README

Cache any data until set expiration time (with automatic keys).

Installation

unzip master.zip as folder site/plugins/kirby3-lapse or
git submodule add https://github.com/bnomei/kirby3-lapse.git site/plugins/kirby3-lapse or
composer require bnomei/kirby3-lapse

Usecase

The Kirby Pages-Cache can cache the output of Page Templates. It invalidates all cache files if any Object in the Panel is changed. This is a good choice if you do not make changes often. But if you do make changes often you need a cache that knows what has been modified and which caches to devalidate and which not.

Sometimes you can not cache the complete Page since...

it contains a form with a csrf hash,
you use content security headers with nouces,
build and cache data for a logicless templating system like handlebars or
you want to cache data from an external source like an API.

Lapse was build to do exactly that: Cache any data until set expiration time.

Usage Examples

Example 1: get/set

$key = hash('xxh3', $page->url()); // unique key
// to delay data creation until need use a callback. do not use a plain array or object.
$data = function () {
    return [1, 2, 3];
};
$data = lapse($key, $data);

Example 2: with custom expiration time

$key = hash('xxh3', $page->url()); // unique key
$expires = 5; // in minutes. default: 0 aka infinite
$data = function () {
    return [1, 2, 3];
};
$data = lapse($key, $data, $expires);

Example 3: page object

$data = lapse(hash('xxh3', $page->url()), function () use ($kirby, $site, $page) {
    // create some data
    return [
        'author' => site()->author(),
        'title' => $page->title(),
        'text' => $page->text()->kirbytext(),
        'url' => $page->url(),
    ];
});

Remove by Key

$key = hash('xxh3', $page->url()); // unique key
$wasRemoved = \Bnomei\Lapse::rm($key);

Static Cache helper - lapseStatic()

Sometimes you need to cache things only for the current request like when reusing Kirbys Collections . The lapseStatic()-helper makes things like that a bit easier. The closure to generate the data will only be called once, set its return value to a static cache and every recurring call to the collection will get the cached collection back from static memory array.

site/plugins/example/index.php

<?php

Kirby::plugin('bnomei/example', [
  'collections' => [
    // collections have to be a closure that is why it is wrapped in a fn
    'recent-courses' => fn() => lapseStatic(
        'recent-courses', // key 
        function () { // value
            return page('courses')->children()->listed()->sortBy('name')->limit(10);
        }
    )
]);

Clever keys

Unique but not modified

Caches use a string value as key to store and later retrieve the data. The key is usually a hash of the objects id plus some meta data like the contents language. Storing data related to a Page using the $key = hash('xxh3', $page->url()); will work just fine. It takes care of the language if you use a multi-language setup since the language is included in the url. But it will expire only if you provide a fixed time or devalidate it yourself.

Modified

The solution is to include the modification timestamp of every object related to the data. So if you store the result of a Page Object with Images being rendered you need to include the modification timestamp of all of these. That will cause the creation of a new cache every time your source changes.

Basic

$keys = [ $page->url().$page->modified() ];
foreach($page->images() as $image) {
    $keys[] = $image->id().$image->modified();
}
$key = hash('xxh3', implode($keys));

Objects

Since version 2 of this plugin you can also forward any of these and the key will be magically created for you.

Page-Objects,
File-Objects and FileVersion-Objects (aka Thumbs),
Collections or
the Site-Object

$objects = [$page, $page->images()];
$data = lapse($objects, ...)

Multi-language support

The keys created by the plugin are tagged with the current language. You will get a different cache value for each language.

AutoID or BoostID

If you use the AutoID plugin or Boost plugin the modification timestamps will be retrieved at almost zero-cpu-cost and not causing the file to be checked on disk.

FAQ

Infinite cache duration by default

Unless you set an expiration when using lapse() the cache file will never devalidate. This is because the plugin is intended to be used with keys defining the expiration like $key = hash('xxh3', $page->id().$page->modified());.

$expires = 5; // in minutes. default: 0 aka infinite
$data = lapse($key, $data, $expires);

When using Memcache or APCu you need to limit the maximum number of caches created since you have a very limited amount if memory of 64MB at default. You can set a limit at bnomei.lapse.indexLimit to something like 300. But be aware that this makes writing to the cache a tiny bit slower since the plugins internal index must be updated.

No cache when debugging

When Kirbys global debug config is set to true the complete plugin cache will be flushed and no caches will be created. This will make you live easier – trust me.

Kirby Field-Objects and serialization

The plugin uses the default Kirby serialization of objects and since memory references are lost anyway all Kirby Field-Objects are stored by calling their ->value() method. The File-Cache uses a json format.

Migrating from v1 of this plugin

$force param has been removed: use proper keys.
all settings have been removed: they are not needed anymore like explained above.

Performance

Use crc32 to generate the hash

xxh3 is the fastest non cryptographic hashing hashing algorithm in PHP 8.1 . The keys for lapse do not need to be encrypted.

Cache Driver

For best performance set the global cache driver to one using the servers memory not files on the harddisk (even on SSDs). Memcache or ApcuCache can be activated on most hosting environments but rarely are by default. Also see bnomei.lapse.indexLimit setting explained above. My Redis Cache Driver and SQLite Cache Driver are faster than other cache drivers and have no memory limit. In all other cases use the very fast PHP Cache Driver or APCu.

return [
  'cache' => [
    'driver' => 'apcu', // php, redis, sqlite
  ],
];

Examples

// lapse v1 could already do this:
// store data until objects are modified with optional expire
$data = lapse(
    $page->id().$page->modified(),
    ['some', 'kind', 'of', 'data'],
    60*24*7 // one week
);

// now it can create magic cache keys from kirby objects
$data = lapse(
    $page, // key with modification date created by lapse based on object 
    function () use ($page) {
        return [
           'title' => $page->title(),
       ];
    }
);

// or from an collection of pages or files
$collection = collection('mycollection');
$data = lapse(
    $collection, // this will turn into a key taking modification date of all objects into consideration
    function () use ($collection) {
        return [ /*...*/ ];
    }
);

// or from an array combining all these
$data = lapse(
    ['myhash', $page, $page->children()->images(), $collection, $site], // will create key from array of objects
    function () use ($site, $page, $collection) {
        return [
            // will not break serialization => automatically store ->value() of fields
            'author' => $site->author(),
            'title' => $page->title(),
            'hero' => $page->children()->images()->first()->srcset()->html(),
            'count' => $collection->count(),
        ];
    }
);

// remove by dynamic key
$wasRemoved = \Bnomei\Lapse::rm(
    ['myhash', $page, $page->children()->images(), $collection, $site]
);

🏎️ if you use autoid or boost the modified lookups will be at almost zero-cpu cost.

Cancel the caching

If you want to cancel the caching you can throw the LapseCancelException in the closure. This will prevent the caching of the data and return null.

$data = lapse(
    $page,
    function () use ($page) {
        if ($page->isUnpublished()) {
            // do not cache unpublished pages
            throw new \Bnomei\LapseCancelException();
        }
        return $page->title()->value();
    }
);
// $data === null for unpublished pages

Disclaimer

This plugin is provided "as is" with no guarantee. Use it at your own risk and always test it yourself before using it in a production environment. If you find any issues, please create a new issue.

License

MIT

It is discouraged to use this plugin in any project that promotes racism, sexism, homophobia, animal abuse, violence or any other form of hate speech.

Credits

based on V2 version of

https://github.com/jenstornell/kirby-time-cache

bnomei / kirby3-lapse

Maintainers

Details