Call Ajax URL in Plugin

Question

Plugin Class File:

function __construct()
    {
        add_shortcode('user_registration_form', array($this, 'shortcode'));
    }

public function hook(){
        add_action( 'wp_ajax_get_product_serial_callback', 'get_product_serial_callback' );
        add_action( 'wp_ajax_nopriv_get_product_serial_callback', 'get_product_serial_callback' );
    }

public function product_serial_ajax() { ?>
        <script type="text/javascript">
                jQuery(document).ready(function(){
                    alert('Hello World!');

                    jQuery.ajax({
                                type: 'GET', 
                                url: "<?php echo admin_url('admin-ajax.php'); ?>",
                                //url: ajaxurl,
                                dataType : "JSON",
                                data : {action: "get_product_serial_callback"},
                                //cache: false, 
                                success: function(data){
                                alert('Eureka')';
                                }
                            });
                });
        </script><?php
    }

function csv_to_array($filename='', $delimiter=',')
    {
            //if(!file_exists($filename) || !is_readable($filename))
            //return FALSE;

            $header = NULL;
            $data = array();
            if (($handle = fopen($filename, 'r')) !== FALSE)
            {
                    while (($row = fgetcsv($handle, 1024, $delimiter)) !== FALSE)
                    {
                            if(!$header)
                                    $header = $row;
                            else
                                    $data[] = array_combine($header, $row);
                    }
                    fclose($handle);
            }
            return $data;
    }

function get_product_serial_callback(){

        $upload_dir = wp_upload_dir();
        $csvFile = $upload_dir['baseurl'].'/Eragon-Serial.csv';
        $csv = $this->csv_to_array($csvFile); //read csv

        foreach ($csv as $serialnum){
                $serial_num_array[]  = $serialnum['product_serial'];
        }

        $json_array = json_encode($serial_num_array);
        echo $json_array;
        die();
    }

function shortcode()
{
    $this->product_serial_ajax();//fetch product serial number
}

However, when encountered ajaxurl is not defined, I changed it ajaxurl which forms in below URL

http://example.com/wp-admin/admin-ajax.php?action=get_product_serial_callback

This too did not helped.

How can I call get_product_serial_callback function in order to fetch the JSON values and set those values in function(data) ?

Answer 1

Put below code in _construct() function and change action name to get_product_serial_callback :-

add_action( 'wp_ajax_get_product_serial_callback', array($this,'get_product_serial_callback') );
add_action( 'wp_ajax_nopriv_get_product_serial_callback', array($this,'get_product_serial_callback' ));

Answer 2

Plugin Class File:

function __construct()
    {


        add_shortcode('user_registration_form', array($this, 'shortcode'));
        wp_register_script('product-serial', plugins_url('bootstrap/js/product-serial.js', __FILE__),array('jquery')); //custom jquery for product serial
        wp_enqueue_script( 'product-serial' ); //custom jquery for product serial

        $this->hook();
    }

    public function hook()
    {
      add_action('wp_ajax_get_product_serial', array( $this,'get_product_serial'));
      add_action('wp_ajax_nopriv_get_product_serial',array( $this,'get_product_serial') );
    }

    public function product_serial_ajax(){ ?>

        <script type="text/javascript">load_product();</script>

        <?php
    }



   //convert csv data into array
    function csv_to_array($filename='', $delimiter=',')
    {
            //if(!file_exists($filename) || !is_readable($filename))
            //return FALSE;

            $header = NULL;
            $data = array();
            if (($handle = fopen($filename, 'r')) !== FALSE)
            {
                    while (($row = fgetcsv($handle, 1024, $delimiter)) !== FALSE)
                    {
                            if(!$header)
                                    $header = $row;
                            else
                                    $data[] = array_combine($header, $row);
                    }
                    fclose($handle);
            }
            return $data;
    }


    //get product serial number
    function get_product_serial(){


        $upload_dir = wp_upload_dir();
        $csvFile = $upload_dir['baseurl'].'/Eragon-Serial.csv';
        $csv = $this->csv_to_array($csvFile); //read csv

        foreach ($csv as $serialnum){
                $serial_num_array[]  = $serialnum['product_serial'];
        }

        $json_array = json_encode($serial_num_array);
        echo $json_array;
        die();
    }

    function shortcode()
    {
      $this->product_serial_ajax(); //fetch product serial number
    }

Seperate JS file

    function load_product(){
         jQuery.ajax({
          type: "GET", 
          url: ajaxurl,
          dataType : "JSON",
          data : {action: "get_product_serial"},
          //cache: false, 
          success: function(data){
            alert('Eureka');
          }
        });
    }

P.S: putting the following in the header.php of my theme worked for me

<script type="text/javascript">
    var ajaxurl = "<?php echo admin_url('admin-ajax.php'); ?>";
    </script>