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   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   * This file is used to deliver a branch from the navigation structure
  20   * in XML format back to a page from an AJAX call
  21   *
  22   * @since Moodle 2.0
  23   * @package core
  24   * @copyright 2009 Sam Hemelryk
  25   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26   */
  27  
  28  define('AJAX_SCRIPT', true);
  29  
  30  /** Include config */
  31  require_once(dirname(__FILE__) . '/../../config.php');
  32  /** Include course lib for its functions */
  33  require_once($CFG->dirroot.'/course/lib.php');
  34  
  35  try {
  36      // Start buffer capture so that we can `remove` any errors
  37      ob_start();
  38      // Require id This is the key for whatever branch we want to get.
  39      // This accepts alphanum because the courses and my courses branches don't have numerical keys.
  40      // For those branches we return the alphanum key, courses and mycourses.
  41      $branchid = required_param('id', PARAM_ALPHANUM);
  42      // This identifies the type of the branch we want to get
  43      $branchtype = required_param('type', PARAM_INT);
  44      // This identifies the block instance requesting AJAX extension
  45      $instanceid = optional_param('instance', null, PARAM_INT);
  46  
  47      $PAGE->set_context(context_system::instance());
  48  
  49      // Create a global nav object
  50      $navigation = new global_navigation_for_ajax($PAGE, $branchtype, $branchid);
  51  
  52      $linkcategories = false;
  53  
  54      if ($instanceid!==null) {
  55          // Get the db record for the block instance
  56          $blockrecord = $DB->get_record('block_instances', array('id'=>$instanceid,'blockname'=>'navigation'));
  57          if ($blockrecord!=false) {
  58  
  59              // Instantiate a block_instance object so we can access config
  60              $block = block_instance('navigation', $blockrecord);
  61  
  62              $trimmode = block_navigation::TRIM_RIGHT;
  63              $trimlength = 50;
  64  
  65              // Set the trim mode
  66              if (!empty($block->config->trimmode)) {
  67                  $trimmode = (int)$block->config->trimmode;
  68              }
  69              // Set the trim length
  70              if (!empty($block->config->trimlength)) {
  71                  $trimlength = (int)$block->config->trimlength;
  72              }
  73              if (!empty($block->config->linkcategories) && $block->config->linkcategories == 'yes') {
  74                  $linkcategories = true;
  75              }
  76          }
  77      }
  78  
  79      // Create a navigation object to use, we can't guarantee PAGE will be complete
  80      if (!isloggedin()) {
  81          $navigation->set_expansion_limit(navigation_node::TYPE_COURSE);
  82      } else {
  83          if (isset($block) && !empty($block->config->expansionlimit)) {
  84              $navigation->set_expansion_limit($block->config->expansionlimit);
  85          }
  86      }
  87      if (isset($block)) {
  88          $block->trim($navigation, $trimmode, $trimlength, ceil($trimlength/2));
  89      }
  90      $converter = new navigation_json();
  91  
  92      // Find the actual branch we are looking for
  93      if ($branchtype != 0) {
  94          $branch = $navigation->find($branchid, $branchtype);
  95      } else if ($branchid === 'mycourses' || $branchid === 'courses') {
  96          $branch = $navigation->find($branchid, navigation_node::TYPE_ROOTNODE);
  97      } else {
  98          throw new coding_exception('Invalid branch type/id passed to AJAX call to load branches.');
  99      }
 100  
 101      // Remove links to categories if required.
 102      if (!$linkcategories) {
 103          foreach ($branch->find_all_of_type(navigation_node::TYPE_CATEGORY) as $category) {
 104              $category->action = null;
 105          }
 106          foreach ($branch->find_all_of_type(navigation_node::TYPE_MY_CATEGORY) as $category) {
 107              $category->action = null;
 108          }
 109      }
 110  
 111      // Stop buffering errors at this point
 112      $html = ob_get_contents();
 113      ob_end_clean();
 114  } catch (Exception $e) {
 115      throw new coding_exception('Error: '.$e->getMessage());
 116  }
 117  
 118  // Check if the buffer contianed anything if it did ERROR!
 119  if (trim($html) !== '') {
 120      throw new coding_exception('Errors were encountered while producing the navigation branch'."\n\n\n".$html);
 121  }
 122  // Check that branch isn't empty... if it is ERROR!
 123  if (empty($branch) || ($branch->nodetype !== navigation_node::NODETYPE_BRANCH && !$branch->isexpandable)) {
 124      throw new coding_exception('No further information available for this branch');
 125  }
 126  
 127  // Prepare an XML converter for the branch
 128  $converter->set_expandable($navigation->get_expandable());
 129  // Set XML headers
 130  header('Content-type: text/plain; charset=utf-8');
 131  // Convert and output the branch as XML
 132  echo $converter->convert($branch);