blocks/moodleblock.class.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 /**
  19  * This file contains the parent class for moodle blocks, block_base.
  20  *
  21  * @package    core
  22  * @subpackage block
  23  * @license    http://www.gnu.org/copyleft/gpl.html GNU Public License
  24  */
  25
  26 /// Constants
  27
  28 /**
  29  * 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 $this->content->footer.
  30  */
  31 define('BLOCK_TYPE_LIST',    1);
  32
  33 /**
  34  * Block type of text. Contents of block should be set to standard html text in the content object as items ($this->content->text). Optionally include footer text in $this->content->footer.
  35  */
  36 define('BLOCK_TYPE_TEXT',    2);
  37 /**
  38  * Block type of tree. $this->content->items is a list of tree_item objects and $this->content->footer is a string.
  39  */
  40 define('BLOCK_TYPE_TREE',    3);
  41
  42 /**
  43  * Class for describing a moodle block, all Moodle blocks derive from this class
  44  *
  45  * @author Jon Papaioannou
  46  * @package blocks
  47  */
  48 class block_base {
  49
  50     /**
  51      * Internal var for storing/caching translated strings
  52      * @var string $str
  53      */
  54     var $str;
  55
  56     /**
  57      * The title of the block to be displayed in the block title area.
  58      * @var string $title
  59      */
  60     var $title         = NULL;
  61
  62     /**
  63      * The type of content that this block creates. Currently support options - BLOCK_TYPE_LIST, BLOCK_TYPE_TEXT
  64      * @var int $content_type
  65      */
  66     var $content_type  = BLOCK_TYPE_TEXT;
  67
  68     /**
  69      * An object to contain the information to be displayed in the block.
  70      * @var stdObject $content
  71      */
  72     var $content       = NULL;
  73
  74     /**
  75      * A string generated by {@link _add_edit_controls()} to display block manipulation links when the user is in editing mode.
  76      * @var string $edit_controls
  77      */
  78     var $edit_controls = NULL;
  79
  80     /**
  81      * The initialized instance of this block object.
  82      * @var block $instance
  83      */
  84     var $instance      = NULL;
  85
  86     /**
  87      * The page that this block is appearing on.
  88      * @var moodle_page
  89      */
  90     public $page       = NULL;
  91
  92     /**
  93      * This blocks's context.
  94      * @var stdClass
  95      */
  96     public $context    = NULL;
  97
  98     /**
  99      * An object containing the instance configuration information for the current instance of this block.
 100      * @var stdObject $config
 101      */
 102     var $config        = NULL;
 103
 104     /**
 105      * How often the cronjob should run, 0 if not at all.
 106      * @var int $cron
 107      */
 108
 109     var $cron          = NULL;
 110
 111 /// Class Functions
 112
 113     /**
 114      * Fake constructor to keep PHP5 happy
 115      *
 116      */
 117     function __construct() {
 118         $this->init();
 119     }
 120
 121     /**
 122      * Function that can be overridden to do extra cleanup before
 123      * the database tables are deleted. (Called once per block, not per instance!)
 124      */
 125     function before_delete() {
 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 true or false, depending on whether this block has any content to display
 185      * and whether the user has permission to view the block
 186      *
 187      * @return boolean
 188      */
 189     function is_empty() {
 190         if ( !has_capability('moodle/block:view', $this->context) ) {
 191             return true;
 192         }
 193
 194         $this->get_content();
 195         return(empty($this->content->text) && empty($this->content->footer));
 196     }
 197
 198     /**
 199      * First sets the current value of $this->content to NULL
 200      * then calls the block's {@link get_content()} function
 201      * to set its value back.
 202      *
 203      * @return stdObject
 204      */
 205     function refresh_content() {
 206         // Nothing special here, depends on content()
 207         $this->content = NULL;
 208         return $this->get_content();
 209     }
 210
 211     /**
 212      * Return a block_contents object representing the full contents of this block.
 213      *
 214      * This internally calls ->get_content(), and then adds the editing controls etc.
 215      *
 216      * You probably should not override this method, but instead override
 217      * {@link html_attributes()}, {@link formatted_contents()} or {@link get_content()},
 218      * {@link hide_header()}, {@link (get_edit_controls)}, etc.
 219      *
 220      * @return block_contents a representation of the block, for rendering.
 221      * @since Moodle 2.0.
 222      */
 223     public function get_content_for_output($output) {
 224         global $CFG;
 225
 226         $bc = new block_contents($this->html_attributes());
 227
 228         $bc->blockinstanceid = $this->instance->id;
 229         $bc->blockpositionid = $this->instance->blockpositionid;
 230
 231         if ($this->instance->visible) {
 232             $bc->content = $this->formatted_contents($output);
 233             if (!empty($this->content->footer)) {
 234                 $bc->footer = $this->content->footer;
 235             }
 236         } else {
 237             $bc->add_class('invisible');
 238         }
 239
 240         if (!$this->hide_header()) {
 241             $bc->title = $this->title;
 242         }
 243
 244         if ($this->page->user_is_editing()) {
 245             $bc->controls = $this->page->blocks->edit_controls($this);
 246         } else {
 247             // we must not use is_empty on hidden blocks
 248             if ($this->is_empty() && !$bc->controls) {
 249                 return null;
 250             }
 251         }
 252
 253         if (empty($CFG->allowuserblockhiding) ||
 254                 (empty($bc->content) && empty($bc->footer))) {
 255             $bc->collapsible = block_contents::NOT_HIDEABLE;
 256         } else if (get_user_preferences('block' . $bc->blockinstanceid . 'hidden', false)) {
 257             $bc->collapsible = block_contents::HIDDEN;
 258         } else {
 259             $bc->collapsible = block_contents::VISIBLE;
 260         }
 261
 262         $bc->annotation = ''; // TODO MDL-19398 need to work out what to say here.
 263
 264         return $bc;
 265     }
 266
 267     /**
 268      * Convert the contents of the block to HTML.
 269      *
 270      * This is used by block base classes like block_list to convert the structured
 271      * $this->content->list and $this->content->icons arrays to HTML. So, in most
 272      * blocks, you probaby want to override the {@link get_contents()} method,
 273      * which generates that structured representation of the contents.
 274      *
 275      * @param $output The core_renderer to use when generating the output.
 276      * @return string the HTML that should appearn in the body of the block.
 277      * @since Moodle 2.0.
 278      */
 279     protected function formatted_contents($output) {
 280         $this->get_content();
 281         $this->get_required_javascript();
 282         if (!empty($this->content->text)) {
 283             return $this->content->text;
 284         } else {
 285             return '';
 286         }
 287     }
 288
 289     /**
 290      * Tests if this block has been implemented correctly.
 291      * Also, $errors isn't used right now
 292      *
 293      * @return boolean
 294      */
 295
 296     function _self_test() {
 297         // Tests if this block has been implemented correctly.
 298         // Also, $errors isn't used right now
 299         $errors = array();
 300
 301         $correct = true;
 302         if ($this->get_title() === NULL) {
 303             $errors[] = 'title_not_set';
 304             $correct = false;
 305         }
 306         if (!in_array($this->get_content_type(), array(BLOCK_TYPE_LIST, BLOCK_TYPE_TEXT, BLOCK_TYPE_TREE))) {
 307             $errors[] = 'invalid_content_type';
 308             $correct = false;
 309         }
 310         //following selftest was not working when roles&capabilities were used from block
 311 /*        if ($this->get_content() === NULL) {
 312             $errors[] = 'content_not_set';
 313             $correct = false;
 314         }*/
 315         $formats = $this->applicable_formats();
 316         if (empty($formats) || array_sum($formats) === 0) {
 317             $errors[] = 'no_formats';
 318             $correct = false;
 319         }
 320
 321         $width = $this->preferred_width();
 322         if (!is_int($width) || $width <= 0) {
 323             $errors[] = 'invalid_width';
 324             $correct = false;
 325         }
 326         return $correct;
 327     }
 328
 329     /**
 330      * Subclasses should override this and return true if the
 331      * subclass block has a config_global.html file.
 332      *
 333      * @return boolean
 334      */
 335     function has_config() {
 336         return false;
 337     }
 338
 339     /**
 340      * Default behavior: save all variables as $CFG properties
 341      * You don't need to override this if you 're satisfied with the above
 342      *
 343      * @param array $data
 344      * @return boolean
 345      */
 346     function config_save($data) {
 347         foreach ($data as $name => $value) {
 348             set_config($name, $value);
 349         }
 350         return true;
 351     }
 352
 353     /**
 354      * Which page types this block may appear on.
 355      *
 356      * The information returned here is processed by the
 357      * {@link blocks_name_allowed_in_format()} function. Look there if you need
 358      * to know exactly how this works.
 359      *
 360      * Default case: everything except mod and tag.
 361      *
 362      * @return array page-type prefix => true/false.
 363      */
 364     function applicable_formats() {
 365         // Default case: the block can be used in courses and site index, but not in activities
 366         return array('all' => true, 'mod' => false, 'tag' => false);
 367     }
 368
 369
 370     /**
 371      * Default return is false - header will be shown
 372      * @return boolean
 373      */
 374     function hide_header() {
 375         return false;
 376     }
 377
 378     /**
 379      * Return any HTML attributes that you want added to the outer <div> that
 380      * of the block when it is output.
 381      *
 382      * Because of the way certain JS events are wired it is a good idea to ensure
 383      * that the default values here still get set.
 384      * I found the easiest way to do this and still set anything you want is to
 385      * override it within your block in the following way
 386      *
 387      * <code php>
 388      * function html_attributes() {
 389      *    $attributes = parent::html_attributes();
 390      *    $attributes['class'] .= ' mynewclass';
 391      *    return $attributes;
 392      * }
 393      * </code>
 394      *
 395      * @return array attribute name => value.
 396      */
 397     function html_attributes() {
 398         $attributes = array(
 399             'id' => 'inst' . $this->instance->id,
 400             'class' => 'block_' . $this->name(). '  block'
 401         );
 402         if ($this->instance_can_be_docked() && get_user_preferences('docked_block_instance_'.$this->instance->id, 0)) {
 403             $attributes['class'] .= ' dock_on_load';
 404         }
 405         return $attributes;
 406     }
 407
 408     /**
 409      * Set up a particular instance of this class given data from the block_insances
 410      * table and the current page. (See {@link block_manager::load_blocks()}.)
 411      *
 412      * @param stdClass $instance data from block_insances, block_positions, etc.
 413      * @param moodle_page $the page this block is on.
 414      */
 415     function _load_instance($instance, $page) {
 416         if (!empty($instance->configdata)) {
 417             $this->config = unserialize(base64_decode($instance->configdata));
 418         }
 419         $this->instance = $instance;
 420         $this->context = get_context_instance(CONTEXT_BLOCK, $instance->id);
 421         $this->page = $page;
 422         $this->specialization();
 423     }
 424
 425     function get_required_javascript() {
 426         if ($this->instance_can_be_docked() && !$this->hide_header()) {
 427             $this->page->requires->js_init_call('M.core_dock.init_genericblock', array($this->instance->id));
 428             user_preference_allow_ajax_update('docked_block_instance_'.$this->instance->id, PARAM_INT);
 429         }
 430     }
 431
 432     /**
 433      * This function is called on your subclass right after an instance is loaded
 434      * Use this function to act on instance data just after it's loaded and before anything else is done
 435      * For instance: if your block will have different title's depending on location (site, course, blog, etc)
 436      */
 437     function specialization() {
 438         // Just to make sure that this method exists.
 439     }
 440
 441     /**
 442      * Is each block of this type going to have instance-specific configuration?
 443      * Normally, this setting is controlled by {@link instance_allow_multiple()}: if multiple
 444      * instances are allowed, then each will surely need its own configuration. However, in some
 445      * cases it may be necessary to provide instance configuration to blocks that do not want to
 446      * allow multiple instances. In that case, make this function return true.
 447      * I stress again that this makes a difference ONLY if {@link instance_allow_multiple()} returns false.
 448      * @return boolean
 449      */
 450     function instance_allow_config() {
 451         return false;
 452     }
 453
 454     /**
 455      * Are you going to allow multiple instances of each block?
 456      * If yes, then it is assumed that the block WILL USE per-instance configuration
 457      * @return boolean
 458      */
 459     function instance_allow_multiple() {
 460         // Are you going to allow multiple instances of each block?
 461         // If yes, then it is assumed that the block WILL USE per-instance configuration
 462         return false;
 463     }
 464
 465     /**
 466      * Default behavior: print the config_instance.html file
 467      * You don't need to override this if you're satisfied with the above
 468      *
 469      * @deprecated since Moodle 2.0.
 470      * @return boolean whether anything was done. Blocks should use edit_form.php.
 471      */
 472     function instance_config_print() {
 473         global $CFG, $DB, $OUTPUT;
 474         // Default behavior: print the config_instance.html file
 475         // You don't need to override this if you're satisfied with the above
 476         if (!$this->instance_allow_multiple() && !$this->instance_allow_config()) {
 477             return false;
 478         }
 479
 480         if (is_file($CFG->dirroot .'/blocks/'. $this->name() .'/config_instance.html')) {
 481             echo $OUTPUT->box_start('generalbox boxaligncenter blockconfiginstance');
 482             include($CFG->dirroot .'/blocks/'. $this->name() .'/config_instance.html');
 483             echo $OUTPUT->box_end();
 484         } else {
 485             notice(get_string('blockconfigbad'), str_replace('blockaction=', 'dummy=', qualified_me()));
 486         }
 487
 488         return true;
 489     }
 490
 491     /**
 492      * Serialize and store config data
 493      */
 494     function instance_config_save($data, $nolongerused = false) {
 495         global $DB;
 496         $DB->set_field('block_instances', 'configdata', base64_encode(serialize($data)),
 497                 array('id' => $this->instance->id));
 498     }
 499
 500     /**
 501      * Replace the instance's configuration data with those currently in $this->config;
 502      */
 503     function instance_config_commit($nolongerused = false) {
 504         global $DB;
 505         $this->instance_config_save($this->config);
 506     }
 507
 508     /**
 509      * Do any additional initialization you may need at the time a new block instance is created
 510      * @return boolean
 511      */
 512     function instance_create() {
 513         return true;
 514     }
 515
 516     /**
 517      * Delete everything related to this instance if you have been using persistent storage other than the configdata field.
 518      * @return boolean
 519      */
 520     function instance_delete() {
 521         return true;
 522     }
 523
 524     /**
 525      * Allows the block class to have a say in the user's ability to edit (i.e., configure) blocks of this type.
 526      * The framework has first say in whether this will be allowed (e.g., no editing allowed unless in edit mode)
 527      * but if the framework does allow it, the block can still decide to refuse.
 528      * @return boolean
 529      */
 530     function user_can_edit() {
 531         global $USER;
 532
 533         if (has_capability('moodle/block:edit', $this->context)) {
 534             return true;
 535         }
 536
 537         // The blocks in My Moodle are a special case.  We want them to inherit from the user context.
 538         if (!empty($USER->id)
 539             && $this->instance->parentcontextid == $this->page->context->id   // Block belongs to this page
 540             && $this->page->context->contextlevel == CONTEXT_USER             // Page belongs to a user
 541             && $this->page->context->instanceid == $USER->id) {               // Page belongs to this user
 542             return has_capability('moodle/my:manageblocks', $this->page->context);
 543         }
 544
 545         return false;
 546     }
 547
 548     /**
 549      * Allows the block class to have a say in the user's ability to create new instances of this block.
 550      * The framework has first say in whether this will be allowed (e.g., no adding allowed unless in edit mode)
 551      * but if the framework does allow it, the block can still decide to refuse.
 552      * This function has access to the complete page object, the creation related to which is being determined.
 553      *
 554      * @param moodle_page $page
 555      * @return boolean
 556      */
 557     function user_can_addto($page) {
 558         global $USER;
 559
 560         if (has_capability('moodle/block:edit', $page->context)) {
 561             return true;
 562         }
 563
 564         // The blocks in My Moodle are a special case and use a different capability.
 565         if (!empty($USER->id)
 566             && $page->context->contextlevel == CONTEXT_USER             // Page belongs to a user
 567             && $page->context->instanceid == $USER->id) {               // Page belongs to this user
 568             return has_capability('moodle/my:manageblocks', $page->context);
 569         }
 570
 571         return false;
 572     }
 573
 574     function get_extra_capabilities() {
 575         return array('moodle/block:view', 'moodle/block:edit');
 576     }
 577
 578     // Methods deprecated in Moodle 2.0 ========================================
 579
 580     /**
 581      * Default case: the block wants to be 180 pixels wide
 582      * @deprecated since Moodle 2.0.
 583      * @return int
 584      */
 585     function preferred_width() {
 586         return 180;
 587     }
 588
 589     /** @deprecated since Moodle 2.0. */
 590     function _print_block() {
 591         throw new coding_exception('_print_block is no longer used. It was a private ' .
 592                 'method of the block class, only for use by the blocks system. You ' .
 593                 'should not have been calling it anyway.');
 594     }
 595
 596     /** @deprecated since Moodle 2.0. */
 597     function _print_shadow() {
 598         throw new coding_exception('_print_shadow is no longer used. It was a private ' .
 599                 'method of the block class, only for use by the blocks system. You ' .
 600                 'should not have been calling it anyway.');
 601     }
 602
 603     /** @deprecated since Moodle 2.0. */
 604     function _title_html() {
 605         throw new coding_exception('_title_html is no longer used. It was a private ' .
 606                 'method of the block class, only for use by the blocks system. You ' .
 607                 'should not have been calling it anyway.');
 608     }
 609
 610     /** @deprecated since Moodle 2.0. */
 611     function _add_edit_controls() {
 612         throw new coding_exception('_add_edit_controls is no longer used. It was a private ' .
 613                 'method of the block class, only for use by the blocks system. You ' .
 614                 'should not have been calling it anyway.');
 615     }
 616
 617     /** @deprecated since Moodle 2.0. */
 618     function config_print() {
 619         throw new coding_exception('config_print() can no longer be used. Blocks should use a settings.php file.');
 620     }
 621
 622     /**
 623      * Can be overridden by the block to prevent the block from being dockable.
 624      *
 625      * @return bool
 626      */
 627     public function instance_can_be_docked() {
 628         global $CFG;
 629         return (!empty($CFG->allowblockstodock) && $this->page->theme->enable_dock);
 630     }
 631
 632     /**
 633      * If overridden and set to true by the block it will not be hidable when
 634      * editing is turned on.
 635      *
 636      * @return bool
 637      */
 638     public function instance_can_be_hidden() {
 639         return true;
 640     }
 641
 642     /** @callback callback functions for comments api */
 643     public static function comment_template($options) {
 644         $ret = <<<EOD
 645 <div class="comment-userpicture">___picture___</div>
 646 <div class="comment-content">
 647     ___name___ - <span>___time___</span>
 648     <div>___content___</div>
 649 </div>
 650 EOD;
 651         return $ret;
 652     }
 653     public static function comment_permissions($options) {
 654         return array('view'=>true, 'post'=>true);
 655     }
 656     public static function comment_url($options) {
 657         return null;
 658     }
 659     public static function comment_display($comments, $options) {
 660         return $comments;
 661     }
 662     public static function comment_add(&$comments, $options) {
 663         return true;
 664     }
 665 }
 666
 667 /**
 668  * Specialized class for displaying a block with a list of icons/text labels
 669  *
 670  * The get_content method should set $this->content->items and (optionally)
 671  * $this->content->icons, instead of $this->content->text.
 672  *
 673  * @author Jon Papaioannou
 674  * @package blocks
 675  */
 676
 677 class block_list extends block_base {
 678     var $content_type  = BLOCK_TYPE_LIST;
 679
 680     function is_empty() {
 681         if ( !has_capability('moodle/block:view', $this->context) ) {
 682             return true;
 683         }
 684
 685         $this->get_content();
 686         return (empty($this->content->items) && empty($this->content->footer));
 687     }
 688
 689     protected function formatted_contents($output) {
 690         $this->get_content();
 691         $this->get_required_javascript();
 692         if (!empty($this->content->items)) {
 693             return $output->list_block_contents($this->content->icons, $this->content->items);
 694         } else {
 695             return '';
 696         }
 697     }
 698
 699     function html_attributes() {
 700         $attributes = parent::html_attributes();
 701         $attributes['class'] .= ' list_block';
 702         return $attributes;
 703     }
 704
 705 }
 706
 707 /**
 708  * Specialized class for displaying a tree menu.
 709  *
 710  * The {@link get_content()} method involves setting the content of
 711  * <code>$this->content->items</code> with an array of {@link tree_item}
 712  * objects (these are the top-level nodes). The {@link tree_item::children}
 713  * property may contain more tree_item objects, and so on. The tree_item class
 714  * itself is abstract and not intended for use, use one of it's subclasses.
 715  *
 716  * Unlike {@link block_list}, the icons are specified as part of the items,
 717  * not in a separate array.
 718  *
 719  * @author Alan Trick
 720  * @package blocks
 721  * @internal this extends block_list so we get is_empty() for free
 722  */
 723 class block_tree extends block_list {
 724
 725     /**
 726      * @var int specifies the manner in which contents should be added to this
 727      * block type. In this case <code>$this->content->items</code> is used with
 728      * {@link tree_item}s.
 729      */
 730     public $content_type = BLOCK_TYPE_TREE;
 731
 732     /**
 733      * Make the formatted HTML ouput.
 734      *
 735      * Also adds the required javascript call to the page output.
 736      *
 737      * @param core_renderer $output
 738      * @return string HTML
 739      */
 740     protected function formatted_contents($output) {
 741         // based of code in admin_tree
 742         global $PAGE; // TODO change this when there is a proper way for blocks to get stuff into head.
 743         static $eventattached;
 744         if ($eventattached===null) {
 745             $eventattached = true;
 746         }
 747         if (!$this->content) {
 748             $this->content = new stdClass;
 749             $this->content->items = array();
 750         }
 751         $this->get_required_javascript();
 752         $this->get_content();
 753         $content = $output->tree_block_contents($this->content->items,array('class'=>'block_tree list'));
 754         if (isset($this->id) && !is_numeric($this->id)) {
 755             $content = $output->box($content, 'block_tree_box', $this->id);
 756         }
 757         return $content;
 758     }
 759 }