BP_Reply_By_Email_Parser::get_parameters PHP Method

    protected static function get_parameters()
    {
        // new items will always have "-new" appended to the querystring
        // we need to strip "-new" to get the querystring
        if (self::is_new_item()) {
            // check to see if user ID is set, if not, return false
            if (empty(self::$user->ID)) {
                return false;
            }
            $new = strrpos(self::$querystring, '-new');
            if ($new !== false) {
                // get rid of "-new" from the querystring
                $qs = substr(self::$querystring, 0, $new);
            } else {
                /**
                 * If new item querystring isn't default, let plugins render querystring.
                 *
                 * Plugins should return a querystring matching whitelisted parameters from the
                 * 'bp_rbe_allowed_params' filter.
                 *
                 * @since 1.0-RC4
                 *
                 * @param string $qs Current string.
                 */
                $qs = (string) apply_filters('bp_rbe_new_item_querystring', self::$querystring);
            }
        } else {
            $qs = self::$querystring;
        }
        // only decode if querystring is a hexadecimal string
        if (ctype_xdigit($qs)) {
            // New posted items will pass $user_id along with $qs for decoding
            // This is done as an additional security measure because the "From" header
            // can be spoofed and is similar to how Basecamp handles posting new items
            if (self::is_new_item()) {
                // pass $user_id to bp_rbe_decode()
                $qs = apply_filters('bp_rbe_decode_qs', bp_rbe_decode(array('string' => $qs, 'param' => self::$user->ID)), $qs, self::$user->ID);
                // Replied items will use the regular $qs for decoding
            } else {
                $qs = apply_filters('bp_rbe_decode_qs', bp_rbe_decode(array('string' => self::$querystring)), $qs, false);
            }
        }
        // These are the default params we want to check for
        $defaults = array('a' => false, 'p' => false, 't' => false, 'm' => false, 'g' => false);
        // Let 3rd-party plugins whitelist additional params
        $defaults = apply_filters('bp_rbe_allowed_params', $defaults, $qs);
        // Parse querystring into an array
        wp_parse_str($qs, $params);
        // Only allow parameters set from $defaults through
        $params = array_intersect_key($params, $defaults);
        // If no params, return false
        if (empty($params)) {
            return false;
        }
        return $params;
    }