README

This package allows you to use lscache together with Laravel.

It provides two middlewares and one facade:

LSCache Middleware to control the cache-control header for LiteSpeed LSCache
LSTags Middleware to control the tag header for LiteSpeed LSCache
LSCache facade to handle purging

Installation

Require this package using composer.

composer require litespeed/lscache-laravel

Laravel uses Auto-Discovery, so you won't have to make any changes to your application, the two middlewares and facade will be available right from the beginning.

Steps for Laravel >=5.1 and <=5.4

The package can be used for Laravel 5.1 to 5.4 as well, however due to lack of Auto-Discovery, a few additional steps have to be performed.

In config/app.php you have to add the following code in your aliases:

'aliases' => [
    ...
    'LSCache'   => Litespeed\LSCache\LSCache::class,
],

In app/Http/Kernel.php you have to add the two middlewares under middleware and routeMiddleware:

protected $middleware = [
    ...
    \Litespeed\LSCache\LSCacheMiddleware::class,
    \Litespeed\LSCache\LSTagsMiddleware::class,
];

protected $routeMiddleware = [
    ...
    'lscache' => \Litespeed\LSCache\LSCacheMiddleware::class,
    'lstags' => \Litespeed\LSCache\LSTagsMiddleware::class,
];

Copy lscache.php to config/:

Copy the package config/lscache.php file to your config/ directory.

important: Do not add the ServiceProvider under providers in config/app.php.

Steps for Laravel 5.5 and above

You should publish the package configuration, which allows you to set the defaults for the X-LiteSpeed-Cache-Control header:

php artisan vendor:publish --provider="Litespeed\LSCache\LSCacheServiceProvider"

Enable CacheLookup for LiteSpeed Cache

To enable CacheLookup for LiteSpeed Cache, you have to include the following code, either on server, vhost or .htaccess level:

<IfModule LiteSpeed>
   CacheLookup on
</IfModule>

Usage

The package comes with 3 functionalities: Setting the cache control headers for lscache, settings specific tags and purging.

cache-control

You'll be able to configure defaults in the config/lscache.php file, here you can set the max-age (default_ttl), the cacheability (default_cacheability) such as public, private or no-cache or enable esi (esi) in the X-LiteSpeed-Cache-Control response header.

If the default_ttl is set to 0, then we won't return the X-LiteSpeed-Cache-Control response header.

You can control the config settings in your .env file as such:

LSCACHE_ESI_ENABLED - accepts true or false to whether you want ESI enabled or not globally; Default false
LSCACHE_DEFAULT_TTL - accepts an integer, this value is in seconds; Default: 0
LSCACHE_DEFAULT_CACHEABILITY - accepts a string, you can use values such as private, no-cache, public or no-vary; Default: no-cache
LSCACHE_GUEST_ONLY - accepts true or false to decide if the cache should be enabled for guests only; Defaults to false

You set the cache-control header for lscache using a middleware, so we can in our routes do something like this:

Route::get('/', function() {
    return view('frontpage');
});

Route::get('/about-us', function() {
    return view('about-us');
})->middleware('lscache:max-age=300;public');

Route::get('/contact', function() {
    return view('contact');
})->middleware('lscache:max-age=10;private;esi=on');

Route::get('/admin', function() {
    return view('admin');
})->middleware('lscache:no-cache');

Below is 4 examples:

the / route will use the default X-LiteSpeed-Cache-Control header that you've configured in config/lscache.php.
the /about-us route sets a max-age of 300 seconds as well as setting the cacheability to public, keep in mind you'll use semi-colon (;) to separate these values.
the /contact route uses a max-age of 10 seconds, uses private cacheability and turns ESI on. Turning ESI on, allows you to use <esi:include> within your blade templates and these will be parsed by the ESI engine in LiteSpeed Web Server.
the /admin route will never be cached by setting a X-LiteSpeed-Cache-Control: no-cache -header.

Now, you'll also be able to apply the same middleware to route groups in Laravel, let's take an example:

Route::group(['prefix' => 'admin', 'middleware' => ['lscache:private;esi=on;max-age=120']], function() {
    Route::get('/dashboard', function() {
        return view('dashboard');
    });

    Route::get('/stats', function() {
        return view('stats');
    })->middleware('lscache:no-cache');
});

In the above case, we've set the whole admin group to be private with esi enabled and a max-age of 120 seconds, however in the /admin/stats route, we override the X-LiteSpeed-Cache-Control header to no-cache.

purge

If we have an admin interface that controls for example a blog, when you publish a new article, you might want to purge the frontpage of the blog so the article appears in the overview.

You'd do this in your controller by doing

<?php

namespace App\Http\Controllers;

use LSCache;

class BlogController extends BaseController
{
    // Your article logic here

    LSCache::purge('/');
}

In the above example, we're simply telling it to add an additional header called X-LiteSpeed-Purge with the value stale,/, this will invalidate the frontpage of the site.

You can also purge everything by doing:

LSCache::purge('*');
// or
LSCache::purgeAll();

One or multiple URIs can be purged by using a comma-separated list:

LSCache::purge('/blog,/about-us,/');
// or
LSCache::purgeItems(['/blog', '/about-us', '/']);

You can purge individual or multiple tags:

LSCache::purge('tag=archive, tag=categories');
// or
LSCache::purgeTags(['archive', 'categories']);

Or if you want to purge private cache by tag:

LSCache::purge('private, tag=users');

You even have the possibility to purge a set of public tags and and purge all the private tags:

LSCache::purge('pubtag1, pubtag2, pubtag3; private, *');

LiteSpeed Cache for Laravel 1.1.0 comes with a stale option turned on by default for the LSCache::purge function, this can be turned off by using false as the second parameter in the purge function:

LSCache::purge('*', false);
// or
LSCache::purge('*', $stale=false);
// or
LSCache::purgeAll(false);

Why stale purge matters

By default the way Lscache works in LiteSpeed is by purging an element in the cache, and next request will generate the cached version.

This works great if you're running a fairly low traffic site, however if your application takes let's say 2 seconds to process a given request, all traffic received to this endpoint within those 2 seconds will end up hitting the backend, and all visitors will hit PHP.

By using the stale, keyword in front the "key" you're purging, you're telling Lscache to purge the item, but if multiple visitors hit the same endpoint right after each other, only the first visitor will be the one generating the cache item, all remaining vistors will get served the stale cached page until the new cached page is available.

Since a page generation should be rather fast, we're only serving this stale content for maybe a couple of seconds, thus also the reason it's being enabled by default.

If your application cannot work with stale content at all, then you can use false or $stale=false as the second parameter in the LSCache::purge() function to disable this functionality.

You can also purge specific public tags by adding ~s after the tag, such as:

LSCache::purge('pubtag1, pubtag2~s, pubtag3; private, privtag1, privtag2', $stale=false);

Only pubtag2 will be served stale.

Laravel Authentication

If you use authentication in Laravel for handling guests and logged-in users, you'll likely want to also separate the cache for people based on this.

This can be done in the .htaccess file simply by using the cache-vary on the Authorization cookie:

RewriteEngine On
RewriteRule .* - [E=Cache-Vary:Authorization]

Note: In the above example we use Authorization, this may have a different name depending on your setup, so it has to be changed accordingly.

litespeed / lscache-laravel

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