PHP POST request with file_get_contents

post.php

<?php
$data = [];

// www-form-urlencoded
$opts = array('http' => array('method' => 'POST', 
			      'header' => 'Content-Type: application/x-www-form-urlencoded', 
			      'content' => http_build_query($data)
			     ));

// json  
$opts = array('http' => array('method' => 'POST', 
			      'header' => 'Content-Type: application/json\r\nAccept: application/json\r\n', 
			      'content' => json_encode($data)
			     ));

$context = stream_context_create($opts);

$result_json = file_get_contents('http://...', FALSE, $context);