Horde_Mime_Part::setMetadata PHP Method

    public function setMetadata($key, $data = null)
    {
        if (is_null($data)) {
            unset($this->_metadata[$key]);
        } else {
            $this->_metadata[$key] = $data;
        }
    }

 /**
  * Parses an armored message into a Horde_Mime_Part object.
  *
  * @param mixed $text  Either the text to parse or a Horde_Stream object.
  *
  * @return mixed  Either null if no PGP data was found, or a
  *                Horde_Mime_Part object. For detached signature data:
  *                the full contents of the armored text (data + sig) is
  *                contained in the SIG_RAW metadata, and the charset is
  *                contained in the SIG_CHARSET metadata, within the
  *                application/pgp-signature part.
  */
 public function parseToPart($text, $charset = 'UTF-8')
 {
     $parts = $this->parse($text);
     if (empty($parts) || count($parts) == 1 && $parts[0]['type'] == self::ARMOR_TEXT) {
         return null;
     }
     $new_part = new Horde_Mime_Part();
     $new_part->setType('multipart/mixed');
     foreach ($parts as $val) {
         switch ($val['type']) {
             case self::ARMOR_TEXT:
                 $part = new Horde_Mime_Part();
                 $part->setType('text/plain');
                 $part->setCharset($charset);
                 $part->setContents(implode("\n", $val['data']));
                 $new_part->addPart($part);
                 break;
             case self::ARMOR_PUBLIC_KEY:
                 $part = new Horde_Mime_Part();
                 $part->setType('application/pgp-keys');
                 $part->setContents(implode("\n", $val['data']));
                 $new_part->addPart($part);
                 break;
             case self::ARMOR_MESSAGE:
                 $part = new Horde_Mime_Part();
                 $part->setType('multipart/encrypted');
                 $part->setMetadata(self::PGP_ARMOR, true);
                 $part->setContentTypeParameter('protocol', 'application/pgp-encrypted');
                 $part1 = new Horde_Mime_Part();
                 $part1->setType('application/pgp-encrypted');
                 $part1->setContents("Version: 1\n");
                 $part2 = new Horde_Mime_Part();
                 $part2->setType('application/octet-stream');
                 $part2->setContents(implode("\n", $val['data']));
                 $part2->setDisposition('inline');
                 $part->addPart($part1);
                 $part->addPart($part2);
                 $new_part->addPart($part);
                 break;
             case self::ARMOR_SIGNED_MESSAGE:
                 if (($sig = current($parts)) && $sig['type'] == self::ARMOR_SIGNATURE) {
                     $part = new Horde_Mime_Part();
                     $part->setType('multipart/signed');
                     // TODO: add micalg parameter
                     $part->setContentTypeParameter('protocol', 'application/pgp-signature');
                     $part1 = new Horde_Mime_Part();
                     $part1->setType('text/plain');
                     $part1->setCharset($charset);
                     $part1_data = implode("\n", $val['data']);
                     $part1->setContents(substr($part1_data, strpos($part1_data, "\n\n") + 2));
                     $part2 = new Horde_Mime_Part();
                     $part2->setType('application/pgp-signature');
                     $part2->setContents(implode("\n", $sig['data']));
                     $part2->setMetadata(self::SIG_CHARSET, $charset);
                     $part2->setMetadata(self::SIG_RAW, implode("\n", $val['data']) . "\n" . implode("\n", $sig['data']));
                     $part->addPart($part1);
                     $part->addPart($part2);
                     $new_part->addPart($part);
                     next($parts);
                 }
         }
     }
     return $new_part;
 }