v0.29.2

docs/CUSTOM_LOCATIONS.md

@@ -110,6 +110,12 @@ All access layers are additive. The request must pass the vhost method policy, l
 
 Authentication, vhost rate limits, security headers, compression, custom error pages and WebSocket policy still apply through the normal vhost pipeline.
 
+## Internal locations and error fallbacks
+
+RustProxy 0.29.1 can mark a Custom location as `internal`. An internal location is addressed by its stable location `id` and is never selected by a public URI match. The vhost main source or another Custom location can use `error_fallback` to internally dispatch configured `403/404/500/502/503/504` responses to that target. The default intercepted status is `404`.
+
+This is an internal request handoff, not an HTTP redirect. The original method, URI/query and request context are retained. The fallback target re-enters normal access/header/cache/compression/response processing. Fallback targets must be enabled internal locations in the same vhost; validation rejects cycles and runtime dispatch is depth-limited. See [0.29.1 implementation note](V0.29.1_IMPLEMENTATION.md).
+
 ## What is intentionally not an Nginx parser
 
 Custom locations do **not** execute arbitrary Nginx directives or configuration snippets. RustProxy does not currently implement location-level `try_files`, per-location filesystem aliases/roots, embedded scripting, arbitrary `if` expressions or arbitrary module directives. Static roots are defined only by reusable Web Services. Use the explicit UI controls and the documented JSON schema instead; unknown fields are rejected on save.