Caching

Caching

oCMS uses a multi-layer caching system to improve performance while ensuring data freshness.

RSS and Atom feeds

Feeds are generated from current database data on every request. They use Cache-Control: public, no-cache and deterministic weak ETags; matching If-None-Match validators return a bodyless 304. Content changes are visible on the next request without clearing the page cache. HEAD retains GET's representation headers, including negotiated compression, and omits the body. Error responses use no-store.

Cache Types

Cache	Purpose	Invalidation
Config	Site settings (site_name, etc.)	On config update
Sitemap	Generated sitemap.xml	On page and language changes, theme activation and settings, and Migrator imports; also expires after 1 hour
Pages	Published page content	On page create/update/delete
Menus	Menu structure and items	On menu/item changes
Languages	Active languages list	On language changes
Translations	Entity translations	On translation changes

Context-Aware Page Caching

Pages are cached using context-aware keys that include language and user role:

{language}:{role}:{slug}

Examples:

• en:anonymous:about-us — English, anonymous visitor
• en:admin:about-us — English, admin user
• ru:anonymous:about-us — Russian, anonymous visitor

This ensures users see content appropriate for their language and access level.

Role Levels

Role	Level	Description
anonymous	0	Not logged in
public	0	Logged in, no special permissions
editor	1	Can edit content
admin	2	Full system access

Admin Panel Bypass

Admin routes (/admin/*) bypass the cache for site configuration lookups to ensure administrators always see fresh data. Frontend routes use the cache for performance.

Cache Backends

In-Memory (Default)

• Single-instance caching
• No external dependencies
• Lost on restart

Redis (Optional)

• Connected at startup when OCMS_REDIS_URL is set; if Redis is unreachable, oCMS logs a warning and falls back to memory
• The backend type and health are shown at /admin/cache, and "clear all" also removes the Redis keys under OCMS_CACHE_PREFIX
• The config, sitemap, page, menu, language and translation caches are held in each instance's own memory. They are not stored in Redis and are not shared between instances, so each instance invalidates only its own copies

Configure with environment variables (see Configuration):

OCMS_REDIS_URL=redis://localhost:6379/0
OCMS_CACHE_PREFIX=ocms:
OCMS_CACHE_TTL=3600

Cache Statistics

View cache statistics at /admin/cache:

• Hit rate per cache type
• Number of cached items
• Cache backend status (Redis/Memory)

Manual Cache Clearing

Clear caches from the admin panel at /admin/cache. You can clear individual cache types or all caches at once.

Automatic Invalidation

Caches are automatically invalidated when content changes:

• Page created/updated/deleted → Page cache + Sitemap cache
• Menu/item changed → Menu cache
• Config changed → Config cache
• Language changed → Language cache
• Translation changed → Translation cache for that entity type

Cache Preloading

On startup, oCMS preloads frequently accessed data:

• Site configuration
• All menus
• Active languages
• Sitemap (not at startup: it is built on the first /sitemap.xml request)