Add sample file for preloading

preload.php

@@ -0,0 +1,113 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <[email protected]>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+/*
+ *---------------------------------------------------------------
+ * Sample file for Preloading
+ *---------------------------------------------------------------
+ * See https://www.php.net/manual/en/opcache.preloading.php
+ *
+ * How to Use:
+ *   1. Set Preload::$paths.
+ *   2. Set opcache.preload in php.ini.
+ *     php.ini:
+ *     opcache.preload=/path/to/preload.php
+ */
+
+// Load the paths config file
+require __DIR__ . '/app/Config/Paths.php';
+
+// Path to the front controller
+define('FCPATH', __DIR__ . DIRECTORY_SEPARATOR . 'public' . DIRECTORY_SEPARATOR);
+
+/**
+ * See https://www.php.net/manual/en/function.str-contains.php#126277
+ */
+if (! function_exists('str_contains')) {
+    /**
+     * Polyfill of str_contains()
+     */
+    function str_contains(string $haystack, string $needle): bool
+    {
+        return empty($needle) || strpos($haystack, $needle) !== false;
+    }
+}
+
+class Preload
+{
+    /**
+     * @var array Paths to preload.
+     */
+    private array $paths = [
+        [
+            'include' => // __DIR__ . '/vendor/codeigniter4/framework/system',
+                __DIR__ . '/system',
+            'exclude' => [
+                // Not needed if you don't use them.
+                '/system/Database/OCI8/',
+                '/system/Database/Postgre/',
+                '/system/Database/SQLSRV/',
+                // Not needed.
+                '/system/Database/Seeder.php',
+                '/system/Test/',
+                '/system/Language/',
+                '/system/CLI/',
+                '/system/Commands/',
+                '/system/Publisher/',
+                '/system/ComposerScripts.php',
+                '/Views/',
+                // Errors occur.
+                '/system/Config/Routes.php',
+                '/system/ThirdParty/',
+            ],
+        ],
+    ];
+
+    public function __construct()
+    {
+        $this->loadAutoloader();
+    }
+
+    private function loadAutoloader()
+    {
+        $paths = new Config\Paths();
+        require rtrim($paths->systemDirectory, '\\/ ') . DIRECTORY_SEPARATOR . 'bootstrap.php';
+    }
+
+    /**
+     * Load PHP files.
+     */
+    public function load()
+    {
+        foreach ($this->paths as $path) {
+            $directory = new RecursiveDirectoryIterator($path['include']);
+            $fullTree  = new RecursiveIteratorIterator($directory);
+            $phpFiles  = new RegexIterator(
+                $fullTree,
+                '/.+((?<!Test)+\.php$)/i',
+                RecursiveRegexIterator::GET_MATCH
+            );
+
+            foreach ($phpFiles as $key => $file) {
+                foreach ($path['exclude'] as $exclude) {
+                    if (str_contains($file[0], $exclude)) {
+                        continue 2;
+                    }
+                }
+
+                require_once $file[0];
+                echo 'Loaded: ' . $file[0] . "\n";
+            }
+        }
+    }
+}
+
+(new Preload())->load();

user_guide_src/source/changelogs/v4.2.0.rst

@@ -85,6 +85,7 @@ Others
     - :ref:`select() <query-builder-select-rawsql>`, :ref:`where() <query-builder-where-rawsql>`, :ref:`like() <query-builder-like-rawsql>` accept the ``CodeIgniter\Database\RawSql`` instance.
 - Debugbar enhancements
     - Debug toolbar is now using ``microtime()`` instead of ``time()``.
+- Added a sample file for `Preloading <https://www.php.net/manual/en/opcache.preloading.php>`_. See **preload.php**.
 
 Changes
 *******