angularjs + cakephp黑洞请求

I have created in the UsersController a method to add new users in database. In the cakephp ctp views files everything is okay, as my request is not black-holed. I am using post for this. But when I move the view to angularjs the request is black-holed. I don't get it. Can some one pls help me.

Here is the UsersController.php code,the function called add is the one doing the stuff:

<?php

class UsersController extends AppController {

public $components = array(
    'RequestHandler',
    'Security',
    'Session',
    'Auth'
);



public function login() {

    if ($this->Session->read('Auth.User')) {
        $this->set(array(
            'message' => array(
                'text' => __('You are logged in!'),
                'type' => 'error'
            ),
            '_serialize' => array('message')
        ));
    }

    if ($this->request->is('post')) {
        if(!empty($this->request->data)){
            $userDetails = $this->User->find('first', array(
                                             'conditions' => array(
                                             'User.username' => $this->request->data['username'],
                                             'User.password' => $this->request->data['password']
                                             )));
            debug($userDetails);
            debug($this->Auth->login());
        }
        if ($this->Auth->login()) {

            $this->set(array(
                'user' => $this->Session->read('Auth.User'),
                '_serialize' => array('user')
            ));
        } else {
            $this->set(array(
                'message' => array(
                    'text' => __('Invalid username or password, try again'),
                    'type' => 'error'
                ),
                '_serialize' => array('message')
            ));
            $this->response->statusCode(401);
        }
    }
}
public function logout() {
    if ($this->Auth->logout()) {
        $this->set(array(
            'message' => array(
                'text' => __('Logout successfully'),
                'type' => 'info'
            ),
            '_serialize' => array('message')
        ));
    }
}

public function add(){

    if($this->request->is('post')){
        if(!empty($this->request->data)){
            $password = $this->request->data['User']['password'];
            $username = $this->request->data['User']['username'];
            //$password = Security::hash($this->request->data['User']['password'], 'sha1', true);

            $password = Security::hash($password.$username, 'sha1', true);
            debug($password);
        }
    }

    //$this->set(array('message',array('error' => __("No data sent")), '_serialize' => array('message')));
}
public function index() {
    $this -> user = $this -> Auth -> user();
    if ($this -> user) {
        $this -> set('users', $this -> User -> find('all'));
        $this -> set('_serialize', array('users'));
    }
    else {
        $this -> set('error', 'user not logged in');
        $this -> set('_serialize', array('error'));
    }

}

public function user($id = null) {

    $this -> layout = null;

    if (!$id) {
        throw new NotFoundException(__('Invalid user'));
    }

    $user = $this -> User -> findById($id);

    if (!$user) {
        throw new NotFoundException(__('Invalid user'));
    }
    $this -> set('user', $user);
}

}
?>

And this is the angular controller:

angular.module('addUser.controllers', []).controller('addUserCtrl', function($scope, $http) {
$scope.register = function() {

    data = {'User':{
        'username' : $scope.username,
        'password' : $scope.password
    }};

    if(data.User.username != undefined && data.User.password != undefined){
        $http.post('API/users/add', data).success(function(data) {
        $scope.users = data.users;
        console.log(data);
    });
    }else{
        console.log('can\'t login');
    }
    /**/

};

});

PS: I am a beginner with cakephp. Thanks a lot and happy coding ;)

I found the solution to the problem, as I went through the entire cakephp book and got this solution, don't know if it is the right one, but for me works okay. This is the reference link and for me it was like the lines are in the book:

public function beforeFilter() {
    $this -> Security -> blackHoleCallback = 'blackhole';

}

public function blackhole($type) {
    return $type;// don't know if it is good or bad practice like this feel free to comment
}