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FileCacheBase.php
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1 <?php
29 abstract class FileCacheBase {
30  protected $mKey;
31  protected $mType = 'object';
32  protected $mExt = 'cache';
33  protected $mFilePath;
34  protected $mUseGzip;
35  /* lazy loaded */
36  protected $mCached;
37 
38  /* @todo configurable? */
39  const MISS_FACTOR = 15; // log 1 every MISS_FACTOR cache misses
40  const MISS_TTL_SEC = 3600; // how many seconds ago is "recent"
41 
42  protected function __construct() {
43  global $wgUseGzip;
44 
45  $this->mUseGzip = (bool)$wgUseGzip;
46  }
47 
52  final protected function baseCacheDirectory() {
53  global $wgFileCacheDirectory;
54 
55  return $wgFileCacheDirectory;
56  }
57 
62  abstract protected function cacheDirectory();
63 
68  protected function cachePath() {
69  if ( $this->mFilePath !== null ) {
70  return $this->mFilePath;
71  }
72 
73  $dir = $this->cacheDirectory();
74  # Build directories (methods include the trailing "/")
75  $subDirs = $this->typeSubdirectory() . $this->hashSubdirectory();
76  # Avoid extension confusion
77  $key = str_replace( '.', '%2E', urlencode( $this->mKey ) );
78  # Build the full file path
79  $this->mFilePath = "{$dir}/{$subDirs}{$key}.{$this->mExt}";
80  if ( $this->useGzip() ) {
81  $this->mFilePath .= '.gz';
82  }
83 
84  return $this->mFilePath;
85  }
86 
91  public function isCached() {
92  if ( $this->mCached === null ) {
93  $this->mCached = file_exists( $this->cachePath() );
94  }
95 
96  return $this->mCached;
97  }
98 
103  public function cacheTimestamp() {
104  $timestamp = filemtime( $this->cachePath() );
105 
106  return ( $timestamp !== false )
107  ? wfTimestamp( TS_MW, $timestamp )
108  : false;
109  }
110 
117  public function isCacheGood( $timestamp = '' ) {
118  global $wgCacheEpoch;
119 
120  if ( !$this->isCached() ) {
121  return false;
122  }
123 
124  $cachetime = $this->cacheTimestamp();
125  $good = ( $timestamp <= $cachetime && $wgCacheEpoch <= $cachetime );
126  wfDebug( __METHOD__ .
127  ": cachetime $cachetime, touched '{$timestamp}' epoch {$wgCacheEpoch}, good $good\n" );
128 
129  return $good;
130  }
131 
136  protected function useGzip() {
137  return $this->mUseGzip;
138  }
139 
144  public function fetchText() {
145  if ( $this->useGzip() ) {
146  $fh = gzopen( $this->cachePath(), 'rb' );
147 
148  return stream_get_contents( $fh );
149  } else {
150  return file_get_contents( $this->cachePath() );
151  }
152  }
153 
159  public function saveText( $text ) {
160  if ( $this->useGzip() ) {
161  $text = gzencode( $text );
162  }
163 
164  $this->checkCacheDirs(); // build parent dir
165  if ( !file_put_contents( $this->cachePath(), $text, LOCK_EX ) ) {
166  wfDebug( __METHOD__ . "() failed saving " . $this->cachePath() . "\n" );
167  $this->mCached = null;
168 
169  return false;
170  }
171 
172  $this->mCached = true;
173 
174  return $text;
175  }
176 
181  public function clearCache() {
182  Wikimedia\suppressWarnings();
183  unlink( $this->cachePath() );
184  Wikimedia\restoreWarnings();
185  $this->mCached = false;
186  }
187 
192  protected function checkCacheDirs() {
193  wfMkdirParents( dirname( $this->cachePath() ), null, __METHOD__ );
194  }
195 
203  protected function typeSubdirectory() {
204  return $this->mType . '/';
205  }
206 
212  protected function hashSubdirectory() {
213  global $wgFileCacheDepth;
214 
215  $subdir = '';
216  if ( $wgFileCacheDepth > 0 ) {
217  $hash = md5( $this->mKey );
218  for ( $i = 1; $i <= $wgFileCacheDepth; $i++ ) {
219  $subdir .= substr( $hash, 0, $i ) . '/';
220  }
221  }
222 
223  return $subdir;
224  }
225 
231  public function incrMissesRecent( WebRequest $request ) {
232  if ( mt_rand( 0, self::MISS_FACTOR - 1 ) == 0 ) {
233  # Get a large IP range that should include the user even if that
234  # person's IP address changes
235  $ip = $request->getIP();
236  if ( !IP::isValid( $ip ) ) {
237  return;
238  }
239 
240  $ip = IP::isIPv6( $ip )
241  ? IP::sanitizeRange( "$ip/32" )
242  : IP::sanitizeRange( "$ip/16" );
243 
244  # Bail out if a request already came from this range...
246  $key = $cache->makeKey( static::class, 'attempt', $this->mType, $this->mKey, $ip );
247  if ( !$cache->add( $key, 1, self::MISS_TTL_SEC ) ) {
248  return; // possibly the same user
249  }
250 
251  # Increment the number of cache misses...
252  $cache->incrWithInit( $this->cacheMissKey( $cache ), self::MISS_TTL_SEC );
253  }
254  }
255 
260  public function getMissesRecent() {
262 
263  return self::MISS_FACTOR * $cache->get( $this->cacheMissKey( $cache ) );
264  }
265 
270  protected function cacheMissKey( BagOStuff $cache ) {
271  return $cache->makeKey( static::class, 'misses', $this->mType, $this->mKey );
272  }
273 }
isCacheGood( $timestamp='')
Check if up to date cache file exists.
getIP()
Work out the IP address based on various globals For trusted proxies, use the XFF client IP (first of...
incrMissesRecent(WebRequest $request)
Roughly increments the cache misses in the last hour by unique visitors.
baseCacheDirectory()
Get the base file cache directory.
makeKey( $class,... $components)
Make a cache key, scoped to this instance&#39;s keyspace.
static getLocalClusterInstance()
Get the main cluster-local cache object.
$wgFileCacheDepth
Depth of the subdirectory hierarchy to be created under $wgFileCacheDirectory.
static sanitizeRange( $range)
Gets rid of unneeded numbers in quad-dotted/octet IP strings For example, 127.111.113.151/24 -> 127.111.113.0/24.
Definition: IP.php:712
cacheTimestamp()
Get the last-modified timestamp of the cache file.
isCached()
Check if the cache file exists.
wfTimestamp( $outputtype=TS_UNIX, $ts=0)
Get a timestamp string in one of various formats.
typeSubdirectory()
Get the cache type subdirectory (with trailing slash) An extending class could use that method to alt...
wfDebug( $text, $dest='all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
Base class for data storage in the file system.
static isValid( $ip)
Validate an IP address.
Definition: IP.php:111
$cache
Definition: mcc.php:33
$wgUseGzip
When using the file cache, we can store the cached HTML gzipped to save disk space.
cachePath()
Get the path to the cache file.
hashSubdirectory()
Return relative multi-level hash subdirectory (with trailing slash) or the empty string if not $wgFil...
cacheDirectory()
Get the base cache directory (not specific to this file)
fetchText()
Get the uncompressed text from the cache.
getMissesRecent()
Roughly gets the cache misses in the last hour by unique visitors.
clearCache()
Clear the cache for this page.
static isIPv6( $ip)
Given a string, determine if it as valid IP in IPv6 only.
Definition: IP.php:88
wfMkdirParents( $dir, $mode=null, $caller=null)
Make directory, and make all parent directories if they don&#39;t exist.
useGzip()
Check if the cache is gzipped.
checkCacheDirs()
Create parent directors of $this->cachePath()
cacheMissKey(BagOStuff $cache)
$wgCacheEpoch
Set this to current time to invalidate all prior cached pages.
$wgFileCacheDirectory
Directory where the cached page will be saved.
saveText( $text)
Save and compress text to the cache.