Add script to delete old unused courses

tests/scripts/delete_old_courses.php

@@ -0,0 +1,70 @@
+<?php
+/**
+ * This deletes courses that were created but no file was ever uploaded, and
+ * that were created previous to a specific date and last used previous to
+ * another specific date (see $creation and $access)
+ * Use this script with caution, as it will completely remove any trace of the
+ * deleted courses.
+ * Please note that this is not written with the inclusion of the concept ot
+ * sessions. As such, it might delete courses but leave the course reference
+ * in the session, which would cause issues.
+ * Launch from the command line.
+ * Usage: php delete_old_courses.php
+ */
+
+exit;
+
+$creation = '2014-01-01';
+$access = '2014-07-01';
+
+require_once '../../main/inc/global.inc.php';
+
+if (PHP_SAPI !== 'cli') {
+    die('This script can only be executed from the command line');
+}
+
+$tableExercise = Database::get_main_table(TABLE_STATISTIC_TRACK_E_EXERCICES);
+$tableCourse = Database::get_main_table(TABLE_MAIN_COURSE);
+
+$sql = "SELECT
+            id, code, directory, db_name, creation_date, last_visit
+        FROM $tableCourse c
+        WHERE creation_date < '$creation' AND last_visit < '$access'
+        ORDER by code
+";
+echo $sql.PHP_EOL;
+
+$result = Database::query($sql);
+$items = Database::store_result($result, 'ASSOC');
+$total = 0;
+$count = 0;
+if (!empty($items)) {
+    foreach ($items as $item) {
+        $size = exec('du -sh '.__DIR__.'/../../courses/'.$item['directory']);
+        echo "Course ".$item['code'].'('.$item['id'].') created on '.$item['creation_date'].' and last used on '.$item['last_visit'].' uses '.substr($size, 0, 8).PHP_EOL;
+        // Check if it's 160K or 9.1M in size, which is the case for 'empty'
+        // courses (created without or with example content)
+        if (substr($size, 0, 4) == '160K' or substr($size, 0, 4) == '9,1M') {
+            CourseManager::delete_course($item['code']);
+            // The normal procedure moves the course directory to archive, so
+            // delete it there as well
+            echo('rm -rf '.__DIR__.'/../../archive/'.$item['directory'].'_*').PHP_EOL;
+            exec('rm -rf '.__DIR__.'/../../archive/'.$item['directory'].'_*');
+            // The normal procedure also created a database dump, but it is
+            // stored in the course folder, so no issue there...       
+            if (substr($size, 0, 4) == '160K') {
+                $total += 160;
+            }
+            if (substr($size, 0, 4) == '9,1M') {
+                $total += 9100;
+            }
+            $count ++;
+            if ($count%100 == 0) {
+                // Print progressive information about the freed space
+                echo '### Until now: '.$total.'K in '.$count.' courses'.PHP_EOL;
+            }
+        }
+    }
+}
+// Print final information about the freed space
+echo $total.'K in '.$count.' courses'.PHP_EOL;