Architecture

Architecture

bext-wp is a small, dependency-free, namespaced (Bext\WP) plugin with a custom autoloader.

Boot

bext-wp.php (normal plugin)   or   mu-loader.php → bext-wp/bext-wp.php (must-use)
        │
        ▼
Plugin::instance()->boot()
        │  builds Env, then registers modules
        ├── always:  Settings, Admin, Health   (so the UI always exists)
        └── gated:   Cache, Cron, SDK          (Env::is_enabled)

Each module exposes register() and is expected to no-op when not behind bext and fail open on any bext call.

Files

File	Responsibility
bext-wp.php	Plugin header, constants, autoloader, boot, deactivation cleanup
mu-loader.php	must-use stub that requires the package from its subdirectory
uninstall.php	removes all bext_wp_* options (multisite-aware)
src/Plugin.php	singleton orchestrator; boots modules
src/Env.php	config resolution (constant > setting > default) + loopback/cloud transport
src/Settings.php	wp-admin Settings page (option bext_wp_settings)
src/Cache.php	purge-on-change + personalization-safe headers + manual purge
src/Cron.php	Action Scheduler taming + queue stats
src/Health.php	config checks + PHP-warning capture
src/Admin.php	dashboard + admin-bar pill
src/SDK.php	wp_mail + job bridge
src/Network.php	multisite network-admin settings + cross-site dashboard/purge (loads only on multisite)
cli/Commands.php	wp bext …
bin/deploy-fleet.sh	copy-per-site installer

Env: the hub

Env is the one place that knows how to talk to bext:

• Config — mode(), is_enabled(), app_id(), purge_on_save_enabled(), anon_cache_control(), sdk_email_enabled(), sdk_jobs_enabled(), cloud getters — each layered constant > setting > default.
• Detection — is_behind_bext() (param / header / sticky flag / mode).
• Transport — endpoint_base() (loopback 127.0.0.1:80 vs cloud URL) + transport_headers() (Host, and Authorization: Bearer in cloud mode), used by purge_proxy(), sdk_request(), bext_get().

State

Option	Autoload	Purpose
bext_wp_settings	yes	the Settings page values
bext_wp_detected	yes	sticky "we've seen a bext signal" flag (auto mode)
bext_wp_purge_log	no	recent purges (dashboard)
bext_wp_recent_warnings	no	captured PHP warnings (dashboard)

Transient bext_wp_test_result holds the last Test connection outcome (60 s).

bext-side touchpoints

• BEXT_SERVER FastCGI param → detection.
• POST /__bext/cache/purge-proxy → fastcgi_cache.invalidate_paths/prefix (the real eviction).
• BEXT_PURGE_TOKEN env → opt-in bearer auth for remote (cloud) purges.
• /__bext/sdk/* (email/queue), /__bext/health → SDK + dashboard.

Compatibility

PHP 7.4+ (no 8.0-only syntax). Multisite-aware (per-blog options; subdirectory full-purge scoped to the blog path). Works with or without WooCommerce / Action Scheduler.