Authentication Portal API

Purpose

Use this skill for HTTP/JSON interactions with a configured authentication portal. Use configuration-authentication for the surrounding portal Caddyfile and configuration-http-integrations for route mounting.

Read these files when details matter:

• ../go-authcrunch/pkg/authn/handle_json_*.go for JSON handlers and response shapes.
• ../go-authcrunch/pkg/authn/handle_http_*.go for browser versus JSON behavior.
• caddyfile_authn_misc.go for enable admin api.

JSON Requests

Portal endpoints return JSON when the request includes either:

Accept: application/json
format=json

Without one of those signals, many endpoints follow browser-oriented behavior such as rendering HTML or redirecting.

Assume endpoint paths are relative to the portal base path. If the portal is served at /auth, then /login means /auth/login, /whoami means /auth/whoami, and admin endpoints are under /auth/api/server/....

Login Challenge Sequence

Programmatic login is challenge-based:

1. POST <base>/login with username and realm.
2. The portal returns sandbox_id, sandbox_secret, and next_challenge.
3. The client posts the same identity plus sandbox_id, current sandbox_secret, challenge_kind, and challenge_response.
4. The portal may rotate sandbox_secret and return another challenge.
5. When all checkpoints pass, the current JSON login path returns authenticated: true, access_token_name, and access_token. The AuthResponse struct has refresh-token fields, but the current handleIssueTokens path in local go-authcrunch does not populate them.

Common challenge kinds are password, totp, and mfa. For WebAuthn/U2F, the client first answers challenge_kind: mfa with challenge_response: webauthn; the next challenge contains a base64-encoded WebAuthn payload. The final response must contain the signed WebAuthn result.

Do not reuse an old sandbox_secret; use the latest value returned by the portal. Sandbox sessions are temporary and separate from the final JWT session.

Status And Identity Endpoints

Use /beacon for a light authentication probe. A valid token returns 200 OK with a plain OK body; an invalid or expired token returns an access-denied JSON response when JSON was requested.

Use /whoami for the current user claims. Useful query parameters include:

• probe=true: include authenticated and expires_in.
• format=json: force JSON when no JSON Accept header is present.
• id_token=true: include the upstream identity provider ID token when an OAuth provider was configured with enable id token cookie.

Send access tokens using the portal-supported Authorization header or cookies that match the portal's token validator configuration. If custom access-token cookie names are used, keep portal and authorization policy names aligned with configuration-authentication-cookies and configuration-crypto.

Admin Server API

Add this inside authentication portal <name> to enable the server/admin API:

authentication portal myportal {
	enable admin api
}

The documented endpoints include:

• GET /api/server/metadata: version, build, and server timestamp metadata.
• POST /api/server/realms: local realm discovery.
• POST /api/server/info: local identity database path, modification time, and password/user policy details for a realm.

Admin API requests require an active authorized session with an admin role. When debugging, check both the Caddyfile directive and the authenticated user's roles before suspecting handler bugs.

Troubleshooting

• Missing JSON response: add Accept: application/json or format=json.
• Login sequence fails after password: verify the client preserved the latest sandbox_id, latest sandbox_secret, and expected challenge_kind.
• MFA prompts unexpectedly: inspect user tokens, require mfa transforms, and auth challenge rules stored in the local user database.
• /whoami omits upstream ID token: verify the OAuth provider uses enable id token cookie ... and the browser/client sends the ID-token cookie.
• /api/refresh_token surprises: the current endpoint is an authenticated JSON endpoint that returns a timestamp; it does not mint a replacement token value.
• Admin endpoint returns unauthorized: verify enable admin api, active portal session, and authp/admin or equivalent portal admin role.