Proper caching and cache avoidance.

.htaccess

@@ -3,4 +3,13 @@
 #RewriteCond %{REQUEST_FILENAME} !-d
 #RewriteRule ^(.*)$ index.php [QSA,L]
 
-# TODO - https://github.com/phanan/htaccess#set-expires-headers
+<IfModule mod_expires.c>
+    ExpiresActive on
+    ExpiresDefault                                      "access plus 1 week"
+    ExpiresByType text/html                             "access plus 0 seconds"
+</IfModule>
+
+<IfModule mod_headers.c>
+    Header unset ETag
+</IfModule>
+FileETag None

one.php

@@ -6,6 +6,8 @@ $config = require 'config.php';
 
 error_reporting(0);
 header('Content-type: text/plain');
+header("Cache-Control: no-cache, must-revalidate");
+header("Expires: Sat, 26 Jul 1997 05:00:00 GMT");
 try {
     $pdo = new MyPDO('sqlite:' . __DIR__ . '/' . $config['database']);