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