PHP: imap_header does not display Request Read Receipt and Priority headers

Question

I'm trying to read the Request Read Receipt and Priority headers from email headers via PHP.

IT seems that imap_header only displays select headers. The message headers below should but do not include the two headers I'm looking for...

 stdClass Object ( 
 [date] => Tue, 30 Jul 2013 18:11:26 -0700 (MST)
 [Date] => Tue, 30 Jul 2013 18:11:26 -0700 (MST) 
 [subject] => Return
 Request Receipt + High Priority Test 
 [Subject] => Return Request
 Receipt + High Priority Test 
 [in_reply_to] => <__@mrmail.com>
 [message_id] => <__@mrmail.com> 
 [toaddress] => __@example.com [to] =>
   Array ( 
   [0] => stdClass Object (
     [mailbox] => __ [host] => example.com
   )
 )

 [fromaddress] => Someone <__@mrmail.com> 
 [from] => 
   Array ( 
     [0] =>
       stdClass Object ( 
         [personal] => Someone 
         [mailbox] => example 
         [host] => mrmail.com 
   )
 )

 [reply_toaddress] => Someone <__@mrmail.com> 
 [reply_to] => 
   Array ( 
     [0] => stdClass Object (
       [personal] => Someone 
       [mailbox] => __ 
       [host] => mrmail.com 
      )
 )

 [senderaddress] => Someone <__@mrmail.com> 
 [sender] => 
   Array ( 
     [0] => stdClass Object ( 
       [personal] => Someone 
       [mailbox] => example 
       [host] => mrmail.com 
      )
 )

 [Recent] => 
 [Unseen] => U 
 [Flagged] => 
 [Answered] => 
 [Deleted] =>
 [Draft] => 
 [Msgno] => 69 
 [MailDate] => 30-Jul-2013 19:18:03 -0600
 [Size] => 2719 
 [udate] => 1375233483

So what function in PHP do I use to iterate through ALL headers?

Answer 1

Figured it out, the array below returns all headers, posting for others...

[edit] Updated so that headers that may appear more than once are checked and an array with their values are added. The $unlimited array is sampled from https://www.rfc-editor.org/rfc/rfc5322#section-3.6.[/edit]

<?php
$th = imap_fetchheader($mbox,$cms->page2);
$th = trim($th);
$th = str_ireplace("\r","\n",$th);
$th = str_ireplace("\n\n","\n",$th);
$p0 = explode("\n",$th);
$current = '';
$unlimited = array('comments','keywords','optional-field','resent-bcc','resent-cc','resent-date','resent-from','resent-msg-id','resent-sender','resent-to','trace');
$headers = array();

foreach ($p0 as $k1)
{
 $k1 = rtrim($k1);
 $a = $k1;
 $b = trim($k1);

 if ($a!==$b)
 {
  $p1 = trim($k1);
  if (in_array($current,$unlimited)) {array_push($headers[strtolower($current)],$p1);}
  else {$headers[strtolower($current)] .= $p1;}
 }
 else if (stristr($k1,':'))
 {
  $p1 = explode(':',$k1,2);
  if (in_array(strtolower($p1[0]),$unlimited))
  {
   if (!isset($headers[strtolower($p1[0])])) {$headers[strtolower($p1[0])] = array($p1[1]);}
   else {array_push($headers[strtolower($current)],$p1[1]);}
  }
  else
  {
   if (!isset($headers[strtolower($p1[0])])) {$headers[strtolower($p1[0])] = $p1[1];}
   else {$headers[strtolower($p1[0])] .= $p1[1];}
  }

  $current = $p1[0];
 }
}

ksort($headers);//Mainly for testing purposes, remove this afterwards.

echo '<div><pre>';
$a = print_r($headers,1);
echo htmlspecialchars($a).'</pre></div>';
?>