caching.md

Caching

Building the route table on every request is cheap, but for large applications you can cache the compiled table to a file and skip re-registration.

Enabling the cache

$router = new Router($request, $response, [
    'cache' => [
        'enable' => true,
        'path'   => __DIR__ . '/var/cache/routes.cache',
        'ttl'    => 86400, // seconds (default: 1 day)
    ],
]);

How it works

• On construction, if a fresh (non-expired) cache file exists, the route table is loaded from it and the router is marked as cached.
• While the router is cached, registration calls (get(), group(), …) are no-ops — the routes already came from the cache.
• When the router is destroyed and it was not loaded from cache, the current route table is written to the cache file.

A typical front controller registers routes unconditionally; on the first request they are compiled and cached, and on subsequent requests (until the TTL expires) they are loaded from the cache:

$router = new Router($request, $response, [
    'cache' => ['enable' => true, 'path' => $cacheFile],
]);

// These run normally the first time, and are skipped once cached.
$router->get('/', 'HomeController@index');
$router->resource('photos', 'PhotoController');

$response = $router->dispatch();

Limitations

• Handlers must be cacheable. String ('Controller@method') and array handlers cache fine. Closures cannot be serialized, so don't enable caching if your routes use closure handlers.
• Delete the cache file (or wait for the TTL) after changing your routes.
• A write failure is reported as a warning and never interrupts the response.

Next: Upgrading from 1.x to 2.0.