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See Release Notes
Long Term Support Release

  • Bug fixes for general core bugs in 4.1.x will end 13 November 2023 (12 months).
  • Bug fixes for security issues in 4.1.x will end 10 November 2025 (36 months).
  • PHP version: minimum PHP 7.4.0 Note: minimum PHP version has increased since Moodle 4.0. PHP 8.0.x is supported too.
/blog/ -> lib.php (source)

Differences Between: [Versions 310 and 401] [Versions 311 and 401] [Versions 39 and 401] [Versions 400 and 401]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Core global functions for Blog.
  19   *
  20   * @package    moodlecore
  21   * @subpackage blog
  22   * @copyright  2009 Nicolas Connault
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  defined('MOODLE_INTERNAL') || die();
  27  
  28  /*
  29   * Library of functions and constants for blog
  30   */
  31  require_once($CFG->dirroot .'/blog/rsslib.php');
  32  
  33  /**
  34   * User can edit a blog entry if this is their own blog entry and they have
  35   * the capability moodle/blog:create, or if they have the capability
  36   * moodle/blog:manageentries.
  37   *
  38   * This also applies to deleting of entries.
  39   */
  40  function blog_user_can_edit_entry($blogentry) {
  41      global $USER;
  42  
  43      $sitecontext = context_system::instance();
  44  
  45      if (has_capability('moodle/blog:manageentries', $sitecontext)) {
  46          return true; // Can edit any blog entry.
  47      }
  48  
  49      if ($blogentry->userid == $USER->id && has_capability('moodle/blog:create', $sitecontext)) {
  50          return true; // Can edit own when having blog:create capability.
  51      }
  52  
  53      return false;
  54  }
  55  
  56  
  57  /**
  58   * Checks to see if a user can view the blogs of another user.
  59   * Only blog level is checked here, the capabilities are enforced
  60   * in blog/index.php
  61   */
  62  function blog_user_can_view_user_entry($targetuserid, $blogentry=null) {
  63      global $CFG, $USER, $DB;
  64  
  65      if (empty($CFG->enableblogs)) {
  66          return false; // Blog system disabled.
  67      }
  68  
  69      if (isloggedin() && $USER->id == $targetuserid) {
  70          return true; // Can view own entries in any case.
  71      }
  72  
  73      $sitecontext = context_system::instance();
  74      if (has_capability('moodle/blog:manageentries', $sitecontext)) {
  75          return true; // Can manage all entries.
  76      }
  77  
  78      // If blog is in draft state, then make sure user have proper capability.
  79      if ($blogentry && $blogentry->publishstate == 'draft' && !has_capability('moodle/blog:viewdrafts', $sitecontext)) {
  80          return false;  // Can not view draft of others.
  81      }
  82  
  83      // If blog entry is not public, make sure user is logged in.
  84      if ($blogentry && $blogentry->publishstate != 'public' && !isloggedin()) {
  85          return false;
  86      }
  87  
  88      // If blogentry is not passed or all above checks pass, then check capability based on system config.
  89      switch ($CFG->bloglevel) {
  90          case BLOG_GLOBAL_LEVEL:
  91              return true;
  92          break;
  93  
  94          case BLOG_SITE_LEVEL:
  95              if (isloggedin()) { // Not logged in viewers forbidden.
  96                  return true;
  97              }
  98              return false;
  99          break;
 100  
 101          case BLOG_USER_LEVEL:
 102          default:
 103              // If user is viewing other user blog, then user should have user:readuserblogs capability.
 104              $personalcontext = context_user::instance($targetuserid);
 105              return has_capability('moodle/user:readuserblogs', $personalcontext);
 106          break;
 107  
 108      }
 109  }
 110  
 111  /**
 112   * remove all associations for the blog entries of a particular user
 113   * @param int userid - id of user whose blog associations will be deleted
 114   */
 115  function blog_remove_associations_for_user($userid) {
 116      global $DB;
 117      throw new coding_exception('function blog_remove_associations_for_user() is not finished');
 118      /*
 119      $blogentries = blog_fetch_entries(array('user' => $userid), 'lasmodified DESC');
 120      foreach ($blogentries as $entry) {
 121          if (blog_user_can_edit_entry($entry)) {
 122              blog_remove_associations_for_entry($entry->id);
 123          }
 124      }
 125       */
 126  }
 127  
 128  /**
 129   * remove all associations for the blog entries of a particular course
 130   * @param int courseid - id of user whose blog associations will be deleted
 131   */
 132  function blog_remove_associations_for_course($courseid) {
 133      global $DB;
 134      $context = context_course::instance($courseid);
 135      $DB->delete_records('blog_association', array('contextid' => $context->id));
 136  }
 137  
 138  /**
 139   * Remove module associated blogs and blog tag instances.
 140   *
 141   * @param  int $modcontextid Module context ID.
 142   */
 143  function blog_remove_associations_for_module($modcontextid) {
 144      global $DB;
 145  
 146      if (!empty($assocblogids = $DB->get_fieldset_select('blog_association', 'blogid',
 147          'contextid = :contextid', ['contextid' => $modcontextid]))) {
 148          list($sql, $params) = $DB->get_in_or_equal($assocblogids, SQL_PARAMS_NAMED);
 149  
 150          $DB->delete_records_select('tag_instance', "itemid $sql", $params);
 151          $DB->delete_records_select('post', "id $sql AND module = :module",
 152              array_merge($params, ['module' => 'blog']));
 153          $DB->delete_records('blog_association', ['contextid' => $modcontextid]);
 154      }
 155  }
 156  
 157  /**
 158   * Given a record in the {blog_external} table, checks the blog's URL
 159   * for new entries not yet copied into Moodle.
 160   * Also attempts to identify and remove deleted blog entries
 161   *
 162   * @param object $externalblog
 163   * @return boolean False if the Feed is invalid
 164   */
 165  function blog_sync_external_entries($externalblog) {
 166      global $CFG, $DB;
 167      require_once($CFG->libdir . '/simplepie/moodle_simplepie.php');
 168  
 169      $rss = new moodle_simplepie();
 170      $rssfile = $rss->registry->create('File', array($externalblog->url));
 171      $filetest = $rss->registry->create('Locator', array($rssfile));
 172  
 173      if (!$filetest->is_feed($rssfile)) {
 174          $externalblog->failedlastsync = 1;
 175          $DB->update_record('blog_external', $externalblog);
 176          return false;
 177      } else if (!empty($externalblog->failedlastsync)) {
 178          $externalblog->failedlastsync = 0;
 179          $DB->update_record('blog_external', $externalblog);
 180      }
 181  
 182      $rss->set_feed_url($externalblog->url);
 183      $rss->init();
 184  
 185      if (empty($rss->data)) {
 186          return null;
 187      }
 188      // Used to identify blog posts that have been deleted from the source feed.
 189      $oldesttimestamp = null;
 190      $uniquehashes = array();
 191  
 192      foreach ($rss->get_items() as $entry) {
 193          // If filtertags are defined, use them to filter the entries by RSS category.
 194          if (!empty($externalblog->filtertags)) {
 195              $containsfiltertag = false;
 196              $categories = $entry->get_categories();
 197              $filtertags = explode(',', $externalblog->filtertags);
 198              $filtertags = array_map('trim', $filtertags);
 199              $filtertags = array_map('strtolower', $filtertags);
 200  
 201              if (!empty($categories)) {
 202                  foreach ($categories as $category) {
 203                      if (in_array(trim(strtolower($category->term)), $filtertags)) {
 204                          $containsfiltertag = true;
 205                      }
 206                  }
 207              }
 208  
 209              if (!$containsfiltertag) {
 210                  continue;
 211              }
 212          }
 213  
 214          $uniquehashes[] = $entry->get_permalink();
 215  
 216          $newentry = new stdClass();
 217          $newentry->userid = $externalblog->userid;
 218          $newentry->module = 'blog_external';
 219          $newentry->content = $externalblog->id;
 220          $newentry->uniquehash = $entry->get_permalink();
 221          $newentry->publishstate = 'site';
 222          $newentry->format = FORMAT_HTML;
 223          // Clean subject of html, just in case.
 224          $newentry->subject = clean_param($entry->get_title(), PARAM_TEXT);
 225          // Observe 128 max chars in DB.
 226          // TODO: +1 to raise this to 255.
 227          if (core_text::strlen($newentry->subject) > 128) {
 228              $newentry->subject = core_text::substr($newentry->subject, 0, 125) . '...';
 229          }
 230          $newentry->summary = $entry->get_description();
 231  
 232          // Used to decide whether to insert or update.
 233          // Uses enty permalink plus creation date if available.
 234          $existingpostconditions = array('uniquehash' => $entry->get_permalink());
 235  
 236          // Our DB doesnt allow null creation or modified timestamps so check the external blog supplied one.
 237          $entrydate = $entry->get_date('U');
 238          if (!empty($entrydate)) {
 239              $existingpostconditions['created'] = $entrydate;
 240          }
 241  
 242          // The post ID or false if post not found in DB.
 243          $postid = $DB->get_field('post', 'id', $existingpostconditions);
 244  
 245          $timestamp = null;
 246          if (empty($entrydate)) {
 247              $timestamp = time();
 248          } else {
 249              $timestamp = $entrydate;
 250          }
 251  
 252          // Only set created if its a new post so we retain the original creation timestamp if the post is edited.
 253          if ($postid === false) {
 254              $newentry->created = $timestamp;
 255          }
 256          $newentry->lastmodified = $timestamp;
 257  
 258          if (empty($oldesttimestamp) || $timestamp < $oldesttimestamp) {
 259              // Found an older post.
 260              $oldesttimestamp = $timestamp;
 261          }
 262  
 263          if (core_text::strlen($newentry->uniquehash) > 255) {
 264              // The URL for this item is too long for the field. Rather than add
 265              // the entry without the link we will skip straight over it.
 266              // RSS spec says recommended length 500, we use 255.
 267              debugging('External blog entry skipped because of oversized URL', DEBUG_DEVELOPER);
 268              continue;
 269          }
 270  
 271          if ($postid === false) {
 272              $id = $DB->insert_record('post', $newentry);
 273  
 274              // Set tags.
 275              if ($tags = core_tag_tag::get_item_tags_array('core', 'blog_external', $externalblog->id)) {
 276                  core_tag_tag::set_item_tags('core', 'post', $id, context_user::instance($externalblog->userid), $tags);
 277              }
 278          } else {
 279              $newentry->id = $postid;
 280              $DB->update_record('post', $newentry);
 281          }
 282      }
 283  
 284      // Look at the posts we have in the database to check if any of them have been deleted from the feed.
 285      // Only checking posts within the time frame returned by the rss feed. Older items may have been deleted or
 286      // may just not be returned anymore. We can't tell the difference so we leave older posts alone.
 287      $sql = "SELECT id, uniquehash
 288                FROM {post}
 289               WHERE module = 'blog_external'
 290                     AND " . $DB->sql_compare_text('content') . " = " . $DB->sql_compare_text(':blogid') . "
 291                     AND created > :ts";
 292      $dbposts = $DB->get_records_sql($sql, array('blogid' => $externalblog->id, 'ts' => $oldesttimestamp));
 293  
 294      $todelete = array();
 295      foreach ($dbposts as $dbpost) {
 296          if ( !in_array($dbpost->uniquehash, $uniquehashes) ) {
 297              $todelete[] = $dbpost->id;
 298          }
 299      }
 300      $DB->delete_records_list('post', 'id', $todelete);
 301  
 302      $DB->update_record('blog_external', array('id' => $externalblog->id, 'timefetched' => time()));
 303  }
 304  
 305  /**
 306   * Given an external blog object, deletes all related blog entries from the post table.
 307   * NOTE: The external blog's id is saved as post.content, a field that is not oterhwise used by blog entries.
 308   * @param object $externablog
 309   */
 310  function blog_delete_external_entries($externalblog) {
 311      global $DB;
 312      require_capability('moodle/blog:manageexternal', context_system::instance());
 313      $DB->delete_records_select('post',
 314                                 "module='blog_external' AND " . $DB->sql_compare_text('content') . " = ?",
 315                                 array($externalblog->id));
 316  }
 317  
 318  /**
 319   * This function checks that blogs are enabled, and that the user can see blogs at all
 320   * @return bool
 321   */
 322  function blog_is_enabled_for_user() {
 323      global $CFG;
 324      return (!empty($CFG->enableblogs) && (isloggedin() || ($CFG->bloglevel == BLOG_GLOBAL_LEVEL)));
 325  }
 326  
 327  /**
 328   * This function gets all of the options available for the current user in respect
 329   * to blogs.
 330   *
 331   * It loads the following if applicable:
 332   * -  Module options {@see blog_get_options_for_module}
 333   * -  Course options {@see blog_get_options_for_course}
 334   * -  User specific options {@see blog_get_options_for_user}
 335   * -  General options (BLOG_LEVEL_GLOBAL)
 336   *
 337   * @param moodle_page $page The page to load for (normally $PAGE)
 338   * @param stdClass $userid Load for a specific user
 339   * @return array An array of options organised by type.
 340   */
 341  function blog_get_all_options(moodle_page $page, stdClass $userid = null) {
 342      global $CFG, $DB, $USER;
 343  
 344      $options = array();
 345  
 346      // If blogs are enabled and the user is logged in and not a guest.
 347      if (blog_is_enabled_for_user()) {
 348          // If the context is the user then assume we want to load for the users context.
 349          if (is_null($userid) && $page->context->contextlevel == CONTEXT_USER) {
 350              $userid = $page->context->instanceid;
 351          }
 352          // Check the userid var.
 353          if (!is_null($userid) && $userid !== $USER->id) {
 354              // Load the user from the userid... it MUST EXIST throw a wobbly if it doesn't!
 355              $user = $DB->get_record('user', array('id' => $userid), '*', MUST_EXIST);
 356          } else {
 357              $user = null;
 358          }
 359  
 360          if ($CFG->useblogassociations && $page->cm !== null) {
 361              // Load for the module associated with the page.
 362              $options[CONTEXT_MODULE] = blog_get_options_for_module($page->cm, $user);
 363          } else if ($CFG->useblogassociations && $page->course->id != SITEID) {
 364              // Load the options for the course associated with the page.
 365              $options[CONTEXT_COURSE] = blog_get_options_for_course($page->course, $user);
 366          }
 367  
 368          // Get the options for the user.
 369          if ($user !== null and !isguestuser($user)) {
 370              // Load for the requested user.
 371              $options[CONTEXT_USER + 1] = blog_get_options_for_user($user);
 372          }
 373          // Load for the current user.
 374          if (isloggedin() and !isguestuser()) {
 375              $options[CONTEXT_USER] = blog_get_options_for_user();
 376          }
 377      }
 378  
 379      // If blog level is global then display a link to view all site entries.
 380      if (!empty($CFG->enableblogs)
 381          && $CFG->bloglevel >= BLOG_GLOBAL_LEVEL
 382          && has_capability('moodle/blog:view', context_system::instance())) {
 383  
 384          $options[CONTEXT_SYSTEM] = array('viewsite' => array(
 385              'string' => get_string('viewsiteentries', 'blog'),
 386              'link' => new moodle_url('/blog/index.php')
 387          ));
 388      }
 389  
 390      // Return the options.
 391      return $options;
 392  }
 393  
 394  /**
 395   * Get all of the blog options that relate to the passed user.
 396   *
 397   * If no user is passed the current user is assumed.
 398   *
 399   * @staticvar array $useroptions Cache so we don't have to regenerate multiple times
 400   * @param stdClass $user
 401   * @return array The array of options for the requested user
 402   */
 403  function blog_get_options_for_user(stdClass $user=null) {
 404      global $CFG, $USER;
 405      // Cache.
 406      static $useroptions = array();
 407  
 408      $options = array();
 409      // Blogs must be enabled and the user must be logged in.
 410      if (!blog_is_enabled_for_user()) {
 411          return $options;
 412      }
 413  
 414      // Sort out the user var.
 415      if ($user === null || $user->id == $USER->id) {
 416          $user = $USER;
 417          $iscurrentuser = true;
 418      } else {
 419          $iscurrentuser = false;
 420      }
 421  
 422      // If we've already generated serve from the cache.
 423      if (array_key_exists($user->id, $useroptions)) {
 424          return $useroptions[$user->id];
 425      }
 426  
 427      $sitecontext = context_system::instance();
 428      $canview = has_capability('moodle/blog:view', $sitecontext);
 429  
 430      if (!$iscurrentuser && $canview && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 431          // Not the current user, but we can view and its blogs are enabled for SITE or GLOBAL.
 432          $options['userentries'] = array(
 433              'string' => get_string('viewuserentries', 'blog', fullname($user)),
 434              'link' => new moodle_url('/blog/index.php', array('userid' => $user->id))
 435          );
 436      } else {
 437          // It's the current user.
 438          if ($canview) {
 439              // We can view our own blogs .... BIG surprise.
 440              $options['view'] = array(
 441                  'string' => get_string('blogentries', 'blog'),
 442                  'link' => new moodle_url('/blog/index.php', array('userid' => $USER->id))
 443              );
 444          }
 445          if (has_capability('moodle/blog:create', $sitecontext)) {
 446              // We can add to our own blog.
 447              $options['add'] = array(
 448                  'string' => get_string('addnewentry', 'blog'),
 449                  'link' => new moodle_url('/blog/edit.php', array('action' => 'add'))
 450              );
 451          }
 452      }
 453      if ($canview && $CFG->enablerssfeeds) {
 454          $options['rss'] = array(
 455              'string' => get_string('rssfeed', 'blog'),
 456              'link' => new moodle_url(rss_get_url($sitecontext->id, $USER->id, 'blog', 'user/'.$user->id))
 457          );
 458      }
 459  
 460      // Cache the options.
 461      $useroptions[$user->id] = $options;
 462      // Return the options.
 463      return $options;
 464  }
 465  
 466  /**
 467   * Get the blog options that relate to the given course for the given user.
 468   *
 469   * @staticvar array $courseoptions A cache so we can save regenerating multiple times
 470   * @param stdClass $course The course to load options for
 471   * @param stdClass $user The user to load options for null == current user
 472   * @return array The array of options
 473   */
 474  function blog_get_options_for_course(stdClass $course, stdClass $user=null) {
 475      global $CFG, $USER;
 476      // Cache.
 477      static $courseoptions = array();
 478  
 479      $options = array();
 480  
 481      // User must be logged in and blogs must be enabled.
 482      if (!blog_is_enabled_for_user()) {
 483          return $options;
 484      }
 485  
 486      // Check that the user can associate with the course.
 487      $sitecontext = context_system::instance();
 488      // Generate the cache key.
 489      $key = $course->id.':';
 490      if (!empty($user)) {
 491          $key .= $user->id;
 492      } else {
 493          $key .= $USER->id;
 494      }
 495      // Serve from the cache if we've already generated for this course.
 496      if (array_key_exists($key, $courseoptions)) {
 497          return $courseoptions[$key];
 498      }
 499  
 500      if (has_capability('moodle/blog:view', $sitecontext)) {
 501          // We can view!
 502          if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 503              // View entries about this course.
 504              $options['courseview'] = array(
 505                  'string' => get_string('viewcourseblogs', 'blog'),
 506                  'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id))
 507              );
 508          }
 509          // View MY entries about this course.
 510          $options['courseviewmine'] = array(
 511              'string' => get_string('viewmyentriesaboutcourse', 'blog'),
 512              'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $USER->id))
 513          );
 514          if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 515              // View the provided users entries about this course.
 516              $options['courseviewuser'] = array(
 517                  'string' => get_string('viewentriesbyuseraboutcourse', 'blog', fullname($user)),
 518                  'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $user->id))
 519              );
 520          }
 521      }
 522  
 523      if (has_capability('moodle/blog:create', $sitecontext)) {
 524          // We can blog about this course.
 525          $options['courseadd'] = array(
 526              'string' => get_string('blogaboutthiscourse', 'blog'),
 527              'link' => new moodle_url('/blog/edit.php', array('action' => 'add', 'courseid' => $course->id))
 528          );
 529      }
 530  
 531      // Cache the options for this course.
 532      $courseoptions[$key] = $options;
 533      // Return the options.
 534      return $options;
 535  }
 536  
 537  /**
 538   * Get the blog options relating to the given module for the given user
 539   *
 540   * @staticvar array $moduleoptions Cache
 541   * @param stdClass|cm_info $module The module to get options for
 542   * @param stdClass $user The user to get options for null == currentuser
 543   * @return array
 544   */
 545  function blog_get_options_for_module($module, $user=null) {
 546      global $CFG, $USER;
 547      // Cache.
 548      static $moduleoptions = array();
 549  
 550      $options = array();
 551      // User must be logged in, blogs must be enabled.
 552      if (!blog_is_enabled_for_user()) {
 553          return $options;
 554      }
 555  
 556      $sitecontext = context_system::instance();
 557  
 558      // Generate the cache key.
 559      $key = $module->id.':';
 560      if (!empty($user)) {
 561          $key .= $user->id;
 562      } else {
 563          $key .= $USER->id;
 564      }
 565      if (array_key_exists($key, $moduleoptions)) {
 566          // Serve from the cache so we don't have to regenerate.
 567          return $moduleoptions[$key];
 568      }
 569  
 570      if (has_capability('moodle/blog:view', $sitecontext)) {
 571          // Save correct module name for later usage.
 572          $modulename = get_string('modulename', $module->modname);
 573  
 574          // We can view!
 575          if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 576              // View all entries about this module.
 577              $a = new stdClass;
 578              $a->type = $modulename;
 579              $options['moduleview'] = array(
 580                  'string' => get_string('viewallmodentries', 'blog', $a),
 581                  'link' => new moodle_url('/blog/index.php', array('modid' => $module->id))
 582              );
 583          }
 584          // View MY entries about this module.
 585          $options['moduleviewmine'] = array(
 586              'string' => get_string('viewmyentriesaboutmodule', 'blog', $modulename),
 587              'link' => new moodle_url('/blog/index.php', array('modid' => $module->id, 'userid' => $USER->id))
 588          );
 589          if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 590              // View the given users entries about this module.
 591              $a = new stdClass;
 592              $a->mod = $modulename;
 593              $a->user = fullname($user);
 594              $options['moduleviewuser'] = array(
 595                  'string' => get_string('blogentriesbyuseraboutmodule', 'blog', $a),
 596                  'link' => new moodle_url('/blog/index.php', array('modid' => $module->id, 'userid' => $user->id))
 597              );
 598          }
 599      }
 600  
 601      if (has_capability('moodle/blog:create', $sitecontext)) {
 602          // The user can blog about this module.
 603          $options['moduleadd'] = array(
 604              'string' => get_string('blogaboutthismodule', 'blog', $modulename),
 605              'link' => new moodle_url('/blog/edit.php', array('action' => 'add', 'modid' => $module->id))
 606          );
 607      }
 608      // Cache the options.
 609      $moduleoptions[$key] = $options;
 610      // Return the options.
 611      return $options;
 612  }
 613  
 614  /**
 615   * This function encapsulates all the logic behind the complex
 616   * navigation, titles and headings of the blog listing page, depending
 617   * on URL params. It looks at URL params and at the current context level.
 618   * It builds and returns an array containing:
 619   *
 620   * 1. heading: The heading displayed above the blog entries
 621   * 2. stradd:  The text to be used as the "Add entry" link
 622   * 3. strview: The text to be used as the "View entries" link
 623   * 4. url:     The moodle_url object used as the base for add and view links
 624   * 5. filters: An array of parameters used to filter blog listings. Used by index.php and the Recent blogs block
 625   *
 626   * All other variables are set directly in $PAGE
 627   *
 628   * It uses the current URL to build these variables.
 629   * A number of mutually exclusive use cases are used to structure this function.
 630   *
 631   * @param  int $courseid   course id the the blog is associated to (can be null).
 632   * @param  int $groupid    group id to filter blogs I can see (can be null)
 633   * @param  int $userid     blog author id (can be null)
 634   * @param  int $tagid      tag id to filter (can be null)
 635   * @param  string $tag     tag name to filter (can be null)
 636   * @param  int $modid      module id the blog is associated to (can be null).
 637   * @param  int $entryid    blog entry id to filter(can be null)
 638   * @param  string $search  string to search (can be null)
 639   * @return array
 640   */
 641  function blog_get_headers($courseid=null, $groupid=null, $userid=null, $tagid=null, $tag=null, $modid=null, $entryid=null,
 642          $search = null) {
 643      global $CFG, $PAGE, $DB, $USER;
 644  
 645      $id       = optional_param('id', null, PARAM_INT);
 646      $tag      = optional_param('tag', $tag, PARAM_NOTAGS);
 647      $tagid    = optional_param('tagid', $tagid, PARAM_INT);
 648      $userid   = optional_param('userid', $userid, PARAM_INT);
 649      $modid    = optional_param('modid', $modid, PARAM_INT);
 650      $entryid  = optional_param('entryid', $entryid, PARAM_INT);
 651      $groupid  = optional_param('groupid', $groupid, PARAM_INT);
 652      $courseid = optional_param('courseid', $courseid, PARAM_INT);
 653      $search   = optional_param('search', $search, PARAM_RAW);
 654      $action   = optional_param('action', null, PARAM_ALPHA);
 655      $confirm  = optional_param('confirm', false, PARAM_BOOL);
 656  
 657      // Ignore userid when action == add.
 658      if ($action == 'add' && $userid) {
 659          unset($userid);
 660          $PAGE->url->remove_params(array('userid'));
 661      } else if ($action == 'add' && $entryid) {
 662          unset($entryid);
 663          $PAGE->url->remove_params(array('entryid'));
 664      }
 665  
 666      $headers = array('title' => '', 'heading' => '', 'cm' => null, 'filters' => array());
 667  
 668      $blogurl = new moodle_url('/blog/index.php');
 669  
 670      $headers['stradd'] = get_string('addnewentry', 'blog');
 671      $headers['strview'] = null;
 672  
 673      $site = $DB->get_record('course', array('id' => SITEID));
 674      $sitecontext = context_system::instance();
 675      // Common Lang strings.
 676      $strparticipants = get_string("participants");
 677      $strblogentries  = get_string("blogentries", 'blog');
 678  
 679      // Prepare record objects as needed.
 680      if (!empty($courseid)) {
 681          $headers['filters']['course'] = $courseid;
 682          $course = $DB->get_record('course', array('id' => $courseid));
 683      }
 684  
 685      if (!empty($userid)) {
 686          $headers['filters']['user'] = $userid;
 687          $user = $DB->get_record('user', array('id' => $userid));
 688      }
 689  
 690      if (!empty($groupid)) { // The groupid always overrides courseid.
 691          $headers['filters']['group'] = $groupid;
 692          $group = $DB->get_record('groups', array('id' => $groupid));
 693          $course = $DB->get_record('course', array('id' => $group->courseid));
 694      }
 695  
 696      $PAGE->set_pagelayout('standard');
 697  
 698      // The modid always overrides courseid, so the $course object may be reset here.
 699      if (!empty($modid) && $CFG->useblogassociations) {
 700  
 701          $headers['filters']['module'] = $modid;
 702          // A groupid param may conflict with this coursemod's courseid. Ignore groupid in that case.
 703          $courseid = $DB->get_field('course_modules', 'course', array('id' => $modid));
 704          $course = $DB->get_record('course', array('id' => $courseid));
 705          $cm = $DB->get_record('course_modules', array('id' => $modid));
 706          $cm->modname = $DB->get_field('modules', 'name', array('id' => $cm->module));
 707          $cm->name = $DB->get_field($cm->modname, 'name', array('id' => $cm->instance));
 708          $a = new stdClass();
 709          $a->type = get_string('modulename', $cm->modname);
 710          $PAGE->set_cm($cm, $course);
 711          $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 712          $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 713      }
 714  
 715      // Case 1: No entry, mod, course or user params: all site entries to be shown (filtered by search and tag/tagid)
 716      // Note: if action is set to 'add' or 'edit', we do this at the end.
 717      if (empty($entryid) && empty($modid) && empty($courseid) && empty($userid) && !in_array($action, array('edit', 'add'))) {
 718          $PAGE->navbar->add($strblogentries, $blogurl);
 719          $strsiteblog = get_string('siteblogheading', 'blog');
 720          $PAGE->set_title($strsiteblog);
 721          $PAGE->set_heading($site->fullname);
 722          $headers['heading'] = $strsiteblog;
 723      }
 724  
 725      // Case 2: only entryid is requested, ignore all other filters. courseid is used to give more contextual information.
 726      if (!empty($entryid)) {
 727          $headers['filters']['entry'] = $entryid;
 728          $sql = 'SELECT u.* FROM {user} u, {post} p WHERE p.id = ? AND p.userid = u.id';
 729          $user = $DB->get_record_sql($sql, array($entryid));
 730          $entry = $DB->get_record('post', array('id' => $entryid));
 731  
 732          $blogurl->param('userid', $user->id);
 733  
 734          if (!empty($course)) {
 735              $mycourseid = $course->id;
 736              $blogurl->param('courseid', $mycourseid);
 737          } else {
 738              $mycourseid = $site->id;
 739          }
 740          $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 741  
 742          $PAGE->navbar->add($strblogentries, $blogurl);
 743  
 744          $blogurl->remove_params('userid');
 745          $PAGE->navbar->add($entry->subject, $blogurl);
 746          $blogentryby = get_string('blogentrybyuser', 'blog', fullname($user));
 747          $PAGE->set_title($entry->subject . moodle_page::TITLE_SEPARATOR . $blogentryby);
 748          $PAGE->set_heading("$shortname: " . fullname($user) . ": $entry->subject");
 749          $headers['heading'] = $blogentryby;
 750  
 751          // We ignore tag and search params.
 752          if (empty($action) || !$CFG->useblogassociations) {
 753              $headers['url'] = $blogurl;
 754              return $headers;
 755          }
 756      }
 757  
 758      if (!empty($userid) && empty($entryid) && ((empty($courseid) && empty($modid)) || !$CFG->useblogassociations)) {
 759          // Case 3: A user's blog entries.
 760  
 761          $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 762          $blogurl->param('userid', $userid);
 763          $PAGE->set_title(fullname($user) . ": " . get_string('blog', 'blog'));
 764          $PAGE->set_heading("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 765          $headers['heading'] = get_string('userblog', 'blog', fullname($user));
 766          $headers['strview'] = get_string('viewuserentries', 'blog', fullname($user));
 767  
 768      } else if (!$CFG->useblogassociations && empty($userid) && !in_array($action, array('edit', 'add'))) {
 769          // Case 4: No blog associations, no userid.
 770  
 771          $strsiteblog = get_string('siteblogheading', 'blog');
 772          $PAGE->set_title($strsiteblog);
 773          $PAGE->set_heading($site->fullname);
 774          $headers['heading'] = $strsiteblog;
 775      } else if (!empty($userid) && !empty($modid) && empty($entryid)) {
 776          // Case 5: Blog entries associated with an activity by a specific user (courseid ignored).
 777  
 778          $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 779          $blogurl->param('userid', $userid);
 780          $blogurl->param('modid', $modid);
 781  
 782          // Course module navigation is handled by build_navigation as the second param.
 783          $headers['cm'] = $cm;
 784          $PAGE->navbar->add(fullname($user), "$CFG->wwwroot/user/view.php?id=$user->id");
 785          $PAGE->navbar->add($strblogentries, $blogurl);
 786  
 787          $PAGE->set_title(fullname($user) . ': ' . get_string('blogentries', 'blog') . moodle_page::TITLE_SEPARATOR . $cm->name);
 788          $PAGE->set_heading("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 789  
 790          $a = new stdClass();
 791          $a->user = fullname($user);
 792          $a->mod = $cm->name;
 793          $a->type = get_string('modulename', $cm->modname);
 794          $headers['heading'] = get_string('blogentriesbyuseraboutmodule', 'blog', $a);
 795          $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 796          $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 797      } else if (!empty($userid) && !empty($courseid) && empty($modid) && empty($entryid)) {
 798          // Case 6: Blog entries associated with a course by a specific user.
 799  
 800          $blogurl->param('userid', $userid);
 801          $blogurl->param('courseid', $courseid);
 802  
 803          $PAGE->set_title($course->fullname);
 804          $PAGE->set_heading($course->fullname);
 805  
 806          $a = new stdClass();
 807          $a->user = fullname($user);
 808          $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 809          $a->type = get_string('course');
 810          $headers['heading'] = get_string('blogentriesbyuseraboutcourse', 'blog', $a);
 811          $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 812          $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 813  
 814          // Remove the userid from the URL to inform the blog_menu block correctly.
 815          $blogurl->remove_params(array('userid'));
 816      } else if (!empty($groupid) && empty($modid) && empty($entryid)) {
 817          // Case 7: Blog entries by members of a group, associated with that group's course.
 818  
 819          $blogurl->param('courseid', $course->id);
 820  
 821          $PAGE->navbar->add($strblogentries, $blogurl);
 822          $blogurl->remove_params(array('courseid'));
 823          $blogurl->param('groupid', $groupid);
 824          $PAGE->navbar->add($group->name, $blogurl);
 825  
 826          $PAGE->set_title($course->fullname);
 827          $PAGE->set_heading($course->fullname);
 828  
 829          $a = new stdClass();
 830          $a->group = $group->name;
 831          $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 832          $a->type = get_string('course');
 833          $headers['heading'] = get_string('blogentriesbygroupaboutcourse', 'blog', $a);
 834          $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 835          $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 836      } else if (!empty($groupid) && !empty($modid) && empty($entryid)) {
 837          // Case 8: Blog entries by members of a group, associated with an activity in that course.
 838  
 839          $headers['cm'] = $cm;
 840          $blogurl->param('modid', $modid);
 841          $PAGE->navbar->add($strblogentries, $blogurl);
 842  
 843          $blogurl->param('groupid', $groupid);
 844          $PAGE->navbar->add($group->name, $blogurl);
 845  
 846          $PAGE->set_title($course->fullname);
 847          $PAGE->set_heading($course->fullname);
 848  
 849          $a = new stdClass();
 850          $a->group = $group->name;
 851          $a->mod = $cm->name;
 852          $a->type = get_string('modulename', $cm->modname);
 853          $headers['heading'] = get_string('blogentriesbygroupaboutmodule', 'blog', $a);
 854          $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 855          $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 856  
 857      } else if (!empty($modid) && empty($userid) && empty($groupid) && empty($entryid)) {
 858          // Case 9: All blog entries associated with an activity.
 859  
 860          $PAGE->set_cm($cm, $course);
 861          $blogurl->param('modid', $modid);
 862          $PAGE->navbar->add($strblogentries, $blogurl);
 863          $PAGE->set_title($course->fullname);
 864          $PAGE->set_heading($course->fullname);
 865          $headers['heading'] = get_string('blogentriesabout', 'blog', $cm->name);
 866          $a = new stdClass();
 867          $a->type = get_string('modulename', $cm->modname);
 868          $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 869          $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 870      } else if (!empty($courseid) && empty($userid) && empty($groupid) && empty($modid) && empty($entryid)) {
 871          // Case 10: All blog entries associated with a course.
 872  
 873          $blogurl->param('courseid', $courseid);
 874          $PAGE->navbar->add($strblogentries, $blogurl);
 875          $PAGE->set_title($course->fullname);
 876          $PAGE->set_heading($course->fullname);
 877          $a = new stdClass();
 878          $a->type = get_string('course');
 879          $headers['heading'] = get_string('blogentriesabout',
 880                                           'blog',
 881                                           format_string($course->fullname,
 882                                                         true,
 883                                                         array('context' => context_course::instance($course->id))));
 884          $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 885          $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 886          $blogurl->remove_params(array('userid'));
 887      }
 888  
 889      if (!in_array($action, array('edit', 'add'))) {
 890          // Append Tag info.
 891          if (!empty($tagid)) {
 892              $headers['filters']['tag'] = $tagid;
 893              $blogurl->param('tagid', $tagid);
 894              $tagrec = $DB->get_record('tag', array('id' => $tagid));
 895              $PAGE->navbar->add($tagrec->name, $blogurl);
 896          } else if (!empty($tag)) {
 897              if ($tagrec = $DB->get_record('tag', array('name' => $tag))) {
 898                  $tagid = $tagrec->id;
 899                  $headers['filters']['tag'] = $tagid;
 900                  $blogurl->param('tag', $tag);
 901                  $PAGE->navbar->add(get_string('tagparam', 'blog', $tag), $blogurl);
 902              }
 903          }
 904  
 905          // Append Search info.
 906          if (!empty($search) && has_capability('moodle/blog:search', $sitecontext)) {
 907              $headers['filters']['search'] = $search;
 908              $blogurl->param('search', $search);
 909              $PAGE->navbar->add(get_string('searchterm', 'blog', s($search)), $blogurl->out());
 910          }
 911      }
 912  
 913      // Append edit mode info.
 914      if (!empty($action) && $action == 'add') {
 915  
 916      } else if (!empty($action) && $action == 'edit') {
 917          $PAGE->navbar->add(get_string('editentry', 'blog'));
 918      }
 919  
 920      if (empty($headers['url'])) {
 921          $headers['url'] = $blogurl;
 922      }
 923      return $headers;
 924  }
 925  
 926  /**
 927   * Shortcut function for getting a count of blog entries associated with a course or a module
 928   * @param int $courseid The ID of the course
 929   * @param int $cmid The ID of the course_modules
 930   * @return string The number of associated entries
 931   */
 932  function blog_get_associated_count($courseid, $cmid=null) {
 933      global $DB;
 934      $context = context_course::instance($courseid);
 935      if ($cmid) {
 936          $context = context_module::instance($cmid);
 937      }
 938      return $DB->count_records('blog_association', array('contextid' => $context->id));
 939  }
 940  
 941  /**
 942   * Running addtional permission check on plugin, for example, plugins
 943   * may have switch to turn on/off comments option, this callback will
 944   * affect UI display, not like pluginname_comment_validate only throw
 945   * exceptions.
 946   * blog_comment_validate will be called before viewing/adding/deleting
 947   * comment, so don't repeat checks.
 948   * Capability check has been done in comment->check_permissions(), we
 949   * don't need to do it again here.
 950   *
 951   * @package  core_blog
 952   * @category comment
 953   *
 954   * @param stdClass $commentparam {
 955   *              context  => context the context object
 956   *              courseid => int course id
 957   *              cm       => stdClass course module object
 958   *              commentarea => string comment area
 959   *              itemid      => int itemid
 960   * }
 961   * @return array
 962   */
 963  function blog_comment_permissions($commentparam) {
 964      global $DB;
 965  
 966      // If blog is public and current user is guest, then don't let him post comments.
 967      $blogentry = $DB->get_record('post', array('id' => $commentparam->itemid), 'publishstate', MUST_EXIST);
 968  
 969      if ($blogentry->publishstate != 'public') {
 970          if (!isloggedin() || isguestuser()) {
 971              return array('post' => false, 'view' => true);
 972          }
 973      }
 974      return array('post' => true, 'view' => true);
 975  }
 976  
 977  /**
 978   * Validate comment parameter before perform other comments actions
 979   *
 980   * @package  core_blog
 981   * @category comment
 982   *
 983   * @param stdClass $comment {
 984   *              context  => context the context object
 985   *              courseid => int course id
 986   *              cm       => stdClass course module object
 987   *              commentarea => string comment area
 988   *              itemid      => int itemid
 989   * }
 990   * @return boolean
 991   */
 992  function blog_comment_validate($commentparam) {
 993      global $CFG, $DB, $USER;
 994  
 995      // Check if blogs are enabled user can comment.
 996      if (empty($CFG->enableblogs) || empty($CFG->blogusecomments)) {
 997          throw new comment_exception('nopermissiontocomment');
 998      }
 999  
1000      // Validate comment area.
1001      if ($commentparam->commentarea != 'format_blog') {
1002          throw new comment_exception('invalidcommentarea');
1003      }
1004  
1005      $blogentry = $DB->get_record('post', array('id' => $commentparam->itemid), '*', MUST_EXIST);
1006  
1007      // Validation for comment deletion.
1008      if (!empty($commentparam->commentid)) {
1009          if ($record = $DB->get_record('comments', array('id' => $commentparam->commentid))) {
1010              if ($record->commentarea != 'format_blog') {
1011                  throw new comment_exception('invalidcommentarea');
1012              }
1013              if ($record->contextid != $commentparam->context->id) {
1014                  throw new comment_exception('invalidcontext');
1015              }
1016              if ($record->itemid != $commentparam->itemid) {
1017                  throw new comment_exception('invalidcommentitemid');
1018              }
1019          } else {
1020              throw new comment_exception('invalidcommentid');
1021          }
1022      }
1023  
1024      // Validate if user has blog view permission.
1025      $sitecontext = context_system::instance();
1026      return has_capability('moodle/blog:view', $sitecontext) &&
1027              blog_user_can_view_user_entry($blogentry->userid, $blogentry);
1028  }
1029  
1030  /**
1031   * Return a list of page types
1032   * @param string $pagetype current page type
1033   * @param stdClass $parentcontext Block's parent context
1034   * @param stdClass $currentcontext Current context of block
1035   */
1036  function blog_page_type_list($pagetype, $parentcontext, $currentcontext) {
1037      return array(
1038          '*' => get_string('page-x', 'pagetype'),
1039          'blog-*' => get_string('page-blog-x', 'blog'),
1040          'blog-index' => get_string('page-blog-index', 'blog'),
1041          'blog-edit' => get_string('page-blog-edit', 'blog')
1042      );
1043  }
1044  
1045  /**
1046   * Add nodes to myprofile page.
1047   *
1048   * @param \core_user\output\myprofile\tree $tree Tree object
1049   * @param stdClass $user user object
1050   * @param bool $iscurrentuser
1051   * @param stdClass $course Course object
1052   *
1053   * @return bool
1054   */
1055  function core_blog_myprofile_navigation(core_user\output\myprofile\tree $tree, $user, $iscurrentuser, $course) {
1056      global $CFG;
1057      if (!blog_is_enabled_for_user() || isguestuser($user)) {
1058          // The guest user cannot post, so it is not possible to view any posts.
1059          // Also blogs might be disabled.
1060          // May as well just bail aggressively here.
1061          return true;
1062      }
1063      if (!blog_user_can_view_user_entry($user->id)) {
1064          return true;
1065      }
1066      $url = new moodle_url("/blog/index.php", array('userid' => $user->id));
1067      if (!empty($course)) {
1068          $url->param('courseid', $course->id);
1069      }
1070      if ($iscurrentuser) {
1071          $title = get_string('blogentries', 'core_blog');
1072      } else {
1073          $title = get_string('myprofileuserblogs', 'core_blog');
1074      }
1075      $blognode = new core_user\output\myprofile\node('miscellaneous', 'blogs', $title, null, $url);
1076      $tree->add_node($blognode);
1077      return true;
1078  }
1079  
1080  /**
1081   * Returns posts tagged with a specified tag.
1082   *
1083   * @param core_tag_tag $tag
1084   * @param bool $exclusivemode if set to true it means that no other entities tagged with this tag
1085   *             are displayed on the page and the per-page limit may be bigger
1086   * @param int $fromctx context id where the link was displayed, may be used by callbacks
1087   *            to display items in the same context first
1088   * @param int $ctx context id where to search for records
1089   * @param bool $rec search in subcontexts as well
1090   * @param int $page 0-based number of page being displayed
1091   * @return \core_tag\output\tagindex
1092   */
1093  function blog_get_tagged_posts($tag, $exclusivemode = false, $fromctx = 0, $ctx = 0, $rec = true, $page = 0) {
1094      global $CFG, $OUTPUT;
1095      require_once($CFG->dirroot.'/user/lib.php');
1096  
1097      $systemcontext = context_system::instance();
1098      $perpage = $exclusivemode ? 20 : 5;
1099      $context = $ctx ? context::instance_by_id($ctx) : context_system::instance();
1100  
1101      $content = '';
1102      if (empty($CFG->enableblogs) || !has_capability('moodle/blog:view', $systemcontext)) {
1103          // Blogs are not enabled or are not visible to the current user.
1104          $totalpages = 0;
1105      } else if ($context->contextlevel != CONTEXT_SYSTEM && empty($CFG->useblogassociations)) {
1106          // No blog entries can be associated to the non-system context.
1107          $totalpages = 0;
1108      } else if (!$rec && $context->contextlevel != CONTEXT_COURSE && $context->contextlevel != CONTEXT_MODULE) {
1109          // No blog entries can be associated with category or block context.
1110          $totalpages = 0;
1111      } else {
1112          require_once($CFG->dirroot.'/blog/locallib.php');
1113  
1114          $filters = array('tag' => $tag->id);
1115          if ($rec) {
1116              if ($context->contextlevel != CONTEXT_SYSTEM) {
1117                  $filters['context'] = $context->id;
1118              }
1119          } else if ($context->contextlevel == CONTEXT_COURSE) {
1120              $filters['course'] = $context->instanceid;
1121          } else if ($context->contextlevel == CONTEXT_MODULE) {
1122              $filters['module'] = $context->instanceid;
1123          }
1124          $bloglisting = new blog_listing($filters);
1125          $blogs = $bloglisting->get_entries($page * $perpage, $perpage);
1126          $totalcount = $bloglisting->count_entries();
1127          $totalpages = ceil($totalcount / $perpage);
1128          if (!empty($blogs)) {
1129              $tagfeed = new core_tag\output\tagfeed();
1130              foreach ($blogs as $blog) {
1131                  $user = fullclone($blog);
1132                  $user->id = $blog->userid;
1133                  $user->deleted = 0;
1134                  $img = $OUTPUT->user_picture($user, array('size' => 35));
1135                  $subject = format_string($blog->subject);
1136  
1137                  if ($blog->publishstate == 'draft') {
1138                      $class = 'dimmed';
1139                  } else {
1140                      $class = '';
1141                  }
1142  
1143                  $url = new moodle_url('/blog/index.php', array('entryid' => $blog->id));
1144                  $subject = html_writer::link($url, $subject, array('class' => $class));
1145  
1146                  $fullname = fullname($user);
1147                  if (user_can_view_profile($user)) {
1148                      $profilelink = new moodle_url('/user/view.php', array('id' => $blog->userid));
1149                      $fullname = html_writer::link($profilelink, $fullname);
1150                  }
1151                  $details = $fullname . ', ' . userdate($blog->created);
1152  
1153                  $tagfeed->add($img, $subject, $details);
1154              }
1155  
1156              $items = $tagfeed->export_for_template($OUTPUT);
1157              $content = $OUTPUT->render_from_template('core_tag/tagfeed', $items);
1158  
1159              $urlparams = array('tagid' => $tag->id);
1160              if ($context->contextlevel == CONTEXT_COURSE) {
1161                  $urlparams['courseid'] = $context->instanceid;
1162              } else if ($context->contextlevel == CONTEXT_MODULE) {
1163                  $urlparams['modid'] = $context->instanceid;
1164              }
1165              $allblogsurl = new moodle_url('/blog/index.php', $urlparams);
1166  
1167              $rv = new core_tag\output\tagindex($tag, 'core', 'post',
1168                      $content,
1169                      $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
1170              $rv->exclusiveurl = $allblogsurl;
1171              return $rv;
1172          }
1173      }
1174  
1175      $rv = new core_tag\output\tagindex($tag, 'core', 'post',
1176              $content,
1177              $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
1178      $rv->exclusiveurl = null;
1179      return $rv;
1180  }
1181  
1182  /**
1183   * Validate the access to a blog.
1184   *
1185   * @param  int $courseid course id the the blog is associated to (can be null).
1186   * @param  int $modid    module id the blog is associated to (can be null).
1187   * @param  int $groupid  group id to filter blogs I can see (can be null)
1188   * @param  int $entryid  blog entry id (can be null)
1189   * @param  int $userid   blog author id (can be null)
1190   * @return array with the calculated course and id
1191   * @since  Moodle 3.6
1192   */
1193  function blog_validate_access($courseid, $modid, $groupid, $entryid, $userid) {
1194      global $CFG, $DB, $USER, $COURSE;
1195  
1196      $sitecontext = context_system::instance();
1197  
1198      // Add courseid if modid or groupid is specified: This is used for navigation and title.
1199      if (!empty($modid) && empty($courseid)) {
1200          $courseid = $DB->get_field('course_modules', 'course', array('id' => $modid));
1201      }
1202  
1203      if (!empty($groupid) && empty($courseid)) {
1204          $courseid = $DB->get_field('groups', 'courseid', array('id' => $groupid));
1205      }
1206  
1207      if (!$userid && has_capability('moodle/blog:view', $sitecontext) && $CFG->bloglevel > BLOG_USER_LEVEL) {
1208          if ($entryid) {
1209              if (!$entryobject = $DB->get_record('post', array('id' => $entryid))) {
1210                  throw new \moodle_exception('nosuchentry', 'blog');
1211              }
1212              $userid = $entryobject->userid;
1213          }
1214      } else if (!$userid) {
1215          $userid = $USER->id;
1216      }
1217  
1218      if (!empty($modid)) {
1219          if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1220              throw new \moodle_exception('courseblogdisable', 'blog');
1221          }
1222          if (!$mod = $DB->get_record('course_modules', array('id' => $modid))) {
1223              throw new \moodle_exception('invalidmoduleid', 'error', $modid);
1224          }
1225          $courseid = $mod->course;
1226      }
1227  
1228      if ((empty($courseid) ? true : $courseid == SITEID) && empty($userid)) {
1229          if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1230              throw new \moodle_exception('siteblogdisable', 'blog');
1231          }
1232          if (!has_capability('moodle/blog:view', $sitecontext)) {
1233              throw new \moodle_exception('cannotviewsiteblog', 'blog');
1234          }
1235  
1236          $COURSE = $DB->get_record('course', array('format' => 'site'));
1237          $courseid = $COURSE->id;
1238      }
1239  
1240      if (!empty($courseid)) {
1241          if (!$course = $DB->get_record('course', array('id' => $courseid))) {
1242              throw new \moodle_exception('invalidcourseid');
1243          }
1244  
1245          $courseid = $course->id;
1246  
1247          if (!has_capability('moodle/blog:view', $sitecontext)) {
1248              throw new \moodle_exception('cannotviewcourseblog', 'blog');
1249          }
1250      } else {
1251          $coursecontext = context_course::instance(SITEID);
1252      }
1253  
1254      if (!empty($groupid)) {
1255          if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1256              throw new \moodle_exception('groupblogdisable', 'blog');
1257          }
1258  
1259          if (! $group = groups_get_group($groupid)) {
1260              throw new \moodle_exception('invalidgroupid', 'blog');
1261          }
1262  
1263          if (!$course = $DB->get_record('course', array('id' => $group->courseid))) {
1264              throw new \moodle_exception('invalidcourseid');
1265          }
1266  
1267          $coursecontext = context_course::instance($course->id);
1268          $courseid = $course->id;
1269  
1270          if (!has_capability('moodle/blog:view', $sitecontext)) {
1271              throw new \moodle_exception('cannotviewcourseorgroupblog', 'blog');
1272          }
1273  
1274          if (groups_get_course_groupmode($course) == SEPARATEGROUPS &&
1275                  !has_capability('moodle/site:accessallgroups', $coursecontext)) {
1276  
1277              if (!groups_is_member($groupid)) {
1278                  throw new \moodle_exception('notmemberofgroup');
1279              }
1280          }
1281      }
1282  
1283      if (!empty($userid)) {
1284          if ($CFG->bloglevel < BLOG_USER_LEVEL) {
1285              throw new \moodle_exception('blogdisable', 'blog');
1286          }
1287  
1288          if (!$user = $DB->get_record('user', array('id' => $userid))) {
1289              throw new \moodle_exception('invaliduserid');
1290          }
1291  
1292          if ($user->deleted) {
1293              throw new \moodle_exception('userdeleted');
1294          }
1295  
1296          if ($USER->id == $userid) {
1297              if (!has_capability('moodle/blog:create', $sitecontext)
1298                && !has_capability('moodle/blog:view', $sitecontext)) {
1299                  throw new \moodle_exception('donothaveblog', 'blog');
1300              }
1301          } else {
1302              if (!has_capability('moodle/blog:view', $sitecontext) || !blog_user_can_view_user_entry($userid)) {
1303                  throw new \moodle_exception('cannotviewcourseblog', 'blog');
1304              }
1305          }
1306      }
1307      return array($courseid, $userid);
1308  }