blog/lib.php

   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         $PAGE->set_title($site->fullname);
 720         $PAGE->set_heading($site->fullname);
 721         $headers['heading'] = get_string('siteblogheading', 'blog');
 722     }
 723
 724     // Case 2: only entryid is requested, ignore all other filters. courseid is used to give more contextual information.
 725     if (!empty($entryid)) {
 726         $headers['filters']['entry'] = $entryid;
 727         $sql = 'SELECT u.* FROM {user} u, {post} p WHERE p.id = ? AND p.userid = u.id';
 728         $user = $DB->get_record_sql($sql, array($entryid));
 729         $entry = $DB->get_record('post', array('id' => $entryid));
 730
 731         $blogurl->param('userid', $user->id);
 732
 733         if (!empty($course)) {
 734             $mycourseid = $course->id;
 735             $blogurl->param('courseid', $mycourseid);
 736         } else {
 737             $mycourseid = $site->id;
 738         }
 739         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 740
 741         $PAGE->navbar->add($strblogentries, $blogurl);
 742
 743         $blogurl->remove_params('userid');
 744         $PAGE->navbar->add($entry->subject, $blogurl);
 745         $PAGE->set_title("$shortname: " . fullname($user) . ": $entry->subject");
 746         $PAGE->set_heading("$shortname: " . fullname($user) . ": $entry->subject");
 747         $headers['heading'] = get_string('blogentrybyuser', 'blog', fullname($user));
 748
 749         // We ignore tag and search params.
 750         if (empty($action) || !$CFG->useblogassociations) {
 751             $headers['url'] = $blogurl;
 752             return $headers;
 753         }
 754     }
 755
 756     if (!empty($userid) && empty($entryid) && ((empty($courseid) && empty($modid)) || !$CFG->useblogassociations)) {
 757         // Case 3: A user's blog entries.
 758
 759         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 760         $blogurl->param('userid', $userid);
 761         $PAGE->set_title("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 762         $PAGE->set_heading("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 763         $headers['heading'] = get_string('userblog', 'blog', fullname($user));
 764         $headers['strview'] = get_string('viewuserentries', 'blog', fullname($user));
 765
 766     } else if (!$CFG->useblogassociations && empty($userid) && !in_array($action, array('edit', 'add'))) {
 767         // Case 4: No blog associations, no userid.
 768
 769         $PAGE->set_title($site->fullname);
 770         $PAGE->set_heading($site->fullname);
 771         $headers['heading'] = get_string('siteblogheading', 'blog');
 772     } else if (!empty($userid) && !empty($modid) && empty($entryid)) {
 773         // Case 5: Blog entries associated with an activity by a specific user (courseid ignored).
 774
 775         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 776         $blogurl->param('userid', $userid);
 777         $blogurl->param('modid', $modid);
 778
 779         // Course module navigation is handled by build_navigation as the second param.
 780         $headers['cm'] = $cm;
 781         $PAGE->navbar->add(fullname($user), "$CFG->wwwroot/user/view.php?id=$user->id");
 782         $PAGE->navbar->add($strblogentries, $blogurl);
 783
 784         $PAGE->set_title("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 785         $PAGE->set_heading("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 786
 787         $a = new stdClass();
 788         $a->user = fullname($user);
 789         $a->mod = $cm->name;
 790         $a->type = get_string('modulename', $cm->modname);
 791         $headers['heading'] = get_string('blogentriesbyuseraboutmodule', 'blog', $a);
 792         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 793         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 794     } else if (!empty($userid) && !empty($courseid) && empty($modid) && empty($entryid)) {
 795         // Case 6: Blog entries associated with a course by a specific user.
 796
 797         $blogurl->param('userid', $userid);
 798         $blogurl->param('courseid', $courseid);
 799
 800         $PAGE->set_title($course->fullname);
 801         $PAGE->set_heading($course->fullname);
 802
 803         $a = new stdClass();
 804         $a->user = fullname($user);
 805         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 806         $a->type = get_string('course');
 807         $headers['heading'] = get_string('blogentriesbyuseraboutcourse', 'blog', $a);
 808         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 809         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 810
 811         // Remove the userid from the URL to inform the blog_menu block correctly.
 812         $blogurl->remove_params(array('userid'));
 813     } else if (!empty($groupid) && empty($modid) && empty($entryid)) {
 814         // Case 7: Blog entries by members of a group, associated with that group's course.
 815
 816         $blogurl->param('courseid', $course->id);
 817
 818         $PAGE->navbar->add($strblogentries, $blogurl);
 819         $blogurl->remove_params(array('courseid'));
 820         $blogurl->param('groupid', $groupid);
 821         $PAGE->navbar->add($group->name, $blogurl);
 822
 823         $PAGE->set_title($course->fullname);
 824         $PAGE->set_heading($course->fullname);
 825
 826         $a = new stdClass();
 827         $a->group = $group->name;
 828         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 829         $a->type = get_string('course');
 830         $headers['heading'] = get_string('blogentriesbygroupaboutcourse', 'blog', $a);
 831         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 832         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 833     } else if (!empty($groupid) && !empty($modid) && empty($entryid)) {
 834         // Case 8: Blog entries by members of a group, associated with an activity in that course.
 835
 836         $headers['cm'] = $cm;
 837         $blogurl->param('modid', $modid);
 838         $PAGE->navbar->add($strblogentries, $blogurl);
 839
 840         $blogurl->param('groupid', $groupid);
 841         $PAGE->navbar->add($group->name, $blogurl);
 842
 843         $PAGE->set_title($course->fullname);
 844         $PAGE->set_heading($course->fullname);
 845
 846         $a = new stdClass();
 847         $a->group = $group->name;
 848         $a->mod = $cm->name;
 849         $a->type = get_string('modulename', $cm->modname);
 850         $headers['heading'] = get_string('blogentriesbygroupaboutmodule', 'blog', $a);
 851         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 852         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 853
 854     } else if (!empty($modid) && empty($userid) && empty($groupid) && empty($entryid)) {
 855         // Case 9: All blog entries associated with an activity.
 856
 857         $PAGE->set_cm($cm, $course);
 858         $blogurl->param('modid', $modid);
 859         $PAGE->navbar->add($strblogentries, $blogurl);
 860         $PAGE->set_title($course->fullname);
 861         $PAGE->set_heading($course->fullname);
 862         $headers['heading'] = get_string('blogentriesabout', 'blog', $cm->name);
 863         $a = new stdClass();
 864         $a->type = get_string('modulename', $cm->modname);
 865         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 866         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 867     } else if (!empty($courseid) && empty($userid) && empty($groupid) && empty($modid) && empty($entryid)) {
 868         // Case 10: All blog entries associated with a course.
 869
 870         $blogurl->param('courseid', $courseid);
 871         $PAGE->navbar->add($strblogentries, $blogurl);
 872         $PAGE->set_title($course->fullname);
 873         $PAGE->set_heading($course->fullname);
 874         $a = new stdClass();
 875         $a->type = get_string('course');
 876         $headers['heading'] = get_string('blogentriesabout',
 877                                          'blog',
 878                                          format_string($course->fullname,
 879                                                        true,
 880                                                        array('context' => context_course::instance($course->id))));
 881         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 882         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 883         $blogurl->remove_params(array('userid'));
 884     }
 885
 886     if (!in_array($action, array('edit', 'add'))) {
 887         // Append Tag info.
 888         if (!empty($tagid)) {
 889             $headers['filters']['tag'] = $tagid;
 890             $blogurl->param('tagid', $tagid);
 891             $tagrec = $DB->get_record('tag', array('id' => $tagid));
 892             $PAGE->navbar->add($tagrec->name, $blogurl);
 893         } else if (!empty($tag)) {
 894             if ($tagrec = $DB->get_record('tag', array('name' => $tag))) {
 895                 $tagid = $tagrec->id;
 896                 $headers['filters']['tag'] = $tagid;
 897                 $blogurl->param('tag', $tag);
 898                 $PAGE->navbar->add(get_string('tagparam', 'blog', $tag), $blogurl);
 899             }
 900         }
 901
 902         // Append Search info.
 903         if (!empty($search) && has_capability('moodle/blog:search', $sitecontext)) {
 904             $headers['filters']['search'] = $search;
 905             $blogurl->param('search', $search);
 906             $PAGE->navbar->add(get_string('searchterm', 'blog', $search), $blogurl->out());
 907         }
 908     }
 909
 910     // Append edit mode info.
 911     if (!empty($action) && $action == 'add') {
 912
 913     } else if (!empty($action) && $action == 'edit') {
 914         $PAGE->navbar->add(get_string('editentry', 'blog'));
 915     }
 916
 917     if (empty($headers['url'])) {
 918         $headers['url'] = $blogurl;
 919     }
 920     return $headers;
 921 }
 922
 923 /**
 924  * Shortcut function for getting a count of blog entries associated with a course or a module
 925  * @param int $courseid The ID of the course
 926  * @param int $cmid The ID of the course_modules
 927  * @return string The number of associated entries
 928  */
 929 function blog_get_associated_count($courseid, $cmid=null) {
 930     global $DB;
 931     $context = context_course::instance($courseid);
 932     if ($cmid) {
 933         $context = context_module::instance($cmid);
 934     }
 935     return $DB->count_records('blog_association', array('contextid' => $context->id));
 936 }
 937
 938 /**
 939  * Running addtional permission check on plugin, for example, plugins
 940  * may have switch to turn on/off comments option, this callback will
 941  * affect UI display, not like pluginname_comment_validate only throw
 942  * exceptions.
 943  * blog_comment_validate will be called before viewing/adding/deleting
 944  * comment, so don't repeat checks.
 945  * Capability check has been done in comment->check_permissions(), we
 946  * don't need to do it again here.
 947  *
 948  * @package  core_blog
 949  * @category comment
 950  *
 951  * @param stdClass $commentparam {
 952  *              context  => context the context object
 953  *              courseid => int course id
 954  *              cm       => stdClass course module object
 955  *              commentarea => string comment area
 956  *              itemid      => int itemid
 957  * }
 958  * @return array
 959  */
 960 function blog_comment_permissions($commentparam) {
 961     global $DB;
 962
 963     // If blog is public and current user is guest, then don't let him post comments.
 964     $blogentry = $DB->get_record('post', array('id' => $commentparam->itemid), 'publishstate', MUST_EXIST);
 965
 966     if ($blogentry->publishstate != 'public') {
 967         if (!isloggedin() || isguestuser()) {
 968             return array('post' => false, 'view' => true);
 969         }
 970     }
 971     return array('post' => true, 'view' => true);
 972 }
 973
 974 /**
 975  * Validate comment parameter before perform other comments actions
 976  *
 977  * @package  core_blog
 978  * @category comment
 979  *
 980  * @param stdClass $comment {
 981  *              context  => context the context object
 982  *              courseid => int course id
 983  *              cm       => stdClass course module object
 984  *              commentarea => string comment area
 985  *              itemid      => int itemid
 986  * }
 987  * @return boolean
 988  */
 989 function blog_comment_validate($commentparam) {
 990     global $CFG, $DB, $USER;
 991
 992     // Check if blogs are enabled user can comment.
 993     if (empty($CFG->enableblogs) || empty($CFG->blogusecomments)) {
 994         throw new comment_exception('nopermissiontocomment');
 995     }
 996
 997     // Validate comment area.
 998     if ($commentparam->commentarea != 'format_blog') {
 999         throw new comment_exception('invalidcommentarea');
1000     }
1001
1002     $blogentry = $DB->get_record('post', array('id' => $commentparam->itemid), '*', MUST_EXIST);
1003
1004     // Validation for comment deletion.
1005     if (!empty($commentparam->commentid)) {
1006         if ($record = $DB->get_record('comments', array('id' => $commentparam->commentid))) {
1007             if ($record->commentarea != 'format_blog') {
1008                 throw new comment_exception('invalidcommentarea');
1009             }
1010             if ($record->contextid != $commentparam->context->id) {
1011                 throw new comment_exception('invalidcontext');
1012             }
1013             if ($record->itemid != $commentparam->itemid) {
1014                 throw new comment_exception('invalidcommentitemid');
1015             }
1016         } else {
1017             throw new comment_exception('invalidcommentid');
1018         }
1019     }
1020
1021     // Validate if user has blog view permission.
1022     $sitecontext = context_system::instance();
1023     return has_capability('moodle/blog:view', $sitecontext) &&
1024             blog_user_can_view_user_entry($blogentry->userid, $blogentry);
1025 }
1026
1027 /**
1028  * Return a list of page types
1029  * @param string $pagetype current page type
1030  * @param stdClass $parentcontext Block's parent context
1031  * @param stdClass $currentcontext Current context of block
1032  */
1033 function blog_page_type_list($pagetype, $parentcontext, $currentcontext) {
1034     return array(
1035         '*' => get_string('page-x', 'pagetype'),
1036         'blog-*' => get_string('page-blog-x', 'blog'),
1037         'blog-index' => get_string('page-blog-index', 'blog'),
1038         'blog-edit' => get_string('page-blog-edit', 'blog')
1039     );
1040 }
1041
1042 /**
1043  * Add nodes to myprofile page.
1044  *
1045  * @param \core_user\output\myprofile\tree $tree Tree object
1046  * @param stdClass $user user object
1047  * @param bool $iscurrentuser
1048  * @param stdClass $course Course object
1049  *
1050  * @return bool
1051  */
1052 function core_blog_myprofile_navigation(core_user\output\myprofile\tree $tree, $user, $iscurrentuser, $course) {
1053     global $CFG;
1054     if (!blog_is_enabled_for_user() || isguestuser($user)) {
1055         // The guest user cannot post, so it is not possible to view any posts.
1056         // Also blogs might be disabled.
1057         // May as well just bail aggressively here.
1058         return true;
1059     }
1060     if (!blog_user_can_view_user_entry($user->id)) {
1061         return true;
1062     }
1063     $url = new moodle_url("/blog/index.php", array('userid' => $user->id));
1064     if (!empty($course)) {
1065         $url->param('courseid', $course->id);
1066     }
1067     if ($iscurrentuser) {
1068         $title = get_string('blogentries', 'core_blog');
1069     } else {
1070         $title = get_string('myprofileuserblogs', 'core_blog');
1071     }
1072     $blognode = new core_user\output\myprofile\node('miscellaneous', 'blogs', $title, null, $url);
1073     $tree->add_node($blognode);
1074     return true;
1075 }
1076
1077 /**
1078  * Returns posts tagged with a specified tag.
1079  *
1080  * @param core_tag_tag $tag
1081  * @param bool $exclusivemode if set to true it means that no other entities tagged with this tag
1082  *             are displayed on the page and the per-page limit may be bigger
1083  * @param int $fromctx context id where the link was displayed, may be used by callbacks
1084  *            to display items in the same context first
1085  * @param int $ctx context id where to search for records
1086  * @param bool $rec search in subcontexts as well
1087  * @param int $page 0-based number of page being displayed
1088  * @return \core_tag\output\tagindex
1089  */
1090 function blog_get_tagged_posts($tag, $exclusivemode = false, $fromctx = 0, $ctx = 0, $rec = true, $page = 0) {
1091     global $CFG, $OUTPUT;
1092     require_once($CFG->dirroot.'/user/lib.php');
1093
1094     $systemcontext = context_system::instance();
1095     $perpage = $exclusivemode ? 20 : 5;
1096     $context = $ctx ? context::instance_by_id($ctx) : context_system::instance();
1097
1098     $content = '';
1099     if (empty($CFG->enableblogs) || !has_capability('moodle/blog:view', $systemcontext)) {
1100         // Blogs are not enabled or are not visible to the current user.
1101         $totalpages = 0;
1102     } else if ($context->contextlevel != CONTEXT_SYSTEM && empty($CFG->useblogassociations)) {
1103         // No blog entries can be associated to the non-system context.
1104         $totalpages = 0;
1105     } else if (!$rec && $context->contextlevel != CONTEXT_COURSE && $context->contextlevel != CONTEXT_MODULE) {
1106         // No blog entries can be associated with category or block context.
1107         $totalpages = 0;
1108     } else {
1109         require_once($CFG->dirroot.'/blog/locallib.php');
1110
1111         $filters = array('tag' => $tag->id);
1112         if ($rec) {
1113             if ($context->contextlevel != CONTEXT_SYSTEM) {
1114                 $filters['context'] = $context->id;
1115             }
1116         } else if ($context->contextlevel == CONTEXT_COURSE) {
1117             $filters['course'] = $context->instanceid;
1118         } else if ($context->contextlevel == CONTEXT_MODULE) {
1119             $filters['module'] = $context->instanceid;
1120         }
1121         $bloglisting = new blog_listing($filters);
1122         $blogs = $bloglisting->get_entries($page * $perpage, $perpage);
1123         $totalcount = $bloglisting->count_entries();
1124         $totalpages = ceil($totalcount / $perpage);
1125         if (!empty($blogs)) {
1126             $tagfeed = new core_tag\output\tagfeed();
1127             foreach ($blogs as $blog) {
1128                 $user = fullclone($blog);
1129                 $user->id = $blog->userid;
1130                 $user->deleted = 0;
1131                 $img = $OUTPUT->user_picture($user, array('size' => 35));
1132                 $subject = format_string($blog->subject);
1133
1134                 if ($blog->publishstate == 'draft') {
1135                     $class = 'dimmed';
1136                 } else {
1137                     $class = '';
1138                 }
1139
1140                 $url = new moodle_url('/blog/index.php', array('entryid' => $blog->id));
1141                 $subject = html_writer::link($url, $subject, array('class' => $class));
1142
1143                 $fullname = fullname($user);
1144                 if (user_can_view_profile($user)) {
1145                     $profilelink = new moodle_url('/user/view.php', array('id' => $blog->userid));
1146                     $fullname = html_writer::link($profilelink, $fullname);
1147                 }
1148                 $details = $fullname . ', ' . userdate($blog->created);
1149
1150                 $tagfeed->add($img, $subject, $details);
1151             }
1152
1153             $items = $tagfeed->export_for_template($OUTPUT);
1154             $content = $OUTPUT->render_from_template('core_tag/tagfeed', $items);
1155
1156             $urlparams = array('tagid' => $tag->id);
1157             if ($context->contextlevel == CONTEXT_COURSE) {
1158                 $urlparams['courseid'] = $context->instanceid;
1159             } else if ($context->contextlevel == CONTEXT_MODULE) {
1160                 $urlparams['modid'] = $context->instanceid;
1161             }
1162             $allblogsurl = new moodle_url('/blog/index.php', $urlparams);
1163
1164             $rv = new core_tag\output\tagindex($tag, 'core', 'post',
1165                     $content,
1166                     $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
1167             $rv->exclusiveurl = $allblogsurl;
1168             return $rv;
1169         }
1170     }
1171
1172     $rv = new core_tag\output\tagindex($tag, 'core', 'post',
1173             $content,
1174             $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
1175     $rv->exclusiveurl = null;
1176     return $rv;
1177 }
1178
1179 /**
1180  * Validate the access to a blog.
1181  *
1182  * @param  int $courseid course id the the blog is associated to (can be null).
1183  * @param  int $modid    module id the blog is associated to (can be null).
1184  * @param  int $groupid  group id to filter blogs I can see (can be null)
1185  * @param  int $entryid  blog entry id (can be null)
1186  * @param  int $userid   blog author id (can be null)
1187  * @return array with the calculated course and id
1188  * @since  Moodle 3.6
1189  */
1190 function blog_validate_access($courseid, $modid, $groupid, $entryid, $userid) {
1191     global $CFG, $DB, $USER, $COURSE;
1192
1193     $sitecontext = context_system::instance();
1194
1195     // Add courseid if modid or groupid is specified: This is used for navigation and title.
1196     if (!empty($modid) && empty($courseid)) {
1197         $courseid = $DB->get_field('course_modules', 'course', array('id' => $modid));
1198     }
1199
1200     if (!empty($groupid) && empty($courseid)) {
1201         $courseid = $DB->get_field('groups', 'courseid', array('id' => $groupid));
1202     }
1203
1204     if (!$userid && has_capability('moodle/blog:view', $sitecontext) && $CFG->bloglevel > BLOG_USER_LEVEL) {
1205         if ($entryid) {
1206             if (!$entryobject = $DB->get_record('post', array('id' => $entryid))) {
1207                 print_error('nosuchentry', 'blog');
1208             }
1209             $userid = $entryobject->userid;
1210         }
1211     } else if (!$userid) {
1212         $userid = $USER->id;
1213     }
1214
1215     if (!empty($modid)) {
1216         if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1217             print_error(get_string('nocourseblogs', 'blog'));
1218         }
1219         if (!$mod = $DB->get_record('course_modules', array('id' => $modid))) {
1220             print_error(get_string('invalidmodid', 'blog'));
1221         }
1222         $courseid = $mod->course;
1223     }
1224
1225     if ((empty($courseid) ? true : $courseid == SITEID) && empty($userid)) {
1226         if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1227             print_error('siteblogdisable', 'blog');
1228         }
1229         if (!has_capability('moodle/blog:view', $sitecontext)) {
1230             print_error('cannotviewsiteblog', 'blog');
1231         }
1232
1233         $COURSE = $DB->get_record('course', array('format' => 'site'));
1234         $courseid = $COURSE->id;
1235     }
1236
1237     if (!empty($courseid)) {
1238         if (!$course = $DB->get_record('course', array('id' => $courseid))) {
1239             print_error('invalidcourseid');
1240         }
1241
1242         $courseid = $course->id;
1243
1244         if (!has_capability('moodle/blog:view', $sitecontext)) {
1245             print_error('cannotviewcourseblog', 'blog');
1246         }
1247     } else {
1248         $coursecontext = context_course::instance(SITEID);
1249     }
1250
1251     if (!empty($groupid)) {
1252         if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1253             print_error('groupblogdisable', 'blog');
1254         }
1255
1256         if (! $group = groups_get_group($groupid)) {
1257             print_error(get_string('invalidgroupid', 'blog'));
1258         }
1259
1260         if (!$course = $DB->get_record('course', array('id' => $group->courseid))) {
1261             print_error('invalidcourseid');
1262         }
1263
1264         $coursecontext = context_course::instance($course->id);
1265         $courseid = $course->id;
1266
1267         if (!has_capability('moodle/blog:view', $sitecontext)) {
1268             print_error(get_string('cannotviewcourseorgroupblog', 'blog'));
1269         }
1270
1271         if (groups_get_course_groupmode($course) == SEPARATEGROUPS &&
1272                 !has_capability('moodle/site:accessallgroups', $coursecontext)) {
1273
1274             if (!groups_is_member($groupid)) {
1275                 print_error('notmemberofgroup');
1276             }
1277         }
1278     }
1279
1280     if (!empty($userid)) {
1281         if ($CFG->bloglevel < BLOG_USER_LEVEL) {
1282             print_error('blogdisable', 'blog');
1283         }
1284
1285         if (!$user = $DB->get_record('user', array('id' => $userid))) {
1286             print_error('invaliduserid');
1287         }
1288
1289         if ($user->deleted) {
1290             print_error('userdeleted');
1291         }
1292
1293         if ($USER->id == $userid) {
1294             if (!has_capability('moodle/blog:create', $sitecontext)
1295               && !has_capability('moodle/blog:view', $sitecontext)) {
1296                 print_error('donothaveblog', 'blog');
1297             }
1298         } else {
1299             if (!has_capability('moodle/blog:view', $sitecontext) || !blog_user_can_view_user_entry($userid)) {
1300                 print_error('cannotviewcourseblog', 'blog');
1301             }
1302         }
1303     }
1304     return array($courseid, $userid);
1305 }