This tutorial will help you to learn how to create rest api in cakephp. For this we need to follow the following steps:

Step1: Create a database and a table say "users"

Step2: Now we will create the Users Model, Veiw and Controller.

    users model:

    class User extends AppModel {


    }

Step3: Create a restful controller: RestUsersController.php

<?php 

class RestUsersController extends AppController {

    public $uses = array('User');
    public $helpers = array('Html', 'Form');
    public $components = array('RequestHandler');
    public function index() {
        $users = $this->User->find('all');
        $this->set(array(
            'users' => $users,
            '_serialize' => array('users')
        ));
    }

    public function add() {
        $this->User->create();
        if ($this->User->save($this->request->data)) {
             $message = 'Created';
        } else {
            $message = 'Error';
        }
        $this->set(array(
            'message' => $message,
            '_serialize' => array('message')
        ));
    }
    public function view($id) {
        $phone = $this->User->findById($id);
        $this->set(array(
            'phone' => $phone,
            '_serialize' => array('phone')
        ));
    }
    public function edit($id) {
        $this->User->id = $id;
        if ($this->User->save($this->request->data)) {
            $message = 'Saved';
        } else {
            $message = 'Error';
        }
        $this->set(array(
            'message' => $message,
            '_serialize' => array('message')
        ));
    }
    public function delete($id) {
        if ($this->User->delete($id)) {
            $message = 'Deleted';
        } else {
            $message = 'Error';
        }
        $this->set(array(
            'message' => $message,
            '_serialize' => array('message')
        ));
    }
}
?>

step 4: Now we will step a test ClientController

This controller uses CakePHPs HttpSocket class to make HTTP request to the REST service. This client can be run from a separate application on a different server to truly test communication between the client and the REST service.

<?php

App::uses('HttpSocket', 'Network/Http');
class ClientController extends AppController {
    public $components = array('Security', 'RequestHandler');

    public function index(){


    }

    public function request_index(){

        // remotely post the information to the server
        $link =  "http://" . $_SERVER['HTTP_HOST'] . $this->webroot.'rest_users.json';
        $data = null;
        $httpSocket = new HttpSocket();
        $response = $httpSocket->get($link, $data );
        $this->set('response_code', $response->code);
        $variables = $this->set('response_body', $response->body);

        $this -> render('/Client/request_response');
    }

    public function request_view($id){

        $link =  "http://" . $_SERVER['HTTP_HOST'] . $this->webroot.'rest_users/'.$id.'.json';
        $data = null;
        $httpSocket = new HttpSocket();
        $response = $httpSocket->get($link, $data );
        $this->set('response_code', $response->code);
        $this->set('response_body', $response->body);

        $this -> render('/Client/request_response');
    }

    public function request_edit($id=1){

        // remotely post the information to the server
        $link =  "http://" . $_SERVER['HTTP_HOST'] . $this->webroot.'rest_users/'.$id.'.json';
        $data = null;
        $httpSocket = new HttpSocket();
        $data['Phone']['name'] = 'Updated Phone Name';
        $data['Phone']['manufacturer'] = 'Updated Phone  Manufacturer';
        $data['Phone']['name'] = 'Updated Phone  Description';
        $response = $httpSocket->put($link, $data );
        $this->set('response_code', $response->code);
        $this->set('response_body', $response->body);

        $this -> render('/Client/request_response');
    }

    public function request_add(){

        // remotely post the information to the server
        $link =  "http://" . $_SERVER['HTTP_HOST'] . $this->webroot.'rest_users.json';
        $data = null;
        $httpSocket = new HttpSocket();
        $data['Phone']['name'] = 'New Phone';
        $data['Phone']['manufacturer'] = 'New Phone Manufacturer';
        $data['Phone']['name'] = 'New Phone Description';
        $response = $httpSocket->post($link, $data );
        $this->set('response_code', $response->code);
        $this->set('response_body', $response->body);

        $this -> render('/Client/request_response');
    }

    public function request_delete($id=4){

        // remotely post the information to the server
        $link =  "http://" . $_SERVER['HTTP_HOST'] . $this->webroot.'rest_users/'.$id.'.json';
        $data = null;
        $httpSocket = new HttpSocket();
        $response = $httpSocket->delete($link, $data );
        $this->set('response_code', $response->code);
        $this->set('response_body', $response->body);

        $this -> render('/Client/request_response');
    }
}

?>

step 5: Now to check if we are the RestUsersController or not:

We tell the security component to unlock the various REST actions for the HTTP requests, otherwise.Hence we change the AppController.php file:

public function beforeFilter() {

    if(in_array($this->params['controller'],array('rest_users'))){
        // For RESTful web service requests, we check the name of our contoller
        $this->Auth->allow();
        // this line should always be there to ensure that all rest calls are secure
        //$this->Security->requireSecure();
        //$this->Security->unlockedActions = array('index','edit','delete','add','view');

    }else{
        // setup out Auth
        $this->Auth->allow();        
    }
}

step 6: For making our application "RESTful" we modify our routes.php as below.

//In app/Config/routes.php...

Router::mapResources('users');
    Router::parseExtensions()

For more information see the link below:

http://miftyisbored.com/complete-restful-service-client-cakephp-tutorial/