User login with API key using PHP code example

Example: login api in php

<?php
// required headers
header("Access-Control-Allow-Origin: http://localhost/rest-api-authentication-example/");
header("Content-Type: application/json; charset=UTF-8");
header("Access-Control-Allow-Methods: POST");
header("Access-Control-Max-Age: 3600");
header("Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With");
 
// database connection will be here