blog/lib.php

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