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 = get_context_instance(CONTEXT_SYSTEM);
  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->bloglevel)) {
  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 = get_context_instance(CONTEXT_SYSTEM);
  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 = get_context_instance(CONTEXT_USER, $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 = get_context_instance(CONTEXT_COURSE, $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     $textlib = textlib_get_instance(); // Going to use textlib services
 154
 155     if (!$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         $textlib = textlib_get_instance();
 243         if ($textlib->strlen($newentry->uniquehash) > 255) {
 244             // The URL for this item is too long for the field. Rather than add
 245             // the entry without the link we will skip straight over it.
 246             // RSS spec says recommended length 500, we use 255.
 247             debugging('External blog entry skipped because of oversized URL', DEBUG_DEVELOPER);
 248             continue;
 249         }
 250
 251         if ($postid === false) {
 252             $id = $DB->insert_record('post', $newentry);
 253
 254             // Set tags
 255             if ($tags = tag_get_tags_array('blog_external', $externalblog->id)) {
 256                 tag_set('post', $id, $tags);
 257             }
 258         } else {
 259             $newentry->id = $postid;
 260             $DB->update_record('post', $newentry);
 261         }
 262     }
 263
 264     // Look at the posts we have in the database to check if any of them have been deleted from the feed.
 265     // Only checking posts within the time frame returned by the rss feed. Older items may have been deleted or
 266     // may just not be returned anymore. We can't tell the difference so we leave older posts alone.
 267     $sql = "SELECT id, uniquehash
 268               FROM {post}
 269              WHERE module = 'blog_external'
 270                    AND " . $DB->sql_compare_text('content') . " = " . $DB->sql_compare_text(':blogid') . "
 271                    AND created > :ts";
 272     $dbposts = $DB->get_records_sql($sql, array('blogid' => $externalblog->id, 'ts' => $oldesttimestamp));
 273
 274     $todelete = array();
 275     foreach($dbposts as $dbpost) {
 276         if ( !in_array($dbpost->uniquehash, $uniquehashes) ) {
 277             $todelete[] = $dbpost->id;
 278         }
 279     }
 280     $DB->delete_records_list('post', 'id', $todelete);
 281
 282     $DB->update_record('blog_external', array('id' => $externalblog->id, 'timefetched' => time()));
 283 }
 284
 285 /**
 286  * Given an external blog object, deletes all related blog entries from the post table.
 287  * NOTE: The external blog's id is saved as post.content, a field that is not oterhwise used by blog entries.
 288  * @param object $externablog
 289  */
 290 function blog_delete_external_entries($externalblog) {
 291     global $DB;
 292     require_capability('moodle/blog:manageexternal', get_context_instance(CONTEXT_SYSTEM));
 293     $DB->delete_records_select('post',
 294                                "module='blog_external' AND " . $DB->sql_compare_text('content') . " = ?",
 295                                array($externalblog->id));
 296 }
 297
 298 /**
 299  * Returns a URL based on the context of the current page.
 300  * This URL points to blog/index.php and includes filter parameters appropriate for the current page.
 301  *
 302  * @param stdclass $context
 303  * @return string
 304  */
 305 function blog_get_context_url($context=null) {
 306     global $CFG;
 307
 308     $viewblogentriesurl = new moodle_url('/blog/index.php');
 309
 310     if (empty($context)) {
 311         global $PAGE;
 312         $context = $PAGE->context;
 313     }
 314
 315     // Change contextlevel to SYSTEM if viewing the site course
 316     if ($context->contextlevel == CONTEXT_COURSE && $context->instanceid == SITEID) {
 317         $context = context_system::instance();
 318     }
 319
 320     $filterparam = '';
 321     $strlevel = '';
 322
 323     switch ($context->contextlevel) {
 324         case CONTEXT_SYSTEM:
 325         case CONTEXT_BLOCK:
 326         case CONTEXT_COURSECAT:
 327             break;
 328         case CONTEXT_COURSE:
 329             $filterparam = 'courseid';
 330             $strlevel = get_string('course');
 331             break;
 332         case CONTEXT_MODULE:
 333             $filterparam = 'modid';
 334             $strlevel = print_context_name($context);
 335             break;
 336         case CONTEXT_USER:
 337             $filterparam = 'userid';
 338             $strlevel = get_string('user');
 339             break;
 340     }
 341
 342     if (!empty($filterparam)) {
 343         $viewblogentriesurl->param($filterparam, $context->instanceid);
 344     }
 345
 346     return $viewblogentriesurl;
 347 }
 348
 349 /**
 350  * This function checks that blogs are enabled, and that the user can see blogs at all
 351  * @return bool
 352  */
 353 function blog_is_enabled_for_user() {
 354     global $CFG;
 355     //return (!empty($CFG->bloglevel) && $CFG->bloglevel <= BLOG_GLOBAL_LEVEL && isloggedin() && !isguestuser());
 356     return (!empty($CFG->bloglevel) && (isloggedin() || ($CFG->bloglevel == BLOG_GLOBAL_LEVEL)));
 357 }
 358
 359 /**
 360  * This function gets all of the options available for the current user in respect
 361  * to blogs.
 362  *
 363  * It loads the following if applicable:
 364  * -  Module options {@see blog_get_options_for_module}
 365  * -  Course options {@see blog_get_options_for_course}
 366  * -  User specific options {@see blog_get_options_for_user}
 367  * -  General options (BLOG_LEVEL_GLOBAL)
 368  *
 369  * @param moodle_page $page The page to load for (normally $PAGE)
 370  * @param stdClass $userid Load for a specific user
 371  * @return array An array of options organised by type.
 372  */
 373 function blog_get_all_options(moodle_page $page, stdClass $userid = null) {
 374     global $CFG, $DB, $USER;
 375
 376     $options = array();
 377
 378     // If blogs are enabled and the user is logged in and not a guest
 379     if (blog_is_enabled_for_user()) {
 380         // If the context is the user then assume we want to load for the users context
 381         if (is_null($userid) && $page->context->contextlevel == CONTEXT_USER) {
 382             $userid = $page->context->instanceid;
 383         }
 384         // Check the userid var
 385         if (!is_null($userid) && $userid!==$USER->id) {
 386             // Load the user from the userid... it MUST EXIST throw a wobbly if it doesn't!
 387             $user = $DB->get_record('user', array('id'=>$userid), '*', MUST_EXIST);
 388         } else {
 389             $user = null;
 390         }
 391
 392         if ($CFG->useblogassociations && $page->cm !== null) {
 393             // Load for the module associated with the page
 394             $options[CONTEXT_MODULE] = blog_get_options_for_module($page->cm, $user);
 395         } else if ($CFG->useblogassociations && $page->course->id != SITEID) {
 396             // Load the options for the course associated with the page
 397             $options[CONTEXT_COURSE] = blog_get_options_for_course($page->course, $user);
 398         }
 399
 400         // Get the options for the user
 401         if ($user !== null and !isguestuser($user)) {
 402             // Load for the requested user
 403             $options[CONTEXT_USER+1] = blog_get_options_for_user($user);
 404         }
 405         // Load for the current user
 406         if (isloggedin() and !isguestuser()) {
 407             $options[CONTEXT_USER] = blog_get_options_for_user();
 408         }
 409     }
 410
 411     // If blog level is global then display a link to view all site entries
 412     if (!empty($CFG->bloglevel) && $CFG->bloglevel >= BLOG_GLOBAL_LEVEL && has_capability('moodle/blog:view', get_context_instance(CONTEXT_SYSTEM))) {
 413         $options[CONTEXT_SYSTEM] = array('viewsite' => array(
 414             'string' => get_string('viewsiteentries', 'blog'),
 415             'link' => new moodle_url('/blog/index.php')
 416         ));
 417     }
 418
 419     // Return the options
 420     return $options;
 421 }
 422
 423 /**
 424  * Get all of the blog options that relate to the passed user.
 425  *
 426  * If no user is passed the current user is assumed.
 427  *
 428  * @staticvar array $useroptions Cache so we don't have to regenerate multiple times
 429  * @param stdClass $user
 430  * @return array The array of options for the requested user
 431  */
 432 function blog_get_options_for_user(stdClass $user=null) {
 433     global $CFG, $USER;
 434     // Cache
 435     static $useroptions = array();
 436
 437     $options = array();
 438     // Blogs must be enabled and the user must be logged in
 439     if (!blog_is_enabled_for_user()) {
 440         return $options;
 441     }
 442
 443     // Sort out the user var
 444     if ($user === null || $user->id == $USER->id) {
 445         $user = $USER;
 446         $iscurrentuser = true;
 447     } else {
 448         $iscurrentuser = false;
 449     }
 450
 451     // If we've already generated serve from the cache
 452     if (array_key_exists($user->id, $useroptions)) {
 453         return $useroptions[$user->id];
 454     }
 455
 456     $sitecontext = get_context_instance(CONTEXT_SYSTEM);
 457     $canview = has_capability('moodle/blog:view', $sitecontext);
 458
 459     if (!$iscurrentuser && $canview && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 460         // Not the current user, but we can view and its blogs are enabled for SITE or GLOBAL
 461         $options['userentries'] = array(
 462             'string' => get_string('viewuserentries', 'blog', fullname($user)),
 463             'link' => new moodle_url('/blog/index.php', array('userid'=>$user->id))
 464         );
 465     } else {
 466         // It's the current user
 467         if ($canview) {
 468             // We can view our own blogs .... BIG surprise
 469             $options['view'] = array(
 470                 'string' => get_string('viewallmyentries', 'blog'),
 471                 'link' => new moodle_url('/blog/index.php', array('userid'=>$USER->id))
 472             );
 473         }
 474         if (has_capability('moodle/blog:create', $sitecontext)) {
 475             // We can add to our own blog
 476             $options['add'] = array(
 477                 'string' => get_string('addnewentry', 'blog'),
 478                 'link' => new moodle_url('/blog/edit.php', array('action'=>'add'))
 479             );
 480         }
 481     }
 482     if ($canview && $CFG->enablerssfeeds) {
 483         $options['rss'] = array(
 484             'string' => get_string('rssfeed', 'blog'),
 485             'link' => new moodle_url(rss_get_url($sitecontext->id, $USER->id, 'blog', 'user/'.$user->id))
 486        );
 487     }
 488
 489     // Cache the options
 490     $useroptions[$user->id] = $options;
 491     // Return the options
 492     return $options;
 493 }
 494
 495 /**
 496  * Get the blog options that relate to the given course for the given user.
 497  *
 498  * @staticvar array $courseoptions A cache so we can save regenerating multiple times
 499  * @param stdClass $course The course to load options for
 500  * @param stdClass $user The user to load options for null == current user
 501  * @return array The array of options
 502  */
 503 function blog_get_options_for_course(stdClass $course, stdClass $user=null) {
 504     global $CFG, $USER;
 505     // Cache
 506     static $courseoptions = array();
 507
 508     $options = array();
 509
 510     // User must be logged in and blogs must be enabled
 511     if (!blog_is_enabled_for_user()) {
 512         return $options;
 513     }
 514
 515     // Check that the user can associate with the course
 516     $sitecontext =      get_context_instance(CONTEXT_SYSTEM);
 517     if (!has_capability('moodle/blog:associatecourse', $sitecontext)) {
 518         return $options;
 519     }
 520     // Generate the cache key
 521     $key = $course->id.':';
 522     if (!empty($user)) {
 523         $key .= $user->id;
 524     } else {
 525         $key .= $USER->id;
 526     }
 527     // Serve from the cache if we've already generated for this course
 528     if (array_key_exists($key, $courseoptions)) {
 529         return $courseoptions[$key];
 530     }
 531
 532     $coursecontext = get_context_instance(CONTEXT_COURSE, $course->id);
 533     $canparticipate = (is_enrolled($coursecontext) or is_viewing($coursecontext));
 534
 535     if (has_capability('moodle/blog:view', $coursecontext)) {
 536         // We can view!
 537         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 538             // View entries about this course
 539             $options['courseview'] = array(
 540                 'string' => get_string('viewcourseblogs', 'blog'),
 541                 'link' => new moodle_url('/blog/index.php', array('courseid'=>$course->id))
 542             );
 543         }
 544         // View MY entries about this course
 545         $options['courseviewmine'] = array(
 546             'string' => get_string('viewmyentriesaboutcourse', 'blog'),
 547             'link' => new moodle_url('/blog/index.php', array('courseid'=>$course->id, 'userid'=>$USER->id))
 548         );
 549         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 550             // View the provided users entries about this course
 551             $options['courseviewuser'] = array(
 552                 'string' => get_string('viewentriesbyuseraboutcourse', 'blog', fullname($user)),
 553                 'link' => new moodle_url('/blog/index.php', array('courseid'=>$course->id, 'userid'=>$user->id))
 554             );
 555         }
 556     }
 557
 558     if (has_capability('moodle/blog:create', $sitecontext) and $canparticipate) {
 559         // We can blog about this course
 560         $options['courseadd'] = array(
 561             'string' => get_string('blogaboutthiscourse', 'blog'),
 562             'link' => new moodle_url('/blog/edit.php', array('action'=>'add', 'courseid'=>$course->id))
 563         );
 564     }
 565
 566
 567     // Cache the options for this course
 568     $courseoptions[$key] = $options;
 569     // Return the options
 570     return $options;
 571 }
 572
 573 /**
 574  * Get the blog options relating to the given module for the given user
 575  *
 576  * @staticvar array $moduleoptions Cache
 577  * @param stdClass|cm_info $module The module to get options for
 578  * @param stdClass $user The user to get options for null == currentuser
 579  * @return array
 580  */
 581 function blog_get_options_for_module($module, $user=null) {
 582     global $CFG, $USER;
 583     // Cache
 584     static $moduleoptions = array();
 585
 586     $options = array();
 587     // User must be logged in, blogs must be enabled
 588     if (!blog_is_enabled_for_user()) {
 589         return $options;
 590     }
 591
 592     // Check the user can associate with the module
 593     $sitecontext =      get_context_instance(CONTEXT_SYSTEM);
 594     if (!has_capability('moodle/blog:associatemodule', $sitecontext)) {
 595         return $options;
 596     }
 597
 598     // Generate the cache key
 599     $key = $module->id.':';
 600     if (!empty($user)) {
 601         $key .= $user->id;
 602     } else {
 603         $key .= $USER->id;
 604     }
 605     if (array_key_exists($key, $moduleoptions)) {
 606         // Serve from the cache so we don't have to regenerate
 607         return $moduleoptions[$module->id];
 608     }
 609
 610     $modcontext = get_context_instance(CONTEXT_MODULE, $module->id);
 611     $canparticipate = (is_enrolled($modcontext) or is_viewing($modcontext));
 612
 613     if (has_capability('moodle/blog:view', $modcontext)) {
 614         // Save correct module name for later usage.
 615         $modulename = get_string('modulename', $module->modname);
 616
 617         // We can view!
 618         if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
 619             // View all entries about this module
 620             $a = new stdClass;
 621             $a->type = $modulename;
 622             $options['moduleview'] = array(
 623                 'string' => get_string('viewallmodentries', 'blog', $a),
 624                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id))
 625             );
 626         }
 627         // View MY entries about this module
 628         $options['moduleviewmine'] = array(
 629             'string' => get_string('viewmyentriesaboutmodule', 'blog', $modulename),
 630             'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$USER->id))
 631         );
 632         if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
 633             // View the given users entries about this module
 634             $a = new stdClass;
 635             $a->mod = $modulename;
 636             $a->user = fullname($user);
 637             $options['moduleviewuser'] = array(
 638                 'string' => get_string('blogentriesbyuseraboutmodule', 'blog', $a),
 639                 'link' => new moodle_url('/blog/index.php', array('modid'=>$module->id, 'userid'=>$user->id))
 640             );
 641         }
 642     }
 643
 644     if (has_capability('moodle/blog:create', $sitecontext) and $canparticipate) {
 645         // The user can blog about this module
 646         $options['moduleadd'] = array(
 647             'string' => get_string('blogaboutthismodule', 'blog', $modulename),
 648             'link' => new moodle_url('/blog/edit.php', array('action'=>'add', 'modid'=>$module->id))
 649         );
 650     }
 651     // Cache the options
 652     $moduleoptions[$key] = $options;
 653     // Return the options
 654     return $options;
 655 }
 656
 657 /**
 658  * This function encapsulates all the logic behind the complex
 659  * navigation, titles and headings of the blog listing page, depending
 660  * on URL params. It looks at URL params and at the current context level.
 661  * It builds and returns an array containing:
 662  *
 663  * 1. heading: The heading displayed above the blog entries
 664  * 2. stradd:  The text to be used as the "Add entry" link
 665  * 3. strview: The text to be used as the "View entries" link
 666  * 4. url:     The moodle_url object used as the base for add and view links
 667  * 5. filters: An array of parameters used to filter blog listings. Used by index.php and the Recent blogs block
 668  *
 669  * All other variables are set directly in $PAGE
 670  *
 671  * It uses the current URL to build these variables.
 672  * A number of mutually exclusive use cases are used to structure this function.
 673  *
 674  * @return array
 675  */
 676 function blog_get_headers($courseid=null, $groupid=null, $userid=null, $tagid=null) {
 677     global $CFG, $PAGE, $DB, $USER;
 678
 679     $id       = optional_param('id', null, PARAM_INT);
 680     $tag      = optional_param('tag', null, PARAM_NOTAGS);
 681     $tagid    = optional_param('tagid', $tagid, PARAM_INT);
 682     $userid   = optional_param('userid', $userid, PARAM_INT);
 683     $modid    = optional_param('modid', null, PARAM_INT);
 684     $entryid  = optional_param('entryid', null, PARAM_INT);
 685     $groupid  = optional_param('groupid', $groupid, PARAM_INT);
 686     $courseid = optional_param('courseid', $courseid, PARAM_INT);
 687     $search   = optional_param('search', null, PARAM_RAW);
 688     $action   = optional_param('action', null, PARAM_ALPHA);
 689     $confirm  = optional_param('confirm', false, PARAM_BOOL);
 690
 691     // Ignore userid when action == add
 692     if ($action == 'add' && $userid) {
 693         unset($userid);
 694         $PAGE->url->remove_params(array('userid'));
 695     } else if ($action == 'add' && $entryid) {
 696         unset($entryid);
 697         $PAGE->url->remove_params(array('entryid'));
 698     }
 699
 700     $headers = array('title' => '', 'heading' => '', 'cm' => null, 'filters' => array());
 701
 702     $blogurl = new moodle_url('/blog/index.php');
 703
 704     // If the title is not yet set, it's likely that the context isn't set either, so skip this part
 705     $pagetitle = $PAGE->title;
 706     if (!empty($pagetitle)) {
 707         $contexturl = blog_get_context_url();
 708
 709         // Look at the context URL, it may have additional params that are not in the current URL
 710         if (!$blogurl->compare($contexturl)) {
 711             $blogurl = $contexturl;
 712             if (empty($courseid)) {
 713                 $courseid = $blogurl->param('courseid');
 714             }
 715             if (empty($modid)) {
 716                 $modid = $blogurl->param('modid');
 717             }
 718         }
 719     }
 720
 721     $headers['stradd'] = get_string('addnewentry', 'blog');
 722     $headers['strview'] = null;
 723
 724     $site = $DB->get_record('course', array('id' => SITEID));
 725     $sitecontext = get_context_instance(CONTEXT_SYSTEM);
 726     // Common Lang strings
 727     $strparticipants = get_string("participants");
 728     $strblogentries  = get_string("blogentries", 'blog');
 729
 730     // Prepare record objects as needed
 731     if (!empty($courseid)) {
 732         $headers['filters']['course'] = $courseid;
 733         $course = $DB->get_record('course', array('id' => $courseid));
 734     }
 735
 736     if (!empty($userid)) {
 737         $headers['filters']['user'] = $userid;
 738         $user = $DB->get_record('user', array('id' => $userid));
 739     }
 740
 741     if (!empty($groupid)) { // groupid always overrides courseid
 742         $headers['filters']['group'] = $groupid;
 743         $group = $DB->get_record('groups', array('id' => $groupid));
 744         $course = $DB->get_record('course', array('id' => $group->courseid));
 745     }
 746
 747     $PAGE->set_pagelayout('standard');
 748
 749     if (!empty($modid) && $CFG->useblogassociations && has_capability('moodle/blog:associatemodule', $sitecontext)) { // modid always overrides courseid, so the $course object may be reset here
 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' => get_context_instance(CONTEXT_COURSE, 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' => get_context_instance(CONTEXT_COURSE, 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' => get_context_instance(CONTEXT_COURSE, 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' => get_context_instance(CONTEXT_COURSE, 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' => get_context_instance(CONTEXT_COURSE, 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' => get_context_instance(CONTEXT_COURSE, SITEID)));
 852         $courseshortname = format_string($course->shortname, true, array('context' => get_context_instance(CONTEXT_COURSE, $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' => get_context_instance(CONTEXT_COURSE, $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' => get_context_instance(CONTEXT_COURSE, SITEID)));
 876         $courseshortname = format_string($course->shortname, true, array('context' => get_context_instance(CONTEXT_COURSE, $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' => get_context_instance(CONTEXT_COURSE, $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' => get_context_instance(CONTEXT_COURSE, SITEID)));
 899         $courseshortname = format_string($course->shortname, true, array('context' => get_context_instance(CONTEXT_COURSE, $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' => get_context_instance(CONTEXT_COURSE, SITEID)));
 923         $courseshortname = format_string($course->shortname, true, array('context' => get_context_instance(CONTEXT_COURSE, $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' => get_context_instance(CONTEXT_COURSE, SITEID)));
 939         $courseshortname = format_string($course->shortname, true, array('context' => get_context_instance(CONTEXT_COURSE, $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' => get_context_instance(CONTEXT_COURSE, $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             $blogurl->param('tag', $tag);
 961             $PAGE->navbar->add(get_string('tagparam', 'blog', $tag), $blogurl);
 962         }
 963
 964         // Append Search info
 965         if (!empty($search)) {
 966             $headers['filters']['search'] = $search;
 967             $blogurl->param('search', $search);
 968             $PAGE->navbar->add(get_string('searchterm', 'blog', $search), $blogurl->out());
 969         }
 970     }
 971
 972     // Append edit mode info
 973     if (!empty($action) && $action == 'add') {
 974
 975     } else if (!empty($action) && $action == 'edit') {
 976         $PAGE->navbar->add(get_string('editentry', 'blog'));
 977     }
 978
 979     if (empty($headers['url'])) {
 980         $headers['url'] = $blogurl;
 981     }
 982     return $headers;
 983 }
 984
 985 /**
 986  * Shortcut function for getting a count of blog entries associated with a course or a module
 987  * @param int $courseid The ID of the course
 988  * @param int $cmid The ID of the course_modules
 989  * @return string The number of associated entries
 990  */
 991 function blog_get_associated_count($courseid, $cmid=null) {
 992     global $DB;
 993     $context = get_context_instance(CONTEXT_COURSE, $courseid);
 994     if ($cmid) {
 995         $context = get_context_instance(CONTEXT_MODULE, $cmid);
 996     }
 997     return $DB->count_records('blog_association', array('contextid' => $context->id));
 998 }
 999
1000 /**
1001  * Running addtional permission check on plugin, for example, plugins
1002  * may have switch to turn on/off comments option, this callback will
1003  * affect UI display, not like pluginname_comment_validate only throw
1004  * exceptions.
1005  * Capability check has been done in comment->check_permissions(), we
1006  * don't need to do it again here.
1007  *
1008  * @param stdClass $comment_param {
1009  *              context  => context the context object
1010  *              courseid => int course id
1011  *              cm       => stdClass course module object
1012  *              commentarea => string comment area
1013  *              itemid      => int itemid
1014  * }
1015  * @return array
1016  */
1017 function blog_comment_permissions($comment_param) {
1018     return array('post'=>true, 'view'=>true);
1019 }
1020
1021 /**
1022  * Validate comment parameter before perform other comments actions
1023  *
1024  * @param stdClass $comment {
1025  *              context  => context the context object
1026  *              courseid => int course id
1027  *              cm       => stdClass course module object
1028  *              commentarea => string comment area
1029  *              itemid      => int itemid
1030  * }
1031  * @return boolean
1032  */
1033 function blog_comment_validate($comment_param) {
1034     global $DB;
1035     // validate comment itemid
1036     if (!$entry = $DB->get_record('post', array('id'=>$comment_param->itemid))) {
1037         throw new comment_exception('invalidcommentitemid');
1038     }
1039     // validate comment area
1040     if ($comment_param->commentarea != 'format_blog') {
1041         throw new comment_exception('invalidcommentarea');
1042     }
1043     // validation for comment deletion
1044     if (!empty($comment_param->commentid)) {
1045         if ($record = $DB->get_record('comments', array('id'=>$comment_param->commentid))) {
1046             if ($record->commentarea != 'format_blog') {
1047                 throw new comment_exception('invalidcommentarea');
1048             }
1049             if ($record->contextid != $comment_param->context->id) {
1050                 throw new comment_exception('invalidcontext');
1051             }
1052             if ($record->itemid != $comment_param->itemid) {
1053                 throw new comment_exception('invalidcommentitemid');
1054             }
1055         } else {
1056             throw new comment_exception('invalidcommentid');
1057         }
1058     }
1059     return true;
1060 }
1061
1062 /**
1063  * Return a list of page types
1064  * @param string $pagetype current page type
1065  * @param stdClass $parentcontext Block's parent context
1066  * @param stdClass $currentcontext Current context of block
1067  */
1068 function blog_page_type_list($pagetype, $parentcontext, $currentcontext) {
1069     return array(
1070         '*'=>get_string('page-x', 'pagetype'),
1071         'blog-*'=>get_string('page-blog-x', 'blog'),
1072         'blog-index'=>get_string('page-blog-index', 'blog'),
1073         'blog-edit'=>get_string('page-blog-edit', 'blog')
1074     );
1075 }