latest.php

<?php
include_once("lib/backend/uvr1611.inc.php");
include_once("lib/error.inc.php");
include_once("lib/config.inc.php");

try {
	header('Cache-Control: no-cache, must-revalidate');
	header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
	header('Content-type: application/json; charset=utf-8');
	
	$config = Config::getInstance();

	$now = time();
	$date = isset($_GET["date"]) ? $_GET["date"] : $now;

	if($date < $now || !$config->app->latestcache) {
		// connect to database
		$database = Database::getInstance();
		echo preg_replace('/"(-?\d+\.?\d*)"/', '$1', json_encode($database->queryLatest($date)));
	}
	else 
	{
		$data = load_cache("uvr1611_latest", $config->app->latestcache);
	
		if(!$data)
		{
			$uvr = Uvr1611::getInstance();
			$latest = $uvr->getLatest();
			$latest["info"]["cached"] = false;
			$data = json_encode($latest);
			save_cache($latest,"uvr1611_latest");
		}
	
		echo $data;
	}
}
catch(Exception $e) {
	sendAjaxError($e);
}

function save_cache($data, $key) {
	$temp = sys_get_temp_dir();
	$key = md5($key);
	$data["info"]["cached"] = true;
	$data = serialize(json_encode($data));
	file_put_contents("$temp/$key", $data);
}

function load_cache($key, $expire) {
	$temp = sys_get_temp_dir();
	$key = md5($key);
	$path = "$temp/$key";
	if(file_exists($path))
	{
		if(time() < (filemtime($path) + $expire)) {
			return unserialize(file_get_contents($path));
		}
		unlink($path);
	}
	return false;
}