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      *
 199      * @return boolean
 200      */
 201     function is_empty() {
 202         $this->get_content();
 203         return(empty($this->content->text) && empty($this->content->footer));
 204     }
 205
 206     /**
 207      * First sets the current value of $this->content to NULL
 208      * then calls the block's {@link get_content()} function
 209      * to set its value back.
 210      *
 211      * @return stdObject
 212      */
 213     function refresh_content() {
 214         // Nothing special here, depends on content()
 215         $this->content = NULL;
 216         return $this->get_content();
 217     }
 218
 219     /**
 220      * Display the block!
 221      */
 222     function _print_block() {
 223         global $COURSE;
 224
 225         // is_empty() includes a call to get_content()
 226         if ($this->is_empty() && empty($COURSE->javascriptportal)) {
 227             if (empty($this->edit_controls)) {
 228                 // No content, no edit controls, so just shut up
 229                 return;
 230             } else {
 231                 // No content but editing, so show something at least
 232                 $this->_print_shadow();
 233             }
 234         } else {
 235             if ($this->hide_header() && empty($this->edit_controls)) {
 236                 // Header wants to hide, no edit controls to show, so no header it is
 237                 print_side_block(NULL, $this->content->text, NULL, NULL, $this->content->footer, $this->html_attributes());
 238             } else {
 239                 // The full treatment, please. Include the title text.
 240                 print_side_block($this->_title_html(), $this->content->text, NULL, NULL, $this->content->footer, $this->html_attributes(), $this->title);
 241             }
 242         }
 243     }
 244
 245     /**
 246      * Block contents are missing. Simply display an empty block so that
 247      * edit controls are accessbile to the user and they are aware that this
 248      * block is in place, even if empty.
 249      */
 250     function _print_shadow() {
 251         print_side_block($this->_title_html(), '&nbsp;', NULL, NULL, '', array('class' => 'hidden'), $this->title);
 252     }
 253
 254
 255     function _title_html() {
 256         global $CFG;
 257
 258         //Accessibility: validation, can't have <div> inside <h2>, use <span>.
 259         $title = '<div class="title">';
 260
 261         if (!empty($CFG->allowuserblockhiding)) {
 262             //Accessibility: added static 'alt' text for the +- icon.
 263             //TODO (nfreear): language string 'hide OR show block'
 264             $title .= '<div class="hide-show">'.
 265                                           '<a title="'.get_string('showhideblock','access').
 266                                           '" href="#" onclick="elementToggleHide(this, true, function(el) {'.
 267                                           'return findParentNode(el, \'DIV\', \'sideblock\'); '.
 268                                           '}, \''.$CFG->pixpath.'\' ); return false;">'.
 269                                           '<img src="'.$CFG->pixpath.'/spacer.gif" '.
 270                                           'id = "togglehide_inst'.$this->instance->id.'" '.
 271                                           'alt="'.get_string('showhideblock','access').'" class="hide-show-image" /></a></div>';
 272         }
 273
 274         //Accesssibility: added H2 (was in, weblib.php: print_side_block)
 275         $title .= '<h2>'.$this->title.'</h2>';
 276
 277         if ($this->edit_controls !== NULL) {
 278             $title .= $this->edit_controls;
 279         }
 280
 281         $title .= '</div>';
 282         return $title;
 283     }
 284
 285     /**
 286      * Sets class $edit_controls var with correct block manipulation links.
 287      *
 288      * @uses $CFG
 289      * @uses $USER
 290      * @param stdObject $options ?
 291      * @todo complete documenting this function. Define $options.
 292      */
 293     function _add_edit_controls($options) {
 294         global $CFG, $USER, $PAGE;
 295
 296         // this is the context relevant to this particular block instance
 297         $blockcontext = get_context_instance(CONTEXT_BLOCK, $this->instance->id);
 298
 299         // context for site or course, i.e. participant list etc
 300         // check to see if user can edit site or course blocks.
 301         // blocks can appear on other pages such as mod and blog pages...
 302
 303         switch ($this->instance->pagetype) {
 304             case 'course-view':
 305                 if (!has_capability('moodle/site:manageblocks', $blockcontext)) {
 306                     return null;
 307                 }
 308             break;
 309             default:
 310
 311             break;
 312         }
 313
 314
 315         if (!isset($this->str)) {
 316             $this->str->delete    = get_string('delete');
 317             $this->str->moveup    = get_string('moveup');
 318             $this->str->movedown  = get_string('movedown');
 319             $this->str->moveright = get_string('moveright');
 320             $this->str->moveleft  = get_string('moveleft');
 321             $this->str->hide      = get_string('hide');
 322             $this->str->show      = get_string('show');
 323             $this->str->configure = get_string('configuration');
 324             $this->str->assignroles = get_string('assignroles', 'role');
 325         }
 326
 327         $movebuttons = '<div class="commands">';
 328
 329         if ($this->instance->visible) {
 330             $icon = '/t/hide.gif';
 331             $title = $this->str->hide;
 332         } else {
 333             $icon = '/t/show.gif';
 334             $title = $this->str->show;
 335         }
 336
 337         if (empty($this->instance->pageid)) {
 338             $this->instance->pageid = 0;
 339         }
 340         if (!empty($PAGE->type) and ($this->instance->pagetype == $PAGE->type) and $this->instance->pageid == $PAGE->id) {
 341             $page = $PAGE;
 342         } else {
 343             $page = page_create_object($this->instance->pagetype, $this->instance->pageid);
 344         }
 345         $script = $page->url_get_full(array('instanceid' => $this->instance->id, 'sesskey' => $USER->sesskey));
 346
 347          // place holder for roles button
 348          $movebuttons .= '<a class="icon roles" title="'. $this->str->assignroles .'" href="'.$CFG->wwwroot.'/'.$CFG->admin.'/roles/assign.php?contextid='.$blockcontext->id.'">' .
 349                         '<img src="'.$CFG->pixpath.'/i/roles.gif" alt="'.$this->str->assignroles.'" /></a>';
 350
 351         $movebuttons .= '<a class="icon hide" title="'. $title .'" href="'.$script.'&amp;blockaction=toggle">' .
 352                         '<img src="'. $CFG->pixpath.$icon .'" alt="'.$title.'" /></a>';
 353
 354         if ($options & BLOCK_CONFIGURE && $this->user_can_edit()) {
 355             $movebuttons .= '<a class="icon edit" title="'. $this->str->configure .'" href="'.$script.'&amp;blockaction=config">' .
 356                             '<img src="'. $CFG->pixpath .'/t/edit.gif" alt="'. $this->str->configure .'" /></a>';
 357         }
 358
 359         $movebuttons .= '<a class="icon delete" title="'. $this->str->delete .'" href="'.$script.'&amp;blockaction=delete">' .
 360                         '<img src="'. $CFG->pixpath .'/t/delete.gif" alt="'. $this->str->delete .'" /></a>';
 361
 362         if ($options & BLOCK_MOVE_LEFT) {
 363             $movebuttons .= '<a class="icon left" title="'. $this->str->moveleft .'" href="'.$script.'&amp;blockaction=moveleft">' .
 364                             '<img src="'. $CFG->pixpath .'/t/left.gif" alt="'. $this->str->moveleft .'" /></a>';
 365         }
 366         if ($options & BLOCK_MOVE_UP) {
 367             $movebuttons .= '<a class="icon up" title="'. $this->str->moveup .'" href="'.$script.'&amp;blockaction=moveup">' .
 368                             '<img src="'. $CFG->pixpath .'/t/up.gif" alt="'. $this->str->moveup .'" /></a>';
 369         }
 370         if ($options & BLOCK_MOVE_DOWN) {
 371             $movebuttons .= '<a class="icon down" title="'. $this->str->movedown .'" href="'.$script.'&amp;blockaction=movedown">' .
 372                             '<img src="'. $CFG->pixpath .'/t/down.gif" alt="'. $this->str->movedown .'" /></a>';
 373         }
 374         if ($options & BLOCK_MOVE_RIGHT) {
 375             $movebuttons .= '<a class="icon right" title="'. $this->str->moveright .'" href="'.$script.'&amp;blockaction=moveright">' .
 376                             '<img src="'. $CFG->pixpath .'/t/right.gif" alt="'. $this->str->moveright .'" /></a>';
 377         }
 378
 379         $movebuttons .= '</div>';
 380         $this->edit_controls = $movebuttons;
 381     }
 382
 383     /**
 384      * Tests if this block has been implemented correctly.
 385      * Also, $errors isn't used right now
 386      *
 387      * @return boolean
 388      */
 389
 390     function _self_test() {
 391         // Tests if this block has been implemented correctly.
 392         // Also, $errors isn't used right now
 393         $errors = array();
 394
 395         $correct = true;
 396         if ($this->get_title() === NULL) {
 397             $errors[] = 'title_not_set';
 398             $correct = false;
 399         }
 400         if (!in_array($this->get_content_type(), array(BLOCK_TYPE_LIST, BLOCK_TYPE_TEXT))) {
 401             $errors[] = 'invalid_content_type';
 402             $correct = false;
 403         }
 404         //following selftest was not working when roles&capabilities were used from block
 405 /*        if ($this->get_content() === NULL) {
 406             $errors[] = 'content_not_set';
 407             $correct = false;
 408         }*/
 409         if ($this->get_version() === NULL) {
 410             $errors[] = 'version_not_set';
 411             $correct = false;
 412         }
 413
 414         $formats = $this->applicable_formats();
 415         if (empty($formats) || array_sum($formats) === 0) {
 416             $errors[] = 'no_formats';
 417             $correct = false;
 418         }
 419
 420         $width = $this->preferred_width();
 421         if (!is_int($width) || $width <= 0) {
 422             $errors[] = 'invalid_width';
 423             $correct = false;
 424         }
 425         return $correct;
 426     }
 427
 428     /**
 429      * Subclasses should override this and return true if the
 430      * subclass block has a config_global.html file.
 431      *
 432      * @return boolean
 433      */
 434     function has_config() {
 435         return false;
 436     }
 437
 438     /**
 439      * Default behavior: print the config_global.html file
 440      * You don't need to override this if you're satisfied with the above
 441      *
 442      * @uses $CFG
 443      * @return boolean
 444      */
 445     function config_print() {
 446         // Default behavior: print the config_global.html file
 447         // You don't need to override this if you're satisfied with the above
 448         if (!$this->has_config()) {
 449             return false;
 450         }
 451         global $CFG;
 452         print_simple_box_start('center', '', '', 5, 'blockconfigglobal');
 453         include($CFG->dirroot.'/blocks/'. $this->name() .'/config_global.html');
 454         print_simple_box_end();
 455         return true;
 456     }
 457
 458     /**
 459      * Default behavior: save all variables as $CFG properties
 460      * You don't need to override this if you 're satisfied with the above
 461      *
 462      * @param array $data
 463      * @return boolean
 464      */
 465     function config_save($data) {
 466         foreach ($data as $name => $value) {
 467             set_config($name, $value);
 468         }
 469         return true;
 470     }
 471
 472     /**
 473      * Default case: the block can be used in all course types
 474      * @return array
 475      * @todo finish documenting this function
 476      */
 477     function applicable_formats() {
 478         // Default case: the block can be used in courses and site index, but not in activities
 479         return array('all' => true, 'mod' => false);
 480     }
 481
 482
 483     /**
 484      * Default case: the block wants to be 180 pixels wide
 485      * @return int
 486      */
 487     function preferred_width() {
 488         return 180;
 489     }
 490
 491     /**
 492      * Default return is false - header will be shown
 493      * @return boolean
 494      */
 495     function hide_header() {
 496         return false;
 497     }
 498
 499     /**
 500      * Default case: an id with the instance and a class with our name in it
 501      * @return array
 502      * @todo finish documenting this function
 503      */
 504     function html_attributes() {
 505         return array('id' => 'inst'.$this->instance->id, 'class' => 'block_'. $this->name());
 506     }
 507
 508     /**
 509      * Given an instance set the class var $instance to it and
 510      * load class var $config
 511      * @param block $instance
 512      * @todo add additional documentation to further explain the format of instance and config
 513      */
 514     function _load_instance($instance) {
 515         if (!empty($instance->configdata)) {
 516             $this->config = unserialize(base64_decode($instance->configdata));
 517         }
 518         // [pj] This line below is supposed to be an optimization (we don't need configdata anymore)
 519         // but what it does is break in PHP5 because the same instance object will be passed to
 520         // this function twice in each page view, and the second time it won't have any configdata
 521         // so it won't work correctly. Thus it's commented out.
 522         // unset($instance->configdata);
 523         $this->instance = $instance;
 524         $this->specialization();
 525     }
 526
 527     /**
 528      * This function is called on your subclass right after an instance is loaded
 529      * Use this function to act on instance data just after it's loaded and before anything else is done
 530      * For instance: if your block will have different title's depending on location (site, course, blog, etc)
 531      */
 532     function specialization() {
 533         // Just to make sure that this method exists.
 534     }
 535
 536     /**
 537      * Is each block of this type going to have instance-specific configuration?
 538      * Normally, this setting is controlled by {@link instance_allow_multiple}: if multiple
 539      * instances are allowed, then each will surely need its own configuration. However, in some
 540      * cases it may be necessary to provide instance configuration to blocks that do not want to
 541      * allow multiple instances. In that case, make this function return true.
 542      * I stress again that this makes a difference ONLY if {@link instance_allow_multiple} returns false.
 543      * @return boolean
 544      * @todo finish documenting this function by explaining per-instance configuration further
 545      */
 546     function instance_allow_config() {
 547         return false;
 548     }
 549
 550     /**
 551      * Are you going to allow multiple instances of each block?
 552      * If yes, then it is assumed that the block WILL USE per-instance configuration
 553      * @return boolean
 554      * @todo finish documenting this function by explaining per-instance configuration further
 555      */
 556     function instance_allow_multiple() {
 557         // Are you going to allow multiple instances of each block?
 558         // If yes, then it is assumed that the block WILL USE per-instance configuration
 559         return false;
 560     }
 561
 562     /**
 563      * Default behavior: print the config_instance.html file
 564      * You don't need to override this if you're satisfied with the above
 565      *
 566      * @uses $CFG
 567      * @return boolean
 568      * @todo finish documenting this function
 569      */
 570     function instance_config_print() {
 571         // Default behavior: print the config_instance.html file
 572         // You don't need to override this if you're satisfied with the above
 573         if (!$this->instance_allow_multiple() && !$this->instance_allow_config()) {
 574             return false;
 575         }
 576         global $CFG;
 577
 578         if (is_file($CFG->dirroot .'/blocks/'. $this->name() .'/config_instance.html')) {
 579             print_simple_box_start('center', '', '', 5, 'blockconfiginstance');
 580             include($CFG->dirroot .'/blocks/'. $this->name() .'/config_instance.html');
 581             print_simple_box_end();
 582         } else {
 583             notice(get_string('blockconfigbad'), str_replace('blockaction=', 'dummy=', qualified_me()));
 584         }
 585
 586         return true;
 587     }
 588
 589     /**
 590      * Serialize and store config data
 591      * @return boolean
 592      * @todo finish documenting this function
 593      */
 594     function instance_config_save($data,$pinned=false) {
 595         $data = stripslashes_recursive($data);
 596         $this->config = $data;
 597         $table = 'block_instance';
 598         if (!empty($pinned)) {
 599             $table = 'block_pinned';
 600         }
 601         return set_field($table, 'configdata', base64_encode(serialize($data)), 'id', $this->instance->id);
 602     }
 603
 604     /**
 605      * Replace the instance's configuration data with those currently in $this->config;
 606      * @return boolean
 607      * @todo finish documenting this function
 608      */
 609     function instance_config_commit($pinned=false) {
 610         $table = 'block_instance';
 611         if (!empty($pinned)) {
 612             $table = 'block_pinned';
 613         }
 614         return set_field($table, 'configdata', base64_encode(serialize($this->config)), 'id', $this->instance->id);
 615     }
 616
 617      /**
 618      * Do any additional initialization you may need at the time a new block instance is created
 619      * @return boolean
 620      * @todo finish documenting this function
 621      */
 622     function instance_create() {
 623         return true;
 624     }
 625
 626      /**
 627      * Delete everything related to this instance if you have been using persistent storage other than the configdata field.
 628      * @return boolean
 629      * @todo finish documenting this function
 630      */
 631     function instance_delete() {
 632         return true;
 633     }
 634
 635      /**
 636      * Allows the block class to have a say in the user's ability to edit (i.e., configure) blocks of this type.
 637      * The framework has first say in whether this will be allowed (e.g., no editing allowed unless in edit mode)
 638      * but if the framework does allow it, the block can still decide to refuse.
 639      * @return boolean
 640      * @todo finish documenting this function
 641      */
 642     function user_can_edit() {
 643         return true;
 644     }
 645
 646      /**
 647      * Allows the block class to have a say in the user's ability to create new instances of this block.
 648      * The framework has first say in whether this will be allowed (e.g., no adding allowed unless in edit mode)
 649      * but if the framework does allow it, the block can still decide to refuse.
 650      * This function has access to the complete page object, the creation related to which is being determined.
 651      * @return boolean
 652      * @todo finish documenting this function
 653      */
 654     function user_can_addto(&$page) {
 655         return true;
 656     }
 657
 658 }
 659
 660 /**
 661  * Specialized class for displaying a block with a list of icons/text labels
 662  *
 663  * @author Jon Papaioannou
 664  * @package blocks
 665  */
 666
 667 class block_list extends block_base {
 668     var $content_type  = BLOCK_TYPE_LIST;
 669
 670     function is_empty() {
 671         $this->get_content();
 672         return (empty($this->content->items) && empty($this->content->footer));
 673     }
 674
 675     function _print_block() {
 676         global $COURSE;
 677
 678         // is_empty() includes a call to get_content()
 679         if ($this->is_empty() && empty($COURSE->javascriptportal)) {
 680             if (empty($this->edit_controls)) {
 681                 // No content, no edit controls, so just shut up
 682                 return;
 683             } else {
 684                 // No content but editing, so show something at least
 685                 $this->_print_shadow();
 686             }
 687         } else {
 688             if ($this->hide_header() && empty($this->edit_controls)) {
 689                 // Header wants to hide, no edit controls to show, so no header it is
 690                 print_side_block(NULL, '', $this->content->items, $this->content->icons,
 691                                  $this->content->footer, $this->html_attributes());
 692             } else {
 693                 // The full treatment, please. Include the title text.
 694                 print_side_block($this->_title_html(), '', $this->content->items, $this->content->icons,
 695                                  $this->content->footer, $this->html_attributes(), $this->title);
 696             }
 697         }
 698     }
 699
 700 }
 701
 702 ?>