3a92a1e04b
Bridges no longer require to check cache file durations manually as get_cached now supports the duration parameter
52 lines
2 KiB
PHP
52 lines
2 KiB
PHP
<?php
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require_once(__DIR__ . '/BridgeInterface.php');
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/**
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* Extension of BridgeAbstract allowing caching of files downloaded over http.
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* TODO allow file cache invalidation by touching files on access, and removing
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* files/directories which have not been touched since ... a long time
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*/
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abstract class HttpCachingBridgeAbstract extends BridgeAbstract {
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/**
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* Maintain locally cached versions of pages to download, to avoid multiple downloads.
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* @param url url to cache
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* @param duration duration of the cache file in seconds (default: 24h/86400s)
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* @return content of the file as string
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*/
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public function get_cached($url, $duration = 86400){
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$filepath = $this->buildCacheFilePath($url);
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if(file_exists($filepath) && filectime($filepath) < time() - $duration){
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$this->debugMessage('Cache file ' . $filepath . ' exceeded duration of ' . $duration . ' seconds.');
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unlink ($filepath);
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$this->debugMessage('Cached file deleted: ' . $filepath);
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}
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if(file_exists($filepath)){
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$this->debugMessage('loading cached file from ' . $filepath . ' for page at url ' . $url);
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// TODO touch file and its parent, and try to do neighbour deletion
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touch($filepath);
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$content = file_get_contents($filepath);
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} else {
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$this->debugMessage('we have no local copy of ' . $url . ' Downloading to ' . $filepath);
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$dir = substr($filepath, 0, strrpos($filepath, '/'));
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if(!is_dir($dir)){
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$this->debugMessage('creating directories for ' . $dir);
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mkdir($dir, 0777, true);
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}
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$content = $this->getContents($url);
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if($content !== false){
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file_put_contents($filepath, $content);
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}
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}
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return str_get_html($content);
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}
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private function buildCacheFilePath($url){
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return __DIR__ . '/../cache/pages/' . sha1($url) . '.cache';
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}
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}
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