LH Cache Warmer

Warms the LiteSpeed cache after a purge by fetching a scoped set of URLs on the current site. Designed for WordPress Multisite as part of the LocalHero platform.

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Description

After a LiteSpeed cache purge, this plugin automatically schedules a background cron job that visits a curated set of URLs as an unauthenticated visitor, ensuring those pages are cached before real users arrive.

The URL set is intentionally scoped to high-value content:

• The front page and its first 5 paginated archive pages (/page/2/ etc.)
• The 20 most recent published posts
• All published pages
• URLs from administrator-configured navigation menus

Password-protected posts and pages are excluded. Admin URLs and external URLs found in menus are excluded. Menu items restricted to logged-in users are excluded automatically at warm time (cron runs as user ID 0).

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Installation

1. Upload the lh-cache-warmer folder to /wp-content/plugins/
2. Activate the plugin on each site where cache warming is desired (not network-activated)
3. Go to Settings > Cache Warmer and configure the menus to include

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Admin Interface

Settings > Cache Warmer

Menus to Warm A list of all registered navigation menus shown as checkboxes. Check any menus whose public-facing URLs should be included in the warm cycle. Only URLs on the current site are included; admin URLs and external links are excluded automatically.

Delay Between Requests (ms) Milliseconds to pause between each outbound request during the warm cycle. Default: 500. Reduce to 200–300ms if warming is too slow; increase if the server shows load spikes during warming.

Manual Warm Triggers a warm cycle immediately (scheduled 1 second from now via WP-Cron). Only shown when no warm cycle is already pending.

URLs to be Warmed A live preview of the deduplicated URL list that will be warmed, with the post/page title, a link to the front-end URL, and an Edit link for posts and pages. Count is shown at the top.

Note: Menu URLs shown here reflect the current admin view. Items restricted to logged-in users will be excluded automatically during the warm cycle.

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How It Works

1. LiteSpeed Cache fires litespeed_purged_all or litespeed_purged_front on a full purge
2. The plugin checks whether a warm cycle is already pending via wp_next_scheduled()
3. If not, it schedules a single wp_schedule_single_event() 30 seconds in the future
4. When the cron fires, it calls get_url_items() to build the URL list, deduplicates, then fetches each URL sequentially via wp_remote_get() with the configured delay between requests
5. The next purge will schedule a fresh cycle

The 30-second delay allows rapid successive purges to settle before warming begins, preventing redundant warm cycles.

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Database

This plugin creates no database tables. Settings are stored per-site using get_option() / update_option() under the key lh_cache_warmer_settings.

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Constants

None.

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Hooks

Actions

Hook	Description
litespeed_purged_all	Triggers a warm cycle schedule
litespeed_purged_front	Triggers a warm cycle schedule
lh_cache_warmer_run	The cron hook that executes the warm cycle

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Options

Option key	Scope	Description
lh_cache_warmer_settings	Per-site	Array containing menu_slugs (array of slugs) and delay_ms (int)

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Cron Jobs

Hook	Type	Description
lh_cache_warmer_run	Single event, scheduled on purge	Fetches all warm URLs sequentially

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Changelog

1.0.1 — 2026-06-07

• Exclude password-protected posts and pages from warm cycle
• Exclude admin URLs from menu items
• Add edit links to URL list on settings page
• Add notice about menu URL discrepancy between admin view and warm cycle
• Add readme.md and index.php directory guards

1.0.0 — 2026-06-07

• Initial release
• Warms front page (pages 1–5), recent posts (last 20), all pages, and configured menu URLs
• Excludes password-protected content, admin URLs, and external URLs
• Settings page with checkbox menu selection, delay configuration, live URL preview, and manual warm trigger
• Deduplicates URLs within each warm cycle
• Skips scheduling if a warm cycle is already pending