how to get json return on php code example

Example 1: php response json

<?PHP
$data = /** whatever you're serializing **/;
header('Content-Type: application/json');
echo json_encode($data);

Example 2: convert text file to json php

<?php
  header('Content-type: application/json');
  echo json_encode( explode("\r\n",file_get_contents('data.txt')) );
?>