Add "create" prompt to open registration page directly #1134
Description
Feature Request
Motivation
Sometimes client apps need to open the registration page directly instead of landing user on login page
The OpenID Connect specification allows to use prompt parameters to configure how the authorization server interacts with the user. While prompt=login, prompt=none, and prompt=consent are commonly supported, an increasing number of identity providers (e.g., Auth0, Keycloak - evidence) have started to support a custom extension: prompt=create. This prompt is used to explicitly trigger a sign-up or account creation flow, rather than a typical sign-in.
Here's an OIDC specification created in December 2022 - link
Description
I propose to extend standard set of AuthorizationRequest.Prompt constant values ("none", "login", "consent", "select_account") with "create".
This will:
- standardize the set of allowed prompt
- add extensive documentation for newcomers with link to specs (as we do it for other values)
- align AppAuth with real-world OIDC implementations (Keycloak, Auth0, etc.)