How to call method name in form action while working with REST API using codeigniter?

See more:

PHP

API

CodeIgniter

Hello everyone I am working on REST API in Codeigniter but i am surprise in normal codeigniter when we give method name after controller for example(localhost/project_name/controller/user_get) it will get all users from table but while working with REST API in Codeigniter I am getting unknown method error please tell me how to define method name while working with rest api in form action

below i have written my code

in view page when i want to click button in form it should call method and retrieve all users

What I have tried:

<form method="post" action="<?=base_url('index.php/Api/user_get')?>">

    <button>Click Here</button>


</form>

controller code

<?php

defined('BASEPATH') OR exit('No direct script access allowed');

require(APPPATH . '/libraries/REST_Controller.php');

class Api extends REST_Controller {

    public function __construct() {
        parent::__construct();
        $this->load->model('user_model');
    }


  public function user_get() {   //this method will get all users from table
            $r = $this->user_model->read();
            $this->response($r);
        }


      public function user_put() { //this method will insert users details 
           $id = $this->uri->segment(3);
            $data = array('name' => $this->input->get('user_name'),
                'pass' => $this->input->get('user_password'),
                'type' => $this->input->get('user_type')
            );
            $r = $this->user_model->update($id, $data);
            $this->response($r);
        }

}

below code is written in model

public function read() {



       $query = $this->db->query("select * from `tbl_user`");

       return $query->result_array();
   }

I am getting error like this mentioned

{"status":false,"error":"Unknown method"}

this the link for image getting error.

https://i.stack.imgur.com/ykktL.png