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', $sitecontext)) {
  77         return true; // Can manage all entries.
  78     }
  79
  80     // If blog is in draft state, then make sure user have proper capability.
  81     if ($blogentry && $blogentry->publishstate == 'draft' && !has_capability('moodle/blog:viewdrafts', $sitecontext)) {
  82         return false;  // Can not view draft of others.
  83     }
  84
  85     // If blog entry is not public, make sure user is logged in.
  86     if ($blogentry && $blogentry->publishstate != 'public' && !isloggedin()) {
  87         return false;
  88     }
  89
  90     // If blogentry is not passed or all above checks pass, then check capability based on system config.
  91     switch ($CFG->bloglevel) {
  92         case BLOG_GLOBAL_LEVEL:
  93             return true;
  94         break;
  95
  96         case BLOG_SITE_LEVEL:
  97             if (isloggedin()) { // Not logged in viewers forbidden.
  98                 return true;
  99             }
 100             return false;
 101         break;
 102
 103         case BLOG_USER_LEVEL:
 104         default:
 105             // If user is viewing other user blog, then user should have user:readuserblogs capability.
 106             $personalcontext = context_user::instance($targetuserid);
 107             return has_capability('moodle/user:readuserblogs', $personalcontext);
 108         break;
 109
 110     }
 111 }
 112
 113 /**
 114  * remove all associations for the blog entries of a particular user
 115  * @param int userid - id of user whose blog associations will be deleted
 116  */
 117 function blog_remove_associations_for_user($userid) {
 118     global $DB;
 119     throw new coding_exception('function blog_remove_associations_for_user() is not finished');
 120     /*
 121     $blogentries = blog_fetch_entries(array('user' => $userid), 'lasmodified DESC');
 122     foreach ($blogentries as $entry) {
 123         if (blog_user_can_edit_entry($entry)) {
 124             blog_remove_associations_for_entry($entry->id);
 125         }
 126     }
 127      */
 128 }
 129
 130 /**
 131  * remove all associations for the blog entries of a particular course
 132  * @param int courseid - id of user whose blog associations will be deleted
 133  */
 134 function blog_remove_associations_for_course($courseid) {
 135     global $DB;
 136     $context = context_course::instance($courseid);
 137     $DB->delete_records('blog_association', array('contextid' => $context->id));
 138 }
 139
 140 /**
 141  * Given a record in the {blog_external} table, checks the blog's URL
 142  * for new entries not yet copied into Moodle.
 143  * Also attempts to identify and remove deleted blog entries
 144  *
 145  * @param object $externalblog
 146  * @return boolean False if the Feed is invalid
 147  */
 148 function blog_sync_external_entries($externalblog) {
 149     global $CFG, $DB;
 150     require_once($CFG->libdir . '/simplepie/moodle_simplepie.php');
 151
 152     $rss = new moodle_simplepie();
 153     $rssfile = $rss->registry->create('File', array($externalblog->url));
 154     $filetest = $rss->registry->create('Locator', array($rssfile));
 155
 156     if (!$filetest->is_feed($rssfile)) {
 157         $externalblog->failedlastsync = 1;
 158         $DB->update_record('blog_external', $externalblog);
 159         return false;
 160     } else if (!empty($externalblog->failedlastsync)) {
 161         $externalblog->failedlastsync = 0;
 162         $DB->update_record('blog_external', $externalblog);
 163     }
 164
 165     $rss->set_feed_url($externalblog->url);
 166     $rss->init();
 167
 168     if (empty($rss->data)) {
 169         return null;
 170     }
 171     //used to identify blog posts that have been deleted from the source feed
 172     $oldesttimestamp = null;
 173     $uniquehashes = array();
 174
 175     foreach ($rss->get_items() as $entry) {
 176         // If filtertags are defined, use them to filter the entries by RSS category
 177         if (!empty($externalblog->filtertags)) {
 178             $containsfiltertag = false;
 179             $categories = $entry->get_categories();
 180             $filtertags = explode(',', $externalblog->filtertags);
 181             $filtertags = array_map('trim', $filtertags);
 182             $filtertags = array_map('strtolower', $filtertags);
 183
 184             foreach ($categories as $category) {
 185                 if (in_array(trim(strtolower($category->term)), $filtertags)) {
 186                     $containsfiltertag = true;
 187                 }
 188             }
 189
 190             if (!$containsfiltertag) {
 191                 continue;
 192             }
 193         }
 194
 195         $uniquehashes[] = $entry->get_permalink();
 196
 197         $newentry = new stdClass();
 198         $newentry->userid = $externalblog->userid;
 199         $newentry->module = 'blog_external';
 200         $newentry->content = $externalblog->id;
 201         $newentry->uniquehash = $entry->get_permalink();
 202         $newentry->publishstate = 'site';
 203         $newentry->format = FORMAT_HTML;
 204         // Clean subject of html, just in case
 205         $newentry->subject = clean_param($entry->get_title(), PARAM_TEXT);
 206         // Observe 128 max chars in DB
 207         // TODO: +1 to raise this to 255
 208         if (core_text::strlen($newentry->subject) > 128) {
 209             $newentry->subject = core_text::substr($newentry->subject, 0, 125) . '...';
 210         }
 211         $newentry->summary = $entry->get_description();
 212
 213         //used to decide whether to insert or update
 214         //uses enty permalink plus creation date if available
 215         $existingpostconditions = array('uniquehash' => $entry->get_permalink());
 216
 217         //our DB doesnt allow null creation or modified timestamps so check the external blog supplied one
 218         $entrydate = $entry->get_date('U');
 219         if (!empty($entrydate)) {
 220             $existingpostconditions['created'] = $entrydate;
 221         }
 222
 223         //the post ID or false if post not found in DB
 224         $postid = $DB->get_field('post', 'id', $existingpostconditions);
 225
 226         $timestamp = null;
 227         if (empty($entrydate)) {
 228             $timestamp = time();
 229         } else {
 230             $timestamp = $entrydate;
 231         }
 232
 233         //only set created if its a new post so we retain the original creation timestamp if the post is edited
 234         if ($postid === false) {
 235             $newentry->created = $timestamp;
 236         }
 237         $newentry->lastmodified = $timestamp;
 238
 239         if (empty($oldesttimestamp) || $timestamp < $oldesttimestamp) {
 240             //found an older post
 241             $oldesttimestamp = $timestamp;
 242         }
 243
 244         if (core_text::strlen($newentry->uniquehash) > 255) {
 245             // The URL for this item is too long for the field. Rather than add
 246             // the entry without the link we will skip straight over it.
 247             // RSS spec says recommended length 500, we use 255.
 248             debugging('External blog entry skipped because of oversized URL', DEBUG_DEVELOPER);
 249             continue;
 250         }
 251
 252         if ($postid === false) {
 253             $id = $DB->insert_record('post', $newentry);
 254
 255             // Set tags
 256             if ($tags = tag_get_tags_array('blog_external', $externalblog->id)) {
 257                 tag_set('post', $id, $tags);
 258             }
 259         } else {
 260             $newentry->id = $postid;
 261             $DB->update_record('post', $newentry);
 262         }
 263     }
 264
 265     // Look at the posts we have in the database to check if any of them have been deleted from the feed.
 266     // Only checking posts within the time frame returned by the rss feed. Older items may have been deleted or
 267     // may just not be returned anymore. We can't tell the difference so we leave older posts alone.
 268     $sql = "SELECT id, uniquehash
 269               FROM {post}
 270              WHERE module = 'blog_external'
 271                    AND " . $DB->sql_compare_text('content') . " = " . $DB->sql_compare_text(':blogid') . "
 272                    AND created > :ts";
 273     $dbposts = $DB->get_records_sql($sql, array('blogid' => $externalblog->id, 'ts' => $oldesttimestamp));
 274
 275     $todelete = array();
 276     foreach($dbposts as $dbpost) {
 277         if ( !in_array($dbpost->uniquehash, $uniquehashes) ) {
 278             $todelete[] = $dbpost->id;
 279         }
 280     }
 281     $DB->delete_records_list('post', 'id', $todelete);
 282
 283     $DB->update_record('blog_external', array('id' => $externalblog->id, 'timefetched' => time()));
 284 }
 285
 286 /**
 287  * Given an external blog object, deletes all related blog entries from the post table.
 288  * NOTE: The external blog's id is saved as post.content, a field that is not oterhwise used by blog entries.
 289  * @param object $externablog
 290  */
 291 function blog_delete_external_entries($externalblog) {
 292     global $DB;
 293     require_capability('moodle/blog:manageexternal', context_system::instance());
 294     $DB->delete_records_select('post',
 295                                "module='blog_external' AND " . $DB->sql_compare_text('content') . " = ?",
 296                                array($externalblog->id));
 297 }
 298
 299 /**
 300  * This function checks that blogs are enabled, and that the user can see blogs at all
 301  * @return bool
 302  */
 303 function blog_is_enabled_for_user() {
 304     global $CFG;
 305     return (!empty($CFG->enableblogs) && (isloggedin() || ($CFG->bloglevel == BLOG_GLOBAL_LEVEL)));
 306 }
 307
 308 /**
 309  * This function gets all of the options available for the current user in respect
 310  * to blogs.
 311  *
 312  * It loads the following if applicable:
 313  * -  Module options {@see blog_get_options_for_module}
 314  * -  Course options {@see blog_get_options_for_course}
 315  * -  User specific options {@see blog_get_options_for_user}
 316  * -  General options (BLOG_LEVEL_GLOBAL)
 317  *
 318  * @param moodle_page $page The page to load for (normally $PAGE)
 319  * @param stdClass $userid Load for a specific user
 320  * @return array An array of options organised by type.
 321  */
 322 function blog_get_all_options(moodle_page $page, stdClass $userid = null) {
 323     global $CFG, $DB, $USER;
 324
 325     $options = array();
 326
 327     // If blogs are enabled and the user is logged in and not a guest
 328     if (blog_is_enabled_for_user()) {
 329         // If the context is the user then assume we want to load for the users context
 330         if (is_null($userid) && $page->context->contextlevel == CONTEXT_USER) {
 331             $userid = $page->context->instanceid;
 332         }
 333         // Check the userid var
 334         if (!is_null($userid) && $userid!==$USER->id) {
 335             // Load the user from the userid... it MUST EXIST throw a wobbly if it doesn't!
 336             $user = $DB->get_record('user', array('id'=>$userid), '*', MUST_EXIST);
 337         } else {
 338             $user = null;
 339         }
 340
 341         if ($CFG->useblogassociations && $page->cm !== null) {
 342             // Load for the module associated with the page
 343             $options[CONTEXT_MODULE] = blog_get_options_for_module($page->cm, $user);
 344         } else if ($CFG->useblogassociations && $page->course->id != SITEID) {
 345             // Load the options for the course associated with the page
 346             $options[CONTEXT_COURSE] = blog_get_options_for_course($page->course, $user);
 347         }
 348
 349         // Get the options for the user
 350         if ($user !== null and !isguestuser($user)) {
 351             // Load for the requested user
 352             $options[CONTEXT_USER+1] = blog_get_options_for_user($user);
 353         }
 354         // Load for the current user
 355         if (isloggedin() and !isguestuser()) {
 356             $options[CONTEXT_USER] = blog_get_options_for_user();
 357         }
 358     }
 359
 360     // If blog level is global then display a link to view all site entries
 361     if (!empty($CFG->enableblogs) && $CFG->bloglevel >= BLOG_GLOBAL_LEVEL && has_capability('moodle/blog:view', context_system::instance())) {
 362         $options[CONTEXT_SYSTEM] = array('viewsite' => array(
 363             'string' => get_string('viewsiteentries', 'blog'),
 364             'link' => new moodle_url('/blog/index.php')
 365         ));
 366     }
 367
 368     // Return the options
 369     return $options;
 370 }
 371
 372 /**
 373  * Get all of the blog options that relate to the passed user.
 374  *
 375  * If no user is passed the current user is assumed.
 376  *
 377  * @staticvar array $useroptions Cache so we don't have to regenerate multiple times
 378  * @param stdClass $user
 379  * @return array The array of options for the requested user
 380  */
 381 function blog_get_options_for_user(stdClass $user=null) {
 382     global $CFG, $USER;
 383     // Cache
 384     static $useroptions = array();
 385
 386     $options = array();
 387     // Blogs must be enabled and the user must be logged in
 388     if (!blog_is_enabled_for_user()) {
 389         return $options;
 390     }
 391
 392     // Sort out the user var
 393     if ($user === null || $user->id == $USER->id) {
 394         $user = $USER;
 395         $iscurrentuser = true;
 396     } else {
 397         $iscurrentuser = false;
 398     }
 399
 400     // If we've already generated serve from the cache
 401     if (array_key_exists($user->id, $useroptions)) {
 402         return $useroptions[$user->id];
 403     }
 404
 405     $sitecontext = context_system::instance();
 406     $canview = has_capability('moodle/blog:view', $sitecontext);
 407
 408     if (!$iscurrentuser && $canview && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 409         // Not the current user, but we can view and its blogs are enabled for SITE or GLOBAL
 410         $options['userentries'] = array(
 411             'string' => get_string('viewuserentries', 'blog', fullname($user)),
 412             'link' => new moodle_url('/blog/index.php', array('userid'=>$user->id))
 413         );
 414     } else {
 415         // It's the current user
 416         if ($canview) {
 417             // We can view our own blogs .... BIG surprise
 418             $options['view'] = array(
 419                 'string' => get_string('viewallmyentries', 'blog'),
 420                 'link' => new moodle_url('/blog/index.php', array('userid'=>$USER->id))
 421             );
 422         }
 423         if (has_capability('moodle/blog:create', $sitecontext)) {
 424             // We can add to our own blog
 425             $options['add'] = array(
 426                 'string' => get_string('addnewentry', 'blog'),
 427                 'link' => new moodle_url('/blog/edit.php', array('action'=>'add'))
 428             );
 429         }
 430     }
 431     if ($canview && $CFG->enablerssfeeds) {
 432         $options['rss'] = array(
 433             'string' => get_string('rssfeed', 'blog'),
 434             'link' => new moodle_url(rss_get_url($sitecontext->id, $USER->id, 'blog', 'user/'.$user->id))
 435        );
 436     }
 437
 438     // Cache the options
 439     $useroptions[$user->id] = $options;
 440     // Return the options
 441     return $options;
 442 }
 443
 444 /**
 445  * Get the blog options that relate to the given course for the given user.
 446  *
 447  * @staticvar array $courseoptions A cache so we can save regenerating multiple times
 448  * @param stdClass $course The course to load options for
 449  * @param stdClass $user The user to load options for null == current user
 450  * @return array The array of options
 451  */
 452 function blog_get_options_for_course(stdClass $course, stdClass $user=null) {
 453     global $CFG, $USER;
 454     // Cache
 455     static $courseoptions = array();
 456
 457     $options = array();
 458
 459     // User must be logged in and blogs must be enabled
 460     if (!blog_is_enabled_for_user()) {
 461         return $options;
 462     }
 463
 464     // Check that the user can associate with the course
 465     $sitecontext = context_system::instance();
 466     // Generate the cache key
 467     $key = $course->id.':';
 468     if (!empty($user)) {
 469         $key .= $user->id;
 470     } else {
 471         $key .= $USER->id;
 472     }
 473     // Serve from the cache if we've already generated for this course
 474     if (array_key_exists($key, $courseoptions)) {
 475         return $courseoptions[$key];
 476     }
 477
 478
 479     if (has_capability('moodle/blog:view', $sitecontext)) {
 480         // We can view!
 481         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 482             // View entries about this course
 483             $options['courseview'] = array(
 484                 'string' => get_string('viewcourseblogs', 'blog'),
 485                 'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id))
 486             );
 487         }
 488         // View MY entries about this course
 489         $options['courseviewmine'] = array(
 490             'string' => get_string('viewmyentriesaboutcourse', 'blog'),
 491             'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $USER->id))
 492         );
 493         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 494             // View the provided users entries about this course
 495             $options['courseviewuser'] = array(
 496                 'string' => get_string('viewentriesbyuseraboutcourse', 'blog', fullname($user)),
 497                 'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $user->id))
 498             );
 499         }
 500     }
 501
 502     if (has_capability('moodle/blog:create', $sitecontext)) {
 503         // We can blog about this course
 504         $options['courseadd'] = array(
 505             'string' => get_string('blogaboutthiscourse', 'blog'),
 506             'link' => new moodle_url('/blog/edit.php', array('action' => 'add', 'courseid' => $course->id))
 507         );
 508     }
 509
 510
 511     // Cache the options for this course
 512     $courseoptions[$key] = $options;
 513     // Return the options
 514     return $options;
 515 }
 516
 517 /**
 518  * Get the blog options relating to the given module for the given user
 519  *
 520  * @staticvar array $moduleoptions Cache
 521  * @param stdClass|cm_info $module The module to get options for
 522  * @param stdClass $user The user to get options for null == currentuser
 523  * @return array
 524  */
 525 function blog_get_options_for_module($module, $user=null) {
 526     global $CFG, $USER;
 527     // Cache
 528     static $moduleoptions = array();
 529
 530     $options = array();
 531     // User must be logged in, blogs must be enabled
 532     if (!blog_is_enabled_for_user()) {
 533         return $options;
 534     }
 535
 536     $sitecontext = context_system::instance();
 537
 538     // Generate the cache key
 539     $key = $module->id.':';
 540     if (!empty($user)) {
 541         $key .= $user->id;
 542     } else {
 543         $key .= $USER->id;
 544     }
 545     if (array_key_exists($key, $moduleoptions)) {
 546         // Serve from the cache so we don't have to regenerate
 547         return $moduleoptions[$key];
 548     }
 549
 550
 551     if (has_capability('moodle/blog:view', $sitecontext)) {
 552         // Save correct module name for later usage.
 553         $modulename = get_string('modulename', $module->modname);
 554
 555         // We can view!
 556         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 557             // View all entries about this module
 558             $a = new stdClass;
 559             $a->type = $modulename;
 560             $options['moduleview'] = array(
 561                 'string' => get_string('viewallmodentries', 'blog', $a),
 562                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id))
 563             );
 564         }
 565         // View MY entries about this module
 566         $options['moduleviewmine'] = array(
 567             'string' => get_string('viewmyentriesaboutmodule', 'blog', $modulename),
 568             'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$USER->id))
 569         );
 570         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 571             // View the given users entries about this module
 572             $a = new stdClass;
 573             $a->mod = $modulename;
 574             $a->user = fullname($user);
 575             $options['moduleviewuser'] = array(
 576                 'string' => get_string('blogentriesbyuseraboutmodule', 'blog', $a),
 577                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$user->id))
 578             );
 579         }
 580     }
 581
 582     if (has_capability('moodle/blog:create', $sitecontext)) {
 583         // The user can blog about this module
 584         $options['moduleadd'] = array(
 585             'string' => get_string('blogaboutthismodule', 'blog', $modulename),
 586             'link' => new moodle_url('/blog/edit.php', array('action'=>'add', 'modid'=>$module->id))
 587         );
 588     }
 589     // Cache the options
 590     $moduleoptions[$key] = $options;
 591     // Return the options
 592     return $options;
 593 }
 594
 595 /**
 596  * This function encapsulates all the logic behind the complex
 597  * navigation, titles and headings of the blog listing page, depending
 598  * on URL params. It looks at URL params and at the current context level.
 599  * It builds and returns an array containing:
 600  *
 601  * 1. heading: The heading displayed above the blog entries
 602  * 2. stradd:  The text to be used as the "Add entry" link
 603  * 3. strview: The text to be used as the "View entries" link
 604  * 4. url:     The moodle_url object used as the base for add and view links
 605  * 5. filters: An array of parameters used to filter blog listings. Used by index.php and the Recent blogs block
 606  *
 607  * All other variables are set directly in $PAGE
 608  *
 609  * It uses the current URL to build these variables.
 610  * A number of mutually exclusive use cases are used to structure this function.
 611  *
 612  * @return array
 613  */
 614 function blog_get_headers($courseid=null, $groupid=null, $userid=null, $tagid=null) {
 615     global $CFG, $PAGE, $DB, $USER;
 616
 617     $id       = optional_param('id', null, PARAM_INT);
 618     $tag      = optional_param('tag', null, PARAM_NOTAGS);
 619     $tagid    = optional_param('tagid', $tagid, PARAM_INT);
 620     $userid   = optional_param('userid', $userid, PARAM_INT);
 621     $modid    = optional_param('modid', null, PARAM_INT);
 622     $entryid  = optional_param('entryid', null, PARAM_INT);
 623     $groupid  = optional_param('groupid', $groupid, PARAM_INT);
 624     $courseid = optional_param('courseid', $courseid, PARAM_INT);
 625     $search   = optional_param('search', null, PARAM_RAW);
 626     $action   = optional_param('action', null, PARAM_ALPHA);
 627     $confirm  = optional_param('confirm', false, PARAM_BOOL);
 628
 629     // Ignore userid when action == add
 630     if ($action == 'add' && $userid) {
 631         unset($userid);
 632         $PAGE->url->remove_params(array('userid'));
 633     } else if ($action == 'add' && $entryid) {
 634         unset($entryid);
 635         $PAGE->url->remove_params(array('entryid'));
 636     }
 637
 638     $headers = array('title' => '', 'heading' => '', 'cm' => null, 'filters' => array());
 639
 640     $blogurl = new moodle_url('/blog/index.php');
 641
 642     $headers['stradd'] = get_string('addnewentry', 'blog');
 643     $headers['strview'] = null;
 644
 645     $site = $DB->get_record('course', array('id' => SITEID));
 646     $sitecontext = context_system::instance();
 647     // Common Lang strings
 648     $strparticipants = get_string("participants");
 649     $strblogentries  = get_string("blogentries", 'blog');
 650
 651     // Prepare record objects as needed
 652     if (!empty($courseid)) {
 653         $headers['filters']['course'] = $courseid;
 654         $course = $DB->get_record('course', array('id' => $courseid));
 655     }
 656
 657     if (!empty($userid)) {
 658         $headers['filters']['user'] = $userid;
 659         $user = $DB->get_record('user', array('id' => $userid));
 660     }
 661
 662     if (!empty($groupid)) { // groupid always overrides courseid
 663         $headers['filters']['group'] = $groupid;
 664         $group = $DB->get_record('groups', array('id' => $groupid));
 665         $course = $DB->get_record('course', array('id' => $group->courseid));
 666     }
 667
 668     $PAGE->set_pagelayout('standard');
 669
 670     // modid always overrides courseid, so the $course object may be reset here
 671     if (!empty($modid) && $CFG->useblogassociations) {
 672
 673         $headers['filters']['module'] = $modid;
 674         // A groupid param may conflict with this coursemod's courseid. Ignore groupid in that case
 675         $courseid = $DB->get_field('course_modules', 'course', array('id'=>$modid));
 676         $course = $DB->get_record('course', array('id' => $courseid));
 677         $cm = $DB->get_record('course_modules', array('id' => $modid));
 678         $cm->modname = $DB->get_field('modules', 'name', array('id' => $cm->module));
 679         $cm->name = $DB->get_field($cm->modname, 'name', array('id' => $cm->instance));
 680         $a = new stdClass();
 681         $a->type = get_string('modulename', $cm->modname);
 682         $PAGE->set_cm($cm, $course);
 683         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 684         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 685     }
 686
 687     // Case 1: No entry, mod, course or user params: all site entries to be shown (filtered by search and tag/tagid)
 688     // Note: if action is set to 'add' or 'edit', we do this at the end
 689     if (empty($entryid) && empty($modid) && empty($courseid) && empty($userid) && !in_array($action, array('edit', 'add'))) {
 690         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 691         $PAGE->navbar->add($strblogentries, $blogurl);
 692         $PAGE->set_title("$shortname: " . get_string('blog', 'blog'));
 693         $PAGE->set_heading("$shortname: " . get_string('blog', 'blog'));
 694         $headers['heading'] = get_string('siteblog', 'blog', $shortname);
 695         // $headers['strview'] = get_string('viewsiteentries', 'blog');
 696     }
 697
 698     // Case 2: only entryid is requested, ignore all other filters. courseid is used to give more contextual information
 699     if (!empty($entryid)) {
 700         $headers['filters']['entry'] = $entryid;
 701         $sql = 'SELECT u.* FROM {user} u, {post} p WHERE p.id = ? AND p.userid = u.id';
 702         $user = $DB->get_record_sql($sql, array($entryid));
 703         $entry = $DB->get_record('post', array('id' => $entryid));
 704
 705         $blogurl->param('userid', $user->id);
 706
 707         if (!empty($course)) {
 708             $mycourseid = $course->id;
 709             $blogurl->param('courseid', $mycourseid);
 710         } else {
 711             $mycourseid = $site->id;
 712         }
 713         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 714
 715         $PAGE->navbar->add($strblogentries, $blogurl);
 716
 717         $blogurl->remove_params('userid');
 718         $PAGE->navbar->add($entry->subject, $blogurl);
 719         $PAGE->set_title("$shortname: " . fullname($user) . ": $entry->subject");
 720         $PAGE->set_heading("$shortname: " . fullname($user) . ": $entry->subject");
 721         $headers['heading'] = get_string('blogentrybyuser', 'blog', fullname($user));
 722
 723         // We ignore tag and search params
 724         if (empty($action) || !$CFG->useblogassociations) {
 725             $headers['url'] = $blogurl;
 726             return $headers;
 727         }
 728     }
 729
 730     // Case 3: A user's blog entries
 731     if (!empty($userid) && empty($entryid) && ((empty($courseid) && empty($modid)) || !$CFG->useblogassociations)) {
 732         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 733         $blogurl->param('userid', $userid);
 734         $PAGE->set_title("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 735         $PAGE->set_heading("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 736         $headers['heading'] = get_string('userblog', 'blog', fullname($user));
 737         $headers['strview'] = get_string('viewuserentries', 'blog', fullname($user));
 738
 739     } else
 740
 741     // Case 4: No blog associations, no userid
 742     if (!$CFG->useblogassociations && empty($userid) && !in_array($action, array('edit', 'add'))) {
 743         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 744         $PAGE->set_title("$shortname: " . get_string('blog', 'blog'));
 745         $PAGE->set_heading("$shortname: " . get_string('blog', 'blog'));
 746         $headers['heading'] = get_string('siteblog', 'blog', $shortname);
 747     } else
 748
 749     // Case 5: Blog entries associated with an activity by a specific user (courseid ignored)
 750     if (!empty($userid) && !empty($modid) && empty($entryid)) {
 751         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 752         $blogurl->param('userid', $userid);
 753         $blogurl->param('modid', $modid);
 754
 755         // Course module navigation is handled by build_navigation as the second param
 756         $headers['cm'] = $cm;
 757         $PAGE->navbar->add(fullname($user), "$CFG->wwwroot/user/view.php?id=$user->id");
 758         $PAGE->navbar->add($strblogentries, $blogurl);
 759
 760         $PAGE->set_title("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 761         $PAGE->set_heading("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 762
 763         $a = new stdClass();
 764         $a->user = fullname($user);
 765         $a->mod = $cm->name;
 766         $a->type = get_string('modulename', $cm->modname);
 767         $headers['heading'] = get_string('blogentriesbyuseraboutmodule', 'blog', $a);
 768         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 769         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 770     } else
 771
 772     // Case 6: Blog entries associated with a course by a specific user
 773     if (!empty($userid) && !empty($courseid) && empty($modid) && empty($entryid)) {
 774         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 775         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 776         $blogurl->param('userid', $userid);
 777         $blogurl->param('courseid', $courseid);
 778
 779         $PAGE->navbar->add($strblogentries, $blogurl);
 780
 781         $PAGE->set_title("$siteshortname: $courseshortname: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 782         $PAGE->set_heading("$siteshortname: $courseshortname: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 783
 784         $a = new stdClass();
 785         $a->user = fullname($user);
 786         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 787         $a->type = get_string('course');
 788         $headers['heading'] = get_string('blogentriesbyuseraboutcourse', 'blog', $a);
 789         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 790         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 791
 792         // Remove the userid from the URL to inform the blog_menu block correctly
 793         $blogurl->remove_params(array('userid'));
 794     } else
 795
 796     // Case 7: Blog entries by members of a group, associated with that group's course
 797     if (!empty($groupid) && empty($modid) && empty($entryid)) {
 798         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 799         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 800         $blogurl->param('courseid', $course->id);
 801
 802         $PAGE->navbar->add($strblogentries, $blogurl);
 803         $blogurl->remove_params(array('courseid'));
 804         $blogurl->param('groupid', $groupid);
 805         $PAGE->navbar->add($group->name, $blogurl);
 806
 807         $PAGE->set_title("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog') . ": $group->name");
 808         $PAGE->set_heading("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog') . ": $group->name");
 809
 810         $a = new stdClass();
 811         $a->group = $group->name;
 812         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 813         $a->type = get_string('course');
 814         $headers['heading'] = get_string('blogentriesbygroupaboutcourse', 'blog', $a);
 815         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 816         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 817     } else
 818
 819     // Case 8: Blog entries by members of a group, associated with an activity in that course
 820     if (!empty($groupid) && !empty($modid) && empty($entryid)) {
 821         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 822         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 823         $headers['cm'] = $cm;
 824         $blogurl->param('modid', $modid);
 825         $PAGE->navbar->add($strblogentries, $blogurl);
 826
 827         $blogurl->param('groupid', $groupid);
 828         $PAGE->navbar->add($group->name, $blogurl);
 829
 830         $PAGE->set_title("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog') . ": $group->name");
 831         $PAGE->set_heading("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog') . ": $group->name");
 832
 833         $a = new stdClass();
 834         $a->group = $group->name;
 835         $a->mod = $cm->name;
 836         $a->type = get_string('modulename', $cm->modname);
 837         $headers['heading'] = get_string('blogentriesbygroupaboutmodule', 'blog', $a);
 838         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 839         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 840
 841     } else
 842
 843     // Case 9: All blog entries associated with an activity
 844     if (!empty($modid) && empty($userid) && empty($groupid) && empty($entryid)) {
 845         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 846         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 847         $PAGE->set_cm($cm, $course);
 848         $blogurl->param('modid', $modid);
 849         $PAGE->navbar->add($strblogentries, $blogurl);
 850         $PAGE->set_title("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog'));
 851         $PAGE->set_heading("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog'));
 852         $headers['heading'] = get_string('blogentriesabout', 'blog', $cm->name);
 853         $a = new stdClass();
 854         $a->type = get_string('modulename', $cm->modname);
 855         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 856         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 857     } else
 858
 859     // Case 10: All blog entries associated with a course
 860     if (!empty($courseid) && empty($userid) && empty($groupid) && empty($modid) && empty($entryid)) {
 861         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 862         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 863         $blogurl->param('courseid', $courseid);
 864         $PAGE->navbar->add($strblogentries, $blogurl);
 865         $PAGE->set_title("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog'));
 866         $PAGE->set_heading("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog'));
 867         $a = new stdClass();
 868         $a->type = get_string('course');
 869         $headers['heading'] = get_string('blogentriesabout', 'blog', format_string($course->fullname, true, array('context' => context_course::instance($course->id))));
 870         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 871         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 872         $blogurl->remove_params(array('userid'));
 873     }
 874
 875     if (!in_array($action, array('edit', 'add'))) {
 876         // Append Tag info
 877         if (!empty($tagid)) {
 878             $headers['filters']['tag'] = $tagid;
 879             $blogurl->param('tagid', $tagid);
 880             $tagrec = $DB->get_record('tag', array('id'=>$tagid));
 881             $PAGE->navbar->add($tagrec->name, $blogurl);
 882         } elseif (!empty($tag)) {
 883             $blogurl->param('tag', $tag);
 884             $PAGE->navbar->add(get_string('tagparam', 'blog', $tag), $blogurl);
 885         }
 886
 887         // Append Search info
 888         if (!empty($search)) {
 889             $headers['filters']['search'] = $search;
 890             $blogurl->param('search', $search);
 891             $PAGE->navbar->add(get_string('searchterm', 'blog', $search), $blogurl->out());
 892         }
 893     }
 894
 895     // Append edit mode info
 896     if (!empty($action) && $action == 'add') {
 897
 898     } else if (!empty($action) && $action == 'edit') {
 899         $PAGE->navbar->add(get_string('editentry', 'blog'));
 900     }
 901
 902     if (empty($headers['url'])) {
 903         $headers['url'] = $blogurl;
 904     }
 905     return $headers;
 906 }
 907
 908 /**
 909  * Shortcut function for getting a count of blog entries associated with a course or a module
 910  * @param int $courseid The ID of the course
 911  * @param int $cmid The ID of the course_modules
 912  * @return string The number of associated entries
 913  */
 914 function blog_get_associated_count($courseid, $cmid=null) {
 915     global $DB;
 916     $context = context_course::instance($courseid);
 917     if ($cmid) {
 918         $context = context_module::instance($cmid);
 919     }
 920     return $DB->count_records('blog_association', array('contextid' => $context->id));
 921 }
 922
 923 /**
 924  * Running addtional permission check on plugin, for example, plugins
 925  * may have switch to turn on/off comments option, this callback will
 926  * affect UI display, not like pluginname_comment_validate only throw
 927  * exceptions.
 928  * blog_comment_validate will be called before viewing/adding/deleting
 929  * comment, so don't repeat checks.
 930  * Capability check has been done in comment->check_permissions(), we
 931  * don't need to do it again here.
 932  *
 933  * @package  core_blog
 934  * @category comment
 935  *
 936  * @param stdClass $comment_param {
 937  *              context  => context the context object
 938  *              courseid => int course id
 939  *              cm       => stdClass course module object
 940  *              commentarea => string comment area
 941  *              itemid      => int itemid
 942  * }
 943  * @return array
 944  */
 945 function blog_comment_permissions($comment_param) {
 946     global $DB;
 947
 948     // If blog is public and current user is guest, then don't let him post comments.
 949     $blogentry = $DB->get_record('post', array('id' => $comment_param->itemid), 'publishstate', MUST_EXIST);
 950
 951     if ($blogentry->publishstate != 'public') {
 952         if (!isloggedin() || isguestuser()) {
 953             return array('post' => false, 'view' => true);
 954         }
 955     }
 956     return array('post' => true, 'view' => true);
 957 }
 958
 959 /**
 960  * Validate comment parameter before perform other comments actions
 961  *
 962  * @package  core_blog
 963  * @category comment
 964  *
 965  * @param stdClass $comment {
 966  *              context  => context the context object
 967  *              courseid => int course id
 968  *              cm       => stdClass course module object
 969  *              commentarea => string comment area
 970  *              itemid      => int itemid
 971  * }
 972  * @return boolean
 973  */
 974 function blog_comment_validate($comment_param) {
 975     global $CFG, $DB, $USER;
 976
 977     // Check if blogs are enabled user can comment.
 978     if (empty($CFG->enableblogs) || empty($CFG->blogusecomments)) {
 979         throw new comment_exception('nopermissiontocomment');
 980     }
 981
 982     // Validate comment area.
 983     if ($comment_param->commentarea != 'format_blog') {
 984         throw new comment_exception('invalidcommentarea');
 985     }
 986
 987     $blogentry = $DB->get_record('post', array('id' => $comment_param->itemid), '*', MUST_EXIST);
 988
 989     // Validation for comment deletion.
 990     if (!empty($comment_param->commentid)) {
 991         if ($record = $DB->get_record('comments', array('id'=>$comment_param->commentid))) {
 992             if ($record->commentarea != 'format_blog') {
 993                 throw new comment_exception('invalidcommentarea');
 994             }
 995             if ($record->contextid != $comment_param->context->id) {
 996                 throw new comment_exception('invalidcontext');
 997             }
 998             if ($record->itemid != $comment_param->itemid) {
 999                 throw new comment_exception('invalidcommentitemid');
1000             }
1001         } else {
1002             throw new comment_exception('invalidcommentid');
1003         }
1004     }
1005
1006     // Validate if user has blog view permission.
1007     $sitecontext = context_system::instance();
1008     return has_capability('moodle/blog:view', $sitecontext) &&
1009             blog_user_can_view_user_entry($blogentry->userid, $blogentry);
1010 }
1011
1012 /**
1013  * Return a list of page types
1014  * @param string $pagetype current page type
1015  * @param stdClass $parentcontext Block's parent context
1016  * @param stdClass $currentcontext Current context of block
1017  */
1018 function blog_page_type_list($pagetype, $parentcontext, $currentcontext) {
1019     return array(
1020         '*'=>get_string('page-x', 'pagetype'),
1021         'blog-*'=>get_string('page-blog-x', 'blog'),
1022         'blog-index'=>get_string('page-blog-index', 'blog'),
1023         'blog-edit'=>get_string('page-blog-edit', 'blog')
1024     );
1025 }