2.4.1.1.13. Server caching

Important points:

  • When enabling caching, make sure the site returns no-cache headers when accessing its admin panel; otherwise, such pages may be cached and become accessible to unauthorized users, or configure exceptions.
  • When using sessions, PHP automatically adds the Cache-Control header to responses, and caching does not work by default. For caching to work, the cache limiter value must be public (see session_cache_limiter).

How caching works

sequenceDiagram autonumber participant client as Client box Hosting participant cache as Cache participant site as Site end client->>cache: Request cache->>cache: Cache check alt Cache exists and is not ignored cache->>client: Response from cache else Cache is missing or being ignored cache->>site: Request end site->>site: Request processing alt Without storing in cache site->>client: Response else With storing in cache site->>cache: Response cache->>cache: Response caching cache->>client: Response end

When using caching, all server responses are stored in the cache, and when receiving new requests, instead of forwarding them to the site scripts for processing, a ready-made response is returned from the cache. Using caching helps to significantly reduce the load on the web server.

The page is not stored in the cache:

  • If the request contains:
    • The Cookie header with the nocache key with a non-empty value and not equal to 0.
    • GET parameter nocache with a non-empty value and not equal to 0.
    • The Authorization header with a non-empty value and not equal to 0.
  • If the response contains:
    • The X-Accel-Expires header with a value of 0.
    • The Set-Cookie header.
    • The Vary header with the special value *.
    • The Cache-Control header with any of the following values: max-age=0, private, no-store, no-cache.
  • If in the "Hosting → My sites → your site → PHP settings" section, the "output_buffering" option is disabled (when buffering is disabled, nginx does not process data from the web server and cannot cache it).

The existing cache is ignored if the request contains the same headers/parameters that prevent the page from being cached (see above). ⚠️ The cache is not overwritten or deleted. For example, when request A was made, the page was stored in the cache, then request B was made with conditions for ignoring the cache — the cache was ignored and the page was returned by the site, if request C is made without conditions for ignoring the cache — the cache that was generated for request A will be returned.

Using the X-Cache-Status response header, you can monitor cache usage:

  • Page was returned by the site:
    • MISS — page was not in the cache.
    • BYPASS — cache was ignored (see above).
    • EXPIRED — cache lifetime has expired.
  • Page was returned from cache:
    • STALE — cache lifetime has expired, but the current version of the page could not be obtained from the site.
    • REVALIDATED — cache lifetime has expired, but it was revalidated using the If-Modified-Since or If-None-Match header.
    • UPDATING — cache lifetime has expired, but the page is being updated from the site.
    • HIT — page was returned from cache.

When the cache is ignored and the response contains the Cache-Control header, the status may be appended with an indication of the reason why the cache was ignored: /PRIVATE, /NO-CACHE, /NO-STORE, /MAX-AGE.

Caching settings

To configure caching in the "Hosting → My sites → your site → Site settings" on the "Caching" tab in the "Site caching settings" section, select the desired mode, specify the cache lifetime, and save your changes:

  • Mode:
    • Disabled — caching is disabled.
    • Enabled — caching with GET parameters (for requests to the same page with different GET parameters and without them, different responses will be returned from the cache).
    • Ignore request parameters — caching with GET parameters ignored (for requests to the same page with different GET parameters or without them, the same response will be returned from the cache).
  • Lifetime — how many minutes after the last use cache will be deleted.
    • Selected individually. For sites with frequent content updates, you can use lower values; for sites with infrequent updates, you can use higher values.

Configure exceptions

You only need to configure exceptions separately for those parts of the site for which the site's scripts do not return cache-ignore headers (see above).

If you want to prevent certain pages or sections of the site from being cached, regardless of whether they have the necessary headers, add rules to exclude them in the "Exceptions from caching" section:

After clicking the "Add" button, enter the following information in the add form:

  • Applying — which part of the URL will be searched:
    • URL starts with — at beginning of URL.
    • URL ends with — at end of URL.
    • URL contains — in any part of URL.
  • URL — a string that will be searched for in the selected part of URL:
    • Domain does not need to be specified.
    • The slash / at the beginning and end is not required.

Here are a few examples:

  • If you select URL starts with and specify the URL as admin, an exception will be added as /admin*, and caching will not be applied to any URLs that start with /admin.
  • If you select URL ends with and specify the URL as page, an exception will be added as */page, and caching will not be applied to any URLs that end with /page.
  • If you select URL contains and specify the URL as contains, the exception will be added as */contains*, and caching will not be applied to any URLs that contain /contains in the middle.

Clear cache

In the "Site caching settings" section, click "Clear cache".

Content
    (6)

    Comments

    WEBUS.in.ua
    2026-07-15 - 11:15 pm
    Чи можна зробити виключення з кешу чимсь іншим крим заголовків веб-сторінки?
    karlov
    2026-07-16 - 09:12 am
    На поточний момент підтримуються тільки заголовки. Можливість виключення каталогів поки що тільки розглядається.
    karlov
    2026-08-04 - 05:30 pm
    Додана можливість налаштування винятків.