Identity Experience Framework and social accounts - azure-ad-b2c

Question

I developed a policy, which allows to login with username and password (B2C user) or using the Microsoft account, connecting the AD as an OpenId Identiy provider. It works fine, but when I login with my Microsoft account, the email is not set:
I guess I have to set something in the following snippet:
<TechnicalProfile Id="AAD-UserWriteUsingAlternativeSecurityId">
<Metadata>
<Item Key="Operation">Write</Item>
<Item Key="RaiseErrorIfClaimsPrincipalAlreadyExists">true</Item>
<Item Key="UserMessageIfClaimsPrincipalAlreadyExists">You are already registered, please press the back button and sign in instead.</Item>
</Metadata>
<IncludeInSso>false</IncludeInSso>
<InputClaimsTransformations>
<InputClaimsTransformation ReferenceId="CreateOtherMailsFromEmail" />
</InputClaimsTransformations>
<InputClaims>
<InputClaim ClaimTypeReferenceId="AlternativeSecurityId" PartnerClaimType="alternativeSecurityId" Required="true" />
</InputClaims>
<PersistedClaims>
<!-- Required claims -->
<PersistedClaim ClaimTypeReferenceId="alternativeSecurityId" />
<PersistedClaim ClaimTypeReferenceId="userPrincipalName" />
<PersistedClaim ClaimTypeReferenceId="mailNickName" DefaultValue="unknown" />
<PersistedClaim ClaimTypeReferenceId="displayName" DefaultValue="unknown" />
<!-- Optional claims -->
<PersistedClaim ClaimTypeReferenceId="otherMails" />
<PersistedClaim ClaimTypeReferenceId="givenName" />
<PersistedClaim ClaimTypeReferenceId="surname" />
</PersistedClaims>
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="objectId" />
<OutputClaim ClaimTypeReferenceId="newUser" PartnerClaimType="newClaimsPrincipalCreated" />
<OutputClaim ClaimTypeReferenceId="otherMails" />
</OutputClaims>
<IncludeTechnicalProfile ReferenceId="AAD-Common" />
<UseTechnicalProfileForSessionManagement ReferenceId="SM-AAD" />
</TechnicalProfile>
I tried to add <PersistedClaim ClaimTypeReferenceId="email"/> to the PersistedClaims, but I get a Bad Request with message: One or more property values specified are invalid.
On this page I see that the correct definition is mail. I also tried to define a new ClaimType and use a ClaimsTransformation to get the value from otherMails, but the field is not set.

Answer 1

This will not work:
<PersistedClaim ClaimTypeReferenceId="email"/>
Because there is no such attribute on the user object called "email".
What you can do is this:
<PersistedClaim ClaimTypeReferenceId="email" PartnerClaimType="signInNames.emailAddress"/>
This will then show up under userPrincipalName in the Azure Portal. It will also mean that the user cannot then sign up with that Email for a local account, essentially you create a "dual/linked account", albeit without a password.
The user then needs to reset the password on this account to access it with Username and Password, if they ever delete their Social Account at Facebook for example.
Another option is to write to otherMails
<PersistedClaim ClaimTypeReferenceId="email" PartnerClaimType="otherMails"/>
This might need to be an array, so use a claimTransform to build an Array first before writing it.
Do not write the email to the mail attribute, the supported attributed for B2C accounts are here.