/** * Retrieves data from cache, if it's there. If it is, but it's expired, * it performs a conditional GET to see if the data is updated. If it * isn't, it down updates the modification time of the cache file and * returns the data. If the cache is not there, or the remote file has been * modified, it is downloaded and cached. * * @param string URL of remote file to retrieve * @param int Length of time to cache file locally before asking the server * if it changed. * @return string File contents */ function retrieveFile($url, $cacheLength, $cacheDir) { $cacheID = md5($url); $cache = new Cache_Lite(array("cacheDir" => $cacheDir, "lifeTime" => $cacheLength)); if ($data = $cache->get($cacheID)) { return $data; } else { // we need to perform a request, so include HTTP_Request include_once 'HTTP/Request.php'; // HTTP_Request has moronic redirect "handling", turn that off (Alexey Borzov) $req = new HTTP_Request($url, array('allowRedirects' => false)); // if $cache->get($cacheID) found the file, but it was expired, // $cache->_file will exist if (isset($cache->_file) && file_exists($cache->_file)) { $req->addHeader('If-Modified-Since', gmdate("D, d M Y H:i:s", filemtime($cache->_file)) . " GMT"); } $req->sendRequest(); if (!($req->getResponseCode() == 304)) { // data is changed, so save it to cache $data = $req->getResponseBody(); $cache->save($data, $cacheID); return $data; } else { // retrieve the data, since the first time we did this failed if ($data = $cache->get($cacheID, 'default', true)) { return $data; } } } Services_ExchangeRates::raiseError("Unable to retrieve file {$url} (unknown reason)", SERVICES_EXCHANGERATES_ERROR_RETRIEVAL_FAILED); return false; }
function _retrieveFile($url, $cacheLength, $cacheDir) { $cacheID = md5($url); $cache = new Cache_Lite(array("cacheDir" => $cacheDir, "lifeTime" => $cacheLength)); if ($data = $cache->get($cacheID)) { return $data; } else { $fp = fopen($url, 'r'); $data = stream_get_contents($fp); if (strlen($data) > 10) { // data is changed, so save it to cache $cache->save($data, $cacheID); return $data; } else { // retrieve the data, since the first time we did this failed if ($data = $cache->get($cacheID, 'default', true)) { return $data; } } } Services_ExchangeRates::raiseError("Unable to retrieve file {$url} (unknown reason)", SERVICES_EXCHANGERATES_ERROR_RETRIEVAL_FAILED); return false; }
/** * Downloads exchange rates in terms of the PLN from the National Bank of * Poland (NBP). This information is updated daily, and is cached by default for 1 hour. * * Returns a multi-dimensional array containing: * 'rates' => associative array of currency codes to exchange rates * 'source' => URL of feed * 'date' => date feed last updated, pulled from the feed (more reliable than file mod time) * * @link http://www.nbp.pl/Kursy/RatesA.html English HTML version * @link http://www.nbp.pl/Kursy/KursyA.html Polish HTML version (with link to XML) * * @param int Length of time to cache (in seconds) * @return array */ function retrieve($cacheLength, $cacheDir) { $return['rates'] = array('PLN' => 1.0); // retrieve XML address $htmlpage = $this->retrieveFile($this->feedHTMLUrl, $cacheLength, $cacheDir); // Example line is: // <div class="file"><a href="xml/a055z020319.xml">powysza tabela w formacie .xml</a></div> if (!preg_match('#href="(xml/a\\d+z\\d+\\.xml)"#', $htmlpage, $match)) { Services_ExchangeRates::raiseError("Retrieved url " . $this->feedHTMLUrl . " has no link to XML page", SERVICES_EXCHANGERATES_RETRIEVAL_FAILED); return false; } $this->feedXMLUrl = $this->feedDir . $match[1]; $return['source'] = $this->_feedXMLUrl; // retrieve the feed from the server or cache $root = $this->retrieveXML($this->feedXMLUrl, $cacheLength, $cacheDir); // get down to array of exchange rates foreach ($root->children as $rateinfo) { if ($rateinfo->name == 'pozycja') { $rateinfo->children[4]->content = strtr($rateinfo->children[4]->content, ',', '.'); $value = $rateinfo->children[2]->content / $rateinfo->children[4]->content; // currency rate $return['rates'][$rateinfo->children[3]->content] = $value; } elseif ($rateinfo->name == 'data_publikacji') { // set date published $return['date'] = $rateinfo->content; } } return $return; }