public function loadForecast()
{
//Open a handle to the DB
$dbh = db_connect();
//Check the DB for a cached forecast
$where = array('lat' => $this->lat, 'lon' => $this->lon);
$cache = db_fetchForecast($dbh, $where);
$forecast = $cache['json'];
$refresh = false;
//If no cache exists, refresh
if ($cache == null) {
$refresh = true;
}
//If freshness is older than threshold, refresh
if ($cache != null) {
$cacheFreshness = new DateTime($cache['fresh']);
$now = new DateTime();
if ($now > $cacheFreshness) {
$refresh = true;
}
}
//If a refresh is needed, pull fresh data, determine its fresh-til DateTime, and push it to the DB
if ($refresh == true) {
$forecast = $this->fetchForecast();
$freshUntil = new DateTime();
$threshold = new DateInterval('PT' . WEATHER_CACHE_MINUTES . 'M');
//Yeah, I hate it too.
$freshUntil->add($threshold);
$what = array('lat' => $this->lat, 'lon' => $this->lon, 'fresh' => $freshUntil->format('Y-m-d H:i:s'), 'json' => $forecast);
db_updateForecast($dbh, $what);
}
//Return either the cached or fresh forecast
return $forecast;
}
function db_updateForecast($dbh, $what)
{
$exists = db_fetchForecast($dbh, $what);
if ($exists == null) {
db_insertForecast($dbh, $what);
return;
}
$stmt = $dbh->prepare("\n\t\tUPDATE `weather_cache`\n\t\tSET\n\t\t`fresh` = :fresh,\n\t\t`json` = :json\n\t\tWHERE `lat` LIKE :lat\n\t\tAND `lon` LIKE :lon;\n\t");
$stmt->bindValue(':lat', $what['lat']);
$stmt->bindValue(':lon', $what['lon']);
$stmt->bindValue(':fresh', $what['fresh']);
$stmt->bindValue(':json', $what['json']);
$stmt->execute();
}
