includes/Action.php

   1 <?php
   2 /**
   3  * Actions are things which can be done to pages (edit, delete, rollback, etc).  They
   4  * are distinct from Special Pages because an action must apply to exactly one page.
   5  *
   6  * To add an action in an extension, create a subclass of Action, and add the key to
   7  * $wgActions.  There is also the deprecated UnknownAction hook
   8  *
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  23  *
  24  * @file
  25  */
  26 abstract class Action {
  27
  28         /**
  29          * Page on which we're performing the action
  30          * @var Article
  31          */
  32         protected $page;
  33
  34         /**
  35          * RequestContext if specified; otherwise we'll use the Context from the Page
  36          * @var RequestContext
  37          */
  38         protected $context;
  39
  40         /**
  41          * The fields used to create the HTMLForm
  42          * @var Array
  43          */
  44         protected $fields;
  45
  46         /**
  47          * Get the Action subclass which should be used to handle this action, false if
  48          * the action is disabled, or null if it's not recognised
  49          * @param $action String
  50          * @param $overrides Array
  51          * @return bool|null|string
  52          */
  53         private final static function getClass( $action, array $overrides ) {
  54                 global $wgActions;
  55                 $action = strtolower( $action );
  56
  57                 if ( !isset( $wgActions[$action] ) ) {
  58                         return null;
  59                 }
  60
  61                 if ( $wgActions[$action] === false ) {
  62                         return false;
  63                 } elseif ( $wgActions[$action] === true && isset( $overrides[$action] ) ) {
  64                         return $overrides[$action];
  65                 } elseif ( $wgActions[$action] === true ) {
  66                         return ucfirst( $action ) . 'Action';
  67                 } else {
  68                         return $wgActions[$action];
  69                 }
  70         }
  71
  72         /**
  73          * Get an appropriate Action subclass for the given action
  74          * @param $action String
  75          * @param $page Article
  76          * @return Action|false|null false if the action is disabled, null
  77          *     if it is not recognised
  78          */
  79         public final static function factory( $action, Page $page ) {
  80                 $class = self::getClass( $action, $page->getActionOverrides() );
  81                 if ( $class ) {
  82                         $obj = new $class( $page );
  83                         return $obj;
  84                 }
  85                 return $class;
  86         }
  87
  88         /**
  89          * Check if a given action is recognised, even if it's disabled
  90          *
  91          * @param $name String: name of an action
  92          * @return Bool
  93          */
  94         public final static function exists( $name ) {
  95                 return self::getClass( $name ) !== null;
  96         }
  97
  98         /**
  99          * Get the RequestContext in use here
 100          * @return RequestContext
 101          */
 102         protected final function getContext() {
 103                 if ( $this->context instanceof RequestContext ) {
 104                         return $this->context;
 105                 }
 106                 return $this->page->getContext();
 107         }
 108
 109         /**
 110          * Get the WebRequest being used for this instance
 111          *
 112          * @return WebRequest
 113          */
 114         protected final function getRequest() {
 115                 return $this->getContext()->getRequest();
 116         }
 117
 118         /**
 119          * Get the OutputPage being used for this instance
 120          *
 121          * @return OutputPage
 122          */
 123         protected final function getOutput() {
 124                 return $this->getContext()->getOutput();
 125         }
 126
 127         /**
 128          * Shortcut to get the User being used for this instance
 129          *
 130          * @return User
 131          */
 132         protected final function getUser() {
 133                 return $this->getContext()->getUser();
 134         }
 135
 136         /**
 137          * Shortcut to get the Skin being used for this instance
 138          *
 139          * @return Skin
 140          */
 141         protected final function getSkin() {
 142                 return $this->getContext()->getSkin();
 143         }
 144
 145         /**
 146          * Shortcut to get the user Language being used for this instance
 147          *
 148          * @return Skin
 149          */
 150         protected final function getLang() {
 151                 return $this->getContext()->getLang();
 152         }
 153
 154         /**
 155          * Shortcut to get the Title object from the page
 156          * @return Title
 157          */
 158         protected final function getTitle() {
 159                 return $this->page->getTitle();
 160         }
 161
 162         /**
 163          * Protected constructor: use Action::factory( $action, $page ) to actually build
 164          * these things in the real world
 165          * @param Page $page
 166          */
 167         protected function __construct( Page $page ) {
 168                 $this->page = $page;
 169         }
 170
 171         /**
 172          * Return the name of the action this object responds to
 173          * @return String lowercase
 174          */
 175         public abstract function getName();
 176
 177         /**
 178          * Get the permission required to perform this action.  Often, but not always,
 179          * the same as the action name
 180          */
 181         public abstract function getRestriction();
 182
 183         /**
 184          * Checks if the given user (identified by an object) can perform this action.  Can be
 185          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 186          * must throw subclasses of ErrorPageError
 187          *
 188          * @param $user User: the user to check, or null to use the context user
 189          * @throws ErrorPageError
 190          */
 191         protected function checkCanExecute( User $user ) {
 192                 if ( $this->requiresWrite() && wfReadOnly() ) {
 193                         throw new ReadOnlyError();
 194                 }
 195
 196                 if ( $this->getRestriction() !== null && !$user->isAllowed( $this->getRestriction() ) ) {
 197                         throw new PermissionsError( $this->getRestriction() );
 198                 }
 199
 200                 if ( $this->requiresUnblock() && $user->isBlocked() ) {
 201                         throw new UserBlockedError( $user->getBlock() );
 202                 }
 203         }
 204
 205         /**
 206          * Whether this action requires the wiki not to be locked
 207          * @return Bool
 208          */
 209         public function requiresWrite() {
 210                 return true;
 211         }
 212
 213         /**
 214          * Whether this action can still be executed by a blocked user
 215          * @return Bool
 216          */
 217         public function requiresUnblock() {
 218                 return true;
 219         }
 220
 221         /**
 222          * Set output headers for noindexing etc.  This function will not be called through
 223          * the execute() entry point, so only put UI-related stuff in here.
 224          */
 225         protected function setHeaders() {
 226                 $out = $this->getOutput();
 227                 $out->setRobotPolicy( "noindex,nofollow" );
 228                 $out->setPageTitle( $this->getPageTitle() );
 229                 $this->getOutput()->setSubtitle( $this->getDescription() );
 230                 $out->setArticleRelated( true );
 231         }
 232
 233         /**
 234          * Returns the name that goes in the \<h1\> page title
 235          *
 236          * @return String
 237          */
 238         protected function getPageTitle() {
 239                 return $this->getTitle()->getPrefixedText();
 240         }
 241
 242         /**
 243          * Returns the description that goes below the \<h1\> tag
 244          *
 245          * @return String
 246          */
 247         protected function getDescription() {
 248                 return wfMsg( strtolower( $this->getName() ) );
 249         }
 250
 251         /**
 252          * The main action entry point.  Do all output for display and send it to the context
 253          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 254          * $this->getOutput(), etc.
 255          * @throws ErrorPageError
 256          */
 257         public abstract function show();
 258
 259         /**
 260          * Execute the action in a silent fashion: do not display anything or release any errors.
 261          * @param $data Array values that would normally be in the POST request
 262          * @param $captureErrors Bool whether to catch exceptions and just return false
 263          * @return Bool whether execution was successful
 264          */
 265         public abstract function execute();
 266 }
 267
 268 abstract class FormAction extends Action {
 269
 270         /**
 271          * Get an HTMLForm descriptor array
 272          * @return Array
 273          */
 274         protected abstract function getFormFields();
 275
 276         /**
 277          * Add pre- or post-text to the form
 278          * @return String HTML which will be sent to $form->addPreText()
 279          */
 280         protected function preText() { return ''; }
 281         protected function postText() { return ''; }
 282
 283         /**
 284          * Play with the HTMLForm if you need to more substantially
 285          * @param $form HTMLForm
 286          */
 287         protected function alterForm( HTMLForm $form ) {}
 288
 289         /**
 290          * Get the HTMLForm to control behaviour
 291          * @return HTMLForm|null
 292          */
 293         protected function getForm() {
 294                 $this->fields = $this->getFormFields();
 295
 296                 // Give hooks a chance to alter the form, adding extra fields or text etc
 297                 wfRunHooks( 'ActionModifyFormFields', array( $this->getName(), &$this->fields, $this->page ) );
 298
 299                 $form = new HTMLForm( $this->fields, $this->getContext() );
 300                 $form->setSubmitCallback( array( $this, 'onSubmit' ) );
 301
 302                 // Retain query parameters (uselang etc)
 303                 $form->addHiddenField( 'action', $this->getName() ); // Might not be the same as the query string
 304                 $params = array_diff_key(
 305                         $this->getRequest()->getQueryValues(),
 306                         array( 'action' => null, 'title' => null )
 307                 );
 308                 $form->addHiddenField( 'redirectparams', wfArrayToCGI( $params ) );
 309
 310                 $form->addPreText( $this->preText() );
 311                 $form->addPostText( $this->postText() );
 312                 $this->alterForm( $form );
 313
 314                 // Give hooks a chance to alter the form, adding extra fields or text etc
 315                 wfRunHooks( 'ActionBeforeFormDisplay', array( $this->getName(), &$form, $this->page ) );
 316
 317                 return $form;
 318         }
 319
 320         /**
 321          * Process the form on POST submission.  If you return false from getFormFields(),
 322          * this will obviously never be reached.  If you don't want to do anything with the
 323          * form, just return false here
 324          * @param  $data Array
 325          * @return Bool|Array true for success, false for didn't-try, array of errors on failure
 326          */
 327         public abstract function onSubmit( $data );
 328
 329         /**
 330          * Do something exciting on successful processing of the form.  This might be to show
 331          * a confirmation message (watch, rollback, etc) or to redirect somewhere else (edit,
 332          * protect, etc).
 333          */
 334         public abstract function onSuccess();
 335
 336         /**
 337          * The basic pattern for actions is to display some sort of HTMLForm UI, maybe with
 338          * some stuff underneath (history etc); to do some processing on submission of that
 339          * form (delete, protect, etc) and to do something exciting on 'success', be that
 340          * display something new or redirect to somewhere.  Some actions have more exotic
 341          * behaviour, but that's what subclassing is for :D
 342          */
 343         public function show() {
 344                 $this->setHeaders();
 345
 346                 // This will throw exceptions if there's a problem
 347                 $this->checkCanExecute( $this->getUser() );
 348
 349                 $form = $this->getForm();
 350                 if ( $form->show() ) {
 351                         $this->onSuccess();
 352                 }
 353         }
 354
 355         /**
 356          * @see Action::execute()
 357          * @throws ErrorPageError
 358          * @param array|null $data
 359          * @param bool $captureErrors
 360          * @return bool
 361          */
 362         public function execute( array $data = null, $captureErrors = true ) {
 363                 try {
 364                         // Set a new context so output doesn't leak.
 365                         $this->context = clone $this->page->getContext();
 366
 367                         // This will throw exceptions if there's a problem
 368                         $this->checkCanExecute( $this->getUser() );
 369
 370                         $fields = array();
 371                         foreach ( $this->fields as $key => $params ) {
 372                                 if ( isset( $data[$key] ) ) {
 373                                         $fields[$key] = $data[$key];
 374                                 } elseif ( isset( $params['default'] ) ) {
 375                                         $fields[$key] = $params['default'];
 376                                 } else {
 377                                         $fields[$key] = null;
 378                                 }
 379                         }
 380                         $status = $this->onSubmit( $fields );
 381                         if ( $status === true ) {
 382                                 // This might do permanent stuff
 383                                 $this->onSuccess();
 384                                 return true;
 385                         } else {
 386                                 return false;
 387                         }
 388                 }
 389                 catch ( ErrorPageError $e ) {
 390                         if ( $captureErrors ) {
 391                                 return false;
 392                         } else {
 393                                 throw $e;
 394                         }
 395                 }
 396         }
 397 }
 398
 399 /**
 400  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
 401  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
 402  * patrol, etc).
 403  */
 404 abstract class FormlessAction extends Action {
 405
 406         /**
 407          * Show something on GET request.
 408          * @return String|null will be added to the HTMLForm if present, or just added to the
 409          *     output if not.  Return null to not add anything
 410          */
 411         public abstract function onView();
 412
 413         /**
 414          * We don't want an HTMLForm
 415          */
 416         protected function getFormFields() {
 417                 return false;
 418         }
 419
 420         public function onSubmit( $data ) {
 421                 return false;
 422         }
 423
 424         public function onSuccess() {
 425                 return false;
 426         }
 427
 428         public function show() {
 429                 $this->setHeaders();
 430
 431                 // This will throw exceptions if there's a problem
 432                 $this->checkCanExecute( $this->getUser() );
 433
 434                 $this->getOutput()->addHTML( $this->onView() );
 435         }
 436
 437         /**
 438          * Execute the action silently, not giving any output.  Since these actions don't have
 439          * forms, they probably won't have any data, but some (eg rollback) may do
 440          * @param $data Array values that would normally be in the GET request
 441          * @param $captureErrors Bool whether to catch exceptions and just return false
 442          * @return Bool whether execution was successful
 443          */
 444         public function execute( array $data = null, $captureErrors = true ) {
 445                 try {
 446                         // Set a new context so output doesn't leak.
 447                         $this->context = clone $this->page->getContext();
 448                         if ( is_array( $data ) ) {
 449                                 $this->context->setRequest( new FauxRequest( $data, false ) );
 450                         }
 451
 452                         // This will throw exceptions if there's a problem
 453                         $this->checkCanExecute( $this->getUser() );
 454
 455                         $this->onView();
 456                         return true;
 457                 }
 458                 catch ( ErrorPageError $e ) {
 459                         if ( $captureErrors ) {
 460                                 return false;
 461                         } else {
 462                                 throw $e;
 463                         }
 464                 }
 465         }
 466 }