rfc822.php

This is the script which used on 10minutemail.com for temporary email.

                $parts      = explode(')', $comment);
                $comment    = $this->_splitCheck($parts, ')');
                $comments[] = $comment;

                // +1 is for the trailing )
                $_mailbox   = substr($_mailbox, strpos($_mailbox, $comment)+strlen($comment)+1);
            } else {
                break;
            }
        }

        foreach ($comments as $comment) {
            $mailbox = str_replace("($comment)", '', $mailbox);
        }

        $mailbox = trim($mailbox);

        // Check for name + route-addr
        if (substr($mailbox, -1) == '>' && substr($mailbox, 0, 1) != '<') {
            $parts  = explode('<', $mailbox);
            $name   = $this->_splitCheck($parts, '<');

            $phrase     = trim($name);
            $route_addr = trim(substr($mailbox, strlen($name.'<'), -1));

            if ($this->_validatePhrase($phrase) === false || ($route_addr = $this->_validateRouteAddr($route_addr)) === false) {
                return false;
            }

        // Only got addr-spec
        } else {
            // First snip angle brackets if present.
            if (substr($mailbox, 0, 1) == '<' && substr($mailbox, -1) == '>') {
                $addr_spec = substr($mailbox, 1, -1);
            } else {
                $addr_spec = $mailbox;
            }

            if (($addr_spec = $this->_validateAddrSpec($addr_spec)) === false) {
                return false;
            }
        }

        // Construct the object that will be returned.
        $mbox = new stdClass();

        // Add the phrase (even if empty) and comments
        $mbox->personal = $phrase;
        $mbox->comment  = isset($comments) ? $comments : array();

        if (isset($route_addr)) {
            $mbox->mailbox = $route_addr['local_part'];
            $mbox->host    = $route_addr['domain'];
            $route_addr['adl'] !== '' ? $mbox->adl = $route_addr['adl'] : '';
        } else {
            $mbox->mailbox = $addr_spec['local_part'];
            $mbox->host    = $addr_spec['domain'];
        }

        $mailbox = $mbox;
        return true;
    }

    /**
     * This function validates a route-addr which is:
     * route-addr = "<" [route] addr-spec ">"
     *
     * Angle brackets have already been removed at the point of
     * getting to this function.
     *
     * @access private
     * @param string $route_addr The string to check.
     * @return mixed False on failure, or an array containing validated address/route information on success.
     */
    function _validateRouteAddr($route_addr)
    {
        // Check for colon.
        if (strpos($route_addr, ':') !== false) {
            $parts = explode(':', $route_addr);
            $route = $this->_splitCheck($parts, ':');
        } else {
            $route = $route_addr;
        }

        // If $route is same as $route_addr then the colon was in
        // quotes or brackets or, of course, non existent.
        if ($route === $route_addr){
            unset($route);
            $addr_spec = $route_addr;
            if (($addr_spec = $this->_validateAddrSpec($addr_spec)) === false) {
                return false;
            }
        } else {
            // Validate route part.
            if (($route = $this->_validateRoute($route)) === false) {
                return false;
            }

            $addr_spec = substr($route_addr, strlen($route . ':'));

            // Validate addr-spec part.
            if (($addr_spec = $this->_validateAddrSpec($addr_spec)) === false) {
                return false;
            }
        }

        if (isset($route)) {
            $return['adl'] = $route;
        } else {
            $return['adl'] = '';
        }

        $return = array_merge($return, $addr_spec);
        return $return;
    }

    /**
     * Function to validate a route, which is:
     * route = 1#("@" domain) ":"
     *
     * @access private
     * @param string $route The string to check.
     * @return mixed False on failure, or the validated $route on success.
     */
    function _validateRoute($route)
    {
        // Split on comma.
        $domains = explode(',', trim($route));

        foreach ($domains as $domain) {
            $domain = str_replace('@', '', trim($domain));
            if (!$this->_validateDomain($domain)) return false;
        }

        return $route;
    }

    /**
     * Function to validate a domain, though this is not quite what
     * you expect of a strict internet domain.
     *
     * domain = sub-domain *("." sub-domain)
     *
     * @access private
     * @param string $domain The string to check.
     * @return mixed False on failure, or the validated domain on success.
     */
    function _validateDomain($domain)
    {
        // Note the different use of $subdomains and $sub_domains
        $subdomains = explode('.', $domain);

        while (count($subdomains) > 0) {
            $sub_domains[] = $this->_splitCheck($subdomains, '.');
            for ($i = 0; $i < $this->index + 1; $i++)
                array_shift($subdomains);
        }

        foreach ($sub_domains as $sub_domain) {
            if (!$this->_validateSubdomain(trim($sub_domain)))
                return false;
        }

        // Managed to get here, so return input.
        return $domain;
    }

    /**
     * Function to validate a subdomain:
     *   subdomain = domain-ref / domain-literal
     *
     * @access private
     * @param string $subdomain The string to check.
     * @return boolean Success or failure.
     */
    function _validateSubdomain($subdomain)
    {
        if (preg_match('|^\[(.*)]$|', $subdomain, $arr)){
            if (!$this->_validateDliteral($arr[1])) return false;
        } else {
            if (!$this->_validateAtom($subdomain)) return false;
        }

        // Got here, so return successful.
        return true;
    }

    /**
     * Function to validate a domain literal:
     *   domain-literal =  "[" *(dtext / quoted-pair) "]"
     *
     * @access private
     * @param string $dliteral The string to check.
     * @return boolean Success or failure.
     */
    function _validateDliteral($dliteral)
    {
        return !preg_match('/(.)[][\x0D\\\\]/', $dliteral, $matches) && $matches[1] != '\\';
    }

    /**
     * Function to validate an addr-spec.
     *
     * addr-spec = local-part "@" domain
     *
     * @access private
     * @param string $addr_spec The string to check.
     * @return mixed False on failure, or the validated addr-spec on success.
     */
    function _validateAddrSpec($addr_spec)
    {
        $addr_spec = trim($addr_spec);

        // Split on @ sign if there is one.
        if (strpos($addr_spec, '@') !== false) {
            $parts      = explode('@', $addr_spec);
            $local_part = $this->_splitCheck($parts, '@');
            $domain     = substr($addr_spec, strlen($local_part . '@'));

        // No @ sign so assume the default domain.
        } else {
            $local_part = $addr_spec;
            $domain     = $this->default_domain;
        }

        if (($local_part = $this->_validateLocalPart($local_part)) === false) return false;
        if (($domain     = $this->_validateDomain($domain)) === false) return false;

        // Got here so return successful.
        return array('local_part' => $local_part, 'domain' => $domain);
    }

    /**
     * Function to validate the local part of an address:
     *   local-part = word *("." word)
     *
     * @access private
     * @param string $local_part
     * @return mixed False on failure, or the validated local part on success.
     */
    function _validateLocalPart($local_part)
    {
        $parts = explode('.', $local_part);
        $words = array();

        // Split the local_part into words.
        while (count($parts) > 0){
            $words[] = $this->_splitCheck($parts, '.');
            for ($i = 0; $i < $this->index + 1; $i++) {
                array_shift($parts);
            }
        }

        // Validate each word.
        foreach ($words as $word) {
            // If this word contains an unquoted space, it is invalid. (6.2.4)
            if (strpos($word, ' ') && $word[0] !== '"')
            {
                return false;
            }

            if ($this->_validatePhrase(trim($word)) === false) return false;
        }

        // Managed to get here, so return the input.
        return $local_part;
    }

    /**
     * Returns an approximate count of how many addresses are in the
     * given string. This is APPROXIMATE as it only splits based on a
     * comma which has no preceding backslash. Could be useful as
     * large amounts of addresses will end up producing *large*
     * structures when used with parseAddressList().
     *
     * @param  string $data Addresses to count
     * @return int          Approximate count
     */
    function approximateCount($data)
    {
        return count(preg_split('/(?<!\\\\),/', $data));
    }

    /**
     * This is a email validating function separate to the rest of the
     * class. It simply validates whether an email is of the common
     * internet form: <user>@<domain>. This can be sufficient for most
     * people. Optional stricter mode can be utilised which restricts
     * mailbox characters allowed to alphanumeric, full stop, hyphen
     * and underscore.
     *
     * @param  string  $data   Address to check
     * @param  boolean $strict Optional stricter mode
     * @return mixed           False if it fails, an indexed array
     *                         username/domain if it matches
     */
    function isValidInetAddress($data, $strict = false)
    {
        $regex = $strict ? '/^([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})$/i' : '/^([*+!.&#$|\'\\%\/0-9a-z^_`{}=?~:-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})$/i';
        if (preg_match($regex, trim($data), $matches)) {
            return array($matches[1], $matches[2]);
        } else {
            return false;
        }
    }

}