MediaWiki  REL1_31
SpecialRandomInCategory.php
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1 <?php
51  protected $extra = []; // Extra SQL statements
53  protected $category = false; // Title object of category
55  protected $maxOffset = 30; // Max amount to fudge randomness by.
57  private $maxTimestamp = null;
59  private $minTimestamp = null;
60 
61  public function __construct( $name = 'RandomInCategory' ) {
62  parent::__construct( $name );
63  }
64 
69  public function setCategory( Title $cat ) {
70  $this->category = $cat;
71  $this->maxTimestamp = null;
72  $this->minTimestamp = null;
73  }
74 
75  protected function getFormFields() {
76  $this->addHelpLink( 'Help:RandomInCategory' );
77 
78  return [
79  'category' => [
80  'type' => 'title',
81  'namespace' => NS_CATEGORY,
82  'relative' => true,
83  'label-message' => 'randomincategory-category',
84  'required' => true,
85  ]
86  ];
87  }
88 
89  public function requiresWrite() {
90  return false;
91  }
92 
93  public function requiresUnblock() {
94  return false;
95  }
96 
97  protected function getDisplayFormat() {
98  return 'ooui';
99  }
100 
101  protected function alterForm( HTMLForm $form ) {
102  $form->setSubmitTextMsg( 'randomincategory-submit' );
103  }
104 
105  protected function setParameter( $par ) {
106  // if subpage present, fake form submission
107  $this->onSubmit( [ 'category' => $par ] );
108  }
109 
110  public function onSubmit( array $data ) {
111  $cat = false;
112 
113  $categoryStr = $data['category'];
114 
115  if ( $categoryStr ) {
116  $cat = Title::newFromText( $categoryStr, NS_CATEGORY );
117  }
118 
119  if ( $cat && $cat->getNamespace() !== NS_CATEGORY ) {
120  // Someone searching for something like "Wikipedia:Foo"
121  $cat = Title::makeTitleSafe( NS_CATEGORY, $categoryStr );
122  }
123 
124  if ( $cat ) {
125  $this->setCategory( $cat );
126  }
127 
128  if ( !$this->category && $categoryStr ) {
129  $msg = $this->msg( 'randomincategory-invalidcategory',
130  wfEscapeWikiText( $categoryStr ) );
131 
132  return Status::newFatal( $msg );
133 
134  } elseif ( !$this->category ) {
135  return false; // no data sent
136  }
137 
138  $title = $this->getRandomTitle();
139 
140  if ( is_null( $title ) ) {
141  $msg = $this->msg( 'randomincategory-nopages',
142  $this->category->getText() );
143 
144  return Status::newFatal( $msg );
145  }
146 
147  $this->getOutput()->redirect( $title->getFullURL() );
148  }
149 
154  public function getRandomTitle() {
155  // Convert to float, since we do math with the random number.
156  $rand = (float)wfRandom();
157  $title = null;
158 
159  // Given that timestamps are rather unevenly distributed, we also
160  // use an offset between 0 and 30 to make any biases less noticeable.
161  $offset = mt_rand( 0, $this->maxOffset );
162 
163  if ( mt_rand( 0, 1 ) ) {
164  $up = true;
165  } else {
166  $up = false;
167  }
168 
169  $row = $this->selectRandomPageFromDB( $rand, $offset, $up );
170 
171  // Try again without the timestamp offset (wrap around the end)
172  if ( !$row ) {
173  $row = $this->selectRandomPageFromDB( false, $offset, $up );
174  }
175 
176  // Maybe the category is really small and offset too high
177  if ( !$row ) {
178  $row = $this->selectRandomPageFromDB( $rand, 0, $up );
179  }
180 
181  // Just get the first entry.
182  if ( !$row ) {
183  $row = $this->selectRandomPageFromDB( false, 0, true );
184  }
185 
186  if ( $row ) {
187  return Title::makeTitle( $row->page_namespace, $row->page_title );
188  }
189 
190  return null;
191  }
192 
204  protected function getQueryInfo( $rand, $offset, $up ) {
205  $op = $up ? '>=' : '<=';
206  $dir = $up ? 'ASC' : 'DESC';
207  if ( !$this->category instanceof Title ) {
208  throw new MWException( 'No category set' );
209  }
210  $qi = [
211  'tables' => [ 'categorylinks', 'page' ],
212  'fields' => [ 'page_title', 'page_namespace' ],
213  'conds' => array_merge( [
214  'cl_to' => $this->category->getDBkey(),
215  ], $this->extra ),
216  'options' => [
217  'ORDER BY' => 'cl_timestamp ' . $dir,
218  'LIMIT' => 1,
219  'OFFSET' => $offset
220  ],
221  'join_conds' => [
222  'page' => [ 'INNER JOIN', 'cl_from = page_id' ]
223  ]
224  ];
225 
226  $dbr = wfGetDB( DB_REPLICA );
227  $minClTime = $this->getTimestampOffset( $rand );
228  if ( $minClTime ) {
229  $qi['conds'][] = 'cl_timestamp ' . $op . ' ' .
230  $dbr->addQuotes( $dbr->timestamp( $minClTime ) );
231  }
232 
233  return $qi;
234  }
235 
241  protected function getTimestampOffset( $rand ) {
242  if ( $rand === false ) {
243  return false;
244  }
245  if ( !$this->minTimestamp || !$this->maxTimestamp ) {
246  try {
247  list( $this->minTimestamp, $this->maxTimestamp ) = $this->getMinAndMaxForCat( $this->category );
248  } catch ( Exception $e ) {
249  // Possibly no entries in category.
250  return false;
251  }
252  }
253 
254  $ts = ( $this->maxTimestamp - $this->minTimestamp ) * $rand + $this->minTimestamp;
255 
256  return intval( $ts );
257  }
258 
266  protected function getMinAndMaxForCat( Title $category ) {
267  $dbr = wfGetDB( DB_REPLICA );
268  $res = $dbr->selectRow(
269  'categorylinks',
270  [
271  'low' => 'MIN( cl_timestamp )',
272  'high' => 'MAX( cl_timestamp )'
273  ],
274  [
275  'cl_to' => $this->category->getDBkey(),
276  ],
277  __METHOD__,
278  [
279  'LIMIT' => 1
280  ]
281  );
282  if ( !$res ) {
283  throw new MWException( 'No entries in category' );
284  }
285 
286  return [ wfTimestamp( TS_UNIX, $res->low ), wfTimestamp( TS_UNIX, $res->high ) ];
287  }
288 
296  private function selectRandomPageFromDB( $rand, $offset, $up, $fname = __METHOD__ ) {
297  $dbr = wfGetDB( DB_REPLICA );
298 
299  $query = $this->getQueryInfo( $rand, $offset, $up );
300  $res = $dbr->select(
301  $query['tables'],
302  $query['fields'],
303  $query['conds'],
304  $fname,
305  $query['options'],
306  $query['join_conds']
307  );
308 
309  return $res->fetchObject();
310  }
311 
312  protected function getGroupName() {
313  return 'redirects';
314  }
315 }
SpecialRandomInCategory\$extra
string[] $extra
Definition: SpecialRandomInCategory.php:51
SpecialRandomInCategory\$minTimestamp
int null $minTimestamp
Definition: SpecialRandomInCategory.php:59
Title\newFromText
static newFromText( $text, $defaultNamespace=NS_MAIN)
Create a new Title from text, such as what one would find in a link.
Definition: Title.php:273
SpecialPage\msg
msg( $key)
Wrapper around wfMessage that sets the current context.
Definition: SpecialPage.php:793
SpecialRandomInCategory\requiresUnblock
requiresUnblock()
Whether this action cannot be executed by a blocked user.
Definition: SpecialRandomInCategory.php:93
SpecialRandomInCategory\getRandomTitle
getRandomTitle()
Choose a random title.
Definition: SpecialRandomInCategory.php:154
SpecialPage\getOutput
getOutput()
Get the OutputPage being used for this instance.
Definition: SpecialPage.php:722
array
the array() calling protocol came about after MediaWiki 1.4rc1.
SpecialRandomInCategory\getTimestampOffset
getTimestampOffset( $rand)
Definition: SpecialRandomInCategory.php:241
SpecialRandomInCategory\getMinAndMaxForCat
getMinAndMaxForCat(Title $category)
Get the lowest and highest timestamp for a category.
Definition: SpecialRandomInCategory.php:266
SpecialRandomInCategory\requiresWrite
requiresWrite()
Whether this action requires the wiki not to be locked.
Definition: SpecialRandomInCategory.php:89
wfTimestamp
wfTimestamp( $outputtype=TS_UNIX, $ts=0)
Get a timestamp string in one of various formats.
Definition: GlobalFunctions.php:1980
SpecialRandomInCategory\alterForm
alterForm(HTMLForm $form)
Play with the HTMLForm if you need to more substantially.
Definition: SpecialRandomInCategory.php:101
StatusValue\newFatal
static newFatal( $message)
Factory function for fatal errors.
Definition: StatusValue.php:68
SpecialRandomInCategory\__construct
__construct( $name='RandomInCategory')
Definition: SpecialRandomInCategory.php:61
FormSpecialPage
Special page which uses an HTMLForm to handle processing.
Definition: FormSpecialPage.php:31
$res
$res
Definition: database.txt:21
php
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:37
$dbr
$dbr
Definition: testCompression.php:50
SpecialRandomInCategory\onSubmit
onSubmit(array $data)
Process the form on POST submission.
Definition: SpecialRandomInCategory.php:110
SpecialRandomInCategory\setParameter
setParameter( $par)
Maybe do something interesting with the subpage parameter.
Definition: SpecialRandomInCategory.php:105
SpecialPage\addHelpLink
addHelpLink( $to, $overrideBaseUrl=false)
Adds help link with an icon via page indicators.
Definition: SpecialPage.php:832
MWException
MediaWiki exception.
Definition: MWException.php:26
wfGetDB
wfGetDB( $db, $groups=[], $wiki=false)
Get a Database object.
Definition: GlobalFunctions.php:2812
SpecialRandomInCategory\setCategory
setCategory(Title $cat)
Set which category to use.
Definition: SpecialRandomInCategory.php:69
$title
namespace and then decline to actually register it file or subcat img or subcat $title
Definition: hooks.txt:964
Title\makeTitle
static makeTitle( $ns, $title, $fragment='', $interwiki='')
Create a new Title from a namespace index and a DB key.
Definition: Title.php:534
DB_REPLICA
const DB_REPLICA
Definition: defines.php:25
NS_CATEGORY
const NS_CATEGORY
Definition: Defines.php:88
list
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
Definition: deferred.txt:11
$fname
if(defined( 'MW_SETUP_CALLBACK')) $fname
Customization point after all loading (constants, functions, classes, DefaultSettings,...
Definition: Setup.php:112
SpecialRandomInCategory\getDisplayFormat
getDisplayFormat()
Get display format for the form.
Definition: SpecialRandomInCategory.php:97
Title\makeTitleSafe
static makeTitleSafe( $ns, $title, $fragment='', $interwiki='')
Create a new Title from a namespace index and a DB key.
Definition: Title.php:562
FormSpecialPage\$par
string $par
The sub-page of the special page.
Definition: FormSpecialPage.php:36
wfEscapeWikiText
wfEscapeWikiText( $text)
Escapes the given text so that it may be output using addWikiText() without any linking,...
Definition: GlobalFunctions.php:1643
SpecialRandomInCategory\$category
Title false $category
Definition: SpecialRandomInCategory.php:53
SpecialRandomInCategory\getFormFields
getFormFields()
Get an HTMLForm descriptor array.
Definition: SpecialRandomInCategory.php:75
SpecialRandomInCategory
Special page to direct the user to a random page.
Definition: SpecialRandomInCategory.php:49
HTMLForm\setSubmitTextMsg
setSubmitTextMsg( $msg)
Set the text for the submit button to a message.
Definition: HTMLForm.php:1356
Title
Represents a title within MediaWiki.
Definition: Title.php:39
$name
Allows to change the fields on the form that will be generated $name
Definition: hooks.txt:302
wfRandom
wfRandom()
Get a random decimal value between 0 and 1, in a way not likely to give duplicate values for any real...
Definition: GlobalFunctions.php:287
SpecialRandomInCategory\getGroupName
getGroupName()
Under which header this special page is listed in Special:SpecialPages See messages 'specialpages-gro...
Definition: SpecialRandomInCategory.php:312
SpecialRandomInCategory\$maxOffset
int $maxOffset
Definition: SpecialRandomInCategory.php:55
SpecialRandomInCategory\getQueryInfo
getQueryInfo( $rand, $offset, $up)
Definition: SpecialRandomInCategory.php:204
SpecialRandomInCategory\$maxTimestamp
int null $maxTimestamp
Definition: SpecialRandomInCategory.php:57
SpecialRandomInCategory\selectRandomPageFromDB
selectRandomPageFromDB( $rand, $offset, $up, $fname=__METHOD__)
Definition: SpecialRandomInCategory.php:296
$query
null for the wiki Added should default to null in handler for backwards compatibility add a value to it if you want to add a cookie that have to vary cache options can modify $query
Definition: hooks.txt:1620
$e
div flags Integer display flags(NO_ACTION_LINK, NO_EXTRA_USER_LINKS) 'LogException' returning false will NOT prevent logging $e
Definition: hooks.txt:2171
HTMLForm
Object handling generic submission, CSRF protection, layout and other logic for UI forms.
Definition: HTMLForm.php:130