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     $rssfile = new moodle_simplepie_file($externalblog->url);
 153     $filetest = new SimplePie_Locator($rssfile);
 154
 155     if (!$filetest->is_feed($rssfile)) {
 156         $externalblog->failedlastsync = 1;
 157         $DB->update_record('blog_external', $externalblog);
 158         return false;
 159     } else if (!empty($externalblog->failedlastsync)) {
 160         $externalblog->failedlastsync = 0;
 161         $DB->update_record('blog_external', $externalblog);
 162     }
 163
 164     $rss = new moodle_simplepie($externalblog->url);
 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  * Returns a URL based on the context of the current page.
 299  * This URL points to blog/index.php and includes filter parameters appropriate for the current page.
 300  *
 301  * @param stdclass $context
 302  * @return string
 303  */
 304 function blog_get_context_url($context=null) {
 305     global $CFG;
 306
 307     $viewblogentriesurl = new moodle_url('/blog/index.php');
 308
 309     if (empty($context)) {
 310         global $PAGE;
 311         $context = $PAGE->context;
 312     }
 313
 314     // Change contextlevel to SYSTEM if viewing the site course
 315     if ($context->contextlevel == CONTEXT_COURSE && $context->instanceid == SITEID) {
 316         $context = context_system::instance();
 317     }
 318
 319     $filterparam = '';
 320     $strlevel = '';
 321
 322     switch ($context->contextlevel) {
 323         case CONTEXT_SYSTEM:
 324         case CONTEXT_BLOCK:
 325         case CONTEXT_COURSECAT:
 326             break;
 327         case CONTEXT_COURSE:
 328             $filterparam = 'courseid';
 329             $strlevel = get_string('course');
 330             break;
 331         case CONTEXT_MODULE:
 332             $filterparam = 'modid';
 333             $strlevel = print_context_name($context);
 334             break;
 335         case CONTEXT_USER:
 336             $filterparam = 'userid';
 337             $strlevel = get_string('user');
 338             break;
 339     }
 340
 341     if (!empty($filterparam)) {
 342         $viewblogentriesurl->param($filterparam, $context->instanceid);
 343     }
 344
 345     return $viewblogentriesurl;
 346 }
 347
 348 /**
 349  * This function checks that blogs are enabled, and that the user can see blogs at all
 350  * @return bool
 351  */
 352 function blog_is_enabled_for_user() {
 353     global $CFG;
 354     return (!empty($CFG->enableblogs) && (isloggedin() || ($CFG->bloglevel == BLOG_GLOBAL_LEVEL)));
 355 }
 356
 357 /**
 358  * This function gets all of the options available for the current user in respect
 359  * to blogs.
 360  *
 361  * It loads the following if applicable:
 362  * -  Module options {@see blog_get_options_for_module}
 363  * -  Course options {@see blog_get_options_for_course}
 364  * -  User specific options {@see blog_get_options_for_user}
 365  * -  General options (BLOG_LEVEL_GLOBAL)
 366  *
 367  * @param moodle_page $page The page to load for (normally $PAGE)
 368  * @param stdClass $userid Load for a specific user
 369  * @return array An array of options organised by type.
 370  */
 371 function blog_get_all_options(moodle_page $page, stdClass $userid = null) {
 372     global $CFG, $DB, $USER;
 373
 374     $options = array();
 375
 376     // If blogs are enabled and the user is logged in and not a guest
 377     if (blog_is_enabled_for_user()) {
 378         // If the context is the user then assume we want to load for the users context
 379         if (is_null($userid) && $page->context->contextlevel == CONTEXT_USER) {
 380             $userid = $page->context->instanceid;
 381         }
 382         // Check the userid var
 383         if (!is_null($userid) && $userid!==$USER->id) {
 384             // Load the user from the userid... it MUST EXIST throw a wobbly if it doesn't!
 385             $user = $DB->get_record('user', array('id'=>$userid), '*', MUST_EXIST);
 386         } else {
 387             $user = null;
 388         }
 389
 390         if ($CFG->useblogassociations && $page->cm !== null) {
 391             // Load for the module associated with the page
 392             $options[CONTEXT_MODULE] = blog_get_options_for_module($page->cm, $user);
 393         } else if ($CFG->useblogassociations && $page->course->id != SITEID) {
 394             // Load the options for the course associated with the page
 395             $options[CONTEXT_COURSE] = blog_get_options_for_course($page->course, $user);
 396         }
 397
 398         // Get the options for the user
 399         if ($user !== null and !isguestuser($user)) {
 400             // Load for the requested user
 401             $options[CONTEXT_USER+1] = blog_get_options_for_user($user);
 402         }
 403         // Load for the current user
 404         if (isloggedin() and !isguestuser()) {
 405             $options[CONTEXT_USER] = blog_get_options_for_user();
 406         }
 407     }
 408
 409     // If blog level is global then display a link to view all site entries
 410     if (!empty($CFG->enableblogs) && $CFG->bloglevel >= BLOG_GLOBAL_LEVEL && has_capability('moodle/blog:view', context_system::instance())) {
 411         $options[CONTEXT_SYSTEM] = array('viewsite' => array(
 412             'string' => get_string('viewsiteentries', 'blog'),
 413             'link' => new moodle_url('/blog/index.php')
 414         ));
 415     }
 416
 417     // Return the options
 418     return $options;
 419 }
 420
 421 /**
 422  * Get all of the blog options that relate to the passed user.
 423  *
 424  * If no user is passed the current user is assumed.
 425  *
 426  * @staticvar array $useroptions Cache so we don't have to regenerate multiple times
 427  * @param stdClass $user
 428  * @return array The array of options for the requested user
 429  */
 430 function blog_get_options_for_user(stdClass $user=null) {
 431     global $CFG, $USER;
 432     // Cache
 433     static $useroptions = array();
 434
 435     $options = array();
 436     // Blogs must be enabled and the user must be logged in
 437     if (!blog_is_enabled_for_user()) {
 438         return $options;
 439     }
 440
 441     // Sort out the user var
 442     if ($user === null || $user->id == $USER->id) {
 443         $user = $USER;
 444         $iscurrentuser = true;
 445     } else {
 446         $iscurrentuser = false;
 447     }
 448
 449     // If we've already generated serve from the cache
 450     if (array_key_exists($user->id, $useroptions)) {
 451         return $useroptions[$user->id];
 452     }
 453
 454     $sitecontext = context_system::instance();
 455     $canview = has_capability('moodle/blog:view', $sitecontext);
 456
 457     if (!$iscurrentuser && $canview && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 458         // Not the current user, but we can view and its blogs are enabled for SITE or GLOBAL
 459         $options['userentries'] = array(
 460             'string' => get_string('viewuserentries', 'blog', fullname($user)),
 461             'link' => new moodle_url('/blog/index.php', array('userid'=>$user->id))
 462         );
 463     } else {
 464         // It's the current user
 465         if ($canview) {
 466             // We can view our own blogs .... BIG surprise
 467             $options['view'] = array(
 468                 'string' => get_string('viewallmyentries', 'blog'),
 469                 'link' => new moodle_url('/blog/index.php', array('userid'=>$USER->id))
 470             );
 471         }
 472         if (has_capability('moodle/blog:create', $sitecontext)) {
 473             // We can add to our own blog
 474             $options['add'] = array(
 475                 'string' => get_string('addnewentry', 'blog'),
 476                 'link' => new moodle_url('/blog/edit.php', array('action'=>'add'))
 477             );
 478         }
 479     }
 480     if ($canview && $CFG->enablerssfeeds) {
 481         $options['rss'] = array(
 482             'string' => get_string('rssfeed', 'blog'),
 483             'link' => new moodle_url(rss_get_url($sitecontext->id, $USER->id, 'blog', 'user/'.$user->id))
 484        );
 485     }
 486
 487     // Cache the options
 488     $useroptions[$user->id] = $options;
 489     // Return the options
 490     return $options;
 491 }
 492
 493 /**
 494  * Get the blog options that relate to the given course for the given user.
 495  *
 496  * @staticvar array $courseoptions A cache so we can save regenerating multiple times
 497  * @param stdClass $course The course to load options for
 498  * @param stdClass $user The user to load options for null == current user
 499  * @return array The array of options
 500  */
 501 function blog_get_options_for_course(stdClass $course, stdClass $user=null) {
 502     global $CFG, $USER;
 503     // Cache
 504     static $courseoptions = array();
 505
 506     $options = array();
 507
 508     // User must be logged in and blogs must be enabled
 509     if (!blog_is_enabled_for_user()) {
 510         return $options;
 511     }
 512
 513     // Check that the user can associate with the course
 514     $sitecontext = context_system::instance();
 515     $coursecontext = context_course::instance($course->id);
 516     if (!has_capability('moodle/blog:associatecourse', $coursecontext)) {
 517         return $options;
 518     }
 519     // Generate the cache key
 520     $key = $course->id.':';
 521     if (!empty($user)) {
 522         $key .= $user->id;
 523     } else {
 524         $key .= $USER->id;
 525     }
 526     // Serve from the cache if we've already generated for this course
 527     if (array_key_exists($key, $courseoptions)) {
 528         return $courseoptions[$key];
 529     }
 530
 531     $canparticipate = (is_enrolled($coursecontext) or is_viewing($coursecontext));
 532
 533     if (has_capability('moodle/blog:view', $coursecontext)) {
 534         // We can view!
 535         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 536             // View entries about this course
 537             $options['courseview'] = array(
 538                 'string' => get_string('viewcourseblogs', 'blog'),
 539                 'link' => new moodle_url('/blog/index.php', array('courseid'=>$course->id))
 540             );
 541         }
 542         // View MY entries about this course
 543         $options['courseviewmine'] = array(
 544             'string' => get_string('viewmyentriesaboutcourse', 'blog'),
 545             'link' => new moodle_url('/blog/index.php', array('courseid'=>$course->id, 'userid'=>$USER->id))
 546         );
 547         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 548             // View the provided users entries about this course
 549             $options['courseviewuser'] = array(
 550                 'string' => get_string('viewentriesbyuseraboutcourse', 'blog', fullname($user)),
 551                 'link' => new moodle_url('/blog/index.php', array('courseid'=>$course->id, 'userid'=>$user->id))
 552             );
 553         }
 554     }
 555
 556     if (has_capability('moodle/blog:create', $sitecontext) and $canparticipate) {
 557         // We can blog about this course
 558         $options['courseadd'] = array(
 559             'string' => get_string('blogaboutthiscourse', 'blog'),
 560             'link' => new moodle_url('/blog/edit.php', array('action'=>'add', 'courseid'=>$course->id))
 561         );
 562     }
 563
 564
 565     // Cache the options for this course
 566     $courseoptions[$key] = $options;
 567     // Return the options
 568     return $options;
 569 }
 570
 571 /**
 572  * Get the blog options relating to the given module for the given user
 573  *
 574  * @staticvar array $moduleoptions Cache
 575  * @param stdClass|cm_info $module The module to get options for
 576  * @param stdClass $user The user to get options for null == currentuser
 577  * @return array
 578  */
 579 function blog_get_options_for_module($module, $user=null) {
 580     global $CFG, $USER;
 581     // Cache
 582     static $moduleoptions = array();
 583
 584     $options = array();
 585     // User must be logged in, blogs must be enabled
 586     if (!blog_is_enabled_for_user()) {
 587         return $options;
 588     }
 589
 590     // Check the user can associate with the module
 591     $modcontext = context_module::instance($module->id);
 592     $sitecontext = context_system::instance();
 593     if (!has_capability('moodle/blog:associatemodule', $modcontext)) {
 594         return $options;
 595     }
 596
 597     // Generate the cache key
 598     $key = $module->id.':';
 599     if (!empty($user)) {
 600         $key .= $user->id;
 601     } else {
 602         $key .= $USER->id;
 603     }
 604     if (array_key_exists($key, $moduleoptions)) {
 605         // Serve from the cache so we don't have to regenerate
 606         return $moduleoptions[$key];
 607     }
 608
 609     $canparticipate = (is_enrolled($modcontext) or is_viewing($modcontext));
 610
 611     if (has_capability('moodle/blog:view', $modcontext)) {
 612         // Save correct module name for later usage.
 613         $modulename = get_string('modulename', $module->modname);
 614
 615         // We can view!
 616         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 617             // View all entries about this module
 618             $a = new stdClass;
 619             $a->type = $modulename;
 620             $options['moduleview'] = array(
 621                 'string' => get_string('viewallmodentries', 'blog', $a),
 622                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id))
 623             );
 624         }
 625         // View MY entries about this module
 626         $options['moduleviewmine'] = array(
 627             'string' => get_string('viewmyentriesaboutmodule', 'blog', $modulename),
 628             'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$USER->id))
 629         );
 630         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 631             // View the given users entries about this module
 632             $a = new stdClass;
 633             $a->mod = $modulename;
 634             $a->user = fullname($user);
 635             $options['moduleviewuser'] = array(
 636                 'string' => get_string('blogentriesbyuseraboutmodule', 'blog', $a),
 637                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$user->id))
 638             );
 639         }
 640     }
 641
 642     if (has_capability('moodle/blog:create', $sitecontext) and $canparticipate) {
 643         // The user can blog about this module
 644         $options['moduleadd'] = array(
 645             'string' => get_string('blogaboutthismodule', 'blog', $modulename),
 646             'link' => new moodle_url('/blog/edit.php', array('action'=>'add', 'modid'=>$module->id))
 647         );
 648     }
 649     // Cache the options
 650     $moduleoptions[$key] = $options;
 651     // Return the options
 652     return $options;
 653 }
 654
 655 /**
 656  * This function encapsulates all the logic behind the complex
 657  * navigation, titles and headings of the blog listing page, depending
 658  * on URL params. It looks at URL params and at the current context level.
 659  * It builds and returns an array containing:
 660  *
 661  * 1. heading: The heading displayed above the blog entries
 662  * 2. stradd:  The text to be used as the "Add entry" link
 663  * 3. strview: The text to be used as the "View entries" link
 664  * 4. url:     The moodle_url object used as the base for add and view links
 665  * 5. filters: An array of parameters used to filter blog listings. Used by index.php and the Recent blogs block
 666  *
 667  * All other variables are set directly in $PAGE
 668  *
 669  * It uses the current URL to build these variables.
 670  * A number of mutually exclusive use cases are used to structure this function.
 671  *
 672  * @return array
 673  */
 674 function blog_get_headers($courseid=null, $groupid=null, $userid=null, $tagid=null) {
 675     global $CFG, $PAGE, $DB, $USER;
 676
 677     $id       = optional_param('id', null, PARAM_INT);
 678     $tag      = optional_param('tag', null, PARAM_NOTAGS);
 679     $tagid    = optional_param('tagid', $tagid, PARAM_INT);
 680     $userid   = optional_param('userid', $userid, PARAM_INT);
 681     $modid    = optional_param('modid', null, PARAM_INT);
 682     $entryid  = optional_param('entryid', null, PARAM_INT);
 683     $groupid  = optional_param('groupid', $groupid, PARAM_INT);
 684     $courseid = optional_param('courseid', $courseid, PARAM_INT);
 685     $search   = optional_param('search', null, PARAM_RAW);
 686     $action   = optional_param('action', null, PARAM_ALPHA);
 687     $confirm  = optional_param('confirm', false, PARAM_BOOL);
 688
 689     // Ignore userid when action == add
 690     if ($action == 'add' && $userid) {
 691         unset($userid);
 692         $PAGE->url->remove_params(array('userid'));
 693     } else if ($action == 'add' && $entryid) {
 694         unset($entryid);
 695         $PAGE->url->remove_params(array('entryid'));
 696     }
 697
 698     $headers = array('title' => '', 'heading' => '', 'cm' => null, 'filters' => array());
 699
 700     $blogurl = new moodle_url('/blog/index.php');
 701
 702     // If the title is not yet set, it's likely that the context isn't set either, so skip this part
 703     $pagetitle = $PAGE->title;
 704     if (!empty($pagetitle)) {
 705         $contexturl = blog_get_context_url();
 706
 707         // Look at the context URL, it may have additional params that are not in the current URL
 708         if (!$blogurl->compare($contexturl)) {
 709             $blogurl = $contexturl;
 710             if (empty($courseid)) {
 711                 $courseid = $blogurl->param('courseid');
 712             }
 713             if (empty($modid)) {
 714                 $modid = $blogurl->param('modid');
 715             }
 716         }
 717     }
 718
 719     $headers['stradd'] = get_string('addnewentry', 'blog');
 720     $headers['strview'] = null;
 721
 722     $site = $DB->get_record('course', array('id' => SITEID));
 723     $sitecontext = context_system::instance();
 724     // Common Lang strings
 725     $strparticipants = get_string("participants");
 726     $strblogentries  = get_string("blogentries", 'blog');
 727
 728     // Prepare record objects as needed
 729     if (!empty($courseid)) {
 730         $headers['filters']['course'] = $courseid;
 731         $course = $DB->get_record('course', array('id' => $courseid));
 732     }
 733
 734     if (!empty($userid)) {
 735         $headers['filters']['user'] = $userid;
 736         $user = $DB->get_record('user', array('id' => $userid));
 737     }
 738
 739     if (!empty($groupid)) { // groupid always overrides courseid
 740         $headers['filters']['group'] = $groupid;
 741         $group = $DB->get_record('groups', array('id' => $groupid));
 742         $course = $DB->get_record('course', array('id' => $group->courseid));
 743     }
 744
 745     $PAGE->set_pagelayout('standard');
 746
 747     // modid always overrides courseid, so the $course object may be reset here
 748     if (!empty($modid) && $CFG->useblogassociations) {
 749
 750         $headers['filters']['module'] = $modid;
 751         // A groupid param may conflict with this coursemod's courseid. Ignore groupid in that case
 752         $courseid = $DB->get_field('course_modules', 'course', array('id'=>$modid));
 753         $course = $DB->get_record('course', array('id' => $courseid));
 754         $cm = $DB->get_record('course_modules', array('id' => $modid));
 755         $cm->modname = $DB->get_field('modules', 'name', array('id' => $cm->module));
 756         $cm->name = $DB->get_field($cm->modname, 'name', array('id' => $cm->instance));
 757         $a = new stdClass();
 758         $a->type = get_string('modulename', $cm->modname);
 759         $PAGE->set_cm($cm, $course);
 760         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 761         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 762     }
 763
 764     // Case 1: No entry, mod, course or user params: all site entries to be shown (filtered by search and tag/tagid)
 765     // Note: if action is set to 'add' or 'edit', we do this at the end
 766     if (empty($entryid) && empty($modid) && empty($courseid) && empty($userid) && !in_array($action, array('edit', 'add'))) {
 767         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 768         $PAGE->navbar->add($strblogentries, $blogurl);
 769         $PAGE->set_title("$shortname: " . get_string('blog', 'blog'));
 770         $PAGE->set_heading("$shortname: " . get_string('blog', 'blog'));
 771         $headers['heading'] = get_string('siteblog', 'blog', $shortname);
 772         // $headers['strview'] = get_string('viewsiteentries', 'blog');
 773     }
 774
 775     // Case 2: only entryid is requested, ignore all other filters. courseid is used to give more contextual information
 776     if (!empty($entryid)) {
 777         $headers['filters']['entry'] = $entryid;
 778         $sql = 'SELECT u.* FROM {user} u, {post} p WHERE p.id = ? AND p.userid = u.id';
 779         $user = $DB->get_record_sql($sql, array($entryid));
 780         $entry = $DB->get_record('post', array('id' => $entryid));
 781
 782         $blogurl->param('userid', $user->id);
 783
 784         if (!empty($course)) {
 785             $mycourseid = $course->id;
 786             $blogurl->param('courseid', $mycourseid);
 787         } else {
 788             $mycourseid = $site->id;
 789         }
 790         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 791
 792         $PAGE->navbar->add($strblogentries, $blogurl);
 793
 794         $blogurl->remove_params('userid');
 795         $PAGE->navbar->add($entry->subject, $blogurl);
 796         $PAGE->set_title("$shortname: " . fullname($user) . ": $entry->subject");
 797         $PAGE->set_heading("$shortname: " . fullname($user) . ": $entry->subject");
 798         $headers['heading'] = get_string('blogentrybyuser', 'blog', fullname($user));
 799
 800         // We ignore tag and search params
 801         if (empty($action) || !$CFG->useblogassociations) {
 802             $headers['url'] = $blogurl;
 803             return $headers;
 804         }
 805     }
 806
 807     // Case 3: A user's blog entries
 808     if (!empty($userid) && empty($entryid) && ((empty($courseid) && empty($modid)) || !$CFG->useblogassociations)) {
 809         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 810         $blogurl->param('userid', $userid);
 811         $PAGE->set_title("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 812         $PAGE->set_heading("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
 813         $headers['heading'] = get_string('userblog', 'blog', fullname($user));
 814         $headers['strview'] = get_string('viewuserentries', 'blog', fullname($user));
 815
 816     } else
 817
 818     // Case 4: No blog associations, no userid
 819     if (!$CFG->useblogassociations && empty($userid) && !in_array($action, array('edit', 'add'))) {
 820         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 821         $PAGE->set_title("$shortname: " . get_string('blog', 'blog'));
 822         $PAGE->set_heading("$shortname: " . get_string('blog', 'blog'));
 823         $headers['heading'] = get_string('siteblog', 'blog', $shortname);
 824     } else
 825
 826     // Case 5: Blog entries associated with an activity by a specific user (courseid ignored)
 827     if (!empty($userid) && !empty($modid) && empty($entryid)) {
 828         $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 829         $blogurl->param('userid', $userid);
 830         $blogurl->param('modid', $modid);
 831
 832         // Course module navigation is handled by build_navigation as the second param
 833         $headers['cm'] = $cm;
 834         $PAGE->navbar->add(fullname($user), "$CFG->wwwroot/user/view.php?id=$user->id");
 835         $PAGE->navbar->add($strblogentries, $blogurl);
 836
 837         $PAGE->set_title("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 838         $PAGE->set_heading("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 839
 840         $a = new stdClass();
 841         $a->user = fullname($user);
 842         $a->mod = $cm->name;
 843         $a->type = get_string('modulename', $cm->modname);
 844         $headers['heading'] = get_string('blogentriesbyuseraboutmodule', 'blog', $a);
 845         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 846         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 847     } else
 848
 849     // Case 6: Blog entries associated with a course by a specific user
 850     if (!empty($userid) && !empty($courseid) && empty($modid) && empty($entryid)) {
 851         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 852         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 853         $blogurl->param('userid', $userid);
 854         $blogurl->param('courseid', $courseid);
 855
 856         $PAGE->navbar->add($strblogentries, $blogurl);
 857
 858         $PAGE->set_title("$siteshortname: $courseshortname: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 859         $PAGE->set_heading("$siteshortname: $courseshortname: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
 860
 861         $a = new stdClass();
 862         $a->user = fullname($user);
 863         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 864         $a->type = get_string('course');
 865         $headers['heading'] = get_string('blogentriesbyuseraboutcourse', 'blog', $a);
 866         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 867         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 868
 869         // Remove the userid from the URL to inform the blog_menu block correctly
 870         $blogurl->remove_params(array('userid'));
 871     } else
 872
 873     // Case 7: Blog entries by members of a group, associated with that group's course
 874     if (!empty($groupid) && empty($modid) && empty($entryid)) {
 875         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 876         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 877         $blogurl->param('courseid', $course->id);
 878
 879         $PAGE->navbar->add($strblogentries, $blogurl);
 880         $blogurl->remove_params(array('courseid'));
 881         $blogurl->param('groupid', $groupid);
 882         $PAGE->navbar->add($group->name, $blogurl);
 883
 884         $PAGE->set_title("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog') . ": $group->name");
 885         $PAGE->set_heading("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog') . ": $group->name");
 886
 887         $a = new stdClass();
 888         $a->group = $group->name;
 889         $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
 890         $a->type = get_string('course');
 891         $headers['heading'] = get_string('blogentriesbygroupaboutcourse', 'blog', $a);
 892         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 893         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 894     } else
 895
 896     // Case 8: Blog entries by members of a group, associated with an activity in that course
 897     if (!empty($groupid) && !empty($modid) && empty($entryid)) {
 898         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 899         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 900         $headers['cm'] = $cm;
 901         $blogurl->param('modid', $modid);
 902         $PAGE->navbar->add($strblogentries, $blogurl);
 903
 904         $blogurl->param('groupid', $groupid);
 905         $PAGE->navbar->add($group->name, $blogurl);
 906
 907         $PAGE->set_title("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog') . ": $group->name");
 908         $PAGE->set_heading("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog') . ": $group->name");
 909
 910         $a = new stdClass();
 911         $a->group = $group->name;
 912         $a->mod = $cm->name;
 913         $a->type = get_string('modulename', $cm->modname);
 914         $headers['heading'] = get_string('blogentriesbygroupaboutmodule', 'blog', $a);
 915         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 916         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 917
 918     } else
 919
 920     // Case 9: All blog entries associated with an activity
 921     if (!empty($modid) && empty($userid) && empty($groupid) && empty($entryid)) {
 922         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 923         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 924         $PAGE->set_cm($cm, $course);
 925         $blogurl->param('modid', $modid);
 926         $PAGE->navbar->add($strblogentries, $blogurl);
 927         $PAGE->set_title("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog'));
 928         $PAGE->set_heading("$siteshortname: $courseshortname: $cm->name: " . get_string('blogentries', 'blog'));
 929         $headers['heading'] = get_string('blogentriesabout', 'blog', $cm->name);
 930         $a = new stdClass();
 931         $a->type = get_string('modulename', $cm->modname);
 932         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 933         $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
 934     } else
 935
 936     // Case 10: All blog entries associated with a course
 937     if (!empty($courseid) && empty($userid) && empty($groupid) && empty($modid) && empty($entryid)) {
 938         $siteshortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
 939         $courseshortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
 940         $blogurl->param('courseid', $courseid);
 941         $PAGE->navbar->add($strblogentries, $blogurl);
 942         $PAGE->set_title("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog'));
 943         $PAGE->set_heading("$siteshortname: $courseshortname: " . get_string('blogentries', 'blog'));
 944         $a = new stdClass();
 945         $a->type = get_string('course');
 946         $headers['heading'] = get_string('blogentriesabout', 'blog', format_string($course->fullname, true, array('context' => context_course::instance($course->id))));
 947         $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
 948         $headers['strview'] = get_string('viewblogentries', 'blog', $a);
 949         $blogurl->remove_params(array('userid'));
 950     }
 951
 952     if (!in_array($action, array('edit', 'add'))) {
 953         // Append Tag info
 954         if (!empty($tagid)) {
 955             $headers['filters']['tag'] = $tagid;
 956             $blogurl->param('tagid', $tagid);
 957             $tagrec = $DB->get_record('tag', array('id'=>$tagid));
 958             $PAGE->navbar->add($tagrec->name, $blogurl);
 959         } elseif (!empty($tag)) {
 960             if ($tagrec = $DB->get_record('tag', array('name' => $tag))) {
 961                 $tagid = $tagrec->id;
 962                 $headers['filters']['tag'] = $tagid;
 963                 $blogurl->param('tag', $tag);
 964                 $PAGE->navbar->add(get_string('tagparam', 'blog', $tag), $blogurl);
 965             }
 966         }
 967
 968         // Append Search info
 969         if (!empty($search)) {
 970             $headers['filters']['search'] = $search;
 971             $blogurl->param('search', $search);
 972             $PAGE->navbar->add(get_string('searchterm', 'blog', $search), $blogurl->out());
 973         }
 974     }
 975
 976     // Append edit mode info
 977     if (!empty($action) && $action == 'add') {
 978
 979     } else if (!empty($action) && $action == 'edit') {
 980         $PAGE->navbar->add(get_string('editentry', 'blog'));
 981     }
 982
 983     if (empty($headers['url'])) {
 984         $headers['url'] = $blogurl;
 985     }
 986     return $headers;
 987 }
 988
 989 /**
 990  * Shortcut function for getting a count of blog entries associated with a course or a module
 991  * @param int $courseid The ID of the course
 992  * @param int $cmid The ID of the course_modules
 993  * @return string The number of associated entries
 994  */
 995 function blog_get_associated_count($courseid, $cmid=null) {
 996     global $DB;
 997     $context = context_course::instance($courseid);
 998     if ($cmid) {
 999         $context = context_module::instance($cmid);
1000     }
1001     return $DB->count_records('blog_association', array('contextid' => $context->id));
1002 }
1003
1004 /**
1005  * Running addtional permission check on plugin, for example, plugins
1006  * may have switch to turn on/off comments option, this callback will
1007  * affect UI display, not like pluginname_comment_validate only throw
1008  * exceptions.
1009  * blog_comment_validate will be called before viewing/adding/deleting
1010  * comment, so don't repeat checks.
1011  * Capability check has been done in comment->check_permissions(), we
1012  * don't need to do it again here.
1013  *
1014  * @package  core_blog
1015  * @category comment
1016  *
1017  * @param stdClass $comment_param {
1018  *              context  => context the context object
1019  *              courseid => int course id
1020  *              cm       => stdClass course module object
1021  *              commentarea => string comment area
1022  *              itemid      => int itemid
1023  * }
1024  * @return array
1025  */
1026 function blog_comment_permissions($comment_param) {
1027     global $DB;
1028
1029     // If blog is public and current user is guest, then don't let him post comments.
1030     $blogentry = $DB->get_record('post', array('id' => $comment_param->itemid), 'publishstate', MUST_EXIST);
1031
1032     if ($blogentry->publishstate != 'public') {
1033         if (!isloggedin() || isguestuser()) {
1034             return array('post' => false, 'view' => true);
1035         }
1036     }
1037     return array('post' => true, 'view' => true);
1038 }
1039
1040 /**
1041  * Validate comment parameter before perform other comments actions
1042  *
1043  * @package  core_blog
1044  * @category comment
1045  *
1046  * @param stdClass $comment {
1047  *              context  => context the context object
1048  *              courseid => int course id
1049  *              cm       => stdClass course module object
1050  *              commentarea => string comment area
1051  *              itemid      => int itemid
1052  * }
1053  * @return boolean
1054  */
1055 function blog_comment_validate($comment_param) {
1056     global $CFG, $DB, $USER;
1057
1058     // Check if blogs are enabled user can comment.
1059     if (empty($CFG->enableblogs) || empty($CFG->blogusecomments)) {
1060         throw new comment_exception('nopermissiontocomment');
1061     }
1062
1063     // Validate comment area.
1064     if ($comment_param->commentarea != 'format_blog') {
1065         throw new comment_exception('invalidcommentarea');
1066     }
1067
1068     $blogentry = $DB->get_record('post', array('id' => $comment_param->itemid), '*', MUST_EXIST);
1069
1070     // Validation for comment deletion.
1071     if (!empty($comment_param->commentid)) {
1072         if ($record = $DB->get_record('comments', array('id'=>$comment_param->commentid))) {
1073             if ($record->commentarea != 'format_blog') {
1074                 throw new comment_exception('invalidcommentarea');
1075             }
1076             if ($record->contextid != $comment_param->context->id) {
1077                 throw new comment_exception('invalidcontext');
1078             }
1079             if ($record->itemid != $comment_param->itemid) {
1080                 throw new comment_exception('invalidcommentitemid');
1081             }
1082         } else {
1083             throw new comment_exception('invalidcommentid');
1084         }
1085     }
1086
1087     // Validate if user has blog view permission.
1088     $sitecontext = context_system::instance();
1089     return has_capability('moodle/blog:view', $sitecontext) &&
1090             blog_user_can_view_user_entry($blogentry->userid, $blogentry);
1091 }
1092
1093 /**
1094  * Return a list of page types
1095  * @param string $pagetype current page type
1096  * @param stdClass $parentcontext Block's parent context
1097  * @param stdClass $currentcontext Current context of block
1098  */
1099 function blog_page_type_list($pagetype, $parentcontext, $currentcontext) {
1100     return array(
1101         '*'=>get_string('page-x', 'pagetype'),
1102         'blog-*'=>get_string('page-blog-x', 'blog'),
1103         'blog-index'=>get_string('page-blog-index', 'blog'),
1104         'blog-edit'=>get_string('page-blog-edit', 'blog')
1105     );
1106 }