MediaWiki  REL1_28
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1 <?php
33  protected static $reservedMemory;
37  protected static $fatalErrorTypes = [
39  /* HHVM's FATAL_ERROR level */ 16777217,
40  ];
44  protected static $handledFatalCallback = false;
49  public static function installHandler() {
50  set_exception_handler( 'MWExceptionHandler::handleException' );
51  set_error_handler( 'MWExceptionHandler::handleError' );
53  // Reserve 16k of memory so we can report OOM fatals
54  self::$reservedMemory = str_repeat( ' ', 16384 );
55  register_shutdown_function( 'MWExceptionHandler::handleFatalError' );
56  }
62  protected static function report( $e ) {
63  try {
64  // Try and show the exception prettily, with the normal skin infrastructure
65  if ( $e instanceof MWException ) {
66  // Delegate to MWException until all subclasses are handled by
67  // MWExceptionRenderer and MWException::report() has been
68  // removed.
69  $e->report();
70  } else {
72  }
73  } catch ( Exception $e2 ) {
74  // Exception occurred from within exception handler
75  // Show a simpler message for the original exception,
76  // don't try to invoke report()
78  }
79  }
89  public static function rollbackMasterChangesAndLog( $e ) {
90  $services = MediaWikiServices::getInstance();
91  if ( $services->isServiceDisabled( 'DBLoadBalancerFactory' ) ) {
92  return; // T147599
93  }
95  $lbFactory = $services->getDBLoadBalancerFactory();
96  if ( $lbFactory->hasMasterChanges() ) {
97  $logger = LoggerFactory::getInstance( 'Bug56269' );
98  $logger->warning(
99  'Exception thrown with an uncommited database transaction: ' .
100  self::getLogMessage( $e ),
101  self::getLogContext( $e )
102  );
103  }
104  $lbFactory->rollbackMasterChanges( __METHOD__ );
105  }
121  public static function handleException( $e ) {
122  try {
123  // Rollback DBs to avoid transaction notices. This may fail
124  // to rollback some DB due to connection issues or exceptions.
125  // However, any sane DB driver will rollback implicitly anyway.
127  } catch ( DBError $e2 ) {
128  // If the DB is unreacheable, rollback() will throw an error
129  // and the error report() method might need messages from the DB,
130  // which would result in an exception loop. PHP may escalate such
131  // errors to "Exception thrown without a stack frame" fatals, but
132  // it's better to be explicit here.
133  self::logException( $e2 );
134  }
137  self::report( $e );
139  // Exit value should be nonzero for the benefit of shell jobs
140  exit( 1 );
141  }
161  public static function handleError(
162  $level, $message, $file = null, $line = null
163  ) {
164  if ( in_array( $level, self::$fatalErrorTypes ) ) {
165  return call_user_func_array(
166  'MWExceptionHandler::handleFatalError', func_get_args()
167  );
168  }
170  // Map error constant to error name (reverse-engineer PHP error
171  // reporting)
172  switch ( $level ) {
174  $levelName = 'Error';
175  break;
176  case E_WARNING:
177  case E_CORE_WARNING:
179  case E_USER_WARNING:
180  $levelName = 'Warning';
181  break;
182  case E_NOTICE:
183  case E_USER_NOTICE:
184  $levelName = 'Notice';
185  break;
186  case E_STRICT:
187  $levelName = 'Strict Standards';
188  break;
189  case E_DEPRECATED:
191  $levelName = 'Deprecated';
192  break;
193  default:
194  $levelName = 'Unknown error';
195  break;
196  }
198  $e = new ErrorException( "PHP $levelName: $message", 0, $level, $file, $line );
199  self::logError( $e, 'error' );
201  // This handler is for logging only. Return false will instruct PHP
202  // to continue regular handling.
203  return false;
204  }
227  public static function handleFatalError(
228  $level = null, $message = null, $file = null, $line = null,
229  $context = null, $trace = null
230  ) {
231  // Free reserved memory so that we have space to process OOM
232  // errors
233  self::$reservedMemory = null;
235  if ( $level === null ) {
236  // Called as a shutdown handler, get data from error_get_last()
237  if ( static::$handledFatalCallback ) {
238  // Already called once (probably as an error handler callback
239  // under HHVM) so don't log again.
240  return false;
241  }
243  $lastError = error_get_last();
244  if ( $lastError !== null ) {
245  $level = $lastError['type'];
246  $message = $lastError['message'];
247  $file = $lastError['file'];
248  $line = $lastError['line'];
249  } else {
250  $level = 0;
251  $message = '';
252  }
253  }
255  if ( !in_array( $level, self::$fatalErrorTypes ) ) {
256  // Only interested in fatal errors, others should have been
257  // handled by MWExceptionHandler::handleError
258  return false;
259  }
261  $msg = "[{exception_id}] PHP Fatal Error: {$message}";
263  // Look at message to see if this is a class not found failure
264  // HHVM: Class undefined: foo
265  // PHP5: Class 'foo' not found
266  if ( preg_match( "/Class (undefined: \w+|'\w+' not found)/", $msg ) ) {
267  // @codingStandardsIgnoreStart Generic.Files.LineLength.TooLong
268  $msg = <<<TXT
269 {$msg}
271 MediaWiki or an installed extension requires this class but it is not embedded directly in MediaWiki's git repository and must be installed separately by the end user.
273 Please see <a href=""></a> for help on installing the required components.
274 TXT;
275  // @codingStandardsIgnoreEnd
276  }
278  // We can't just create an exception and log it as it is likely that
279  // the interpreter has unwound the stack already. If that is true the
280  // stacktrace we would get would be functionally empty. If however we
281  // have been called as an error handler callback *and* HHVM is in use
282  // we will have been provided with a useful stacktrace that we can
283  // log.
284  $trace = $trace ?: debug_backtrace();
285  $logger = LoggerFactory::getInstance( 'fatal' );
286  $logger->error( $msg, [
287  'exception' => [
288  'class' => 'ErrorException',
289  'message' => "PHP Fatal Error: {$message}",
290  'code' => $level,
291  'file' => $file,
292  'line' => $line,
293  'trace' => static::redactTrace( $trace ),
294  ],
295  'exception_id' => wfRandomString( 8 ),
296  ] );
298  // Remember call so we don't double process via HHVM's fatal
299  // notifications and the shutdown hook behavior
300  static::$handledFatalCallback = true;
301  return false;
302  }
314  public static function getRedactedTraceAsString( $e ) {
315  return self::prettyPrintTrace( self::getRedactedTrace( $e ) );
316  }
326  public static function prettyPrintTrace( array $trace, $pad = '' ) {
327  $text = '';
329  $level = 0;
330  foreach ( $trace as $level => $frame ) {
331  if ( isset( $frame['file'] ) && isset( $frame['line'] ) ) {
332  $text .= "{$pad}#{$level} {$frame['file']}({$frame['line']}): ";
333  } else {
334  // 'file' and 'line' are unset for calls via call_user_func
335  // (bug 55634) This matches behaviour of
336  // Exception::getTraceAsString to instead display "[internal
337  // function]".
338  $text .= "{$pad}#{$level} [internal function]: ";
339  }
341  if ( isset( $frame['class'] ) && isset( $frame['type'] ) && isset( $frame['function'] ) ) {
342  $text .= $frame['class'] . $frame['type'] . $frame['function'];
343  } elseif ( isset( $frame['function'] ) ) {
344  $text .= $frame['function'];
345  } else {
346  $text .= 'NO_FUNCTION_GIVEN';
347  }
349  if ( isset( $frame['args'] ) ) {
350  $text .= '(' . implode( ', ', $frame['args'] ) . ")\n";
351  } else {
352  $text .= "()\n";
353  }
354  }
356  $level = $level + 1;
357  $text .= "{$pad}#{$level} {main}";
359  return $text;
360  }
373  public static function getRedactedTrace( $e ) {
374  return static::redactTrace( $e->getTrace() );
375  }
387  public static function redactTrace( array $trace ) {
388  return array_map( function ( $frame ) {
389  if ( isset( $frame['args'] ) ) {
390  $frame['args'] = array_map( function ( $arg ) {
391  return is_object( $arg ) ? get_class( $arg ) : gettype( $arg );
392  }, $frame['args'] );
393  }
394  return $frame;
395  }, $trace );
396  }
409  public static function getLogId( $e ) {
410  wfDeprecated( __METHOD__, '1.27' );
411  return WebRequest::getRequestId();
412  }
421  public static function getURL() {
423  if ( !isset( $wgRequest ) || $wgRequest instanceof FauxRequest ) {
424  return false;
425  }
426  return $wgRequest->getRequestURL();
427  }
436  public static function getLogMessage( $e ) {
437  $id = WebRequest::getRequestId();
438  $type = get_class( $e );
439  $file = $e->getFile();
440  $line = $e->getLine();
441  $message = $e->getMessage();
442  $url = self::getURL() ?: '[no req]';
444  return "[$id] $url $type from line $line of $file: $message";
445  }
451  public static function getPublicLogMessage( $e ) {
452  $reqId = WebRequest::getRequestId();
453  $type = get_class( $e );
454  return '[' . $reqId . '] '
455  . gmdate( 'Y-m-d H:i:s' ) . ': '
456  . 'Fatal exception of type "' . $type . '"';
457  }
469  public static function getLogContext( $e ) {
470  return [
471  'exception' => $e,
472  'exception_id' => WebRequest::getRequestId(),
473  ];
474  }
487  public static function getStructuredExceptionData( $e ) {
488  global $wgLogExceptionBacktrace;
489  $data = [
490  'id' => WebRequest::getRequestId(),
491  'type' => get_class( $e ),
492  'file' => $e->getFile(),
493  'line' => $e->getLine(),
494  'message' => $e->getMessage(),
495  'code' => $e->getCode(),
496  'url' => self::getURL() ?: null,
497  ];
499  if ( $e instanceof ErrorException &&
500  ( error_reporting() & $e->getSeverity() ) === 0
501  ) {
502  // Flag surpressed errors
503  $data['suppressed'] = true;
504  }
506  if ( $wgLogExceptionBacktrace ) {
507  $data['backtrace'] = self::getRedactedTrace( $e );
508  }
510  $previous = $e->getPrevious();
511  if ( $previous !== null ) {
512  $data['previous'] = self::getStructuredExceptionData( $previous );
513  }
515  return $data;
516  }
571  public static function jsonSerializeException( $e, $pretty = false, $escaping = 0 ) {
573  return FormatJson::encode( $data, $pretty, $escaping );
574  }
585  public static function logException( $e ) {
586  if ( !( $e instanceof MWException ) || $e->isLoggable() ) {
587  $logger = LoggerFactory::getInstance( 'exception' );
588  $logger->error(
589  self::getLogMessage( $e ),
590  self::getLogContext( $e )
591  );
594  if ( $json !== false ) {
595  $logger = LoggerFactory::getInstance( 'exception-json' );
596  $logger->error( $json, [ 'private' => true ] );
597  }
599  Hooks::run( 'LogException', [ $e, false ] );
600  }
601  }
610  protected static function logError( ErrorException $e, $channel ) {
611  // The set_error_handler callback is independent from error_reporting.
612  // Filter out unwanted errors manually (e.g. when
613  // MediaWiki\suppressWarnings is active).
614  $suppressed = ( error_reporting() & $e->getSeverity() ) === 0;
615  if ( !$suppressed ) {
616  $logger = LoggerFactory::getInstance( $channel );
617  $logger->error(
618  self::getLogMessage( $e ),
619  self::getLogContext( $e )
620  );
621  }
623  // Include all errors in the json log (surpressed errors will be flagged)
625  if ( $json !== false ) {
626  $logger = LoggerFactory::getInstance( "{$channel}-json" );
627  $logger->error( $json, [ 'private' => true ] );
628  }
630  Hooks::run( 'LogException', [ $e, $suppressed ] );
631  }
632 }
static $handledFatalCallback
Definition: MWExceptionHandler.php:44
static getRedactedTrace( $e)
Return a copy of an exception's backtrace as an array.
Definition: MWExceptionHandler.php:373
WebRequest clone which takes values from a provided array.
Definition: FauxRequest.php:33
static logError(ErrorException $e, $channel)
Log an exception that wasn't thrown but made to wrap an error.
Definition: MWExceptionHandler.php:610
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
Definition: APACHE-LICENSE-2.0.txt:3
the array() calling protocol came about after MediaWiki 1.4rc1.
We use the convention $dbr for read and $dbw for write to help you keep track of whether the database object is a the world will explode Or to be a subsequent write query which succeeded on the master may fail when replicated to the slave due to a unique key collision Replication on the slave will stop and it may take hours to repair the database and get it back online Setting read_only in my cnf on the slave will avoid this but given the dire we prefer to have as many checks as possible We provide a but the wrapper functions like please read the documentation for except in special pages derived from QueryPage It s a common pitfall for new developers to submit code containing SQL queries which examine huge numbers of rows Remember that COUNT * is(N), counting rows in atable is like counting beans in a bucket.------------------------------------------------------------------------ Replication------------------------------------------------------------------------The largest installation of MediaWiki, Wikimedia, uses a large set ofslave MySQL servers replicating writes made to a master MySQL server. Itis important to understand the issues associated with this setup if youwant to write code destined for Wikipedia.It 's often the case that the best algorithm to use for a given taskdepends on whether or not replication is in use. Due to our unabashedWikipedia-centrism, we often just use the replication-friendly version, but if you like, you can use wfGetLB() ->getServerCount() > 1 tocheck to see if replication is in use.===Lag===Lag primarily occurs when large write queries are sent to the master.Writes on the master are executed in parallel, but they are executed inserial when they are replicated to the slaves. The master writes thequery to the binlog when the transaction is committed. The slaves pollthe binlog and start executing the query as soon as it appears. They canservice reads while they are performing a write query, but will not readanything more from the binlog and thus will perform no more writes. Thismeans that if the write query runs for a long time, the slaves will lagbehind the master for the time it takes for the write query to complete.Lag can be exacerbated by high read load. MediaWiki 's load balancer willstop sending reads to a slave when it is lagged by more than 30 seconds.If the load ratios are set incorrectly, or if there is too much loadgenerally, this may lead to a slave permanently hovering around 30seconds lag.If all slaves are lagged by more than 30 seconds, MediaWiki will stopwriting to the database. All edits and other write operations will berefused, with an error returned to the user. This gives the slaves achance to catch up. Before we had this mechanism, the slaves wouldregularly lag by several minutes, making review of recent editsdifficult.In addition to this, MediaWiki attempts to ensure that the user seesevents occurring on the wiki in chronological order. A few seconds of lagcan be tolerated, as long as the user sees a consistent picture fromsubsequent requests. This is done by saving the master binlog positionin the session, and then at the start of each request, waiting for theslave to catch up to that position before doing any reads from it. Ifthis wait times out, reads are allowed anyway, but the request isconsidered to be in "lagged slave mode". Lagged slave mode can bechecked by calling wfGetLB() ->getLaggedSlaveMode(). The onlypractical consequence at present is a warning displayed in the pagefooter.===Lag avoidance===To avoid excessive lag, queries which write large numbers of rows shouldbe split up, generally to write one row at a time. Multi-row INSERT ...SELECT queries are the worst offenders should be avoided altogether.Instead do the select first and then the insert.===Working with lag===Despite our best efforts, it 's not practical to guarantee a low-lagenvironment. Lag will usually be less than one second, but mayoccasionally be up to 30 seconds. For scalability, it 's very importantto keep load on the master low, so simply sending all your queries tothe master is not the answer. So when you have a genuine need forup-to-date data, the following approach is advised:1) Do a quick query to the master for a sequence number or timestamp 2) Run the full query on the slave and check if it matches the data you gotfrom the master 3) If it doesn 't, run the full query on the masterTo avoid swamping the master every time the slaves lag, use of thisapproach should be kept to a minimum. In most cases you should just readfrom the slave and let the user deal with the delay.------------------------------------------------------------------------ Lock contention------------------------------------------------------------------------Due to the high write rate on Wikipedia(and some other wikis), MediaWiki developers need to be very careful to structure their writesto avoid long-lasting locks. By default, MediaWiki opens a transactionat the first query, and commits it before the output is sent. Locks willbe held from the time when the query is done until the commit. So youcan reduce lock time by doing as much processing as possible before youdo your write queries.Often this approach is not good enough, and it becomes necessary toenclose small groups of queries in their own transaction. Use thefollowing syntax:$dbw=wfGetDB(DB_MASTER
Handler class for MWExceptions.
Definition: MWExceptionHandler.php:28
static redactTrace(array $trace)
Redact a stacktrace generated by Exception::getTrace(), debug_backtrace() or similar means.
Definition: MWExceptionHandler.php:387
static installHandler()
Install handlers with PHP.
Definition: MWExceptionHandler.php:49
static jsonSerializeException( $e, $pretty=false, $escaping=0)
Serialize an Exception object to JSON.
Definition: MWExceptionHandler.php:571
Definition: doMaintenance.php:117
const ALL_OK
Skip escaping as many characters as reasonably possible.
Definition: FormatJson.php:55
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
static getPublicLogMessage( $e)
Definition: MWExceptionHandler.php:451
static encode( $value, $pretty=false, $escaping=0)
Returns the JSON representation of a value.
Definition: FormatJson.php:127
static handleFatalError( $level=null, $message=null, $file=null, $line=null, $context=null, $trace=null)
Dual purpose callback used as both a set_error_handler() callback and a registered shutdown function.
Definition: MWExceptionHandler.php:227
MediaWiki exception.
Definition: MWException.php:26
static prettyPrintTrace(array $trace, $pad='')
Generate a string representation of a stacktrace.
Definition: MWExceptionHandler.php:326
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such and we might be restricted by PHP settings such as safe mode or open_basedir We cannot assume that the software even has read access anywhere useful Many shared hosts run all users web applications under the same user
Definition: distributors.txt:9
wfDeprecated( $function, $version=false, $component=false, $callerOffset=2)
Throws a warning that $function is deprecated.
Definition: GlobalFunctions.php:1126
static getURL()
If the exception occurred in the course of responding to a request, returns the requested URL.
Definition: MWExceptionHandler.php:421
static handleException( $e)
Exception handler which simulates the appropriate catch() handling:
Definition: MWExceptionHandler.php:121
static getLogMessage( $e)
Get a message formatting the exception message and its origin.
Definition: MWExceptionHandler.php:436
design txt This is a brief overview of the new design More thorough and up to date information is available on the documentation wiki at etc Handles the details of getting and saving to the user table of the and dealing with sessions and cookies OutputPage Encapsulates the entire HTML page that will be sent in response to any server request It is used by calling its functions to add in any and then calling but I prefer the flexibility This should also do the output encoding The system allocates a global one in $wgOut Title Represents the title of an and does all the work of translating among various forms such as plain database etc For and for historical it also represents a few features of articles that don t involve their such as access rights See also title txt Article Encapsulates access to the page table of the database The object represents a an and maintains state such as etc Revision Encapsulates individual page revision data and access to the revision text blobs storage system Higher level code should never touch text storage directly
Definition: design.txt:34
static $fatalErrorTypes
Definition: MWExceptionHandler.php:37
static rollbackMasterChangesAndLog( $e)
If there are any open database transactions, roll them back and log the stack trace of the exception ...
Definition: MWExceptionHandler.php:89
A helper class for throttling authentication attempts.
static getLogContext( $e)
Get a PSR-3 log event context from an Exception.
Definition: MWExceptionHandler.php:469
this hook is for auditing only RecentChangesLinked and Watchlist RecentChangesLinked and Watchlist e g Watchlist removed from all revisions and log entries to which it was applied This gives extensions a chance to take it off their books as the deletion has already been partly carried out by this point or something similar the user will be unable to create the tag set and then return false from the hook function Ensure you consume the ChangeTagAfterDelete hook to carry out custom deletion actions as context called by AbstractContent::getParserOutput May be used to override the normal model specific rendering of page content as context as context the output can only depend on parameters provided to this hook not on global state indicating whether full HTML should be generated If generation of HTML may be but other information should still be present in the ParserOutput object to manipulate or replace but no entry for that model exists in $wgContentHandlers if desired whether it is OK to use $contentModel on $title Handler functions that modify $ok should generally return false to prevent further hooks from further modifying $ok inclusive false for true for descending in case the handler function wants to provide a converted Content object Note that $result getContentModel() must return $toModel. 'CustomEditor' $rcid is used in generating this variable which contains information about the new such as the revision s whether the revision was marked as a minor edit or not
Definition: hooks.txt:1159
static $reservedMemory
Definition: MWExceptionHandler.php:33
Definition: MWExceptionRenderer.php:28
when a variable name is used in a it is silently declared as a new masking the global
Definition: design.txt:93
static logException( $e)
Log an exception to the exception log (if enabled).
Definition: MWExceptionHandler.php:585
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the whether in Source or Object that is based or other modifications as a an original work of authorship For the purposes of this Derivative Works shall not include works that remain separable or merely the Work and Derivative Works thereof Contribution shall mean any work of including the original version of the Work and any modifications or additions to that Work or Derivative Works that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner For the purposes of this submitted means any form of or written communication sent to the Licensor or its including but not limited to communication on electronic mailing source code control and issue tracking systems that are managed by
Definition: APACHE-LICENSE-2.0.txt:49
static getLogId( $e)
Get the ID for this exception.
Definition: MWExceptionHandler.php:409
static configuration should be added through ResourceLoaderGetConfigVars instead can be used to get the real title after the basic globals have been set but before ordinary actions take place or wrap services the preferred way to define a new service is the $wgServiceWiringFiles array $services
Definition: hooks.txt:2162
Database error base class.
Definition: DBError.php:26
namespace are movable Hooks may change this value to override the return value of MWNamespace::isMovable(). 'NewDifferenceEngine' do that in ParserLimitReportFormat instead use this to modify the parameters of the image and a DIV can begin in one section and end in another Make sure your code can handle that case gracefully See the EditSectionClearerLink extension for an example zero but section is usually empty its values are the globals values before the output is cached one of or reset my talk my contributions etc etc otherwise the built in rate limiting checks are if enabled allows for interception of redirect as a string mapping parameter names to values & $type
Definition: hooks.txt:2259
Definition: cdb.php:59
Some information about database access in MediaWiki By Tim January Database layout For information about the MediaWiki database such as a description of the tables and their please see
Definition: database.txt:2
=Architecture==Two class hierarchies are used to provide the functionality associated with the different content models:*Content interface(and AbstractContent base class) define functionality that acts on the concrete content of a page, and *ContentHandler base class provides functionality specific to a content model, but not acting on concrete content. The most important function of ContentHandler is to act as a factory for the appropriate implementation of Content. These Content objects are to be used by MediaWiki everywhere, instead of passing page content around as text. All manipulation and analysis of page content must be done via the appropriate methods of the Content object. For each content model, a subclass of ContentHandler has to be registered with $wgContentHandlers. The ContentHandler object for a given content model can be obtained using ContentHandler::getForModelID($id). Also Title, WikiPage and Revision now have getContentHandler() methods for convenience. ContentHandler objects are singletons that provide functionality specific to the content type, but not directly acting on the content of some page. ContentHandler::makeEmptyContent() and ContentHandler::unserializeContent() can be used to create a Content object of the appropriate type. However, it is recommended to instead use WikiPage::getContent() resp. Revision::getContent() to get a page 's content as a Content object. These two methods should be the ONLY way in which page content is accessed. Another important function of ContentHandler objects is to define custom action handlers for a content model, see ContentHandler::getActionOverrides(). This is similar to what WikiPage::getActionOverrides() was already doing.==Serialization==With the ContentHandler facility, page content no longer has to be text based. Objects implementing the Content interface are used to represent and handle the content internally. For storage and data exchange, each content model supports at least one serialization format via ContentHandler::serializeContent($content). The list of supported formats for a given content model can be accessed using ContentHandler::getSupportedFormats(). Content serialization formats are identified using MIME type like strings. The following formats are built in:*text/x-wiki - wikitext *text/javascript - for js pages *text/css - for css pages *text/plain - for future use, e.g. with plain text messages. *text/html - for future use, e.g. with plain html messages. *application/vnd.php.serialized - for future use with the api and for extensions *application/json - for future use with the api, and for use by extensions *application/xml - for future use with the api, and for use by extensions In PHP, use the corresponding CONTENT_FORMAT_XXX constant. Note that when using the API to access page content, especially action=edit, action=parse and action=query &prop=revisions, the model and format of the content should always be handled explicitly. Without that information, interpretation of the provided content is not reliable. The same applies to XML dumps generated via maintenance/dumpBackup.php or Special:Export. Also note that the API will provide encapsulated, serialized content - so if the API was called with format=json, and contentformat is also json(or rather, application/json), the page content is represented as a string containing an escaped json structure. Extensions that use JSON to serialize some types of page content may provide specialized API modules that allow access to that content in a more natural form.==Compatibility==The ContentHandler facility is introduced in a way that should allow all existing code to keep functioning at least for pages that contain wikitext or other text based content. However, a number of functions and hooks have been deprecated in favor of new versions that are aware of the page 's content model, and will now generate warnings when used. Most importantly, the following functions have been deprecated:*Revisions::getText() is deprecated in favor Revisions::getContent() *WikiPage::getText() is deprecated in favor WikiPage::getContent() Also, the old Article::getContent()(which returns text) is superceded by Article::getContentObject(). However, both methods should be avoided since they do not provide clean access to the page 's actual content. For instance, they may return a system message for non-existing pages. Use WikiPage::getContent() instead. Code that relies on a textual representation of the page content should eventually be rewritten. However, ContentHandler::getContentText() provides a stop-gap that can be used to get text for a page. Its behavior is controlled by $wgContentHandlerTextFallback it
Definition: contenthandler.txt:108
and(b) You must cause any modified files to carry prominent notices stating that You changed the files
div flags Integer display flags(NO_ACTION_LINK, NO_EXTRA_USER_LINKS) 'LogException' returning false will NOT prevent logging a wrapping ErrorException $suppressed
Definition: hooks.txt:2105
Definition: load.php:50
static output( $e, $mode, $eNew=null)
Definition: MWExceptionRenderer.php:35
static getStructuredExceptionData( $e)
Get a structured representation of an Exception.
Definition: MWExceptionHandler.php:487
static report( $e)
Report an exception to the user.
Definition: MWExceptionHandler.php:62
We ve cleaned up the code here by removing clumps of infrequently used code and moving them off somewhere else It s much easier for someone working with this code to see what s _really_ going on
Definition: hooks.txt:86
Definition: APACHE-LICENSE-2.0.txt:114
static getRequestId()
Get the unique request ID.
Definition: WebRequest.php:272
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:9
MediaWiki Logger LoggerFactory implements a PSR[0] compatible message logging system Named Psr Log LoggerInterface instances can be obtained from the MediaWiki Logger LoggerFactory::getInstance() static method. MediaWiki\Logger\LoggerFactory expects a class implementing the MediaWiki\Logger\Spi interface to act as a factory for new Psr\Log\LoggerInterface instances. The "Spi" in MediaWiki\Logger\Spi stands for "service provider interface". An SPI is an API intended to be implemented or extended by a third party. This software design pattern is intended to enable framework extension and replaceable components. It is specifically used in the MediaWiki\Logger\LoggerFactory service to allow alternate PSR-3 logging implementations to be easily integrated with MediaWiki. The service provider interface allows the backend logging library to be implemented in multiple ways. The $wgMWLoggerDefaultSpi global provides the classname of the default MediaWiki\Logger\Spi implementation to be loaded at runtime. This can either be the name of a class implementing the MediaWiki\Logger\Spi with a zero argument const ructor or a callable that will return an MediaWiki\Logger\Spi instance. Alternately the MediaWiki\Logger\LoggerFactory MediaWiki Logger LoggerFactory
Definition: logger.txt:5
null for the wiki Added in
Definition: hooks.txt:1558
#define the
if(! $wgDBerrorLogTZ) $wgRequest
Definition: Setup.php:664
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency MediaWikiServices
Definition: injection.txt:23
static run( $event, array $args=[], $deprecatedVersion=null)
Call hook functions defined in Hooks::register and $wgHooks.
Definition: Hooks.php:131
static handleError( $level, $message, $file=null, $line=null)
Handler for set_error_handler() callback notifications.
Definition: MWExceptionHandler.php:161
shown</td >< td > a href
Definition: All_system_messages.txt:2667
static getRedactedTraceAsString( $e)
Generate a string representation of an exception's stack trace.
Definition: MWExceptionHandler.php:314
div flags Integer display flags(NO_ACTION_LINK, NO_EXTRA_USER_LINKS) 'LogException' returning false will NOT prevent logging $e
Definition: hooks.txt:2105
const AS_RAW
Definition: MWExceptionRenderer.php:27
wfRandomString( $length=32)
Get a random string containing a number of pseudo-random hex characters.
Definition: GlobalFunctions.php:334