blog/lib.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 /**
  19  * Core global functions for Blog.
  20  *
  21  * @package    moodlecore
  22  * @subpackage blog
  23  * @copyright  2009 Nicolas Connault
  24  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25  */
  26
  27 defined('MOODLE_INTERNAL') || die();
  28
  29 /**
  30  * Library of functions and constants for blog
  31  */
  32 require_once($CFG->dirroot .'/blog/rsslib.php');
  33 require_once($CFG->dirroot.'/tag/lib.php');
  34
  35 /**
  36  * User can edit a blog entry if this is their own blog entry and they have
  37  * the capability moodle/blog:create, or if they have the capability
  38  * moodle/blog:manageentries.
  39  *
  40  * This also applies to deleting of entries.
  41  */
  42 function blog_user_can_edit_entry($blogentry) {
  43     global $USER;
  44
  45     $sitecontext = context_system::instance();
  46
  47     if (has_capability('moodle/blog:manageentries', $sitecontext)) {
  48         return true; // can edit any blog entry
  49     }
  50
  51     if ($blogentry->userid == $USER->id && has_capability('moodle/blog:create', $sitecontext)) {
  52         return true; // can edit own when having blog:create capability
  53     }
  54
  55     return false;
  56 }
  57
  58
  59 /**
  60  * Checks to see if a user can view the blogs of another user.
  61  * Only blog level is checked here, the capabilities are enforced
  62  * in blog/index.php
  63  */
  64 function blog_user_can_view_user_entry($targetuserid, $blogentry=null) {
  65     global $CFG, $USER, $DB;
  66
  67     if (empty($CFG->enableblogs)) {
  68         return false; // blog system disabled
  69     }
  70
  71     if (isloggedin() && $USER->id == $targetuserid) {
  72         return true; // can view own entries in any case
  73     }
  74
  75     $sitecontext = context_system::instance();
  76     if (has_capability('moodle/blog:manageentries', $sitecontext)) {
  77         return true; // can manage all entries
  78     }
  79
  80     // coming for 1 entry, make sure it's not a draft
  81     if ($blogentry && $blogentry->publishstate == 'draft' && !has_capability('moodle/blog:viewdrafts', $sitecontext)) {
  82         return false;  // can not view draft of others
  83     }
  84
  85     // coming for 0 entry, make sure user is logged in, if not a public blog
  86     if ($blogentry && $blogentry->publishstate != 'public' && !isloggedin()) {
  87         return false;
  88     }
  89
  90     switch ($CFG->bloglevel) {
  91         case BLOG_GLOBAL_LEVEL:
  92             return true;
  93         break;
  94
  95         case BLOG_SITE_LEVEL:
  96             if (isloggedin()) { // not logged in viewers forbidden
  97                 return true;
  98             }
  99             return false;
 100         break;
 101
 102         case BLOG_USER_LEVEL:
 103         default:
 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  * Given a record in the {blog_external} table, checks the blog's URL
 140  * for new entries not yet copied into Moodle.
 141  * Also attempts to identify and remove deleted blog entries
 142  *
 143  * @param object $externalblog
 144  * @return boolean False if the Feed is invalid
 145  */
 146 function blog_sync_external_entries($externalblog) {
 147     global $CFG, $DB;
 148     require_once($CFG->libdir . '/simplepie/moodle_simplepie.php');
 149
 150     $rss = new moodle_simplepie();
 151     $rssfile = $rss->registry->create('File', array($externalblog->url));
 152     $filetest = $rss->registry->create('Locator', array($rssfile));
 153
 154     if (!$filetest->is_feed($rssfile)) {
 155         $externalblog->failedlastsync = 1;
 156         $DB->update_record('blog_external', $externalblog);
 157         return false;
 158     } else if (!empty($externalblog->failedlastsync)) {
 159         $externalblog->failedlastsync = 0;
 160         $DB->update_record('blog_external', $externalblog);
 161     }
 162
 163     $rss->set_feed_url($externalblog->url);
 164     $rss->init();
 165
 166     if (empty($rss->data)) {
 167         return null;
 168     }
 169     //used to identify blog posts that have been deleted from the source feed
 170     $oldesttimestamp = null;
 171     $uniquehashes = array();
 172
 173     foreach ($rss->get_items() as $entry) {
 174         // If filtertags are defined, use them to filter the entries by RSS category
 175         if (!empty($externalblog->filtertags)) {
 176             $containsfiltertag = false;
 177             $categories = $entry->get_categories();
 178             $filtertags = explode(',', $externalblog->filtertags);
 179             $filtertags = array_map('trim', $filtertags);
 180             $filtertags = array_map('strtolower', $filtertags);
 181
 182             foreach ($categories as $category) {
 183                 if (in_array(trim(strtolower($category->term)), $filtertags)) {
 184                     $containsfiltertag = true;
 185                 }
 186             }
 187
 188             if (!$containsfiltertag) {
 189                 continue;
 190             }
 191         }
 192
 193         $uniquehashes[] = $entry->get_permalink();
 194
 195         $newentry = new stdClass();
 196         $newentry->userid = $externalblog->userid;
 197         $newentry->module = 'blog_external';
 198         $newentry->content = $externalblog->id;
 199         $newentry->uniquehash = $entry->get_permalink();
 200         $newentry->publishstate = 'site';
 201         $newentry->format = FORMAT_HTML;
 202         // Clean subject of html, just in case
 203         $newentry->subject = clean_param($entry->get_title(), PARAM_TEXT);
 204         // Observe 128 max chars in DB
 205         // TODO: +1 to raise this to 255
 206         if (textlib::strlen($newentry->subject) > 128) {
 207             $newentry->subject = textlib::substr($newentry->subject, 0, 125) . '...';
 208         }
 209         $newentry->summary = $entry->get_description();
 210
 211         //used to decide whether to insert or update
 212         //uses enty permalink plus creation date if available
 213         $existingpostconditions = array('uniquehash' => $entry->get_permalink());
 214
 215         //our DB doesnt allow null creation or modified timestamps so check the external blog supplied one
 216         $entrydate = $entry->get_date('U');
 217         if (!empty($entrydate)) {
 218             $existingpostconditions['created'] = $entrydate;
 219         }
 220
 221         //the post ID or false if post not found in DB
 222         $postid = $DB->get_field('post', 'id', $existingpostconditions);
 223
 224         $timestamp = null;
 225         if (empty($entrydate)) {
 226             $timestamp = time();
 227         } else {
 228             $timestamp = $entrydate;
 229         }
 230
 231         //only set created if its a new post so we retain the original creation timestamp if the post is edited
 232         if ($postid === false) {
 233             $newentry->created = $timestamp;
 234         }
 235         $newentry->lastmodified = $timestamp;
 236
 237         if (empty($oldesttimestamp) || $timestamp < $oldesttimestamp) {
 238             //found an older post
 239             $oldesttimestamp = $timestamp;
 240         }
 241
 242         if (textlib::strlen($newentry->uniquehash) > 255) {
 243             // The URL for this item is too long for the field. Rather than add
 244             // the entry without the link we will skip straight over it.
 245             // RSS spec says recommended length 500, we use 255.
 246             debugging('External blog entry skipped because of oversized URL', DEBUG_DEVELOPER);
 247             continue;
 248         }
 249
 250         if ($postid === false) {
 251             $id = $DB->insert_record('post', $newentry);
 252
 253             // Set tags
 254             if ($tags = tag_get_tags_array('blog_external', $externalblog->id)) {
 255                 tag_set('post', $id, $tags);
 256             }
 257         } else {
 258             $newentry->id = $postid;
 259             $DB->update_record('post', $newentry);
 260         }
 261     }
 262
 263     // Look at the posts we have in the database to check if any of them have been deleted from the feed.
 264     // Only checking posts within the time frame returned by the rss feed. Older items may have been deleted or
 265     // may just not be returned anymore. We can't tell the difference so we leave older posts alone.
 266     $sql = "SELECT id, uniquehash
 267               FROM {post}
 268              WHERE module = 'blog_external'
 269                    AND " . $DB->sql_compare_text('content') . " = " . $DB->sql_compare_text(':blogid') . "
 270                    AND created > :ts";
 271     $dbposts = $DB->get_records_sql($sql, array('blogid' => $externalblog->id, 'ts' => $oldesttimestamp));
 272
 273     $todelete = array();
 274     foreach($dbposts as $dbpost) {
 275         if ( !in_array($dbpost->uniquehash, $uniquehashes) ) {
 276             $todelete[] = $dbpost->id;
 277         }
 278     }
 279     $DB->delete_records_list('post', 'id', $todelete);
 280
 281     $DB->update_record('blog_external', array('id' => $externalblog->id, 'timefetched' => time()));
 282 }
 283
 284 /**
 285  * Given an external blog object, deletes all related blog entries from the post table.
 286  * NOTE: The external blog's id is saved as post.content, a field that is not oterhwise used by blog entries.
 287  * @param object $externablog
 288  */
 289 function blog_delete_external_entries($externalblog) {
 290     global $DB;
 291     require_capability('moodle/blog:manageexternal', context_system::instance());
 292     $DB->delete_records_select('post',
 293                                "module='blog_external' AND " . $DB->sql_compare_text('content') . " = ?",
 294                                array($externalblog->id));
 295 }
 296
 297 /**
 298  * This function checks that blogs are enabled, and that the user can see blogs at all
 299  * @return bool
 300  */
 301 function blog_is_enabled_for_user() {
 302     global $CFG;
 303     return (!empty($CFG->enableblogs) && (isloggedin() || ($CFG->bloglevel == BLOG_GLOBAL_LEVEL)));
 304 }
 305
 306 /**
 307  * This function gets all of the options available for the current user in respect
 308  * to blogs.
 309  *
 310  * It loads the following if applicable:
 311  * -  Module options {@see blog_get_options_for_module}
 312  * -  Course options {@see blog_get_options_for_course}
 313  * -  User specific options {@see blog_get_options_for_user}
 314  * -  General options (BLOG_LEVEL_GLOBAL)
 315  *
 316  * @param moodle_page $page The page to load for (normally $PAGE)
 317  * @param stdClass $userid Load for a specific user
 318  * @return array An array of options organised by type.
 319  */
 320 function blog_get_all_options(moodle_page $page, stdClass $userid = null) {
 321     global $CFG, $DB, $USER;
 322
 323     $options = array();
 324
 325     // If blogs are enabled and the user is logged in and not a guest
 326     if (blog_is_enabled_for_user()) {
 327         // If the context is the user then assume we want to load for the users context
 328         if (is_null($userid) && $page->context->contextlevel == CONTEXT_USER) {
 329             $userid = $page->context->instanceid;
 330         }
 331         // Check the userid var
 332         if (!is_null($userid) && $userid!==$USER->id) {
 333             // Load the user from the userid... it MUST EXIST throw a wobbly if it doesn't!
 334             $user = $DB->get_record('user', array('id'=>$userid), '*', MUST_EXIST);
 335         } else {
 336             $user = null;
 337         }
 338
 339         if ($CFG->useblogassociations && $page->cm !== null) {
 340             // Load for the module associated with the page
 341             $options[CONTEXT_MODULE] = blog_get_options_for_module($page->cm, $user);
 342         } else if ($CFG->useblogassociations && $page->course->id != SITEID) {
 343             // Load the options for the course associated with the page
 344             $options[CONTEXT_COURSE] = blog_get_options_for_course($page->course, $user);
 345         }
 346
 347         // Get the options for the user
 348         if ($user !== null and !isguestuser($user)) {
 349             // Load for the requested user
 350             $options[CONTEXT_USER+1] = blog_get_options_for_user($user);
 351         }
 352         // Load for the current user
 353         if (isloggedin() and !isguestuser()) {
 354             $options[CONTEXT_USER] = blog_get_options_for_user();
 355         }
 356     }
 357
 358     // If blog level is global then display a link to view all site entries
 359     if (!empty($CFG->enableblogs) && $CFG->bloglevel >= BLOG_GLOBAL_LEVEL && has_capability('moodle/blog:view', context_system::instance())) {
 360         $options[CONTEXT_SYSTEM] = array('viewsite' => array(
 361             'string' => get_string('viewsiteentries', 'blog'),
 362             'link' => new moodle_url('/blog/index.php')
 363         ));
 364     }
 365
 366     // Return the options
 367     return $options;
 368 }
 369
 370 /**
 371  * Get all of the blog options that relate to the passed user.
 372  *
 373  * If no user is passed the current user is assumed.
 374  *
 375  * @staticvar array $useroptions Cache so we don't have to regenerate multiple times
 376  * @param stdClass $user
 377  * @return array The array of options for the requested user
 378  */
 379 function blog_get_options_for_user(stdClass $user=null) {
 380     global $CFG, $USER;
 381     // Cache
 382     static $useroptions = array();
 383
 384     $options = array();
 385     // Blogs must be enabled and the user must be logged in
 386     if (!blog_is_enabled_for_user()) {
 387         return $options;
 388     }
 389
 390     // Sort out the user var
 391     if ($user === null || $user->id == $USER->id) {
 392         $user = $USER;
 393         $iscurrentuser = true;
 394     } else {
 395         $iscurrentuser = false;
 396     }
 397
 398     // If we've already generated serve from the cache
 399     if (array_key_exists($user->id, $useroptions)) {
 400         return $useroptions[$user->id];
 401     }
 402
 403     $sitecontext = context_system::instance();
 404     $canview = has_capability('moodle/blog:view', $sitecontext);
 405
 406     if (!$iscurrentuser && $canview && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 407         // Not the current user, but we can view and its blogs are enabled for SITE or GLOBAL
 408         $options['userentries'] = array(
 409             'string' => get_string('viewuserentries', 'blog', fullname($user)),
 410             'link' => new moodle_url('/blog/index.php', array('userid'=>$user->id))
 411         );
 412     } else {
 413         // It's the current user
 414         if ($canview) {
 415             // We can view our own blogs .... BIG surprise
 416             $options['view'] = array(
 417                 'string' => get_string('viewallmyentries', 'blog'),
 418                 'link' => new moodle_url('/blog/index.php', array('userid'=>$USER->id))
 419             );
 420         }
 421         if (has_capability('moodle/blog:create', $sitecontext)) {
 422             // We can add to our own blog
 423             $options['add'] = array(
 424                 'string' => get_string('addnewentry', 'blog'),
 425                 'link' => new moodle_url('/blog/edit.php', array('action'=>'add'))
 426             );
 427         }
 428     }
 429     if ($canview && $CFG->enablerssfeeds) {
 430         $options['rss'] = array(
 431             'string' => get_string('rssfeed', 'blog'),
 432             'link' => new moodle_url(rss_get_url($sitecontext->id, $USER->id, 'blog', 'user/'.$user->id))
 433        );
 434     }
 435
 436     // Cache the options
 437     $useroptions[$user->id] = $options;
 438     // Return the options
 439     return $options;
 440 }
 441
 442 /**
 443  * Get the blog options that relate to the given course for the given user.
 444  *
 445  * @staticvar array $courseoptions A cache so we can save regenerating multiple times
 446  * @param stdClass $course The course to load options for
 447  * @param stdClass $user The user to load options for null == current user
 448  * @return array The array of options
 449  */
 450 function blog_get_options_for_course(stdClass $course, stdClass $user=null) {
 451     global $CFG, $USER;
 452     // Cache
 453     static $courseoptions = array();
 454
 455     $options = array();
 456
 457     // User must be logged in and blogs must be enabled
 458     if (!blog_is_enabled_for_user()) {
 459         return $options;
 460     }
 461
 462     // Check that the user can associate with the course
 463     $sitecontext = context_system::instance();
 464     // Generate the cache key
 465     $key = $course->id.':';
 466     if (!empty($user)) {
 467         $key .= $user->id;
 468     } else {
 469         $key .= $USER->id;
 470     }
 471     // Serve from the cache if we've already generated for this course
 472     if (array_key_exists($key, $courseoptions)) {
 473         return $courseoptions[$key];
 474     }
 475
 476
 477     if (has_capability('moodle/blog:view', $sitecontext)) {
 478         // We can view!
 479         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 480             // View entries about this course
 481             $options['courseview'] = array(
 482                 'string' => get_string('viewcourseblogs', 'blog'),
 483                 'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id))
 484             );
 485         }
 486         // View MY entries about this course
 487         $options['courseviewmine'] = array(
 488             'string' => get_string('viewmyentriesaboutcourse', 'blog'),
 489             'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $USER->id))
 490         );
 491         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 492             // View the provided users entries about this course
 493             $options['courseviewuser'] = array(
 494                 'string' => get_string('viewentriesbyuseraboutcourse', 'blog', fullname($user)),
 495                 'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $user->id))
 496             );
 497         }
 498     }
 499
 500     if (has_capability('moodle/blog:create', $sitecontext)) {
 501         // We can blog about this course
 502         $options['courseadd'] = array(
 503             'string' => get_string('blogaboutthiscourse', 'blog'),
 504             'link' => new moodle_url('/blog/edit.php', array('action' => 'add', 'courseid' => $course->id))
 505         );
 506     }
 507
 508
 509     // Cache the options for this course
 510     $courseoptions[$key] = $options;
 511     // Return the options
 512     return $options;
 513 }
 514
 515 /**
 516  * Get the blog options relating to the given module for the given user
 517  *
 518  * @staticvar array $moduleoptions Cache
 519  * @param stdClass|cm_info $module The module to get options for
 520  * @param stdClass $user The user to get options for null == currentuser
 521  * @return array
 522  */
 523 function blog_get_options_for_module($module, $user=null) {
 524     global $CFG, $USER;
 525     // Cache
 526     static $moduleoptions = array();
 527
 528     $options = array();
 529     // User must be logged in, blogs must be enabled
 530     if (!blog_is_enabled_for_user()) {
 531         return $options;
 532     }
 533
 534     $sitecontext = context_system::instance();
 535
 536     // Generate the cache key
 537     $key = $module->id.':';
 538     if (!empty($user)) {
 539         $key .= $user->id;
 540     } else {
 541         $key .= $USER->id;
 542     }
 543     if (array_key_exists($key, $moduleoptions)) {
 544         // Serve from the cache so we don't have to regenerate
 545         return $moduleoptions[$key];
 546     }
 547
 548
 549     if (has_capability('moodle/blog:view', $sitecontext)) {
 550         // Save correct module name for later usage.
 551         $modulename = get_string('modulename', $module->modname);
 552
 553         // We can view!
 554         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 555             // View all entries about this module
 556             $a = new stdClass;
 557             $a->type = $modulename;
 558             $options['moduleview'] = array(
 559                 'string' => get_string('viewallmodentries', 'blog', $a),
 560                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id))
 561             );
 562         }
 563         // View MY entries about this module
 564         $options['moduleviewmine'] = array(
 565             'string' => get_string('viewmyentriesaboutmodule', 'blog', $modulename),
 566             'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$USER->id))
 567         );
 568         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 569             // View the given users entries about this module
 570             $a = new stdClass;
 571             $a->mod = $modulename;
 572             $a->user = fullname($user);
 573             $options['moduleviewuser'] = array(
 574                 'string' => get_string('blogentriesbyuseraboutmodule', 'blog', $a),
 575                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$user->id))
 576             );
 577         }
 578     }
 579
 580     if (has_capability('moodle/blog:create', $sitecontext)) {
 581         // The user can blog about this module
 582         $options['moduleadd'] = array(
 583             'string' => get_string('blogaboutthismodule', 'blog', $modulename),
 584             'link' => new moodle_url('/blog/edit.php', array('action'=>'add', 'modid'=>$module->id))
 585         );
 586     }
 587     // Cache the options
 588     $moduleoptions[$key] = $options;
 589     // Return the options
 590     return $options;
 591 }
 592
 593 /**
 594  * This function encapsulates all the logic behind the complex
 595  * navigation, titles and headings of the blog listing page, depending
 596  * on URL params. It looks at URL params and at the current context level.
 597  * It builds and returns an array containing:
 598  *
 599  * 1. heading: The heading displayed above the blog entries
 600  * 2. stradd:  The text to be used as the "Add entry" link
 601  * 3. strview: The text to be used as the "View entries" link
 602  * 4. url:     The moodle_url object used as the base for add and view links
 603  * 5. filters: An array of parameters used to filter blog listings. Used by index.php and the Recent blogs block
 604  *
 605  * All other variables are set directly in $PAGE
 606  *
 607  * It uses the current URL to build these variables.
 608  * A number of mutually exclusive use cases are used to structure this function.
 609  *
 610  * @return array
 611  */
 612 function blog_get_headers($courseid=null, $groupid=null, $userid=null, $tagid=null) {
 613     global $CFG, $PAGE, $DB, $USER;
 614
 615     $id       = optional_param('id', null, PARAM_INT);
 616     $tag      = optional_param('tag', null, PARAM_NOTAGS);
 617     $tagid    = optional_param('tagid', $tagid, PARAM_INT);
 618     $userid   = optional_param('userid', $userid, PARAM_INT);
 619     $modid    = optional_param('modid', null, PARAM_INT);
 620     $entryid  = optional_param('entryid', null, PARAM_INT);
 621     $groupid  = optional_param('groupid', $groupid, PARAM_INT);
 622     $courseid = optional_param('courseid', $courseid, PARAM_INT);
 623     $search   = optional_param('search', null, PARAM_RAW);
 624     $action   = optional_param('action', null, PARAM_ALPHA);
 625     $confirm  = optional_param('confirm', false, PARAM_BOOL);
 626
 627     // Ignore userid when action == add
 628     if ($action == 'add' && $userid) {
 629         unset($userid);
 630         $PAGE->url->remove_params(array('userid'));
 631     } else if ($action == 'add' && $entryid) {
 632         unset($entryid);
 633         $PAGE->url->remove_params(array('entryid'));
 634     }
 635
 636     $headers = array('title' => '', 'heading' => '', 'cm' => null, 'filters' => array());
 637
 638     $blogurl = new moodle_url('/blog/index.php');
 639
 640     $headers['stradd'] = get_string('addnewentry', 'blog');
 641     $headers['strview'] = null;
 642
 643     $site = $DB->get_record('course', array('id' => SITEID));
 644     $sitecontext = context_system::instance();
 645     // Common Lang strings
 646     $strparticipants = get_string("participants");
 647     $strblogentries  = get_string("blogentries", 'blog');
 648
 649     // Prepare record objects as needed
 650     if (!empty($courseid)) {
 651         $headers['filters']['course'] = $courseid;
 652         $course = $DB->get_record('course', array('id' => $courseid));
 653     }
 654
 655     if (!empty($userid)) {
 656         $headers['filters']['user'] = $userid;
 657         $user = $DB->get_record('user', array('id' => $userid));
 658     }
 659
 660     if (!empty($groupid)) { // groupid always overrides courseid
 661         $headers['filters']['group'] = $groupid;
 662         $group = $DB->get_record('groups', array('id' => $groupid));
 663         $course = $DB->get_record('course', array('id' => $group->courseid));
 664     }
 665
 666     $PAGE->set_pagelayout('standard');
 667
 668     // modid always overrides courseid, so the $course object may be reset here
 669     if (!empty($modid) && $CFG->useblogassociations) {
 670
 671         $headers['filters']['module'] = $modid;
 672         // A groupid param may conflict with this coursemod's courseid. Ignore groupid in that case
 673         $courseid = $DB->get_field('course_modules', 'course', array('id'=>$modid));
 674         $course = $DB->get_record('course', array('id' => $courseid));
 675         $cm = $DB->get_record('course_modules', array('id' => $modid));
 676         $cm->modname = $DB->get_field('modules', 'name', array('id' => $cm->module));
 677         $cm->name = $DB->get_field($cm->modname, 'name', array('id' => $cm->instance));
 678         $a = new stdClass();
 679         $a->type = get_string('modulename', $cm->modname);
 680         $PAGE->set_cm($cm, $course);
 681         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 682         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 683     }
 684
 685     // Case 1: No entry, mod, course or user params: all site entries to be shown (filtered by search and tag/tagid)
 686     // Note: if action is set to 'add' or 'edit', we do this at the end
 687     if (empty($entryid) && empty($modid) && empty($courseid) && empty($userid) && !in_array($action, array('edit', 'add'))) {
 688         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 689         $PAGE->navbar->add($strblogentries, $blogurl);
 690         $PAGE->set_title("$shortname: " . get_string('blog', 'blog'));
 691         $PAGE->set_heading("$shortname: " . get_string('blog', 'blog'));
 692         $headers['heading'] = get_string('siteblog', 'blog', $shortname);
 693         // $headers['strview'] = get_string('viewsiteentries', 'blog');
 694     }
 695
 696     // Case 2: only entryid is requested, ignore all other filters. courseid is used to give more contextual information
 697     if (!empty($entryid)) {
 698         $headers['filters']['entry'] = $entryid;
 699         $sql = 'SELECT u.* FROM {user} u, {post} p WHERE p.id = ? AND p.userid = u.id';
 700         $user = $DB->get_record_sql($sql, array($entryid));
 701         $entry = $DB->get_record('post', array('id' => $entryid));
 702
 703         $blogurl->param('userid', $user->id);
 704
 705         if (!empty($course)) {
 706             $mycourseid = $course->id;
 707             $blogurl->param('courseid', $mycourseid);
 708         } else {
 709             $mycourseid = $site->id;
 710         }
 711         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 712
 713         $PAGE->navbar->add($strblogentries, $blogurl);
 714
 715         $blogurl->remove_params('userid');
 716         $PAGE->navbar->add($entry->subject, $blogurl);
 717         $PAGE->set_title("$shortname: " . fullname($user) . ": $entry->subject");
 718         $PAGE->set_heading("$shortname: " . fullname($user) . ": $entry->subject");
 719         $headers['heading'] = get_string('blogentrybyuser', 'blog', fullname($user));
 720
 721         // We ignore tag and search params
 722         if (empty($action) || !$CFG->useblogassociations) {
 723             $headers['url'] = $blogurl;
 724             return $headers;
 725         }
 726     }
 727
 728     // Case 3: A user's blog entries
 729     if (!empty($userid) && empty($entryid) && ((empty($courseid) && empty($modid)) || !$CFG->useblogassociations)) {
 730         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 731         $blogurl->param('userid', $userid);
 732         $PAGE->set_title("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 733         $PAGE->set_heading("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 734         $headers['heading'] = get_string('userblog', 'blog', fullname($user));
 735         $headers['strview'] = get_string('viewuserentries', 'blog', fullname($user));
 736
 737     } else
 738
 739     // Case 4: No blog associations, no userid
 740     if (!$CFG->useblogassociations && empty($userid) && !in_array($action, array('edit', 'add'))) {
 741         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 742         $PAGE->set_title("$shortname: " . get_string('blog', 'blog'));
 743         $PAGE->set_heading("$shortname: " . get_string('blog', 'blog'));
 744         $headers['heading'] = get_string('siteblog', 'blog', $shortname);
 745     } else
 746
 747     // Case 5: Blog entries associated with an activity by a specific user (courseid ignored)
 748     if (!empty($userid) && !empty($modid) && empty($entryid)) {
 749         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 750         $blogurl->param('userid', $userid);
 751         $blogurl->param('modid', $modid);
 752
 753         // Course module navigation is handled by build_navigation as the second param
 754         $headers['cm'] = $cm;
 755         $PAGE->navbar->add(fullname($user), "$CFG->wwwroot/user/view.php?id=$user->id");
 756         $PAGE->navbar->add($strblogentries, $blogurl);
 757
 758         $PAGE->set_title("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 759         $PAGE->set_heading("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 760
 761         $a = new stdClass();
 762         $a->user = fullname($user);
 763         $a->mod = $cm->name;
 764         $a->type = get_string('modulename', $cm->modname);
 765         $headers['heading'] = get_string('blogentriesbyuseraboutmodule', 'blog', $a);
 766         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 767         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 768     } else
 769
 770     // Case 6: Blog entries associated with a course by a specific user
 771     if (!empty($userid) && !empty($courseid) && empty($modid) && empty($entryid)) {
 772         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 773         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 774         $blogurl->param('userid', $userid);
 775         $blogurl->param('courseid', $courseid);
 776
 777         $PAGE->navbar->add($strblogentries, $blogurl);
 778
 779         $PAGE->set_title("$siteshortname: $courseshortname: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 780         $PAGE->set_heading("$siteshortname: $courseshortname: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 781
 782         $a = new stdClass();
 783         $a->user = fullname($user);
 784         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 785         $a->type = get_string('course');
 786         $headers['heading'] = get_string('blogentriesbyuseraboutcourse', 'blog', $a);
 787         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 788         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 789
 790         // Remove the userid from the URL to inform the blog_menu block correctly
 791         $blogurl->remove_params(array('userid'));
 792     } else
 793
 794     // Case 7: Blog entries by members of a group, associated with that group's course
 795     if (!empty($groupid) && empty($modid) && empty($entryid)) {
 796         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 797         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 798         $blogurl->param('courseid', $course->id);
 799
 800         $PAGE->navbar->add($strblogentries, $blogurl);
 801         $blogurl->remove_params(array('courseid'));
 802         $blogurl->param('groupid', $groupid);
 803         $PAGE->navbar->add($group->name, $blogurl);
 804
 805         $PAGE->set_title("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog') . ": $group->name");
 806         $PAGE->set_heading("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog') . ": $group->name");
 807
 808         $a = new stdClass();
 809         $a->group = $group->name;
 810         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 811         $a->type = get_string('course');
 812         $headers['heading'] = get_string('blogentriesbygroupaboutcourse', 'blog', $a);
 813         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 814         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 815     } else
 816
 817     // Case 8: Blog entries by members of a group, associated with an activity in that course
 818     if (!empty($groupid) && !empty($modid) && empty($entryid)) {
 819         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 820         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 821         $headers['cm'] = $cm;
 822         $blogurl->param('modid', $modid);
 823         $PAGE->navbar->add($strblogentries, $blogurl);
 824
 825         $blogurl->param('groupid', $groupid);
 826         $PAGE->navbar->add($group->name, $blogurl);
 827
 828         $PAGE->set_title("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog') . ": $group->name");
 829         $PAGE->set_heading("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog') . ": $group->name");
 830
 831         $a = new stdClass();
 832         $a->group = $group->name;
 833         $a->mod = $cm->name;
 834         $a->type = get_string('modulename', $cm->modname);
 835         $headers['heading'] = get_string('blogentriesbygroupaboutmodule', 'blog', $a);
 836         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 837         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 838
 839     } else
 840
 841     // Case 9: All blog entries associated with an activity
 842     if (!empty($modid) && empty($userid) && empty($groupid) && empty($entryid)) {
 843         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 844         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 845         $PAGE->set_cm($cm, $course);
 846         $blogurl->param('modid', $modid);
 847         $PAGE->navbar->add($strblogentries, $blogurl);
 848         $PAGE->set_title("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog'));
 849         $PAGE->set_heading("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog'));
 850         $headers['heading'] = get_string('blogentriesabout', 'blog', $cm->name);
 851         $a = new stdClass();
 852         $a->type = get_string('modulename', $cm->modname);
 853         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 854         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 855     } else
 856
 857     // Case 10: All blog entries associated with a course
 858     if (!empty($courseid) && empty($userid) && empty($groupid) && empty($modid) && empty($entryid)) {
 859         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 860         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 861         $blogurl->param('courseid', $courseid);
 862         $PAGE->navbar->add($strblogentries, $blogurl);
 863         $PAGE->set_title("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog'));
 864         $PAGE->set_heading("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog'));
 865         $a = new stdClass();
 866         $a->type = get_string('course');
 867         $headers['heading'] = get_string('blogentriesabout', 'blog', format_string($course->fullname, true, array('context' => context_course::instance($course->id))));
 868         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 869         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 870         $blogurl->remove_params(array('userid'));
 871     }
 872
 873     if (!in_array($action, array('edit', 'add'))) {
 874         // Append Tag info
 875         if (!empty($tagid)) {
 876             $headers['filters']['tag'] = $tagid;
 877             $blogurl->param('tagid', $tagid);
 878             $tagrec = $DB->get_record('tag', array('id'=>$tagid));
 879             $PAGE->navbar->add($tagrec->name, $blogurl);
 880         } elseif (!empty($tag)) {
 881             $blogurl->param('tag', $tag);
 882             $PAGE->navbar->add(get_string('tagparam', 'blog', $tag), $blogurl);
 883         }
 884
 885         // Append Search info
 886         if (!empty($search)) {
 887             $headers['filters']['search'] = $search;
 888             $blogurl->param('search', $search);
 889             $PAGE->navbar->add(get_string('searchterm', 'blog', $search), $blogurl->out());
 890         }
 891     }
 892
 893     // Append edit mode info
 894     if (!empty($action) && $action == 'add') {
 895
 896     } else if (!empty($action) && $action == 'edit') {
 897         $PAGE->navbar->add(get_string('editentry', 'blog'));
 898     }
 899
 900     if (empty($headers['url'])) {
 901         $headers['url'] = $blogurl;
 902     }
 903     return $headers;
 904 }
 905
 906 /**
 907  * Shortcut function for getting a count of blog entries associated with a course or a module
 908  * @param int $courseid The ID of the course
 909  * @param int $cmid The ID of the course_modules
 910  * @return string The number of associated entries
 911  */
 912 function blog_get_associated_count($courseid, $cmid=null) {
 913     global $DB;
 914     $context = context_course::instance($courseid);
 915     if ($cmid) {
 916         $context = context_module::instance($cmid);
 917     }
 918     return $DB->count_records('blog_association', array('contextid' => $context->id));
 919 }
 920
 921 /**
 922  * Running addtional permission check on plugin, for example, plugins
 923  * may have switch to turn on/off comments option, this callback will
 924  * affect UI display, not like pluginname_comment_validate only throw
 925  * exceptions.
 926  * Capability check has been done in comment->check_permissions(), we
 927  * don't need to do it again here.
 928  *
 929  * @package  core_blog
 930  * @category comment
 931  *
 932  * @param stdClass $comment_param {
 933  *              context  => context the context object
 934  *              courseid => int course id
 935  *              cm       => stdClass course module object
 936  *              commentarea => string comment area
 937  *              itemid      => int itemid
 938  * }
 939  * @return array
 940  */
 941 function blog_comment_permissions($comment_param) {
 942     return array('post'=>true, 'view'=>true);
 943 }
 944
 945 /**
 946  * Validate comment parameter before perform other comments actions
 947  *
 948  * @package  core_blog
 949  * @category comment
 950  *
 951  * @param stdClass $comment {
 952  *              context  => context the context object
 953  *              courseid => int course id
 954  *              cm       => stdClass course module object
 955  *              commentarea => string comment area
 956  *              itemid      => int itemid
 957  * }
 958  * @return boolean
 959  */
 960 function blog_comment_validate($comment_param) {
 961     global $DB;
 962     // validate comment itemid
 963     if (!$entry = $DB->get_record('post', array('id'=>$comment_param->itemid))) {
 964         throw new comment_exception('invalidcommentitemid');
 965     }
 966     // validate comment area
 967     if ($comment_param->commentarea != 'format_blog') {
 968         throw new comment_exception('invalidcommentarea');
 969     }
 970     // validation for comment deletion
 971     if (!empty($comment_param->commentid)) {
 972         if ($record = $DB->get_record('comments', array('id'=>$comment_param->commentid))) {
 973             if ($record->commentarea != 'format_blog') {
 974                 throw new comment_exception('invalidcommentarea');
 975             }
 976             if ($record->contextid != $comment_param->context->id) {
 977                 throw new comment_exception('invalidcontext');
 978             }
 979             if ($record->itemid != $comment_param->itemid) {
 980                 throw new comment_exception('invalidcommentitemid');
 981             }
 982         } else {
 983             throw new comment_exception('invalidcommentid');
 984         }
 985     }
 986     return true;
 987 }
 988
 989 /**
 990  * Return a list of page types
 991  * @param string $pagetype current page type
 992  * @param stdClass $parentcontext Block's parent context
 993  * @param stdClass $currentcontext Current context of block
 994  */
 995 function blog_page_type_list($pagetype, $parentcontext, $currentcontext) {
 996     return array(
 997         '*'=>get_string('page-x', 'pagetype'),
 998         'blog-*'=>get_string('page-blog-x', 'blog'),
 999         'blog-index'=>get_string('page-blog-index', 'blog'),
1000         'blog-edit'=>get_string('page-blog-edit', 'blog')
1001     );
1002 }