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 extends ContextSource {
  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          * Protected constructor: use Action::factory( $action, $page ) to actually build
 100          * these things in the real world
 101          * @param Page $page
 102          */
 103         protected function __construct( Page $page ) {
 104                 $this->page = $page;
 105         }
 106
 107         /**
 108          * Return the name of the action this object responds to
 109          * @return String lowercase
 110          */
 111         public abstract function getName();
 112
 113         /**
 114          * Get the permission required to perform this action.  Often, but not always,
 115          * the same as the action name
 116          */
 117         public abstract function getRestriction();
 118
 119         /**
 120          * Checks if the given user (identified by an object) can perform this action.  Can be
 121          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 122          * must throw subclasses of ErrorPageError
 123          *
 124          * @param $user User: the user to check, or null to use the context user
 125          * @throws ErrorPageError
 126          */
 127         protected function checkCanExecute( User $user ) {
 128                 $right = $this->getRestriction();
 129                 if ( $right !== null ) {
 130                         $errors = $this->getTitle()->getUserPermissionsErrors( $right, $user );
 131                         if ( count( $errors ) ) {
 132                                 throw new PermissionsError( $right, $errors );
 133                         }
 134                 }
 135
 136                 if ( $this->requiresUnblock() && $user->isBlocked() ) {
 137                         $block = $user->mBlock;
 138                         throw new UserBlockedError( $block );
 139                 }
 140
 141                 // This should be checked at the end so that the user won't think the
 142                 // error is only temporary when he also don't have the rights to execute
 143                 // this action
 144                 if ( $this->requiresWrite() && wfReadOnly() ) {
 145                         throw new ReadOnlyError();
 146                 }
 147         }
 148
 149         /**
 150          * Whether this action requires the wiki not to be locked
 151          * @return Bool
 152          */
 153         public function requiresWrite() {
 154                 return true;
 155         }
 156
 157         /**
 158          * Whether this action can still be executed by a blocked user
 159          * @return Bool
 160          */
 161         public function requiresUnblock() {
 162                 return true;
 163         }
 164
 165         /**
 166          * Set output headers for noindexing etc.  This function will not be called through
 167          * the execute() entry point, so only put UI-related stuff in here.
 168          */
 169         protected function setHeaders() {
 170                 $out = $this->getOutput();
 171                 $out->setRobotPolicy( "noindex,nofollow" );
 172                 $out->setPageTitle( $this->getPageTitle() );
 173                 $this->getOutput()->setSubtitle( $this->getDescription() );
 174                 $out->setArticleRelated( true );
 175         }
 176
 177         /**
 178          * Returns the name that goes in the \<h1\> page title
 179          *
 180          * @return String
 181          */
 182         protected function getPageTitle() {
 183                 return $this->getTitle()->getPrefixedText();
 184         }
 185
 186         /**
 187          * Returns the description that goes below the \<h1\> tag
 188          *
 189          * @return String
 190          */
 191         protected function getDescription() {
 192                 return wfMsg( strtolower( $this->getName() ) );
 193         }
 194
 195         /**
 196          * The main action entry point.  Do all output for display and send it to the context
 197          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 198          * $this->getOutput(), etc.
 199          * @throws ErrorPageError
 200          */
 201         public abstract function show();
 202
 203         /**
 204          * Execute the action in a silent fashion: do not display anything or release any errors.
 205          * @param $data Array values that would normally be in the POST request
 206          * @param $captureErrors Bool whether to catch exceptions and just return false
 207          * @return Bool whether execution was successful
 208          */
 209         public abstract function execute();
 210 }
 211
 212 abstract class FormAction extends Action {
 213
 214         /**
 215          * Get an HTMLForm descriptor array
 216          * @return Array
 217          */
 218         protected abstract function getFormFields();
 219
 220         /**
 221          * Add pre- or post-text to the form
 222          * @return String HTML which will be sent to $form->addPreText()
 223          */
 224         protected function preText() { return ''; }
 225
 226         /**
 227          * @return string
 228          */
 229         protected function postText() { return ''; }
 230
 231         /**
 232          * Play with the HTMLForm if you need to more substantially
 233          * @param $form HTMLForm
 234          */
 235         protected function alterForm( HTMLForm $form ) {}
 236
 237         /**
 238          * Get the HTMLForm to control behaviour
 239          * @return HTMLForm|null
 240          */
 241         protected function getForm() {
 242                 $this->fields = $this->getFormFields();
 243
 244                 // Give hooks a chance to alter the form, adding extra fields or text etc
 245                 wfRunHooks( 'ActionModifyFormFields', array( $this->getName(), &$this->fields, $this->page ) );
 246
 247                 $form = new HTMLForm( $this->fields, $this->getContext() );
 248                 $form->setSubmitCallback( array( $this, 'onSubmit' ) );
 249
 250                 // Retain query parameters (uselang etc)
 251                 $form->addHiddenField( 'action', $this->getName() ); // Might not be the same as the query string
 252                 $params = array_diff_key(
 253                         $this->getRequest()->getQueryValues(),
 254                         array( 'action' => null, 'title' => null )
 255                 );
 256                 $form->addHiddenField( 'redirectparams', wfArrayToCGI( $params ) );
 257
 258                 $form->addPreText( $this->preText() );
 259                 $form->addPostText( $this->postText() );
 260                 $this->alterForm( $form );
 261
 262                 // Give hooks a chance to alter the form, adding extra fields or text etc
 263                 wfRunHooks( 'ActionBeforeFormDisplay', array( $this->getName(), &$form, $this->page ) );
 264
 265                 return $form;
 266         }
 267
 268         /**
 269          * Process the form on POST submission.  If you return false from getFormFields(),
 270          * this will obviously never be reached.  If you don't want to do anything with the
 271          * form, just return false here
 272          * @param  $data Array
 273          * @return Bool|Array true for success, false for didn't-try, array of errors on failure
 274          */
 275         public abstract function onSubmit( $data );
 276
 277         /**
 278          * Do something exciting on successful processing of the form.  This might be to show
 279          * a confirmation message (watch, rollback, etc) or to redirect somewhere else (edit,
 280          * protect, etc).
 281          */
 282         public abstract function onSuccess();
 283
 284         /**
 285          * The basic pattern for actions is to display some sort of HTMLForm UI, maybe with
 286          * some stuff underneath (history etc); to do some processing on submission of that
 287          * form (delete, protect, etc) and to do something exciting on 'success', be that
 288          * display something new or redirect to somewhere.  Some actions have more exotic
 289          * behaviour, but that's what subclassing is for :D
 290          */
 291         public function show() {
 292                 $this->setHeaders();
 293
 294                 // This will throw exceptions if there's a problem
 295                 $this->checkCanExecute( $this->getUser() );
 296
 297                 $form = $this->getForm();
 298                 if ( $form->show() ) {
 299                         $this->onSuccess();
 300                 }
 301         }
 302
 303         /**
 304          * @see Action::execute()
 305          * @throws ErrorPageError
 306          * @param array|null $data
 307          * @param bool $captureErrors
 308          * @return bool
 309          */
 310         public function execute( array $data = null, $captureErrors = true ) {
 311                 try {
 312                         // Set a new context so output doesn't leak.
 313                         $this->context = clone $this->page->getContext();
 314
 315                         // This will throw exceptions if there's a problem
 316                         $this->checkCanExecute( $this->getUser() );
 317
 318                         $fields = array();
 319                         foreach ( $this->fields as $key => $params ) {
 320                                 if ( isset( $data[$key] ) ) {
 321                                         $fields[$key] = $data[$key];
 322                                 } elseif ( isset( $params['default'] ) ) {
 323                                         $fields[$key] = $params['default'];
 324                                 } else {
 325                                         $fields[$key] = null;
 326                                 }
 327                         }
 328                         $status = $this->onSubmit( $fields );
 329                         if ( $status === true ) {
 330                                 // This might do permanent stuff
 331                                 $this->onSuccess();
 332                                 return true;
 333                         } else {
 334                                 return false;
 335                         }
 336                 }
 337                 catch ( ErrorPageError $e ) {
 338                         if ( $captureErrors ) {
 339                                 return false;
 340                         } else {
 341                                 throw $e;
 342                         }
 343                 }
 344         }
 345 }
 346
 347 /**
 348  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
 349  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
 350  * patrol, etc).
 351  */
 352 abstract class FormlessAction extends Action {
 353
 354         /**
 355          * Show something on GET request.
 356          * @return String|null will be added to the HTMLForm if present, or just added to the
 357          *     output if not.  Return null to not add anything
 358          */
 359         public abstract function onView();
 360
 361         /**
 362          * We don't want an HTMLForm
 363          */
 364         protected function getFormFields() {
 365                 return false;
 366         }
 367
 368         public function onSubmit( $data ) {
 369                 return false;
 370         }
 371
 372         public function onSuccess() {
 373                 return false;
 374         }
 375
 376         public function show() {
 377                 $this->setHeaders();
 378
 379                 // This will throw exceptions if there's a problem
 380                 $this->checkCanExecute( $this->getUser() );
 381
 382                 $this->getOutput()->addHTML( $this->onView() );
 383         }
 384
 385         /**
 386          * Execute the action silently, not giving any output.  Since these actions don't have
 387          * forms, they probably won't have any data, but some (eg rollback) may do
 388          * @param $data Array values that would normally be in the GET request
 389          * @param $captureErrors Bool whether to catch exceptions and just return false
 390          * @return Bool whether execution was successful
 391          */
 392         public function execute( array $data = null, $captureErrors = true ) {
 393                 try {
 394                         // Set a new context so output doesn't leak.
 395                         $this->context = clone $this->page->getContext();
 396                         if ( is_array( $data ) ) {
 397                                 $this->context->setRequest( new FauxRequest( $data, false ) );
 398                         }
 399
 400                         // This will throw exceptions if there's a problem
 401                         $this->checkCanExecute( $this->getUser() );
 402
 403                         $this->onView();
 404                         return true;
 405                 }
 406                 catch ( ErrorPageError $e ) {
 407                         if ( $captureErrors ) {
 408                                 return false;
 409                         } else {
 410                                 throw $e;
 411                         }
 412                 }
 413         }
 414 }