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Installation

Before installing and activating the LSCache plugin, deactivate all other full-page cache plugins.

Tip

You can still use other types of cache (like object cache), but only one page cache can be used at a time, so you’ll need to disable any other page caches, if you want to use LSCache.

Module Installation

Note

Please see the Overview for the server-level requirements before attempting to install this module.

  • Download the LiteSpeed Cache Module to your local computer from our GitHub repository.
  • Place the following code in the .htaccess file at the document root:
        <IfModule LiteSpeed>
        CacheLookup on
        </IfModule>
    
  • Visit http://example.com/admin/modules/install (where example.com/ is your site's domain) to install the LSCache plugin.

Tip

This import method requires that you have the Drupal core module Update manager enabled. Without it, the above link may not work.

  • Using the Choose File button, find the plugin you downloaded from GitHub, upload it, and press Install.
  • A confirmation screen should appear. Click Enable newly added modules or visit http://example.com/drupal/admin/modules directly.

  • Use the filter box to search for the LiteSpeed module, if the list is long.
  • Check the checkbox next to LiteSpeed Cache.
  • Click Install.

Verify Your Site is Being Cached

Video

See a video demonstration of this topic here.

Verify Cache Miss

You can verify a page is being served from LSCache through the following steps:

  1. From a non-logged-in browser, navigate to your site, and open the developer tools (usually, right-click > Inspect). Open the Network tab.
  2. Refresh the page.
  3. Click the first resource. This should be an HTML file. For example, if your page is http://example.com/webapp/, your first resource should either be something like example.com/webapp/ or webapp/.
  4. You should see headings similar to these:
    X-LiteSpeed-Cache: miss
    X-LiteSpeed-Cache-Control:public,max-age=1800
    X-LiteSpeed-Tag:B1_F,B1_ 
    
    These headings mean the page had not yet been cached, but that LiteSpeed has now stored it, and it will be served from cache with the next request.
  5. Reload the page and you should see X-LiteSpeed-Cache: hit in the response header. This means the page is being served by LSCache and is configured correctly.
    Verify Cache Hit

Alternative Headers

The X-LiteSpeed-Cache header is most common, but you may see X-LSADC-Cache if your site is served by LiteSpeed Web ADC. You may also see X-QC-Cache if your site was served via QUIC.cloud CDN. These alternate headers are also an indication that LSCache is working properly on your site.

Important

If you don't see X-LiteSpeed-Cache: hit or X-LiteSpeed-Cache: miss (or any of the alternative headers), then there is a problem with the LSCache configuration.

Non-Cacheable Pages

Sometimes there are pages which should not be cached. To verify that such pages have indeed been excluded from caching, check the developer tools as described above.

You should see headings similar to these:

X-LiteSpeed-Cache-Control:no-cache, esi=on
X-LiteSpeed-Tag:B1_F,B1_ 

X-LiteSpeed-Cache-Control, when set to no-cache, indicates that LiteSpeed Server has served your page dynamically, and that it was intentionally not served from cache.

LSCache Check Tool

There's a simple way to see if a URL is cached by LiteSpeed: the LSCache Check Tool.

Enter the URL you wish to check, and the tool will respond with an easy-to-read Yes or No result, and a display of the URL's response headers, in case you want to examine the results more closely.

LSCache Check

In addition to LSCache support, the tool can detect cache hits, and can detect when sites are using LiteSpeed Web ADC or QUIC.cloud CDN for caching.

Additionally, a Stale Cache Warning will alert you if browser cache is detected on dynamic pages. This is because browser cache may interfere with the delivery of fresh content.


Last update: June 4, 2021