In application/libraries/REST_Controller.php find the following function:

protected function _check_login($username = '', $password = NULL)</pre>
 {
 if (empty($username))
 {
 return FALSE;
 }

 $auth_source = strtolower($this->config->item('auth_source'));

if ($auth_source == 'ldap')
 {
 log_message('debug', 'performing LDAP authentication for $username');
 return $this->_perform_ldap_auth($username, $password);
 }

$valid_logins = & $this->config->item('rest_valid_logins');

if ( ! array_key_exists($username, $valid_logins))
 {
 return FALSE;
 }

// If actually NULL (not empty string) then do not check it
 if ($password !== NULL AND $valid_logins[$username] != $password)
 {
 return FALSE;
 }
 return TRUE;
 }

And replace it with the following:

protected function _check_login($username = '', $password = NULL)</pre>
{
 if (empty($username))
 {
 return FALSE;
 }
 return $this->tank_auth->login($username, $password, FALSE, FALSE, TRUE);
 }

If you are not auto loading the tank auth library, be sure to do that in your constructor as well.

<?php
 function print_nice($elem,$max_level=10,$print_nice_stack=array()){
 if(is_array($elem) || is_object($elem)){
 if(in_array(&$elem,$print_nice_stack,true)){
 echo "<font color=red>RECURSION</font>";
 return;
 }
 $print_nice_stack[]=&$elem;
 if($max_level<1){
 echo "<font color=red>nivel maximo alcanzado</font>";
 return;
 }
 $max_level--;
 echo "<table border=1 cellspacing=0 cellpadding=3 width=100%>";
 if(is_array($elem)){
 echo '<tr><td colspan=2  style="background-color:#333333;"><strong><font  color=white>ARRAY</font></strong></td></tr>';
 }else{
 echo '<tr><td colspan=2 style="background-color:#333333;"><strong>';
 echo '<font color=white>OBJECT Type: '.get_class($elem).'</font></strong></td></tr>';
 }
 $color=0;
 foreach($elem as $k => $v){
 if($max_level%2){
 $rgb=($color++%2)?"#888888":"#BBBBBB";
 }else{
 $rgb=($color++%2)?"#8888BB":"#BBBBFF";
 }
 echo '<tr><td valign="top" style="width:40px;background-color:'.$rgb.';">';
 echo '<strong>'.$k."</strong></td><td>";
 print_nice($v,$max_level,$print_nice_stack);
 echo "</td></tr>";
 }
 echo "</table>";
 return;
 }
 if($elem === null){
 echo "<font color=green>NULL</font>";
 }elseif($elem === 0){
 echo "0";
 }elseif($elem === true){
 echo "<font color=green>TRUE</font>";
 }elseif($elem === false){
 echo "<font color=green>FALSE</font>";
 }elseif($elem === ""){
 echo "<font color=green>EMPTY STRING</font>";
 }else{
 echo str_replace("\n","<strong><font color=red>*</font></strong><br>\n",$elem);
 }
 }
 ?>