Cursor rule

1---
2description: 
3globs: 
4alwaysApply: false
5---
6# Moodle Performance Optimization
7 
8## Purpose
9Ensure PHP code follows Moodle performance best practices for optimal execution speed and resource usage.
10 
11## Instructions
12When writing PHP code for Moodle, implement these performance optimizations:
13 
141. **Database Queries**: Minimize database calls, use bulk operations when possible
152. **Caching**: Use Moodle's caching API (`cache::make()`) for expensive operations
163. **Memory Management**: Avoid loading large datasets into memory, use pagination
174. **File Operations**: Use Moodle's file API, avoid direct file system access
185. **Session Handling**: Minimize session writes, use `$SESSION` sparingly
196. **Output Buffering**: Use `ob_start()` and `ob_end_flush()` for large outputs
207. **Error Logging**: Use `debugging()` instead of `error_log()` in production
218. **Plugin Loading**: Lazy load plugins and dependencies when possible
22 
23## Examples
24 
25```php
26<?php
27// File: ./includes/performance_example.php
28 
29/**
30 * Example of performance-optimized code
31 */
32function get_optimized_course_data($courseids) {
33    global $DB;
34    
35    // Use caching for expensive operations
36    $cache = cache::make('core', 'course_data');
37    $cachekey = 'course_data_' . md5(serialize($courseids));
38    
39    $cacheddata = $cache->get($cachekey);
40    if ($cacheddata !== false) {
41        return $cacheddata;
42    }
43    
44    // Bulk database query instead of multiple queries
45    list($insql, $params) = $DB->get_in_or_equal($courseids, SQL_PARAMS_NAMED);
46    $sql = "SELECT c.*, COUNT(e.userid) as enrolled_users
47            FROM {course} c
48            LEFT JOIN {enrol} e ON c.id = e.courseid
49            WHERE c.id $insql
50            GROUP BY c.id";
51    
52    $courses = $DB->get_records_sql($sql, $params);
53    
54    // Cache the result for 5 minutes
55    $cache->set($cachekey, $courses, 300);
56    
57    return $courses;
58}
59 
60/**
61 * Efficient file handling
62 */
63function process_files_efficiently($contextid) {
64    $fs = get_file_storage();
65    
66    // Use file iterator for large file sets
67    $files = $fs->get_area_files($contextid, 'mod_assign', 'submission');
68    
69    foreach ($files as $file) {
70        if ($file->is_directory()) {
71            continue;
72        }
73        
74        // Process file without loading entire content into memory
75        $content = $file->get_content();
76        // Process content in chunks if large
77    }
78}
79```
80 
81## Exceptions
82- Development environments may use different performance settings
83- Debugging may require bypassing some optimizations
84