84956c4daf
This allows to specify the cache duration for a specific url without the need to delete the cache file first. Instead the cache file is automatically deleted if the duration elapsed.
96 lines
3.4 KiB
PHP
96 lines
3.4 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, $duration = 86400){
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// TODO build this from the variable given to Cache
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$cacheDir = __DIR__ . '/../cache/pages/';
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$filepath = $this->buildCacheFilePath($url, $cacheDir);
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if(file_exists($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 ' . $url);
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// TODO touch file and its parent, and try to do neighbour deletion
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$this->refresh_in_cache($cacheDir, $filepath);
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$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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public function get_cached_time($url){
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// TODO build this from the variable given to Cache
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$cacheDir = __DIR__ . '/../cache/pages/';
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$filepath = $this->buildCacheFilePath($url, $cacheDir);
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if(!file_exists($filepath)){
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$this->get_cached($url);
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}
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return filectime($filepath);
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}
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private function refresh_in_cache($cacheDir, $filepath){
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$currentPath = $filepath;
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while(!$cacheDir == $currentPath){
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touch($currentPath);
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$currentPath = dirname($currentPath);
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}
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}
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private function buildCacheFilePath($url, $cacheDir){
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$simplified_url = str_replace(
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['http://', 'https://', '?', '&', '='],
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['', '', '/', '/', '/'],
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$url);
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if(substr($cacheDir, -1) !== '/'){
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$cacheDir .= '/';
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}
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$filepath = $cacheDir . $simplified_url;
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if(substr($filepath, -1) === '/'){
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$filepath .= 'index.html';
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}
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return $filepath;
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}
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public function remove_from_cache($url){
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// TODO build this from the variable given to Cache
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$cacheDir = __DIR__ . '/../cache/pages/';
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$filepath = $this->buildCacheFilePath($url, $cacheDir);
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$this->debugMessage('removing from cache \'' . $filepath . '\'');
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unlink($filepath);
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}
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}
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