Caching and i18n

GoPress treats cache and internationalization as core services because both affect routes, templates, admin labels, settings, SEO, and frontend rendering.

Multi-level Cache

Cache keys include the language dimension so translated pages never share HTML entries. Content writes, menu updates, settings changes, theme switches, and plugin activation changes invalidate the corresponding tags or cache paths. The admin cache page also provides manual all-cache, page-cache, and fragment-cache operations.

Redis is optional. When it is missing or unavailable, GoPress continues with the in-process cache and database rather than making the site unavailable.

Redis keys are namespaced per site as gopress:<namespace>:, and clearing all caches or invalidating by prefix only touches the current site's keys. The namespace comes from [redis].namespace or, when unset, is derived from the database connection and table prefix, so several sites can safely share one Redis database. See Configuration.

Core i18n Architecture

Core owns localization primitives; an optional multilingual plugin contributes database overrides and management UI through public contracts:

core/i18n.Manager
  -> layered messages published as immutable bundle snapshots
  -> LoadThemeLocales / LoadLocalesFS / AddMessages
  -> T(ctx, key)
  -> TranslateOption / TranslateSettings

core/option registry
  -> RegisterTranslatable(key, section, label)
  -> IsTranslatable / AllTranslatableKeys

resolution priority
  1. override layer: database StringTranslation via AddMessages
     domain="theme" for UI; domain="option" for settings
  2. extension layer: namespaced plugin locale catalogs (LoadLocalesFS)
  3. theme layer: the active theme's locales/ files
  4. original message ID

A go-i18n bundle must not change while it is being read, so the manager never mutates the bundle in use. After any layer changes it builds a new bundle from all layers and publishes it atomically. Localizers keep the snapshot they were created with, so in-flight requests finish consistently while new requests use the new snapshot. Theme activation replaces the whole theme layer: after switching to a theme that lacks a key (or has no locales/ directory), the previous theme's text no longer leaks through. The database override layer survives theme switches. Bundle() returns a read-only snapshot; extensions change translations through AddMessages or LoadLocalesFS.

This fallback chain keeps a page usable when a translation is incomplete. Core remains a complete single-language CMS when no plugin supplies database translations.

UI Strings

Themes place JSON messages under locales/ and use {{T .Ctx "welcome"}} in templates. A multilingual extension may add or override messages in the database without editing theme files.

Translatable Settings

Themes register copy-oriented option keys such as hero headings or About text. Core translates only registered keys when rendering the settings map:

func registerTranslatableOptions() {
    option.RegisterTranslatable("home_hero_title", "hero", "Hero title")
    option.RegisterTranslatable("home_about_title", "about", "About title")
}

func (p *PageData) TranslateSettings(c *gin.Context, manager *i18n.Manager) {
    p.Settings = manager.TranslateSettings(
        c, p.Settings, option.IsTranslatable, option.AllTranslatableKeys())
}

Template Helpers

{{T .Ctx "welcome"}}
{{currentLang .Ctx}}
{{langPrefixURL .Ctx "/about"}}
{{archiveURL "product"}}
{{contentURL . "product"}}
{{taxonomyURL "category" .Slug}}

product is only an example theme-defined type. The URL helpers consult the rewrite registry, so custom type names and changed rewrite_slug values do not require hard-coded link changes.

Language Scope

A multilingual plugin can add language-aware content and term queries through the generic Content and Taxonomy Scope APIs, resolve per-language menus through menu hooks, and add URL prefixes through core helpers. Core and themes do not import or inspect that plugin; without it, the same APIs retain single-language behavior.

See the Multilingual Plugin for content and Category/Tag translation, canonical URL detection, menu assignment, SEO alternates, and language-switching behavior.