i<count($hash['per_recipient']); $i++){
            $temp = $this->standard_parser(explode("\r\n", $hash['per_recipient'][$i]));
            $arr = @explode (';', $temp['Final-recipient']);
            $temp['Final-recipient'] = $this->format_final_recipient_array($arr);
            //$temp['Final-recipient']['type'] = trim($arr[0]);
            //$temp['Final-recipient']['addr'] = trim($arr[1]);
            $arr = @explode (';', $temp['Original-recipient']);
            $temp['Original-recipient']='';
            $temp['Original-recipient']['type'] = @trim($arr[0]);
            $temp['Original-recipient']['addr'] = @trim($arr[1]);
            $arr = @explode (';', $temp['Diagnostic-code']);
            $temp['Diagnostic-code']='';
            $temp['Diagnostic-code']['type'] = @trim($arr[0]);
            $temp['Diagnostic-code']['text'] = @trim($arr[1]);
            // now this is wierd: plenty of times you see the status code is a permanent failure,
            // but the diagnostic code is a temporary failure.  So we will assert the most general
            // temporary failure in this case.
            $ddc = $this->decode_diagnostic_code($temp['Diagnostic-code']['text']);
            $judgement = $this->get_action_from_status_code($ddc);
            if($judgement == 'transient'){
                if(stristr($temp['Action'],'failed')!==FALSE){
                    $temp['Action']='transient';
                    $temp['Status']='4.3.0';
                }
            }
            $hash['per_recipient'][$i]='';
            $hash['per_recipient'][$i]=$temp;
        }
        return $hash;
    }

    /**
     * Extract the head from the body of the returning mail
     *
     * @param $mime_sections
     * @return array
     */
    private function get_head_from_returned_message_body_part($mime_sections){
        $temp = explode("\r\n\r\n", $mime_sections[returned_message_body_part]);
        $head = $this->standard_parser($temp[1]);
        $head['From'] = $this->extract_address($head['From']);
        $head['To'] = $this->extract_address($head['To']);
        return $head;
    }

    /**
     * Extracts the address of a string
     *
     * @param $str
     * @return mixed
     */
    private function extract_address($str){
        $from_stuff = preg_split('/[ \"\'\<\>:\(\)\[\]]/', $str);
        foreach ($from_stuff as $things){
            if (strpos($things, '@')!==FALSE){$from = $things;}
        }
        return $from;
    }

    /**
     * Tries to extract the recipent from a string
     *
     * @param $per_rcpt
     * @return mixed|string
     */
    private function find_recipient($per_rcpt){
        $recipient = '';
        if($per_rcpt['Original-recipient']['addr'] !== ''){
            $recipient = $per_rcpt['Original-recipient']['addr'];
        }
        else if($per_rcpt['Final-recipient']['addr'] !== ''){
            $recipient = $per_rcpt['Final-recipient']['addr'];
        }
        $recipient = $this->strip_angle_brackets($recipient);
        return $recipient;
    }

    /**
     * Tries to extract the type of the mail
     *
     * @return bool|string ("bounce"|"fbl"|false)
     */
    private function find_type(){
        if($this->looks_like_a_bounce)
            return "bounce";
        else if($this->looks_like_an_FBL)
            return "fbl";
        else
            return false;
    }

    /**
     * Parses the DSN fields
     *
     * @param $dsn_fields
     * @return mixed
     */
    private function parse_dsn_fields($dsn_fields){
        if(!is_array($dsn_fields)) $dsn_fields = explode("\r\n\r\n", $dsn_fields);
        $j = 0;
        reset($dsn_fields);
        for($i=0; $i<count($dsn_fields); $i++){
            $dsn_fields[$i] = trim($dsn_fields[$i]);
            if($i==0)
                $hash['mime_header'] = $dsn_fields[0];
            elseif($i==1 && !preg_match('/(Final|Original)-Recipient/',$dsn_fields[1])) {
                // some mta's don't output the per_message part, which means
                // the second element in the array should really be
                // per_recipient - test with Final-Recipient - which should always
                // indicate that the part is a per_recipient part
                $hash['per_message'] = $dsn_fields[1];
            }
            else {
                if($dsn_fields[$i] == '--') continue;
                $hash['per_recipient'][$j] = $dsn_fields[$i];
                $j++;
            }
        }
        return $hash;
    }

    /**
     * Formats the status code
     *
     * @param $code
     * @return string
     */
    private function format_status_code($code){
        $ret = "";
        if(preg_match('/([245]\.[01234567]\.[012345678])(.*)/', $code, $matches)){
            $ret['code'] = $matches[1];
            $ret['text'] = $matches[2];
        }
        else if(preg_match('/([245][01234567][012345678])(.*)/', $code, $matches)){
            preg_match_all("/./", $matches[1], $out);
            $ret['code'] = $out[0];
            $ret['text'] = $matches[2];
        }
        return $ret;
    }

    /**
     * Extract the status message
     *
     * @param $code
     * @return string
     */
    private function fetch_status_messages($code){
        include_once ("rfc1893.error.codes.php");
        $ret = $this->format_status_code($code);
        $arr = explode('.', $ret['code']);
        $str = "<P><B>". $status_code_classes[$arr[0]]['title'] . "</B> - " .$status_code_classes[$arr[0]]['descr']. "  <B>". $status_code_subclasses[$arr[1].".".$arr[2]]['title'] . "</B> - " .$status_code_subclasses[$arr[1].".".$arr[2]]['descr']. "</P>";
        return $str;
    }

    /**
     * Extract the action from the status code
     *
     * @param $code
     * @return string (success|transient|failed|)
     */
    private function get_action_from_status_code($code){
        if($code=='') return '';
        $ret = $this->format_status_code($code);
        $stat = $ret['code'][0];
        switch($stat){
            case(2):
                return 'success';
                break;
            case(4):
                return 'transient';
                break;
            case(5):
                return 'failed';
                break;
            default:
                return '';
                break;
        }
    }

    /**
     * Decode the Diagnostic Code
     *
     * @param $dcode
     * @return mixed
     */
    private function decode_diagnostic_code($dcode){
        if(preg_match("/(\d\.\d\.\d)\s/", $dcode, $array)){
            return $array[1];
        }
        else if(preg_match("/(\d\d\d)\s/", $dcode, $array)){
            return $array[1];
        }
    }

    /**
     * Determines if it is a bounce mail
     *
     * @return bool
     */
    private function is_a_bounce(){
        if(preg_match("/(mail delivery failed|failure notice|warning: message|delivery status notif|delivery failure|delivery problem|spam eater|returned mail|undeliverable|returned mail|delivery errors|mail status report|mail system error|failure delivery|delivery notification|delivery has failed|undelivered mail|returned email|returning message to sender|returned to sender|message delayed|mdaemon notification|mailserver notification|mail delivery system|nondeliverable mail|mail transaction failed)|auto.{0,20}reply|vacation|(out|away|on holiday).*office/i", $this->head_hash['Subject'])) {
            return true;
        }
        if(@preg_match('/auto_reply/',$this->head_hash['Precedence'])) {
            return true;
        }
        if(preg_match("/^(postmaster|mailer-daemon)\@?/i", $this->head_hash['From'])) {
            return true;
        }
        return false;
    }

    /**
     * Extract e-mail adresses from the body part
     *
     * @param $first_body_part
     * @return array
     */
    private function find_email_addresses($first_body_part){
        // not finished yet.  This finds only one address.
        if(preg_match("/\b([A-Z0-9._%-]+@[A-Z0-9.-]+\.[A-Z]{2,4})\b/i", $first_body_part, $matches)){
            return array($matches[1]);
        }
        else
            return array();
    }


    /**
     * ???
     *
     * @return bool
     */
    private function is_an_ARF(){
        if(@preg_match('/feedback-report/',$this->head_hash['Content-type']['report-type'])) return true;
        if(@preg_match('/scomp/',$this->head_hash['X-loop'])) return true;
        if(isset($this->head_hash['X-hmxmroriginalrecipient']))  {
            $this->is_hotmail_fbl = TRUE;
            $this->recipient = $this->head_hash['X-hmxmroriginalrecipient'];
            return true;
        }
        if(isset($this->first_body_hash['X-hmxmroriginalrecipient']) )  {
            $this->is_hotmail_fbl = TRUE;
            $this->recipient = $this->first_body_hash['X-hmxmroriginalrecipient'];
            return true;
        }
        return false;
    }

    /**
     * Try to check if it is an autoresponder
     *
     * @return bool
     */
    private function is_an_autoresponse() {
        if (preg_match('/^=\?utf-8\?B\?(.*?)\?=/', $this->head_hash['Subject'], $matches))
            $subj = base64_decode($matches[1]);
        else
            $subj = $this->head_hash['Subject'];
        foreach ($this->autorespondlist as $a) {
            if (preg_match("/$a/i", $subj)) {
                return true;
            }
        }
        return false;
    }


    /**
     * Find a web beacon(?)
     *
     * @param $body
     * @param $preg
     * @return string
     */
    public function find_web_beacon($body, $preg){
        if(!isset($preg) || !$preg)
            return "";
        if(preg_match($preg, $body, $matches))
            return $matches[1];
    }

    /**
     * Finds a specific x-header
     *
     * @param $xheader
     * @return string
     */
    public function find_x_header($xheader){
        $xheader = ucfirst(strtolower($xheader));
        // check the header
        if(isset($this->head_hash[$xheader])){
            return $this->head_hash[$xheader];
        }
        // check the body too
        $tmp_body_hash = $this->standard_parser($this->body_hash);
        if(isset($tmp_body_hash[$xheader])){
            return $tmp_body_hash[$xheader];
        }
        return "";
    }

    /**
     * Exract angle brackets from string
     *
     * @param $recipient
     * @return mixed
     */
    private function strip_angle_brackets($recipient){
        $recipient = str_replace('<', '', $recipient);
        $recipient = str_replace('>', '', $recipient);
        return $recipient;
    }


    /**
     * Formats the final recipient
     *
     * @param $arr
     * @return array
     */
    private function format_final_recipient_array($arr){
        $output = array('addr'=>'',
                        'type'=>'');
        if(strpos($arr[0], '@')!==FALSE){
            $output['addr'] = @$this->strip_angle_brackets($arr[0]);
            $output['type'] = (!empty($arr[1])) ? @trim($arr[1]) : 'unknown';
        }
        else{
            $output['type'] = @trim($arr[0]);
            $output['addr'] = @$this->strip_angle_brackets($arr[1]);
        }
        return $output;
    }
}/** END class BounceHandler **/