Resolve the public login credential

Reports whether the "Connect as public user" button can be offered, and with which credential. Anything unexpected — no network, a blocked host, a malformed descriptor, or public access switched off upstream — comes back as unavailable. There is deliberately no built-in fallback value; a credential with a default in the source is a credential that gets published the first time the file moves.

Usage

.public_credential(
  url = getOption("CafriplotsR.public_access_url", .public_credential_url),
  timeout = 5,
  force = FALSE
)

Arguments

url

Descriptor to read. Defaults to the published one, or to `getOption("CafriplotsR.public_access_url")` when set — which is how a test, or a site mirroring the descriptor behind its own firewall, points this elsewhere.

timeout

Seconds to wait for it. Kept short: this runs while the user is looking at the login screen.

force

Skip the cache and ask again.

Value

A list with: - `available`: logical, whether public login can be offered - `user`, `password`: the credential, empty strings when unavailable - `message`: text to show in place of the button, possibly empty

Details

Environment variables win over the published descriptor. A served deployment injects them (see `deployment/taxonomic_match/`) and must not depend on a third-party host being reachable to let anyone in.