Invalidating Cache Entries (or entire cache programmatically) about surge

[kovshenin]

Nice! blogid is just an arbitrary string, there's no standard way, you can really flag a cached entry with any string you like, as long as it can be successfully encoded to an decoded from JSON, it should be ok.

[kovshenin]

@MadtownLems you can use Surge\flag() to set specific flags when a page is being rendered, for example if it's rendered using block-1, block-2 and block-3, you can add those flags to the request, then use Surge\expire() to expire block-1 when it's updated, which would invalidate all pages with that flag.

There are some examples in the existing invalidation routines: https://github.com/kovshenin/surge/blob/main/include/invalidate.php

Hope that helps!

[MadtownLems]

Hope that helps!

I wish it did 😅

I've taken a look at invalidate.php many times now (as well as https://konstantin.blog/2021/wordpress-cache-invalidation-with-flags/ ) and still have no idea how I might use Surge\flag().

We have Surge network activated on a MultiSite network, and what I'm really trying to do is figure out a way to clear a single subsite's entire cache on certain events.

I've also been looking at /wp-content/cache/surge/flags.json.php and am trying to understand how the flags stored in this file differentiate between sites in the multisite 🤔

Any insights you can provide would be much appreciated. 🙏

[kovshenin]

@MadtownLems here's an example:

// Flag each entry with the current blog id.
add_action( 'template_redirect', function() {
    Surge\flag( sprintf( 'blogid:%d', get_current_blog_id() ) );
} );

// Expire all subsite cache on certain events.
add_action( 'certain_event', function() {
    Surge\expire( sprintf( 'blogid:%d', get_current_blog_id() ) );
} );

[MadtownLems]

here's an example:

Perfect! Exactly what I was looking for. I had no idea that "blogid:" was a valid flag, as I didn't see it anywhere else in invalidate.php.

Question: Are the available flags some standard thing that I can read about somewhere?