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