includes/actions/Action.php

   1 <?php
   2 /**
   3  * Base classes for actions done on pages.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  18  *
  19  * @file
  20  */
  21
  22 use MediaWiki\MediaWikiServices;
  23
  24 /**
  25  * @defgroup Actions Actions
  26  */
  27
  28 /**
  29  * Actions are things which can be done to pages (edit, delete, rollback, etc).  They
  30  * are distinct from Special Pages because an action must apply to exactly one page.
  31  *
  32  * To add an action in an extension, create a subclass of Action, and add the key to
  33  * $wgActions.
  34  *
  35  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
  36  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
  37  * patrol, etc). The FormAction and FormlessAction classes represent these two groups.
  38  */
  39 abstract class Action implements MessageLocalizer {
  40
  41         /**
  42          * Page on which we're performing the action
  43          * @since 1.17
  44          * @var WikiPage|Article|ImagePage|CategoryPage|Page $page
  45          */
  46         protected $page;
  47
  48         /**
  49          * IContextSource if specified; otherwise we'll use the Context from the Page
  50          * @since 1.17
  51          * @var IContextSource $context
  52          */
  53         protected $context;
  54
  55         /**
  56          * The fields used to create the HTMLForm
  57          * @since 1.17
  58          * @var array $fields
  59          */
  60         protected $fields;
  61
  62         /**
  63          * Get the Action subclass which should be used to handle this action, false if
  64          * the action is disabled, or null if it's not recognised
  65          * @param string $action
  66          * @param array $overrides
  67          * @return bool|null|string|callable|Action
  68          */
  69         final private static function getClass( $action, array $overrides ) {
  70                 global $wgActions;
  71                 $action = strtolower( $action );
  72
  73                 if ( !isset( $wgActions[$action] ) ) {
  74                         return null;
  75                 }
  76
  77                 if ( $wgActions[$action] === false ) {
  78                         return false;
  79                 } elseif ( $wgActions[$action] === true && isset( $overrides[$action] ) ) {
  80                         return $overrides[$action];
  81                 } elseif ( $wgActions[$action] === true ) {
  82                         return ucfirst( $action ) . 'Action';
  83                 } else {
  84                         return $wgActions[$action];
  85                 }
  86         }
  87
  88         /**
  89          * Get an appropriate Action subclass for the given action
  90          * @since 1.17
  91          * @param string $action
  92          * @param Page $page
  93          * @param IContextSource|null $context
  94          * @return Action|bool|null False if the action is disabled, null
  95          *     if it is not recognised
  96          */
  97         final public static function factory( $action, Page $page, IContextSource $context = null ) {
  98                 $classOrCallable = self::getClass( $action, $page->getActionOverrides() );
  99
 100                 if ( is_string( $classOrCallable ) ) {
 101                         if ( !class_exists( $classOrCallable ) ) {
 102                                 return false;
 103                         }
 104                         return new $classOrCallable( $page, $context );
 105                 }
 106
 107                 if ( is_callable( $classOrCallable ) ) {
 108                         return $classOrCallable( $page, $context );
 109                 }
 110
 111                 return $classOrCallable;
 112         }
 113
 114         /**
 115          * Get the action that will be executed, not necessarily the one passed
 116          * passed through the "action" request parameter. Actions disabled in
 117          * $wgActions will be replaced by "nosuchaction".
 118          *
 119          * @since 1.19
 120          * @param IContextSource $context
 121          * @return string Action name
 122          */
 123         final public static function getActionName( IContextSource $context ) {
 124                 global $wgActions;
 125
 126                 $request = $context->getRequest();
 127                 $actionName = $request->getVal( 'action', 'view' );
 128
 129                 // Check for disabled actions
 130                 if ( isset( $wgActions[$actionName] ) && $wgActions[$actionName] === false ) {
 131                         $actionName = 'nosuchaction';
 132                 }
 133
 134                 // Workaround for T22966: inability of IE to provide an action dependent
 135                 // on which submit button is clicked.
 136                 if ( $actionName === 'historysubmit' ) {
 137                         if ( $request->getBool( 'revisiondelete' ) ) {
 138                                 $actionName = 'revisiondelete';
 139                         } elseif ( $request->getBool( 'editchangetags' ) ) {
 140                                 $actionName = 'editchangetags';
 141                         } else {
 142                                 $actionName = 'view';
 143                         }
 144                 } elseif ( $actionName === 'editredlink' ) {
 145                         $actionName = 'edit';
 146                 }
 147
 148                 // Trying to get a WikiPage for NS_SPECIAL etc. will result
 149                 // in WikiPage::factory throwing "Invalid or virtual namespace -1 given."
 150                 // For SpecialPages et al, default to action=view.
 151                 if ( !$context->canUseWikiPage() ) {
 152                         return 'view';
 153                 }
 154
 155                 $action = self::factory( $actionName, $context->getWikiPage(), $context );
 156                 if ( $action instanceof Action ) {
 157                         return $action->getName();
 158                 }
 159
 160                 return 'nosuchaction';
 161         }
 162
 163         /**
 164          * Check if a given action is recognised, even if it's disabled
 165          * @since 1.17
 166          *
 167          * @param string $name Name of an action
 168          * @return bool
 169          */
 170         final public static function exists( $name ) {
 171                 return self::getClass( $name, [] ) !== null;
 172         }
 173
 174         /**
 175          * Get the IContextSource in use here
 176          * @since 1.17
 177          * @return IContextSource
 178          */
 179         final public function getContext() {
 180                 if ( $this->context instanceof IContextSource ) {
 181                         return $this->context;
 182                 } elseif ( $this->page instanceof Article ) {
 183                         // NOTE: $this->page can be a WikiPage, which does not have a context.
 184                         wfDebug( __METHOD__ . ": no context known, falling back to Article's context.\n" );
 185                         return $this->page->getContext();
 186                 }
 187
 188                 wfWarn( __METHOD__ . ': no context known, falling back to RequestContext::getMain().' );
 189                 return RequestContext::getMain();
 190         }
 191
 192         /**
 193          * Get the WebRequest being used for this instance
 194          * @since 1.17
 195          *
 196          * @return WebRequest
 197          */
 198         final public function getRequest() {
 199                 return $this->getContext()->getRequest();
 200         }
 201
 202         /**
 203          * Get the OutputPage being used for this instance
 204          * @since 1.17
 205          *
 206          * @return OutputPage
 207          */
 208         final public function getOutput() {
 209                 return $this->getContext()->getOutput();
 210         }
 211
 212         /**
 213          * Shortcut to get the User being used for this instance
 214          * @since 1.17
 215          *
 216          * @return User
 217          */
 218         final public function getUser() {
 219                 return $this->getContext()->getUser();
 220         }
 221
 222         /**
 223          * Shortcut to get the Skin being used for this instance
 224          * @since 1.17
 225          *
 226          * @return Skin
 227          */
 228         final public function getSkin() {
 229                 return $this->getContext()->getSkin();
 230         }
 231
 232         /**
 233          * Shortcut to get the user Language being used for this instance
 234          *
 235          * @return Language
 236          */
 237         final public function getLanguage() {
 238                 return $this->getContext()->getLanguage();
 239         }
 240
 241         /**
 242          * Shortcut to get the Title object from the page
 243          * @since 1.17
 244          *
 245          * @return Title
 246          */
 247         final public function getTitle() {
 248                 return $this->page->getTitle();
 249         }
 250
 251         /**
 252          * Get a Message object with context set
 253          * Parameters are the same as wfMessage()
 254          *
 255          * @param string|string[]|MessageSpecifier $key
 256          * @param mixed ...$params
 257          * @return Message
 258          */
 259         final public function msg( $key, ...$params ) {
 260                 return $this->getContext()->msg( $key, ...$params );
 261         }
 262
 263         /**
 264          * Only public since 1.21
 265          *
 266          * @param Page $page
 267          * @param IContextSource|null $context
 268          */
 269         public function __construct( Page $page, IContextSource $context = null ) {
 270                 if ( $context === null ) {
 271                         wfWarn( __METHOD__ . ' called without providing a Context object.' );
 272                         // NOTE: We could try to initialize $context using $page->getContext(),
 273                         //      if $page is an Article. That however seems to not work seamlessly.
 274                 }
 275
 276                 $this->page = $page;
 277                 $this->context = $context;
 278         }
 279
 280         /**
 281          * Return the name of the action this object responds to
 282          * @since 1.17
 283          *
 284          * @return string Lowercase name
 285          */
 286         abstract public function getName();
 287
 288         /**
 289          * Get the permission required to perform this action.  Often, but not always,
 290          * the same as the action name
 291          * @since 1.17
 292          *
 293          * @return string|null
 294          */
 295         public function getRestriction() {
 296                 return null;
 297         }
 298
 299         /**
 300          * Checks if the given user (identified by an object) can perform this action.  Can be
 301          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 302          * must throw subclasses of ErrorPageError
 303          * @since 1.17
 304          *
 305          * @param User $user The user to check, or null to use the context user
 306          * @throws UserBlockedError|ReadOnlyError|PermissionsError
 307          */
 308         protected function checkCanExecute( User $user ) {
 309                 $right = $this->getRestriction();
 310                 if ( $right !== null ) {
 311                         $errors = $this->getTitle()->getUserPermissionsErrors( $right, $user );
 312                         if ( count( $errors ) ) {
 313                                 throw new PermissionsError( $right, $errors );
 314                         }
 315                 }
 316
 317                 // If the action requires an unblock, explicitly check the user's block.
 318                 if ( $this->requiresUnblock() && $user->isBlockedFrom( $this->getTitle() ) ) {
 319                         $block = $user->getBlock();
 320                         if ( $block ) {
 321                                 throw new UserBlockedError( $block );
 322                         }
 323
 324                         throw new PermissionsError( $this->getName(), [ 'badaccess-group0' ] );
 325                 }
 326
 327                 // This should be checked at the end so that the user won't think the
 328                 // error is only temporary when he also don't have the rights to execute
 329                 // this action
 330                 if ( $this->requiresWrite() && wfReadOnly() ) {
 331                         throw new ReadOnlyError();
 332                 }
 333         }
 334
 335         /**
 336          * Whether this action requires the wiki not to be locked
 337          * @since 1.17
 338          *
 339          * @return bool
 340          */
 341         public function requiresWrite() {
 342                 return true;
 343         }
 344
 345         /**
 346          * Whether this action can still be executed by a blocked user
 347          * @since 1.17
 348          *
 349          * @return bool
 350          */
 351         public function requiresUnblock() {
 352                 return true;
 353         }
 354
 355         /**
 356          * Set output headers for noindexing etc.  This function will not be called through
 357          * the execute() entry point, so only put UI-related stuff in here.
 358          * @since 1.17
 359          */
 360         protected function setHeaders() {
 361                 $out = $this->getOutput();
 362                 $out->setRobotPolicy( 'noindex,nofollow' );
 363                 $out->setPageTitle( $this->getPageTitle() );
 364                 $out->setSubtitle( $this->getDescription() );
 365                 $out->setArticleRelated( true );
 366         }
 367
 368         /**
 369          * Returns the name that goes in the \<h1\> page title
 370          *
 371          * @return string
 372          */
 373         protected function getPageTitle() {
 374                 return $this->getTitle()->getPrefixedText();
 375         }
 376
 377         /**
 378          * Returns the description that goes below the \<h1\> tag
 379          * @since 1.17
 380          *
 381          * @return string HTML
 382          */
 383         protected function getDescription() {
 384                 return $this->msg( strtolower( $this->getName() ) )->escaped();
 385         }
 386
 387         /**
 388          * Adds help link with an icon via page indicators.
 389          * Link target can be overridden by a local message containing a wikilink:
 390          * the message key is: lowercase action name + '-helppage'.
 391          * @param string $to Target MediaWiki.org page title or encoded URL.
 392          * @param bool $overrideBaseUrl Whether $url is a full URL, to avoid MW.o.
 393          * @since 1.25
 394          */
 395         public function addHelpLink( $to, $overrideBaseUrl = false ) {
 396                 $msg = wfMessage( MediaWikiServices::getInstance()->getContentLanguage()->lc(
 397                         self::getActionName( $this->getContext() )
 398                         ) . '-helppage' );
 399
 400                 if ( !$msg->isDisabled() ) {
 401                         $helpUrl = Skin::makeUrl( $msg->plain() );
 402                         $this->getOutput()->addHelpLink( $helpUrl, true );
 403                 } else {
 404                         $this->getOutput()->addHelpLink( $to, $overrideBaseUrl );
 405                 }
 406         }
 407
 408         /**
 409          * The main action entry point.  Do all output for display and send it to the context
 410          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 411          * $this->getOutput(), etc.
 412          * @since 1.17
 413          *
 414          * @throws ErrorPageError
 415          */
 416         abstract public function show();
 417
 418         /**
 419          * Call wfTransactionalTimeLimit() if this request was POSTed
 420          * @since 1.26
 421          */
 422         protected function useTransactionalTimeLimit() {
 423                 if ( $this->getRequest()->wasPosted() ) {
 424                         wfTransactionalTimeLimit();
 425                 }
 426         }
 427
 428         /**
 429          * Indicates whether this action may perform database writes
 430          * @return bool
 431          * @since 1.27
 432          */
 433         public function doesWrites() {
 434                 return false;
 435         }
 436 }