coinex_api.php

<?php
function api_query($http_method, $method, array $req = array()) {
	$key = '';
	$secret = '';

	$post_data = $http_method == 'POST' ? json_encode($req) : '';
	$sign = hash_hmac('sha512', $post_data, $secret);

	$headers = array(
		'Content-type: application/json',
		'API-Key: '.$key,
		'API-Sign: '.$sign
	);

	static $ch = null;
	if (is_null($ch)) {
		$ch = curl_init();
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
		curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; CoinEx API PHP client; '.php_uname('s').'; PHP/'.phpversion().')');
	}
	curl_setopt($ch, CURLOPT_URL, 'https://coinex.pw/api/v2/'.$method);
	if ($http_method == 'POST') curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
	curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);

	$res = curl_exec($ch);
	if ($res === false) throw new Exception('Could not get reply: '.curl_error($ch));

	$dec = json_decode($res, true);
	if (!$dec) throw new Exception('Invalid data received, please make sure connection is working and requested API exists');
	return $dec;
}
$req = array();
$order = array();

$order['trade_pair_id'] = 15;
$order['amount'] = 100000000;
$order['rate'] = 500000;
$order['bid'] = false;
$req['order'] = $order;

$result = api_query('POST', 'orders', $req);
#$result = api_query('POST', 'orders/44685/cancel');
#$result = api_query('GET', 'balances');

echo print_r($result), "\n";
?>

Was this code not meant to be run? I'm receiving error 422 Unprocessable Entity using my API keys. (I've been having difficulties testing my own script and decided to test this for insights.)