blocks/moodleblock.class.php

   1 <?php  // $Id$
   2
   3 /**
   4  * This file contains the parent class for moodle blocks, block_base.
   5  *
   6  * @author Jon Papaioannou
   7  * @version  $Id$
   8  * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
   9  * @package blocks
  10  */
  11
  12 /// Constants
  13
  14 /**
  15  * Block type of list. Contents of block should be set as an associative array in the content object as items ($this->content->items). Optionally include footer text in $this->content->footer.
  16  */
  17 define('BLOCK_TYPE_LIST',    1);
  18
  19 /**
  20  * Block type of text. Contents of block should be set to standard html text in the content object as items ($this->content->text). Optionally include footer text in $this->content->footer.
  21  */
  22 define('BLOCK_TYPE_TEXT',    2);
  23
  24 /**
  25  * Class for describing a moodle block, all Moodle blocks derive from this class
  26  *
  27  * @author Jon Papaioannou
  28  * @package blocks
  29  */
  30 class block_base {
  31
  32     /**
  33      * Internal var for storing/caching translated strings
  34      * @var string $str
  35      */
  36     var $str;
  37
  38     /**
  39      * The title of the block to be displayed in the block title area.
  40      * @var string $title
  41      */
  42     var $title         = NULL;
  43
  44     /**
  45      * The type of content that this block creates. Currently support options - BLOCK_TYPE_LIST, BLOCK_TYPE_TEXT
  46      * @var int $content_type
  47      */
  48     var $content_type  = BLOCK_TYPE_TEXT;
  49
  50     /**
  51      * An object to contain the information to be displayed in the block.
  52      * @var stdObject $content
  53      */
  54     var $content       = NULL;
  55
  56     /**
  57      * A string generated by {@link _add_edit_controls()} to display block manipulation links when the user is in editing mode.
  58      * @var string $edit_controls
  59      */
  60     var $edit_controls = NULL;
  61
  62     /**
  63      * The current version that the block type defines.
  64      * @var string $version
  65      */
  66     var $version       = NULL;
  67
  68     /**
  69      * The initialized instance of this block object.
  70      * @var block $instance
  71      */
  72     var $instance      = NULL;
  73
  74     /**
  75      * An object containing the instance configuration information for the current instance of this block.
  76      * @var stdObject $config
  77      */
  78     var $config        = NULL;
  79
  80     /**
  81      * How often the cronjob should run, 0 if not at all.
  82      * @var int $cron
  83      */
  84
  85     var $cron          = NULL;
  86
  87
  88 /// Class Functions
  89
  90     /**
  91      * The class constructor
  92      *
  93      */
  94     function block_base() {
  95         $this->init();
  96     }
  97
  98     /**
  99      * Fake constructor to keep PHP5 happy
 100      *
 101      */
 102     function __construct() {
 103         $this->block_base();
 104     }
 105
 106     /**
 107      * Function that can be overridden to do extra setup after
 108      * the database install. (Called once per block, not per instance!)
 109      */
 110     function after_install() {
 111     }
 112
 113     /**
 114      * Function that can be overridden to do extra cleanup before
 115      * the database tables are deleted. (Called once per block, not per instance!)
 116      */
 117     function before_delete() {
 118     }
 119
 120     /**
 121      * Function that can be overridden to do extra setup after a block instance has been
 122      * restored from backup. For example, it may need to alter any dates that the block
 123      * stores, if the $restore->course_startdateoffset is set.
 124      */
 125     function after_restore($restore) {
 126     }
 127
 128     /**
 129      * Returns the block name, as present in the class name,
 130      * the database, the block directory, etc etc.
 131      *
 132      * @return string
 133      */
 134     function name() {
 135         // Returns the block name, as present in the class name,
 136         // the database, the block directory, etc etc.
 137         static $myname;
 138         if ($myname === NULL) {
 139             $myname = strtolower(get_class($this));
 140             $myname = substr($myname, strpos($myname, '_') + 1);
 141         }
 142         return $myname;
 143     }
 144
 145     /**
 146      * Parent class version of this function simply returns NULL
 147      * This should be implemented by the derived class to return
 148      * the content object.
 149      *
 150      * @return stdObject
 151      */
 152     function get_content() {
 153         // This should be implemented by the derived class.
 154         return NULL;
 155     }
 156
 157     /**
 158      * Returns the class $title var value.
 159      *
 160      * Intentionally doesn't check if a title is set.
 161      * This is already done in {@link _self_test()}
 162      *
 163      * @return string $this->title
 164      */
 165     function get_title() {
 166         // Intentionally doesn't check if a title is set. This is already done in _self_test()
 167         return $this->title;
 168     }
 169
 170     /**
 171      * Returns the class $content_type var value.
 172      *
 173      * Intentionally doesn't check if content_type is set.
 174      * This is already done in {@link _self_test()}
 175      *
 176      * @return string $this->content_type
 177      */
 178     function get_content_type() {
 179         // Intentionally doesn't check if a content_type is set. This is already done in _self_test()
 180         return $this->content_type;
 181     }
 182
 183     /**
 184      * Returns the class $version var value.
 185      *
 186      * Intentionally doesn't check if a version is set.
 187      * This is already done in {@link _self_test()}
 188      *
 189      * @return string $this->version
 190      */
 191     function get_version() {
 192         // Intentionally doesn't check if a version is set. This is already done in _self_test()
 193         return $this->version;
 194     }
 195
 196     /**
 197      * Returns true or false, depending on whether this block has any content to display
 198      * and whether the user has permission to view the block
 199      *
 200      * @return boolean
 201      */
 202     function is_empty() {
 203
 204         $context = get_context_instance(CONTEXT_BLOCK, $this->instance->id);
 205
 206         if ( !has_capability('moodle/block:view', $context) ) {
 207             return true;
 208         }
 209
 210         $this->get_content();
 211         return(empty($this->content->text) && empty($this->content->footer));
 212     }
 213
 214     /**
 215      * First sets the current value of $this->content to NULL
 216      * then calls the block's {@link get_content()} function
 217      * to set its value back.
 218      *
 219      * @return stdObject
 220      */
 221     function refresh_content() {
 222         // Nothing special here, depends on content()
 223         $this->content = NULL;
 224         return $this->get_content();
 225     }
 226
 227     /**
 228      * Display the block!
 229      */
 230     function _print_block() {
 231         global $COURSE;
 232
 233         // is_empty() includes a call to get_content()
 234         if ($this->is_empty() && empty($COURSE->javascriptportal)) {
 235             if (empty($this->edit_controls)) {
 236                 // No content, no edit controls, so just shut up
 237                 return;
 238             } else {
 239                 // No content but editing, so show something at least
 240                 $this->_print_shadow();
 241             }
 242         } else {
 243             if ($this->hide_header() && empty($this->edit_controls)) {
 244                 // Header wants to hide, no edit controls to show, so no header it is
 245                 print_side_block(NULL, $this->content->text, NULL, NULL, $this->content->footer, $this->html_attributes());
 246             } else {
 247                 // The full treatment, please. Include the title text.
 248                 print_side_block($this->_title_html(), $this->content->text, NULL, NULL, $this->content->footer, $this->html_attributes(), $this->title);
 249             }
 250         }
 251     }
 252
 253     /**
 254      * Block contents are missing. Simply display an empty block so that
 255      * edit controls are accessbile to the user and they are aware that this
 256      * block is in place, even if empty.
 257      */
 258     function _print_shadow() {
 259         print_side_block($this->_title_html(), '&nbsp;', NULL, NULL, '', array('class' => 'hidden'), $this->title);
 260     }
 261
 262
 263     function _title_html() {
 264         global $CFG;
 265
 266         //Accessibility: validation, can't have <div> inside <h2>, use <span>.
 267         $title = '<div class="title">';
 268
 269         if (!empty($CFG->allowuserblockhiding)) {
 270             //Accessibility: added static 'alt' text for the +- icon.
 271             //TODO (nfreear): language string 'hide OR show block'
 272             $title .= '<div class="hide-show">'.
 273                 '<a title="'.get_string('showhideblock','access').
 274                 '" href="#" onclick="elementToggleHide(this, true, function(el) {'.
 275                 'return findParentNode(el, \'DIV\', \'sideblock\'); '.
 276                 '}, \''.$CFG->pixpath.'\' ); return false;">'.
 277                 '<img src="'.$CFG->pixpath.'/spacer.gif" '.
 278                 'id = "togglehide_inst'.$this->instance->id.'" '.
 279                 'alt="'.get_string('showhideblock','access').'" class="hide-show-image" /></a></div>';
 280         }
 281
 282         //Accesssibility: added H2 (was in, weblib.php: print_side_block)
 283         $title .= '<h2>'.$this->title.'</h2>';
 284
 285         if ($this->edit_controls !== NULL) {
 286             $title .= $this->edit_controls;
 287         }
 288
 289         $title .= '</div>';
 290         return $title;
 291     }
 292
 293     /**
 294      * Sets class $edit_controls var with correct block manipulation links.
 295      *
 296      * @uses $CFG
 297      * @uses $USER
 298      * @param stdObject $options ?
 299      * @todo complete documenting this function. Define $options.
 300      */
 301     function _add_edit_controls($options) {
 302         global $CFG, $USER, $PAGE;
 303
 304         // this is the context relevant to this particular block instance
 305         $blockcontext = get_context_instance(CONTEXT_BLOCK, $this->instance->id);
 306
 307         // context for site or course, i.e. participant list etc
 308         // check to see if user can edit site or course blocks.
 309         // blocks can appear on other pages such as mod and blog pages...
 310
 311         switch ($this->instance->pagetype) {
 312             case 'course-view':
 313                 if (!has_capability('moodle/site:manageblocks', $blockcontext)) {
 314                     return null;
 315                 }
 316             break;
 317             default:
 318
 319             break;
 320         }
 321
 322
 323         if (!isset($this->str)) {
 324             $this->str->delete    = get_string('delete');
 325             $this->str->moveup    = get_string('moveup');
 326             $this->str->movedown  = get_string('movedown');
 327             $this->str->moveright = get_string('moveright');
 328             $this->str->moveleft  = get_string('moveleft');
 329             $this->str->hide      = get_string('hide');
 330             $this->str->show      = get_string('show');
 331             $this->str->configure = get_string('configuration');
 332             $this->str->assignroles = get_string('assignroles', 'role');
 333         }
 334
 335         // RTL support - exchange right and left arrows
 336         if (right_to_left()) {
 337             $rightarrow = 'left.gif';
 338             $leftarrow  = 'right.gif';
 339         } else {
 340             $rightarrow = 'right.gif';
 341             $leftarrow  = 'left.gif';
 342         }
 343
 344         $movebuttons = '<div class="commands">';
 345
 346         if ($this->instance->visible) {
 347             $icon = '/t/hide.gif';
 348             $title = $this->str->hide;
 349         } else {
 350             $icon = '/t/show.gif';
 351             $title = $this->str->show;
 352         }
 353
 354         if (empty($this->instance->pageid)) {
 355             $this->instance->pageid = 0;
 356         }
 357         if (!empty($PAGE->type) and ($this->instance->pagetype == $PAGE->type) and $this->instance->pageid == $PAGE->id) {
 358             $page = $PAGE;
 359         } else {
 360             $page = page_create_object($this->instance->pagetype, $this->instance->pageid);
 361         }
 362         $script = $page->url_get_full(array('instanceid' => $this->instance->id, 'sesskey' => $USER->sesskey));
 363
 364         // place holder for roles button
 365         $movebuttons .= '<a class="icon roles" title="'. $this->str->assignroles .'" href="'.$CFG->wwwroot.'/'.$CFG->admin.'/roles/assign.php?contextid='.$blockcontext->id.'">' .
 366                         '<img src="'.$CFG->pixpath.'/i/roles.gif" alt="'.$this->str->assignroles.'" /></a>';
 367
 368         if ($this->user_can_edit()) {
 369             $movebuttons .= '<a class="icon hide" title="'. $title .'" href="'.$script.'&amp;blockaction=toggle">' .
 370                             '<img src="'. $CFG->pixpath.$icon .'" alt="'.$title.'" /></a>';
 371         }
 372
 373         if ($options & BLOCK_CONFIGURE && $this->user_can_edit()) {
 374             $movebuttons .= '<a class="icon edit" title="'. $this->str->configure .'" href="'.$script.'&amp;blockaction=config">' .
 375                             '<img src="'. $CFG->pixpath .'/t/edit.gif" alt="'. $this->str->configure .'" /></a>';
 376         }
 377
 378         if ($this->user_can_addto($page)) {
 379             $movebuttons .= '<a class="icon delete" title="'. $this->str->delete .'" href="'.$script.'&amp;blockaction=delete">' .
 380                             '<img src="'. $CFG->pixpath .'/t/delete.gif" alt="'. $this->str->delete .'" /></a>';
 381         }
 382
 383         if ($options & BLOCK_MOVE_LEFT) {
 384             $movebuttons .= '<a class="icon left" title="'. $this->str->moveleft .'" href="'.$script.'&amp;blockaction=moveleft">' .
 385                             '<img src="'. $CFG->pixpath .'/t/'.$leftarrow.'" alt="'. $this->str->moveleft .'" /></a>';
 386         }
 387         if ($options & BLOCK_MOVE_UP) {
 388             $movebuttons .= '<a class="icon up" title="'. $this->str->moveup .'" href="'.$script.'&amp;blockaction=moveup">' .
 389                             '<img src="'. $CFG->pixpath .'/t/up.gif" alt="'. $this->str->moveup .'" /></a>';
 390         }
 391         if ($options & BLOCK_MOVE_DOWN) {
 392             $movebuttons .= '<a class="icon down" title="'. $this->str->movedown .'" href="'.$script.'&amp;blockaction=movedown">' .
 393                             '<img src="'. $CFG->pixpath .'/t/down.gif" alt="'. $this->str->movedown .'" /></a>';
 394         }
 395         if ($options & BLOCK_MOVE_RIGHT) {
 396             $movebuttons .= '<a class="icon right" title="'. $this->str->moveright .'" href="'.$script.'&amp;blockaction=moveright">' .
 397                             '<img src="'. $CFG->pixpath .'/t/'.$rightarrow.'" alt="'. $this->str->moveright .'" /></a>';
 398         }
 399
 400         $movebuttons .= '</div>';
 401         $this->edit_controls = $movebuttons;
 402     }
 403
 404     /**
 405      * Tests if this block has been implemented correctly.
 406      * Also, $errors isn't used right now
 407      *
 408      * @return boolean
 409      */
 410
 411     function _self_test() {
 412         // Tests if this block has been implemented correctly.
 413         // Also, $errors isn't used right now
 414         $errors = array();
 415
 416         $correct = true;
 417         if ($this->get_title() === NULL) {
 418             $errors[] = 'title_not_set';
 419             $correct = false;
 420         }
 421         if (!in_array($this->get_content_type(), array(BLOCK_TYPE_LIST, BLOCK_TYPE_TEXT))) {
 422             $errors[] = 'invalid_content_type';
 423             $correct = false;
 424         }
 425         //following selftest was not working when roles&capabilities were used from block
 426 /*        if ($this->get_content() === NULL) {
 427             $errors[] = 'content_not_set';
 428             $correct = false;
 429         }*/
 430         if ($this->get_version() === NULL) {
 431             $errors[] = 'version_not_set';
 432             $correct = false;
 433         }
 434
 435         $formats = $this->applicable_formats();
 436         if (empty($formats) || array_sum($formats) === 0) {
 437             $errors[] = 'no_formats';
 438             $correct = false;
 439         }
 440
 441         $width = $this->preferred_width();
 442         if (!is_int($width) || $width <= 0) {
 443             $errors[] = 'invalid_width';
 444             $correct = false;
 445         }
 446         return $correct;
 447     }
 448
 449     /**
 450      * Subclasses should override this and return true if the
 451      * subclass block has a config_global.html file.
 452      *
 453      * @return boolean
 454      */
 455     function has_config() {
 456         return false;
 457     }
 458
 459     /**
 460      * Default behavior: print the config_global.html file
 461      * You don't need to override this if you're satisfied with the above
 462      *
 463      * @uses $CFG
 464      * @return boolean
 465      */
 466     function config_print() {
 467         // Default behavior: print the config_global.html file
 468         // You don't need to override this if you're satisfied with the above
 469         if (!$this->has_config()) {
 470             return false;
 471         }
 472         global $CFG;
 473         print_simple_box_start('center', '', '', 5, 'blockconfigglobal');
 474         include($CFG->dirroot.'/blocks/'. $this->name() .'/config_global.html');
 475         print_simple_box_end();
 476         return true;
 477     }
 478
 479     /**
 480      * Default behavior: save all variables as $CFG properties
 481      * You don't need to override this if you 're satisfied with the above
 482      *
 483      * @param array $data
 484      * @return boolean
 485      */
 486     function config_save($data) {
 487         foreach ($data as $name => $value) {
 488             set_config($name, $value);
 489         }
 490         return true;
 491     }
 492
 493     /**
 494      * Default case: the block can be used in all course types
 495      * @return array
 496      * @todo finish documenting this function
 497      */
 498     function applicable_formats() {
 499         // Default case: the block can be used in courses and site index, but not in activities
 500         return array('all' => true, 'mod' => false, 'tag' => false);
 501     }
 502
 503
 504     /**
 505      * Default case: the block wants to be 180 pixels wide
 506      * @return int
 507      */
 508     function preferred_width() {
 509         return 180;
 510     }
 511
 512     /**
 513      * Default return is false - header will be shown
 514      * @return boolean
 515      */
 516     function hide_header() {
 517         return false;
 518     }
 519
 520     /**
 521      * Default case: an id with the instance and a class with our name in it
 522      * @return array
 523      * @todo finish documenting this function
 524      */
 525     function html_attributes() {
 526         return array('id' => 'inst'.$this->instance->id, 'class' => 'block_'. $this->name());
 527     }
 528
 529     /**
 530      * Given an instance set the class var $instance to it and
 531      * load class var $config
 532      * @param block $instance
 533      * @todo add additional documentation to further explain the format of instance and config
 534      */
 535     function _load_instance($instance) {
 536         if (!empty($instance->configdata)) {
 537             $this->config = unserialize(base64_decode($instance->configdata));
 538         }
 539         // [pj] This line below is supposed to be an optimization (we don't need configdata anymore)
 540         // but what it does is break in PHP5 because the same instance object will be passed to
 541         // this function twice in each page view, and the second time it won't have any configdata
 542         // so it won't work correctly. Thus it's commented out.
 543         // unset($instance->configdata);
 544         $this->instance = $instance;
 545         $this->specialization();
 546     }
 547
 548     /**
 549      * This function is called on your subclass right after an instance is loaded
 550      * Use this function to act on instance data just after it's loaded and before anything else is done
 551      * For instance: if your block will have different title's depending on location (site, course, blog, etc)
 552      */
 553     function specialization() {
 554         // Just to make sure that this method exists.
 555     }
 556
 557     /**
 558      * Is each block of this type going to have instance-specific configuration?
 559      * Normally, this setting is controlled by {@link instance_allow_multiple}: if multiple
 560      * instances are allowed, then each will surely need its own configuration. However, in some
 561      * cases it may be necessary to provide instance configuration to blocks that do not want to
 562      * allow multiple instances. In that case, make this function return true.
 563      * I stress again that this makes a difference ONLY if {@link instance_allow_multiple} returns false.
 564      * @return boolean
 565      * @todo finish documenting this function by explaining per-instance configuration further
 566      */
 567     function instance_allow_config() {
 568         return false;
 569     }
 570
 571     /**
 572      * Are you going to allow multiple instances of each block?
 573      * If yes, then it is assumed that the block WILL USE per-instance configuration
 574      * @return boolean
 575      * @todo finish documenting this function by explaining per-instance configuration further
 576      */
 577     function instance_allow_multiple() {
 578         // Are you going to allow multiple instances of each block?
 579         // If yes, then it is assumed that the block WILL USE per-instance configuration
 580         return false;
 581     }
 582
 583     /**
 584      * Default behavior: print the config_instance.html file
 585      * You don't need to override this if you're satisfied with the above
 586      *
 587      * @uses $CFG
 588      * @return boolean
 589      * @todo finish documenting this function
 590      */
 591     function instance_config_print() {
 592         // Default behavior: print the config_instance.html file
 593         // You don't need to override this if you're satisfied with the above
 594         if (!$this->instance_allow_multiple() && !$this->instance_allow_config()) {
 595             return false;
 596         }
 597         global $CFG;
 598
 599         if (is_file($CFG->dirroot .'/blocks/'. $this->name() .'/config_instance.html')) {
 600             print_simple_box_start('center', '', '', 5, 'blockconfiginstance');
 601             include($CFG->dirroot .'/blocks/'. $this->name() .'/config_instance.html');
 602             print_simple_box_end();
 603         } else {
 604             notice(get_string('blockconfigbad'), str_replace('blockaction=', 'dummy=', qualified_me()));
 605         }
 606
 607         return true;
 608     }
 609
 610     /**
 611      * Serialize and store config data
 612      * @return boolean
 613      * @todo finish documenting this function
 614      */
 615     function instance_config_save($data,$pinned=false) {
 616         $data = stripslashes_recursive($data);
 617         $this->config = $data;
 618         $table = 'block_instance';
 619         if (!empty($pinned)) {
 620             $table = 'block_pinned';
 621         }
 622         return set_field($table, 'configdata', base64_encode(serialize($data)), 'id', $this->instance->id);
 623     }
 624
 625     /**
 626      * Replace the instance's configuration data with those currently in $this->config;
 627      * @return boolean
 628      * @todo finish documenting this function
 629      */
 630     function instance_config_commit($pinned=false) {
 631         $table = 'block_instance';
 632         if (!empty($pinned)) {
 633             $table = 'block_pinned';
 634         }
 635         return set_field($table, 'configdata', base64_encode(serialize($this->config)), 'id', $this->instance->id);
 636     }
 637
 638      /**
 639      * Do any additional initialization you may need at the time a new block instance is created
 640      * @return boolean
 641      * @todo finish documenting this function
 642      */
 643     function instance_create() {
 644         return true;
 645     }
 646
 647      /**
 648      * Delete everything related to this instance if you have been using persistent storage other than the configdata field.
 649      * @return boolean
 650      * @todo finish documenting this function
 651      */
 652     function instance_delete() {
 653         return true;
 654     }
 655
 656      /**
 657      * Allows the block class to have a say in the user's ability to edit (i.e., configure) blocks of this type.
 658      * The framework has first say in whether this will be allowed (e.g., no editing allowed unless in edit mode)
 659      * but if the framework does allow it, the block can still decide to refuse.
 660      * @return boolean
 661      * @todo finish documenting this function
 662      */
 663     function user_can_edit() {
 664         return true;
 665     }
 666
 667      /**
 668      * Allows the block class to have a say in the user's ability to create new instances of this block.
 669      * The framework has first say in whether this will be allowed (e.g., no adding allowed unless in edit mode)
 670      * but if the framework does allow it, the block can still decide to refuse.
 671      * This function has access to the complete page object, the creation related to which is being determined.
 672      * @return boolean
 673      * @todo finish documenting this function
 674      */
 675     function user_can_addto(&$page) {
 676         return true;
 677     }
 678
 679 }
 680
 681 /**
 682  * Specialized class for displaying a block with a list of icons/text labels
 683  *
 684  * @author Jon Papaioannou
 685  * @package blocks
 686  */
 687
 688 class block_list extends block_base {
 689     var $content_type  = BLOCK_TYPE_LIST;
 690
 691     function is_empty() {
 692         $this->get_content();
 693         return (empty($this->content->items) && empty($this->content->footer));
 694     }
 695
 696     function _print_block() {
 697         global $COURSE;
 698
 699         // is_empty() includes a call to get_content()
 700         if ($this->is_empty() && empty($COURSE->javascriptportal)) {
 701             if (empty($this->edit_controls)) {
 702                 // No content, no edit controls, so just shut up
 703                 return;
 704             } else {
 705                 // No content but editing, so show something at least
 706                 $this->_print_shadow();
 707             }
 708         } else {
 709             if ($this->hide_header() && empty($this->edit_controls)) {
 710                 // Header wants to hide, no edit controls to show, so no header it is
 711                 print_side_block(NULL, '', $this->content->items, $this->content->icons,
 712                                  $this->content->footer, $this->html_attributes());
 713             } else {
 714                 // The full treatment, please. Include the title text.
 715                 print_side_block($this->_title_html(), '', $this->content->items, $this->content->icons,
 716                                  $this->content->footer, $this->html_attributes(), $this->title);
 717             }
 718         }
 719     }
 720
 721 }
 722
 723 ?>