1a2a48e129
Previously folder hierarchies were created based on the input URL which could result in very deep folder structures. Using SHA1 file names also allows to check for old files more effectively (via fileatime)
67 lines
2.4 KiB
PHP
67 lines
2.4 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, $duration = 86400){
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$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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public function get_cached_time($url){
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$filepath = $this->buildCacheFilePath($url);
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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 buildCacheFilePath($url){
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return __DIR__ . '/../cache/pages/' . sha1($url) . '.cache';
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}
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public function remove_from_cache($url){
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$filepath = $this->buildCacheFilePath($url);
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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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