:title
Request Context Params

:sig
SCRIPT_URL, BASE_URL, ROUTE_PATH, ROUTE_PAGE, ROUTE_PATH_RAW, ROUTE_VALID

:see
request_script_url
request_base_url
request_query_path
request_query_route
route_path_sanitize
route_path_is_safe
0_Request

:content
UCE populates several convenience request parameters before invoking page, component, CLI, custom HTTP, or WebSocket handlers:

- `context.params["SCRIPT_URL"]`: canonical script URL, with `/index.uce` collapsed to the containing directory URL
- `context.params["BASE_URL"]`: canonical directory URL for the script
- `context.params["ROUTE_PATH"]`: sanitized first keyless query-string segment, defaulting to `index` when no route was supplied
- `context.params["ROUTE_PAGE"]`: first segment of `ROUTE_PATH`
- `context.params["ROUTE_PATH_RAW"]`: normalized but not trusted route input, for diagnostics only
- `context.params["ROUTE_VALID"]`: `1` when the supplied/defaulted route is safe, `0` when the supplied route was rejected

`ROUTE_PATH` is safe to compose under an application-controlled route root. Unsafe route input such as `..`, `.`, empty interior segments, backslashes, dots in filenames, or other non route-segment characters is rejected by the runtime and yields an empty `ROUTE_PATH` with `ROUTE_VALID=0`.

These are useful for front-controller apps that use URLs like `/?dashboard` or `/?workspace/projects` while still accepting ordinary named query parameters.
