functions.util.php

<?php

/* REST API class */
class APIREST {

	private $url;

	public function __construct($url) {
		$this->url = $url;
	}

	/**
	* @param $httpheader array of headers
	* @return response
	*/
	public function call($httpheader, $method, $query = NULL) {

		try {

			$curl = curl_init();
			if (FALSE === $curl)
				throw new Exception('Failed to initialize');

			$curl_opt = array(
				CURLOPT_URL => $this->url,
				CURLOPT_RETURNTRANSFER => true,
				CURLOPT_ENCODING => "",
				CURLOPT_MAXREDIRS => 10,
				CURLOPT_TIMEOUT => 60, /* number of seconds to wait for response */
				CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
				CURLOPT_CUSTOMREQUEST => $method,
				CURLOPT_POSTFIELDS => $query,
				CURLOPT_HTTPHEADER => $httpheader
			);
			curl_setopt_array($curl, $curl_opt);

			$response = curl_exec($curl);
			if (FALSE === $response)
				throw new Exception(curl_error($curl), curl_errno($curl));

			$http_status = curl_getinfo($curl, CURLINFO_HTTP_CODE);

			if (200 != $http_status)
				throw new Exception($response, $http_status);
			curl_close($curl);

		} catch(Exception $e) {
			$response= $e->getCode() . $e->getMessage();
			echo $response;
		}

		return $response;
	}
}

/* get timestamp */

function milliseconds() {

	list($msec, $sec) = explode(' ', microtime());
	return (int) ($sec . substr($msec, 2, 3));

}

/* encrypt key */

function hmac($msg, $secret) {

	$hmac = hash_hmac('sha256', $msg, $secret, true);
	$hmac = base64_encode($hmac);
	return $hmac;

}

/* array depth */

function countdim($array) {

	if (is_array(reset($array))) {
		$return = countdim(reset($array)) + 1;
	} else {
		$return = 1;
	}
	return $return;

}

/*
asset pair only reported on weekdays
expect some asset pairs are not recorded on weekends, for instance fiat currencies like $AUD to $USD
*/

function weekends($class) {

	if ($class == 'fiat' || $class == 'stock') {
		$weekend = FALSE;
	} else {
		$weekend = TRUE;
	}
	return $weekend;

}

/* count number of observations falling on weekends */

function count_on_weekends($from, $to, $period_ms) {

	$wmiss = 0;
	for ($j = $from; $j <= $to; $j += $period_ms) {
		$day = date('l', $j / 1000);
		if (!($day == 'Sunday' || $day == 'Monday')) $wmiss++;
	}
	return $wmiss;

}