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          * IContextSource if specified; otherwise we'll use the Context from the Page
  36          * @var IContextSource
  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, array() ) !== null;
  96         }
  97
  98         /**
  99          * Get the IContextSource in use here
 100          * @return IContextSource
 101          */
 102         protected final function getContext() {
 103                 if ( $this->context instanceof IContextSource ) {
 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                         $block = $user->mBlock;
 202                         throw new UserBlockedError( $block );
 203                 }
 204         }
 205
 206         /**
 207          * Whether this action requires the wiki not to be locked
 208          * @return Bool
 209          */
 210         public function requiresWrite() {
 211                 return true;
 212         }
 213
 214         /**
 215          * Whether this action can still be executed by a blocked user
 216          * @return Bool
 217          */
 218         public function requiresUnblock() {
 219                 return true;
 220         }
 221
 222         /**
 223          * Set output headers for noindexing etc.  This function will not be called through
 224          * the execute() entry point, so only put UI-related stuff in here.
 225          */
 226         protected function setHeaders() {
 227                 $out = $this->getOutput();
 228                 $out->setRobotPolicy( "noindex,nofollow" );
 229                 $out->setPageTitle( $this->getPageTitle() );
 230                 $this->getOutput()->setSubtitle( $this->getDescription() );
 231                 $out->setArticleRelated( true );
 232         }
 233
 234         /**
 235          * Returns the name that goes in the \<h1\> page title
 236          *
 237          * @return String
 238          */
 239         protected function getPageTitle() {
 240                 return $this->getTitle()->getPrefixedText();
 241         }
 242
 243         /**
 244          * Returns the description that goes below the \<h1\> tag
 245          *
 246          * @return String
 247          */
 248         protected function getDescription() {
 249                 return wfMsg( strtolower( $this->getName() ) );
 250         }
 251
 252         /**
 253          * The main action entry point.  Do all output for display and send it to the context
 254          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 255          * $this->getOutput(), etc.
 256          * @throws ErrorPageError
 257          */
 258         public abstract function show();
 259
 260         /**
 261          * Execute the action in a silent fashion: do not display anything or release any errors.
 262          * @param $data Array values that would normally be in the POST request
 263          * @param $captureErrors Bool whether to catch exceptions and just return false
 264          * @return Bool whether execution was successful
 265          */
 266         public abstract function execute();
 267 }
 268
 269 abstract class FormAction extends Action {
 270
 271         /**
 272          * Get an HTMLForm descriptor array
 273          * @return Array
 274          */
 275         protected abstract function getFormFields();
 276
 277         /**
 278          * Add pre- or post-text to the form
 279          * @return String HTML which will be sent to $form->addPreText()
 280          */
 281         protected function preText() { return ''; }
 282         protected function postText() { return ''; }
 283
 284         /**
 285          * Play with the HTMLForm if you need to more substantially
 286          * @param $form HTMLForm
 287          */
 288         protected function alterForm( HTMLForm $form ) {}
 289
 290         /**
 291          * Get the HTMLForm to control behaviour
 292          * @return HTMLForm|null
 293          */
 294         protected function getForm() {
 295                 $this->fields = $this->getFormFields();
 296
 297                 // Give hooks a chance to alter the form, adding extra fields or text etc
 298                 wfRunHooks( 'ActionModifyFormFields', array( $this->getName(), &$this->fields, $this->page ) );
 299
 300                 $form = new HTMLForm( $this->fields, $this->getContext() );
 301                 $form->setSubmitCallback( array( $this, 'onSubmit' ) );
 302
 303                 // Retain query parameters (uselang etc)
 304                 $form->addHiddenField( 'action', $this->getName() ); // Might not be the same as the query string
 305                 $params = array_diff_key(
 306                         $this->getRequest()->getQueryValues(),
 307                         array( 'action' => null, 'title' => null )
 308                 );
 309                 $form->addHiddenField( 'redirectparams', wfArrayToCGI( $params ) );
 310
 311                 $form->addPreText( $this->preText() );
 312                 $form->addPostText( $this->postText() );
 313                 $this->alterForm( $form );
 314
 315                 // Give hooks a chance to alter the form, adding extra fields or text etc
 316                 wfRunHooks( 'ActionBeforeFormDisplay', array( $this->getName(), &$form, $this->page ) );
 317
 318                 return $form;
 319         }
 320
 321         /**
 322          * Process the form on POST submission.  If you return false from getFormFields(),
 323          * this will obviously never be reached.  If you don't want to do anything with the
 324          * form, just return false here
 325          * @param  $data Array
 326          * @return Bool|Array true for success, false for didn't-try, array of errors on failure
 327          */
 328         public abstract function onSubmit( $data );
 329
 330         /**
 331          * Do something exciting on successful processing of the form.  This might be to show
 332          * a confirmation message (watch, rollback, etc) or to redirect somewhere else (edit,
 333          * protect, etc).
 334          */
 335         public abstract function onSuccess();
 336
 337         /**
 338          * The basic pattern for actions is to display some sort of HTMLForm UI, maybe with
 339          * some stuff underneath (history etc); to do some processing on submission of that
 340          * form (delete, protect, etc) and to do something exciting on 'success', be that
 341          * display something new or redirect to somewhere.  Some actions have more exotic
 342          * behaviour, but that's what subclassing is for :D
 343          */
 344         public function show() {
 345                 $this->setHeaders();
 346
 347                 // This will throw exceptions if there's a problem
 348                 $this->checkCanExecute( $this->getUser() );
 349
 350                 $form = $this->getForm();
 351                 if ( $form->show() ) {
 352                         $this->onSuccess();
 353                 }
 354         }
 355
 356         /**
 357          * @see Action::execute()
 358          * @throws ErrorPageError
 359          * @param array|null $data
 360          * @param bool $captureErrors
 361          * @return bool
 362          */
 363         public function execute( array $data = null, $captureErrors = true ) {
 364                 try {
 365                         // Set a new context so output doesn't leak.
 366                         $this->context = clone $this->page->getContext();
 367
 368                         // This will throw exceptions if there's a problem
 369                         $this->checkCanExecute( $this->getUser() );
 370
 371                         $fields = array();
 372                         foreach ( $this->fields as $key => $params ) {
 373                                 if ( isset( $data[$key] ) ) {
 374                                         $fields[$key] = $data[$key];
 375                                 } elseif ( isset( $params['default'] ) ) {
 376                                         $fields[$key] = $params['default'];
 377                                 } else {
 378                                         $fields[$key] = null;
 379                                 }
 380                         }
 381                         $status = $this->onSubmit( $fields );
 382                         if ( $status === true ) {
 383                                 // This might do permanent stuff
 384                                 $this->onSuccess();
 385                                 return true;
 386                         } else {
 387                                 return false;
 388                         }
 389                 }
 390                 catch ( ErrorPageError $e ) {
 391                         if ( $captureErrors ) {
 392                                 return false;
 393                         } else {
 394                                 throw $e;
 395                         }
 396                 }
 397         }
 398 }
 399
 400 /**
 401  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
 402  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
 403  * patrol, etc).
 404  */
 405 abstract class FormlessAction extends Action {
 406
 407         /**
 408          * Show something on GET request.
 409          * @return String|null will be added to the HTMLForm if present, or just added to the
 410          *     output if not.  Return null to not add anything
 411          */
 412         public abstract function onView();
 413
 414         /**
 415          * We don't want an HTMLForm
 416          */
 417         protected function getFormFields() {
 418                 return false;
 419         }
 420
 421         public function onSubmit( $data ) {
 422                 return false;
 423         }
 424
 425         public function onSuccess() {
 426                 return false;
 427         }
 428
 429         public function show() {
 430                 $this->setHeaders();
 431
 432                 // This will throw exceptions if there's a problem
 433                 $this->checkCanExecute( $this->getUser() );
 434
 435                 $this->getOutput()->addHTML( $this->onView() );
 436         }
 437
 438         /**
 439          * Execute the action silently, not giving any output.  Since these actions don't have
 440          * forms, they probably won't have any data, but some (eg rollback) may do
 441          * @param $data Array values that would normally be in the GET request
 442          * @param $captureErrors Bool whether to catch exceptions and just return false
 443          * @return Bool whether execution was successful
 444          */
 445         public function execute( array $data = null, $captureErrors = true ) {
 446                 try {
 447                         // Set a new context so output doesn't leak.
 448                         $this->context = clone $this->page->getContext();
 449                         if ( is_array( $data ) ) {
 450                                 $this->context->setRequest( new FauxRequest( $data, false ) );
 451                         }
 452
 453                         // This will throw exceptions if there's a problem
 454                         $this->checkCanExecute( $this->getUser() );
 455
 456                         $this->onView();
 457                         return true;
 458                 }
 459                 catch ( ErrorPageError $e ) {
 460                         if ( $captureErrors ) {
 461                                 return false;
 462                         } else {
 463                                 throw $e;
 464                         }
 465                 }
 466         }
 467 }