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caches: Refactor the API (#1060)

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- For consistency, functions should always return null on non-existing data.

- WordPressPluginUpdateBridge appears to have used its own cache instance in the past. Obviously not used anymore.

- Since $key can be anything, the cache implementation must ensure to assign the related data reliably; most commonly by serializing and hashing the key in an appropriate way.

- Even though the default path for storage is perfectly fine, some people may want to use a different location. This is an example how a cache implementation is responsible for its requirements.
This commit is contained in:
fulmeek 2019-04-29 20:12:43 +02:00 committed by LogMANOriginal
parent 3b8f3da09d
commit 21d3bf3b60
8 changed files with 121 additions and 84 deletions
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4
actions/DisplayAction.php
View file

@ -86,9 +86,9 @@ class DisplayAction extends ActionAbstract {
// Initialize cache
$cache = Cache::create(Configuration::getConfig('cache', 'type'));
$cache->setPath(PATH_CACHE);
$cache->setScope('');
$cache->purgeCache(86400); // 24 hours
$cache->setParameters($cache_params);
$cache->setKey($cache_params);
$items = array();
$infos = array();

4
bridges/ElloBridge.php
View file

@ -121,8 +121,8 @@ class ElloBridge extends BridgeAbstract {
private function getAPIKey() {
$cache = Cache::create(Configuration::getConfig('cache', 'type'));
$cache->setPath(PATH_CACHE);
$cache->setParameters(['key']);
$cache->setScope(get_called_class());
$cache->setKey(['key']);
$key = $cache->loadData();
if($key == null) {

12
bridges/WordPressPluginUpdateBridge.php
View file

@ -71,16 +71,4 @@ class WordPressPluginUpdateBridge extends BridgeAbstract {
return parent::getName();
}
private function getCachedDate($url){
Debug::log('getting pubdate from url ' . $url . '');
// Initialize cache
$cache = Cache::create(Configuration::getConfig('cache', 'type'));
$cache->setPath(PATH_CACHE . 'pages/');
$params = [$url];
$cache->setParameters($params);
// Get cachefile timestamp
$time = $cache->getTime();
return ($time !== false ? $time : time());
}
}

72
caches/FileCache.php
View file

@ -3,20 +3,21 @@
* Cache with file system
*/
class FileCache implements CacheInterface {
protected $path;
protected $param;
protected $key;
public function loadData(){
if(file_exists($this->getCacheFile())) {
return unserialize(file_get_contents($this->getCacheFile()));
}
return null;
}
public function saveData($datas){
public function saveData($data){
// Notice: We use plain serialize() here to reduce memory footprint on
// large input data.
$writeStream = file_put_contents($this->getCacheFile(), serialize($datas));
$writeStream = file_put_contents($this->getCacheFile(), serialize($data));
if($writeStream === false) {
throw new \Exception('Cannot write the cache... Do you have the right permissions ?');
@ -29,13 +30,14 @@ class FileCache implements CacheInterface {
$cacheFile = $this->getCacheFile();
clearstatcache(false, $cacheFile);
if(file_exists($cacheFile)) {
return filemtime($cacheFile);
$time = filemtime($cacheFile);
return ($time !== false) ? $time : null;
}
return false;
return null;
}
public function purgeCache($duration){
public function purgeCache($seconds){
$cachePath = $this->getPath();
if(file_exists($cachePath)) {
$cacheIterator = new RecursiveIteratorIterator(
@ -47,7 +49,7 @@ class FileCache implements CacheInterface {
if(in_array($cacheFile->getBasename(), array('.', '..', '.gitkeep')))
continue;
elseif($cacheFile->isFile()) {
if(filemtime($cacheFile->getPathname()) < time() - $duration)
if(filemtime($cacheFile->getPathname()) < time() - $seconds)
unlink($cacheFile->getPathname());
}
}
@ -55,34 +57,34 @@ class FileCache implements CacheInterface {
}
/**
* Set cache path
* Set scope
* @return self
*/
public function setPath($path){
if(is_null($path) || !is_string($path)) {
throw new \Exception('The given path is invalid!');
public function setScope($scope){
if(is_null($scope) || !is_string($scope)) {
throw new \Exception('The given scope is invalid!');
}
$this->path = $path;
// Make sure path ends with '/' or '\'
$lastchar = substr($this->path, -1, 1);
if($lastchar !== '/' && $lastchar !== '\\')
$this->path .= '/';
if(!is_dir($this->path))
mkdir($this->path, 0755, true);
$this->path = PATH_CACHE . trim($scope, " \t\n\r\0\x0B\\\/") . '/';
return $this;
}
/**
* Set HTTP GET parameters
* Set key
* @return self
*/
public function setParameters(array $param){
$this->param = array_map('strtolower', $param);
public function setKey($key){
if (!empty($key) && is_array($key)) {
$key = array_map('strtolower', $key);
}
$key = json_encode($key);
if (!is_string($key)) {
throw new \Exception('The given key is invalid!');
}
$this->key = $key;
return $this;
}
@ -90,9 +92,15 @@ class FileCache implements CacheInterface {
* Return cache path (and create if not exist)
* @return string Cache path
*/
protected function getPath(){
private function getPath(){
if(is_null($this->path)) {
throw new \Exception('Call "setPath" first!');
throw new \Exception('Call "setScope" first!');
}
if(!is_dir($this->path)) {
if (mkdir($this->path, 0755, true) !== true) {
throw new \Exception('Unable to create ' . $this->path);
}
}
return $this->path;
@ -102,7 +110,7 @@ class FileCache implements CacheInterface {
* Get the file name use for cache store
* @return string Path to the file cache
*/
protected function getCacheFile(){
private function getCacheFile(){
return $this->getPath() . $this->getCacheName();
}
@ -110,13 +118,11 @@ class FileCache implements CacheInterface {
* Determines file name for store the cache
* return string
*/
protected function getCacheName(){
if(is_null($this->param)) {
throw new \Exception('Call "setParameters" first!');
private function getCacheName(){
if(is_null($this->key)) {
throw new \Exception('Call "setKey" first!');
}
// Change character when making incompatible changes to prevent loading
// errors due to incompatible file contents \|/
return hash('md5', http_build_query($this->param) . 'A') . '.cache';
return hash('md5', $this->key) . '.cache';
}
}

60
caches/SQLiteCache.php
View file

@ -3,16 +3,25 @@
* Cache based on SQLite 3 <https://www.sqlite.org>
*/
class SQLiteCache implements CacheInterface {
protected $path;
protected $param;
protected $scope;
protected $key;
private $db = null;
public function __construct() {
if (!extension_loaded('sqlite3'))
if (!extension_loaded('sqlite3')) {
die('"sqlite3" extension not loaded. Please check "php.ini"');
}
$file = PATH_CACHE . 'cache.sqlite';
$file = Configuration::getConfig(get_called_class(), 'file');
if (empty($file)) {
die('Configuration for ' . get_called_class() . ' missing. Please check your config.ini.php');
}
if (dirname($file) == '.') {
$file = PATH_CACHE . $file;
} elseif (!is_dir(dirname($file))) {
die('Invalid configuration for ' . get_called_class() . '. Please check your config.ini.php');
}
if (!is_file($file)) {
$this->db = new SQLite3($file);
@ -39,10 +48,10 @@ class SQLiteCache implements CacheInterface {
return null;
}
public function saveData($datas){
public function saveData($data){
$Qupdate = $this->db->prepare('INSERT OR REPLACE INTO storage (key, value, updated) VALUES (:key, :value, :updated)');
$Qupdate->bindValue(':key', $this->getCacheKey());
$Qupdate->bindValue(':value', serialize($datas));
$Qupdate->bindValue(':value', serialize($data));
$Qupdate->bindValue(':updated', time());
$Qupdate->execute();
@ -60,40 +69,53 @@ class SQLiteCache implements CacheInterface {
}
}
return false;
return null;
}
public function purgeCache($duration){
public function purgeCache($seconds){
$Qdelete = $this->db->prepare('DELETE FROM storage WHERE updated < :expired');
$Qdelete->bindValue(':expired', time() - $duration);
$Qdelete->bindValue(':expired', time() - $seconds);
$Qdelete->execute();
}
/**
* Set cache path
* Set scope
* @return self
*/
public function setPath($path){
$this->path = $path;
public function setScope($scope){
if(is_null($scope) || !is_string($scope)) {
throw new \Exception('The given scope is invalid!');
}
$this->scope = $scope;
return $this;
}
/**
* Set HTTP GET parameters
* Set key
* @return self
*/
public function setParameters(array $param){
$this->param = array_map('strtolower', $param);
public function setKey($key){
if (!empty($key) && is_array($key)) {
$key = array_map('strtolower', $key);
}
$key = json_encode($key);
if (!is_string($key)) {
throw new \Exception('The given key is invalid!');
}
$this->key = $key;
return $this;
}
////////////////////////////////////////////////////////////////////////////
protected function getCacheKey(){
if(is_null($this->param)) {
throw new \Exception('Call "setParameters" first!');
private function getCacheKey(){
if(is_null($this->key)) {
throw new \Exception('Call "setKey" first!');
}
return hash('sha1', $this->path . http_build_query($this->param), true);
return hash('sha1', $this->scope . $this->key, true);
}
}

5
config.default.ini.php
View file

@ -52,3 +52,8 @@ username = ""
; The password for authentication. Insert this password when prompted for login.
; Use a strong password to prevent others from guessing your login!
password = ""
; --- Cache specific configuration ---------------------------------------------
[SQLiteCache]
file = "cache.sqlite"

40
lib/CacheInterface.php
View file

@ -13,38 +13,54 @@
/**
* The cache interface
*
* @todo Add missing function to the interface
* @todo Explain parameters and return values in more detail
* @todo Return self more often (to allow call chaining)
*/
interface CacheInterface {
/**
* Set scope of the current cache
*
* If $scope is an empty string, the cache is set to a global context.
*
* @param string $scope The scope the data is related to
*/
public function setScope($scope);
/**
* Set key to assign the current data
*
* Since $key can be anything, the cache implementation must ensure to
* assign the related data reliably; most commonly by serializing and
* hashing the key in an appropriate way.
*
* @param array $key The key the data is related to
*/
public function setKey($key);
/**
* Loads data from cache
*
* @return mixed The cache data
* @return mixed The cached data or null
*/
public function loadData();
/**
* Stores data to the cache
*
* @param mixed $datas The data to store
* @param mixed $data The data to store
* @return self The cache object
*/
public function saveData($datas);
public function saveData($data);
/**
* Returns the timestamp for the curent cache file
* Returns the timestamp for the curent cache data
*
* @return int Timestamp
* @return int Timestamp or null
*/
public function getTime();
/**
* Removes any data that is older than the specified duration from cache
* Removes any data that is older than the specified age from cache
*
* @param int $duration The cache duration in seconds
* @param int $seconds The cache age in seconds
*/
public function purgeCache($duration);
public function purgeCache($seconds);
}

8
lib/contents.php
View file

@ -46,11 +46,11 @@ function getContents($url, $header = array(), $opts = array()){
// Initialize cache
$cache = Cache::create(Configuration::getConfig('cache', 'type'));
$cache->setPath(PATH_CACHE . 'server/');
$cache->setScope('server');
$cache->purgeCache(86400); // 24 hours (forced)
$params = [$url];
$cache->setParameters($params);
$cache->setKey($params);
// Use file_get_contents if in CLI mode with no root certificates defined
if(php_sapi_name() === 'cli' && empty(ini_get('curl.cainfo'))) {
@ -271,11 +271,11 @@ function getSimpleHTMLDOMCached($url,
// Initialize cache
$cache = Cache::create(Configuration::getConfig('cache', 'type'));
$cache->setPath(PATH_CACHE . 'pages/');
$cache->setScope('pages');
$cache->purgeCache(86400); // 24 hours (forced)
$params = [$url];
$cache->setParameters($params);
$cache->setKey($params);
// Determine if cached file is within duration
$time = $cache->getTime();