heds up.. wp_remote_post, the Wordpress way

fetch_token.php

<?php
function get_POI_token($POI_URL_BASE, $POI_URL_TOKEN, $POI_PASS, $POI_USER, $POI_ID, $POI_SECRET){
//   do your houseworks..
	$url = $POI_URL_BASE.$POI_URL_TOKEN;
	$username = $POI_USER;
	$password = $POI_PASS;
	$client_id = $POI_ID;
	$client_secret = $POI_SECRET;
//   some wanted url encoded
	$args = array(
		'headers' => array(
			'Content-Type' => 'application/x-www-form-urlencoded',
			'Cache-Control' => 'no-cache'
		),

		"body" => "grant_type=password&client_id={$client_id}&client_secret={$client_secret}&username={$username}&password={$password}"
//     some likes it as json
		// 'headers' => array(
		// 	'Content-Type' => 'application/json',
		// ),
		// 'data' => json_encode(
		// 	array(
		// 		"grant_type" => "password",
		// 		'password' => $password,
		// 		'username' => $username,
		// 		'client_id' => $client_id,
		// 		'client_secret' => $client_secret
		// 	)
		// )
  	);
	$response = wp_remote_post($url, $args);
	if($response['response']['code'] == 200){
		$body = json_decode(wp_remote_retrieve_body($response));
		$payload = array(
			'token' => $body->access_token,
			'expires_in' => $body->expires_in
		);
		return $payload;
	}else{
		return false;
	}
}