Redirect to Apple OAuth
Generate an Apple OAuth URL for redirect-based authentication.
fluid_shop must be supplied in practice — this operation returns 422
without it — even though it is declared as an optional parameter, because
the requirement is enforced by the action rather than by parameter
validation. Treat it as mandatory when calling.
It is placed in the OAuth state (alongside a server-issued nonce, cached
for replay rejection) so the callback can resolve the company. Apple returns
to a bare redirect URI, so without it the shop is lost and white-label
customers are locked out.
The response mode is fixed server-side to form_post (Apple POSTs
directly to the callback rather than redirecting), so it is not a request
parameter.
Query Parameters
Company subdomain the sign-in belongs to, carried through the OAuth round-trip in state. Omitting it returns 422 — Apple sign-in cannot resolve a company without it.
Response
Success
OAuth provider URL for redirect-based authentication
Provider key this URL belongs to (e.g. google, facebook, apple).
Fully-formed provider authorization URL to redirect the user to; carries the server-issued OAuth state.
Callback URI the provider returns to after the user authorizes; must match the value registered with the provider.