MediaWiki  master
LCStoreDB.php
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1 <?php
24 use Wikimedia\ScopedCallback;
25 
31 class LCStoreDB implements LCStore {
33  private $code;
35  private $server;
36 
38  private $batch = [];
39 
41  private $dbw;
43  private $writesDone = false;
45  private $readOnly = false;
46 
47  public function __construct( $params ) {
48  $this->server = $params['server'] ?? [];
49  }
50 
51  public function get( $code, $key ) {
52  if ( $this->server || $this->writesDone ) {
53  // If a server configuration map is specified, always used that connection
54  // for reads and writes. Otherwise, if writes occurred in finishWrite(), make
55  // sure those changes are always visible.
56  $db = $this->getWriteConnection();
57  } else {
58  $db = wfGetDB( DB_REPLICA );
59  }
60 
61  $value = $db->newSelectQueryBuilder()
62  ->select( 'lc_value' )
63  ->from( 'l10n_cache' )
64  ->where( [ 'lc_lang' => $code, 'lc_key' => $key ] )
65  ->caller( __METHOD__ )->fetchField();
66 
67  return ( $value !== false ) ? unserialize( $db->decodeBlob( $value ) ) : null;
68  }
69 
70  public function startWrite( $code ) {
71  if ( $this->readOnly ) {
72  return;
73  } elseif ( !$code ) {
74  throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
75  }
76 
77  $dbw = $this->getWriteConnection();
78  $this->readOnly = $dbw->isReadOnly();
79 
80  $this->code = $code;
81  $this->batch = [];
82  }
83 
84  public function finishWrite() {
85  if ( $this->readOnly ) {
86  return;
87  } elseif ( $this->code === null ) {
88  throw new MWException( __CLASS__ . ': must call startWrite() before finishWrite()' );
89  }
90 
91  $scope = Profiler::instance()->getTransactionProfiler()->silenceForScope();
92  $dbw = $this->getWriteConnection();
93  $dbw->startAtomic( __METHOD__ );
94  try {
95  $dbw->newDeleteQueryBuilder()
96  ->deleteFrom( 'l10n_cache' )
97  ->where( [ 'lc_lang' => $this->code ] )
98  ->caller( __METHOD__ )->execute();
99  foreach ( array_chunk( $this->batch, 500 ) as $rows ) {
100  $dbw->newInsertQueryBuilder()
101  ->insertInto( 'l10n_cache' )
102  ->rows( $rows )
103  ->caller( __METHOD__ )->execute();
104  }
105  $this->writesDone = true;
106  } catch ( DBQueryError $e ) {
107  if ( $dbw->wasReadOnlyError() ) {
108  $this->readOnly = true; // just avoid site down time
109  } else {
110  throw $e;
111  }
112  }
113  $dbw->endAtomic( __METHOD__ );
114  ScopedCallback::consume( $scope );
115 
116  $this->code = null;
117  $this->batch = [];
118  }
119 
120  public function set( $key, $value ) {
121  if ( $this->readOnly ) {
122  return;
123  } elseif ( $this->code === null ) {
124  throw new MWException( __CLASS__ . ': must call startWrite() before set()' );
125  }
126 
127  $dbw = $this->getWriteConnection();
128 
129  $this->batch[] = [
130  'lc_lang' => $this->code,
131  'lc_key' => $key,
132  'lc_value' => $dbw->encodeBlob( serialize( $value ) )
133  ];
134  }
135 
139  private function getWriteConnection() {
140  if ( !$this->dbw ) {
141  if ( $this->server ) {
142  $dbFactory = MediaWikiServices::getInstance()->getDatabaseFactory();
143  $this->dbw = $dbFactory->create( $this->server['type'], $this->server );
144  if ( !$this->dbw ) {
145  throw new MWException( __CLASS__ . ': failed to obtain a DB connection' );
146  }
147  } else {
148  $this->dbw = wfGetDB( DB_PRIMARY );
149  }
150  }
151 
152  return $this->dbw;
153  }
154 }
wfGetDB( $db, $groups=[], $wiki=false)
Get a Database object.
LCStore implementation which uses the standard DB functions to store data.
Definition: LCStoreDB.php:31
finishWrite()
Finish a write transaction.
Definition: LCStoreDB.php:84
startWrite( $code)
Start a write transaction.
Definition: LCStoreDB.php:70
__construct( $params)
Definition: LCStoreDB.php:47
MediaWiki exception.
Definition: MWException.php:33
Service locator for MediaWiki core services.
static instance()
Singleton.
Definition: Profiler.php:108
Interface for the persistence layer of LocalisationCache.
Definition: LCStore.php:40
Basic database interface for live and lazy-loaded relation database handles.
Definition: IDatabase.php:36
endAtomic( $fname=__METHOD__)
Ends an atomic section of SQL statements.
newDeleteQueryBuilder()
Get an DeleteQueryBuilder bound to this connection.
startAtomic( $fname=__METHOD__, $cancelable=self::ATOMIC_NOT_CANCELABLE)
Begin an atomic section of SQL statements.
newInsertQueryBuilder()
Get an InsertQueryBuilder bound to this connection.
isReadOnly()
Check if this DB server is marked as read-only according to load balancer info.
encodeBlob( $b)
Some DBMSs have a special format for inserting into blob fields, they don't allow simple quoted strin...
wasReadOnlyError()
Determines if the last failure was due to the database being read-only.
const DB_REPLICA
Definition: defines.php:26
const DB_PRIMARY
Definition: defines.php:28