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 /**
  23  * @defgroup Actions Action done on pages
  24  */
  25
  26 /**
  27  * Actions are things which can be done to pages (edit, delete, rollback, etc).  They
  28  * are distinct from Special Pages because an action must apply to exactly one page.
  29  *
  30  * To add an action in an extension, create a subclass of Action, and add the key to
  31  * $wgActions.  There is also the deprecated UnknownAction hook
  32  *
  33  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
  34  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
  35  * patrol, etc). The FormAction and FormlessAction classes represent these two groups.
  36  */
  37 abstract class Action {
  38
  39         /**
  40          * Page on which we're performing the action
  41          * @since 1.17
  42          * @var WikiPage|Article|ImagePage|CategoryPage|Page $page
  43          */
  44         protected $page;
  45
  46         /**
  47          * IContextSource if specified; otherwise we'll use the Context from the Page
  48          * @since 1.17
  49          * @var IContextSource $context
  50          */
  51         protected $context;
  52
  53         /**
  54          * The fields used to create the HTMLForm
  55          * @since 1.17
  56          * @var array $fields
  57          */
  58         protected $fields;
  59
  60         /**
  61          * Get the Action subclass which should be used to handle this action, false if
  62          * the action is disabled, or null if it's not recognised
  63          * @param string $action
  64          * @param array $overrides
  65          * @return bool|null|string|callable
  66          */
  67         final private static function getClass( $action, array $overrides ) {
  68                 global $wgActions;
  69                 $action = strtolower( $action );
  70
  71                 if ( !isset( $wgActions[$action] ) ) {
  72                         return null;
  73                 }
  74
  75                 if ( $wgActions[$action] === false ) {
  76                         return false;
  77                 } elseif ( $wgActions[$action] === true && isset( $overrides[$action] ) ) {
  78                         return $overrides[$action];
  79                 } elseif ( $wgActions[$action] === true ) {
  80                         return ucfirst( $action ) . 'Action';
  81                 } else {
  82                         return $wgActions[$action];
  83                 }
  84         }
  85
  86         /**
  87          * Get an appropriate Action subclass for the given action
  88          * @since 1.17
  89          * @param string $action
  90          * @param Page $page
  91          * @param IContextSource $context
  92          * @return Action|bool|null False if the action is disabled, null
  93          *     if it is not recognised
  94          */
  95         final public static function factory( $action, Page $page, IContextSource $context = null ) {
  96                 $classOrCallable = self::getClass( $action, $page->getActionOverrides() );
  97
  98                 if ( is_string( $classOrCallable ) ) {
  99                         $obj = new $classOrCallable( $page, $context );
 100                         return $obj;
 101                 }
 102
 103                 if ( is_callable( $classOrCallable ) ) {
 104                         return call_user_func_array( $classOrCallable, array( $page, $context ) );
 105                 }
 106
 107                 return $classOrCallable;
 108         }
 109
 110         /**
 111          * Get the action that will be executed, not necessarily the one passed
 112          * passed through the "action" request parameter. Actions disabled in
 113          * $wgActions will be replaced by "nosuchaction".
 114          *
 115          * @since 1.19
 116          * @param IContextSource $context
 117          * @return string Action name
 118          */
 119         final public static function getActionName( IContextSource $context ) {
 120                 global $wgActions;
 121
 122                 $request = $context->getRequest();
 123                 $actionName = $request->getVal( 'action', 'view' );
 124
 125                 // Check for disabled actions
 126                 if ( isset( $wgActions[$actionName] ) && $wgActions[$actionName] === false ) {
 127                         $actionName = 'nosuchaction';
 128                 }
 129
 130                 // Workaround for bug #20966: inability of IE to provide an action dependent
 131                 // on which submit button is clicked.
 132                 if ( $actionName === 'historysubmit' ) {
 133                         if ( $request->getBool( 'revisiondelete' ) ) {
 134                                 $actionName = 'revisiondelete';
 135                         } else {
 136                                 $actionName = 'view';
 137                         }
 138                 } elseif ( $actionName == 'editredlink' ) {
 139                         $actionName = 'edit';
 140                 }
 141
 142                 // Trying to get a WikiPage for NS_SPECIAL etc. will result
 143                 // in WikiPage::factory throwing "Invalid or virtual namespace -1 given."
 144                 // For SpecialPages et al, default to action=view.
 145                 if ( !$context->canUseWikiPage() ) {
 146                         return 'view';
 147                 }
 148
 149                 $action = Action::factory( $actionName, $context->getWikiPage(), $context );
 150                 if ( $action instanceof Action ) {
 151                         return $action->getName();
 152                 }
 153
 154                 return 'nosuchaction';
 155         }
 156
 157         /**
 158          * Check if a given action is recognised, even if it's disabled
 159          * @since 1.17
 160          *
 161          * @param string $name Name of an action
 162          * @return bool
 163          */
 164         final public static function exists( $name ) {
 165                 return self::getClass( $name, array() ) !== null;
 166         }
 167
 168         /**
 169          * Get the IContextSource in use here
 170          * @since 1.17
 171          * @return IContextSource
 172          */
 173         final public function getContext() {
 174                 if ( $this->context instanceof IContextSource ) {
 175                         return $this->context;
 176                 } elseif ( $this->page instanceof Article ) {
 177                         // NOTE: $this->page can be a WikiPage, which does not have a context.
 178                         wfDebug( __METHOD__ . ": no context known, falling back to Article's context.\n" );
 179                         return $this->page->getContext();
 180                 }
 181
 182                 wfWarn( __METHOD__ . ': no context known, falling back to RequestContext::getMain().' );
 183                 return RequestContext::getMain();
 184         }
 185
 186         /**
 187          * Get the WebRequest being used for this instance
 188          * @since 1.17
 189          *
 190          * @return WebRequest
 191          */
 192         final public function getRequest() {
 193                 return $this->getContext()->getRequest();
 194         }
 195
 196         /**
 197          * Get the OutputPage being used for this instance
 198          * @since 1.17
 199          *
 200          * @return OutputPage
 201          */
 202         final public function getOutput() {
 203                 return $this->getContext()->getOutput();
 204         }
 205
 206         /**
 207          * Shortcut to get the User being used for this instance
 208          * @since 1.17
 209          *
 210          * @return User
 211          */
 212         final public function getUser() {
 213                 return $this->getContext()->getUser();
 214         }
 215
 216         /**
 217          * Shortcut to get the Skin being used for this instance
 218          * @since 1.17
 219          *
 220          * @return Skin
 221          */
 222         final public function getSkin() {
 223                 return $this->getContext()->getSkin();
 224         }
 225
 226         /**
 227          * Shortcut to get the user Language being used for this instance
 228          *
 229          * @return Language
 230          */
 231         final public function getLanguage() {
 232                 return $this->getContext()->getLanguage();
 233         }
 234
 235         /**
 236          * Shortcut to get the Title object from the page
 237          * @since 1.17
 238          *
 239          * @return Title
 240          */
 241         final public function getTitle() {
 242                 return $this->page->getTitle();
 243         }
 244
 245         /**
 246          * Get a Message object with context set
 247          * Parameters are the same as wfMessage()
 248          *
 249          * @return Message
 250          */
 251         final public function msg() {
 252                 $params = func_get_args();
 253                 return call_user_func_array( array( $this->getContext(), 'msg' ), $params );
 254         }
 255
 256         /**
 257          * Constructor.
 258          *
 259          * Only public since 1.21
 260          *
 261          * @param Page $page
 262          * @param IContextSource $context
 263          */
 264         public function __construct( Page $page, IContextSource $context = null ) {
 265                 if ( $context === null ) {
 266                         wfWarn( __METHOD__ . ' called without providing a Context object.' );
 267                         // NOTE: We could try to initialize $context using $page->getContext(),
 268                         //      if $page is an Article. That however seems to not work seamlessly.
 269                 }
 270
 271                 $this->page = $page;
 272                 $this->context = $context;
 273         }
 274
 275         /**
 276          * Return the name of the action this object responds to
 277          * @since 1.17
 278          *
 279          * @return string Lowercase name
 280          */
 281         abstract public function getName();
 282
 283         /**
 284          * Get the permission required to perform this action.  Often, but not always,
 285          * the same as the action name
 286          * @since 1.17
 287          *
 288          * @return string|null
 289          */
 290         public function getRestriction() {
 291                 return null;
 292         }
 293
 294         /**
 295          * Checks if the given user (identified by an object) can perform this action.  Can be
 296          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 297          * must throw subclasses of ErrorPageError
 298          * @since 1.17
 299          *
 300          * @param User $user The user to check, or null to use the context user
 301          * @throws UserBlockedError|ReadOnlyError|PermissionsError
 302          */
 303         protected function checkCanExecute( User $user ) {
 304                 $right = $this->getRestriction();
 305                 if ( $right !== null ) {
 306                         $errors = $this->getTitle()->getUserPermissionsErrors( $right, $user );
 307                         if ( count( $errors ) ) {
 308                                 throw new PermissionsError( $right, $errors );
 309                         }
 310                 }
 311
 312                 if ( $this->requiresUnblock() && $user->isBlocked() ) {
 313                         $block = $user->getBlock();
 314                         throw new UserBlockedError( $block );
 315                 }
 316
 317                 // This should be checked at the end so that the user won't think the
 318                 // error is only temporary when he also don't have the rights to execute
 319                 // this action
 320                 if ( $this->requiresWrite() && wfReadOnly() ) {
 321                         throw new ReadOnlyError();
 322                 }
 323         }
 324
 325         /**
 326          * Whether this action requires the wiki not to be locked
 327          * @since 1.17
 328          *
 329          * @return bool
 330          */
 331         public function requiresWrite() {
 332                 return true;
 333         }
 334
 335         /**
 336          * Whether this action can still be executed by a blocked user
 337          * @since 1.17
 338          *
 339          * @return bool
 340          */
 341         public function requiresUnblock() {
 342                 return true;
 343         }
 344
 345         /**
 346          * Set output headers for noindexing etc.  This function will not be called through
 347          * the execute() entry point, so only put UI-related stuff in here.
 348          * @since 1.17
 349          */
 350         protected function setHeaders() {
 351                 $out = $this->getOutput();
 352                 $out->setRobotPolicy( "noindex,nofollow" );
 353                 $out->setPageTitle( $this->getPageTitle() );
 354                 $this->getOutput()->setSubtitle( $this->getDescription() );
 355                 $out->setArticleRelated( true );
 356         }
 357
 358         /**
 359          * Returns the name that goes in the \<h1\> page title
 360          *
 361          * @return string
 362          */
 363         protected function getPageTitle() {
 364                 return $this->getTitle()->getPrefixedText();
 365         }
 366
 367         /**
 368          * Returns the description that goes below the \<h1\> tag
 369          * @since 1.17
 370          *
 371          * @return string
 372          */
 373         protected function getDescription() {
 374                 return $this->msg( strtolower( $this->getName() ) )->escaped();
 375         }
 376
 377         /**
 378          * The main action entry point.  Do all output for display and send it to the context
 379          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 380          * $this->getOutput(), etc.
 381          * @since 1.17
 382          *
 383          * @throws ErrorPageError
 384          */
 385         abstract public function show();
 386 }