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ParserCache Class Reference

Cache for ParserOutput objects corresponding to the latest page revisions. More...

Collaboration diagram for ParserCache:

Public Member Functions

 __construct (string $name, BagOStuff $cache, string $cacheEpoch, HookContainer $hookContainer, JsonCodec $jsonCodec, IBufferingStatsdDataFactory $stats, LoggerInterface $logger, TitleFactory $titleFactory, WikiPageFactory $wikiPageFactory, $useJson=false)
 Setup a cache pathway with a given back-end storage mechanism. More...
 
 deleteOptionsKey (PageRecord $page)
 
 get (PageRecord $page, $popts, $useOutdated=false)
 Retrieve the ParserOutput from ParserCache. More...
 
 getCacheStorage ()
 Get the backend BagOStuff instance that powers the parser cache. More...
 
 getDirty (PageRecord $page, $popts)
 Retrieve the ParserOutput from ParserCache, even if it's outdated. More...
 
 getMetadata (PageRecord $page, int $staleConstraint=self::USE_ANYTHING)
 Returns the ParserCache metadata about the given page considering the given options. More...
 
 makeParserOutputKey (PageRecord $page, ParserOptions $options, array $usedOptions=null)
 Get a key that will be used by the ParserCache to store the content for a given page considering the given options and the array of used options. More...
 
 save (ParserOutput $parserOutput, PageRecord $page, $popts, $cacheTime=null, $revId=null)
 
 setJsonSupport (bool $readJson, bool $writeJson)
 

Public Attributes

const USE_CURRENT_ONLY = 0
 Constants for self::getKey() More...
 
const USE_EXPIRED = 1
 Use expired data if current data is unavailable. More...
 
const USE_OUTDATED = 2
 Use expired data or data from different revisions if current data is unavailable. More...
 

Private Member Functions

 checkExpired (CacheTime $entry, PageRecord $page, int $staleConstraint, string $cacheTier)
 Check if $entry expired for $page given the $staleConstraint when fetching from $cacheTier. More...
 
 checkOutdated (CacheTime $entry, PageRecord $page, int $staleConstraint, string $cacheTier)
 Check if $entry belongs to the latest revision of $page given $staleConstraint when fetched from $cacheTier. More...
 
 encodeAsJson (CacheTime $obj, string $key)
 
 incrementStats (PageRecord $page, $metricSuffix)
 
 makeMetadataKey (PageRecord $page)
 
 restoreFromJson (string $jsonData, string $key, string $expectedClass)
 

Private Attributes

BagOStuff $cache
 
string $cacheEpoch
 Anything cached prior to this is invalidated. More...
 
HookRunner $hookRunner
 
JsonCodec $jsonCodec
 
LoggerInterface $logger
 
BagOStuff $metadataProcCache
 small in-process cache to store metadata. More...
 
string $name
 The name of this ParserCache. More...
 
bool $readJson = false
 
IBufferingStatsdDataFactory $stats
 
TitleFactory $titleFactory
 
WikiPageFactory $wikiPageFactory
 
bool $writeJson = false
 
const USE_ANYTHING = 3
 Use expired data and data from different revisions, and if all else fails vary on all variable options. More...
 

Detailed Description

Cache for ParserOutput objects corresponding to the latest page revisions.

The ParserCache is a two-tiered cache backed by BagOStuff which supports varying the stored content on the values of ParserOptions used during a page parse.

First tier is keyed by the page ID and stores ParserCacheMetadata, which contains information about cache expiration and the list of ParserOptions used during the parse of the page. For example, if only 'dateformat' and 'userlang' options were accessed by the parser when producing output for the page, array [ 'dateformat', 'userlang' ] will be stored in the metadata cache. This means none of the other existing options had any effect on the output.

The second tier of the cache contains ParserOutput objects. The key for the second tier is constructed from the page ID and values of those ParserOptions used during a page parse which affected the output. Upon cache lookup, the list of used option names is retrieved from tier 1 cache, and only the values of those options are hashed together with the page ID to produce a key, while the rest of the options are ignored. Following the example above where only [ 'dateformat', 'userlang' ] options changed the parser output for a page, the key will look like 'page_id!dateformat=default:userlang=ru'. Thus any cache lookup with dateformat=default and userlang=ru will hit the same cache entry regardless of the values of the rest of the options, since they were not accessed during a parse and thus did not change the output.

See also
ParserOutput::recordOption()
ParserOutput::getUsedOptions()
ParserOptions::allCacheVaryingOptions()

Definition at line 63 of file ParserCache.php.

Constructor & Destructor Documentation

◆ __construct()

ParserCache::__construct ( string  $name,
BagOStuff  $cache,
string  $cacheEpoch,
HookContainer  $hookContainer,
JsonCodec  $jsonCodec,
IBufferingStatsdDataFactory  $stats,
LoggerInterface  $logger,
TitleFactory  $titleFactory,
WikiPageFactory  $wikiPageFactory,
  $useJson = false 
)

Setup a cache pathway with a given back-end storage mechanism.

This class use an invalidation strategy that is compatible with MultiWriteBagOStuff in async replication mode.

Parameters
string$name
BagOStuff$cache
string$cacheEpochAnything before this timestamp is invalidated
HookContainer$hookContainer
JsonCodec$jsonCodec
IBufferingStatsdDataFactory$stats
LoggerInterface$logger
TitleFactory$titleFactory
WikiPageFactory$wikiPageFactory
bool$useJsonTemporary feature flag, remove before 1.36 is released.

Definition at line 153 of file ParserCache.php.

References $cache, $cacheEpoch, $jsonCodec, $logger, $name, $stats, $titleFactory, and $wikiPageFactory.

Member Function Documentation

◆ checkExpired()

ParserCache::checkExpired ( CacheTime  $entry,
PageRecord  $page,
int  $staleConstraint,
string  $cacheTier 
)
private

Check if $entry expired for $page given the $staleConstraint when fetching from $cacheTier.

Parameters
CacheTime$entry
PageRecord$page
int$staleConstraintOne of USE_* constants.
string$cacheTier
Returns
bool

Definition at line 542 of file ParserCache.php.

References CacheTime\getCacheTime(), Page\PageRecord\getTouched(), and incrementStats().

Referenced by get(), and getMetadata().

◆ checkOutdated()

ParserCache::checkOutdated ( CacheTime  $entry,
PageRecord  $page,
int  $staleConstraint,
string  $cacheTier 
)
private

Check if $entry belongs to the latest revision of $page given $staleConstraint when fetched from $cacheTier.

Parameters
CacheTime$entry
PageRecord$page
int$staleConstraintOne of USE_* constants.
string$cacheTier
Returns
bool

Definition at line 570 of file ParserCache.php.

References CacheTime\getCacheRevisionId(), Page\PageRecord\getLatest(), and incrementStats().

Referenced by get(), and getMetadata().

◆ deleteOptionsKey()

ParserCache::deleteOptionsKey ( PageRecord  $page)
Parameters
PageRecord$page
Since
1.28

Definition at line 183 of file ParserCache.php.

References MediaWiki\DAO\WikiAwareEntity\assertWiki(), and makeMetadataKey().

◆ encodeAsJson()

ParserCache::encodeAsJson ( CacheTime  $obj,
string  $key 
)
private
Parameters
CacheTime$obj
string$key
Returns
string|null

Definition at line 626 of file ParserCache.php.

Referenced by save().

◆ get()

ParserCache::get ( PageRecord  $page,
  $popts,
  $useOutdated = false 
)

Retrieve the ParserOutput from ParserCache.

false if not found or outdated.

Parameters
PageRecord$page
ParserOptions$popts
bool$useOutdated(default false)
Returns
ParserOutput|false

Definition at line 328 of file ParserCache.php.

References MediaWiki\DAO\WikiAwareEntity\assertWiki(), checkExpired(), checkOutdated(), Page\PageIdentity\exists(), getMetadata(), incrementStats(), Page\PageRecord\isRedirect(), makeParserOutputKey(), BagOStuff\READ_VERIFIED, restoreFromJson(), USE_CURRENT_ONLY, and USE_OUTDATED.

◆ getCacheStorage()

ParserCache::getCacheStorage ( )

Get the backend BagOStuff instance that powers the parser cache.

Since
1.30
Access: internal
Returns
BagOStuff

Definition at line 529 of file ParserCache.php.

References $cache.

◆ getDirty()

ParserCache::getDirty ( PageRecord  $page,
  $popts 
)

Retrieve the ParserOutput from ParserCache, even if it's outdated.

Parameters
PageRecord$page
ParserOptions$popts
Returns
ParserOutput|false

Definition at line 196 of file ParserCache.php.

References MediaWiki\DAO\WikiAwareEntity\assertWiki(), and true.

Referenced by RefreshLinksJob\getParserOutputFromCache().

◆ getMetadata()

ParserCache::getMetadata ( PageRecord  $page,
int  $staleConstraint = self::USE_ANYTHING 
)

Returns the ParserCache metadata about the given page considering the given options.

Note
Which parser options influence the cache key is controlled via ParserOutput::recordOption() or ParserOptions::addExtraKey().
Parameters
PageRecord$page
int$staleConstraintone of the self::USE_ constants
Returns
ParserCacheMetadata|null
Since
1.36

Definition at line 226 of file ParserCache.php.

References MediaWiki\DAO\WikiAwareEntity\assertWiki(), checkExpired(), checkOutdated(), incrementStats(), makeMetadataKey(), BagOStuff\READ_VERIFIED, and restoreFromJson().

Referenced by get().

◆ incrementStats()

ParserCache::incrementStats ( PageRecord  $page,
  $metricSuffix 
)
private
Parameters
PageRecord$page
string$metricSuffix

Definition at line 206 of file ParserCache.php.

Referenced by checkExpired(), checkOutdated(), get(), getMetadata(), and save().

◆ makeMetadataKey()

ParserCache::makeMetadataKey ( PageRecord  $page)
private
Parameters
PageRecord$page
Returns
string

Definition at line 280 of file ParserCache.php.

References Page\PageIdentity\getId().

Referenced by deleteOptionsKey(), getMetadata(), and save().

◆ makeParserOutputKey()

ParserCache::makeParserOutputKey ( PageRecord  $page,
ParserOptions  $options,
array  $usedOptions = null 
)

Get a key that will be used by the ParserCache to store the content for a given page considering the given options and the array of used options.

Warning
The exact format of the key is considered internal and is subject to change, thus should not be used as storage or long-term caching key. This is intended to be used for logging or keying something transient.
Parameters
PageRecord$page
ParserOptions$options
array | null$usedOptionsDefaults to all cache verying options.
Returns
string
Access: internal
Since
1.36

Definition at line 300 of file ParserCache.php.

References $title, $wgRequest, ParserOptions\allCacheVaryingOptions(), Page\PageIdentity\getId(), and ParserOptions\optionsHash().

Referenced by get(), and save().

◆ restoreFromJson()

ParserCache::restoreFromJson ( string  $jsonData,
string  $key,
string  $expectedClass 
)
private
Parameters
string$jsonData
string$key
string$expectedClass
Returns
CacheTime|ParserOutput|null

Definition at line 606 of file ParserCache.php.

Referenced by get(), and getMetadata().

◆ save()

ParserCache::save ( ParserOutput  $parserOutput,
PageRecord  $page,
  $popts,
  $cacheTime = null,
  $revId = null 
)

◆ setJsonSupport()

ParserCache::setJsonSupport ( bool  $readJson,
bool  $writeJson 
)
Note
setter for temporary feature flags, for use in testing.
Access: internal
Parameters
bool$readJson
bool$writeJson

Definition at line 595 of file ParserCache.php.

References $readJson, and $writeJson.

Member Data Documentation

◆ $cache

BagOStuff ParserCache::$cache
private

Definition at line 89 of file ParserCache.php.

Referenced by __construct(), and getCacheStorage().

◆ $cacheEpoch

string ParserCache::$cacheEpoch
private

Anything cached prior to this is invalidated.

Definition at line 96 of file ParserCache.php.

Referenced by __construct().

◆ $hookRunner

HookRunner ParserCache::$hookRunner
private

Definition at line 99 of file ParserCache.php.

◆ $jsonCodec

JsonCodec ParserCache::$jsonCodec
private

Definition at line 102 of file ParserCache.php.

Referenced by __construct().

◆ $logger

LoggerInterface ParserCache::$logger
private

Definition at line 108 of file ParserCache.php.

Referenced by __construct().

◆ $metadataProcCache

BagOStuff ParserCache::$metadataProcCache
private

small in-process cache to store metadata.

It's needed multiple times during the request, for example to build a PoolWorkArticleView key, and then to fetch the actual ParserCache entry.

Definition at line 122 of file ParserCache.php.

◆ $name

string ParserCache::$name
private

The name of this ParserCache.

Used as a root of the cache key.

Definition at line 86 of file ParserCache.php.

Referenced by __construct().

◆ $readJson

bool ParserCache::$readJson = false
private
Note
Temporary feature flag, remove before 1.36 is released.

Definition at line 134 of file ParserCache.php.

Referenced by setJsonSupport().

◆ $stats

IBufferingStatsdDataFactory ParserCache::$stats
private

Definition at line 105 of file ParserCache.php.

Referenced by __construct().

◆ $titleFactory

TitleFactory ParserCache::$titleFactory
private

Definition at line 111 of file ParserCache.php.

Referenced by __construct().

◆ $wikiPageFactory

WikiPageFactory ParserCache::$wikiPageFactory
private

Definition at line 114 of file ParserCache.php.

Referenced by __construct().

◆ $writeJson

bool ParserCache::$writeJson = false
private
Note
Temporary feature flag, remove before 1.36 is released.

Definition at line 128 of file ParserCache.php.

Referenced by setJsonSupport().

◆ USE_ANYTHING

const ParserCache::USE_ANYTHING = 3
private

Use expired data and data from different revisions, and if all else fails vary on all variable options.

Definition at line 83 of file ParserCache.php.

◆ USE_CURRENT_ONLY

const ParserCache::USE_CURRENT_ONLY = 0

Constants for self::getKey()

Since
1.30
1.36 the constants were made public Use only current data

Definition at line 71 of file ParserCache.php.

Referenced by get().

◆ USE_EXPIRED

const ParserCache::USE_EXPIRED = 1

Use expired data if current data is unavailable.

Definition at line 74 of file ParserCache.php.

◆ USE_OUTDATED

const ParserCache::USE_OUTDATED = 2

Use expired data or data from different revisions if current data is unavailable.

Definition at line 77 of file ParserCache.php.

Referenced by get().


The documentation for this class was generated from the following file: