[Feature Request] [L] MSAL.NET supports Prompt.Create so that customers can implement self-service sign-up

[jmprieur]

Is your feature request related to a problem? Please describe.
When developers want to implement self-service # for their apps, they can use a prompt=create, triggered by a "Sign-up" link in their app. The end user can then enter the 'create account' experience.

Describe the solution you'd like
MSAL.NET should propose a new property named Create in the Prompt class. When using this property, MSAL.NET would send 'prompt=create' to the authorize endpoint, which will trigger the sign-up experience.

Additional context

Example URL:
https://#.microsoftonline.com/d014fd44-d398-4813-a3a9-8cd725f7f356/oauth2/authorize?
client_id=da53de5a-636b-425f-ad57-0f62d6f974c7
&response_type=id_token
&resource=da53de5a-636b-425f-ad57-0f62d6f974c7
&scope=openid
&nonce=default_nonce
&redirect_uri=https://jwt.ms
&prompt=create

The draft OIDC spec for this is here: https://openid.net/specs/openid-connect-prompt-create-1_0.html

Work to do

• Expose a new Create property in Prompt.
• Wire-up the prompt so that 'prompt=create' is sent to the authorize endpoint when this prompt is used.
• Update the wiki page, or better redirect it to the docs.ms page, which would, however need to be synced
  Update after release
• Update the docs.ms AcquireToken desktop scenario page.
  MS Docs PR Merge after release
• Update Microsoft.Identity.Web documentation to explain how to trigger a sign-up experience
  Updated: Web Apps / Enabling sign-up experience

Out of scope for this work item:

• Update the desktop sample to showcase this new prompt.
• Update the Xamarin sample to showcase this new prompt
• Update the desktop tutorial to showcase this new prompt

[jmprieur]

@bgavrilMS this is something we committed to for Q3. I'd suggest we take it for next sprint / the release after next

cc: @henrik-me

[bgavrilMS]

Not applicable to WAM

[bgavrilMS]

@jmprieur - this prompt works for the application you provided in the example, but not for others. This will be confusing to people. Is there a config in the app registration that must be performed?

[jmprieur]

@bgavrilMS
yes there is an app registration that needs to be performed, @bgavrilMS: this is for external identities:https://docs.microsoft.com/en-us/azure/active-directory/external-identities/self-service-sign-up-user-flow

[jmprieur]

We probably don't want to update the samples ...?

[pmaytak]

@jmprieur @jennyf19
For Identity Web, I updated Web Apps / Enabling sign-up experience wiki. Would it be useful to add that # action to Identity.Web.UI AccountController?

[jmprieur]

@pmaytak : I don't think so ... this is only for external identities ...