public function __construct() {
    
    $this->load->helper('url');
    $this->load->library('session');
    $this->load->config('mx_acl', TRUE);
    
    $this->_config = $this->config->item('mx_acl');
    $this->_cache_path = $this->config->item('cache_path');
    
    /* previous flashdata is available to views */
    $this->load->vars($this->_config['error_var'], $this->session->flashdata($this->_config['error_var']));
    
    /* run the access control check now */
    ($this->_config['check_uri']) AND $this->check_uri();
}

/**
 * Check the current uri and user privileges against the cached ACL array
 * Redirect if access is denied
 *
 * @return void
 */
public function check_uri() {
    
    /* Load the cached access control list or show error */
    (is_file($cached_acl = $this->_cache_path.'mx_acl'.EXT)) OR show_error($this->_config['error_msg']);
    
    $acl = include $cached_acl;

    /* Match current url to access list */
    if (is_array($acl) AND $acl = $this->match_uri($this->current_uri(), $acl)) {
        
        /* Check session group against access level group */
        $allow_access = (bool)(in_array($this->session->userdata($this->_config['session_var']), $acl['allowed']));
            
         /* Additional check to allow IP addresses in range */
        if ( ! $allow_access AND isset($acl['ipl'])) $allow_access = $this->check_ip($acl['ipl']);
            
        if ($allow_access == FALSE)    {
            
            /* Set a return url into the session */
            $this->session->set_userdata('return_url', $this->uri->uri_string());
            
            /* set the error message... */
            $error_msg = (isset($acl['error_msg'])) ? $acl['error_msg'] : $this->_config['error_msg'];
                
            /* set a flash message... */
            $this->session->set_flashdata($this->_config['error_var'], $error_msg);        
                
            /* redirect to absolute url */
            die(header("Location: ".$acl['error_uri'], TRUE, 302));
        }
    }
}

/**
 * Return the access control profile for a given url
 *
 * @return string
 * @param string $current_uri
 * @param array  $acl
 */
private function match_uri($current_uri, $acl) {
    if (array_key_exists($current_uri, $acl)) {
        return $acl[$current_uri];            
    } else {
        if ($pos = strripos($current_uri, '/')) {
            return $this->match_uri(substr($current_uri, 0, $pos), $acl);
        }
    }
}

/**
 * Returns the current uri string from segments
 *
 * @return string
 */
private function current_uri() {
    return implode('/', $this->uri->rsegments);
}

/**
 * Checks the remote IP address against the specified $ipl array
 *
 * @return bool
 * @param array $ipl
 * @param string $remote_ip[optional]
 */    
 private function check_ip($ipl, $remote_ip = NULL) {
    
    /* Convert ip address into a double (for lousy OSes)*/
    $remote_ip = floatval(ip2long(($this->session->userdata('ip_address'))));
    
    /* Loop through the ip list array */
    foreach ($ipl as $allowed_ip) {
        
        /* Replace '*' (for IP ranges) with a suitable range number */
        $min = str_replace("*", "0", $allowed_ip);        
        $max = str_replace("*", "255", $allowed_ip);

        /* Check for a match */
        if (($remote_ip >= floatval(ip2long($min))) AND ($remote_ip <= floatval(ip2long($max)))) {
            return TRUE;
        }
    }
}

public function __get($var)    {
    static $CI;
    (is_object($CI)) OR $CI = get_instance();
    return $CI->$var;
}

} /* End of file MX_ACL.php / / Location: ./application/libraries/MX_ACL.php */

最后修改于 2010-03-08