How do I get an OID claim in ASPCore from Azure B2C - asp.net-core

Question

Why do I want this?
I'm trying to get a unique identifier from my user which I can connect to database records. There are reasons I don't want to use the Email as the identifier. I read that SUB claim isn't supported with B2C, and to use OID in it's place.
Steps I've Taken
So, I've set up that both of my policies return Object ID on Azure B2C:
I'm using individual SignIn and SignUp policies at the moment, and I get all of the claims back, including the email claim which I specified I wanted to be returned. I cannot however find a claim related to OID or SUB.
User.Claims
Nets me the following results:
The single breadcrumb of hope that I have found is this claim:
Type: http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier
Value: Not supported currently. Use oid claim.
Questions
Have I missed some additional step that you need to perform to retrieve this particular claim?
Has anyone had any success retrieving an OID or SUB from Azure B2C?

Answer 1

Well, this is embarrassing, I must have looked over this line about 30 times and not noticed...
I was retrieving the OID token, it's claim type was:
http://schemas.microsoft.com/identity/claims/objectidentifier
As can be clearly seen in my provided screenshots. I'll leave this question up as, the schema may throw someone else off.

Answer 2

I struggled with this for a little while and this post helped me.
To update things with some code, the below will obtain the object identifier value (unique user id in Azure)
User.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value
Thanks for pointing out the differences in the schema/types!

Answer 3

If you are using the Microsoft.Identity.Web package there is now a ClaimsPrincipalExtensions class that provides an extension method, so that you can simply use:
// using Microsoft.Identity.Web;
User.GetObjectId();
This uses the oid or http://schemas.microsoft.com/identity/claims/objectidentifier claim.

Answer 4

Since the links above are broken and this is something that I really struggled to find a working example of, here is a code fragment of what I ended up using;
using System.IdentityModel.Tokens.Jwt;
...
string oid;
string pTokenInput = Request.Headers["x-ms-token-aad-id-token"].ToString();
var lJWTHandler = new JwtSecurityTokenHandler();
if (lJWTHandler.CanReadToken(pTokenInput)
{
var lToken = lJWTHandler.ReadJwtToken(pTokenInput);
if (lToken.Payload.ContainsKey("oid"))
oid = lToken.Payload["oid"].ToString();
}
Hopefully, this will help someone else...

Answer 5

It seems that you do not necessarily need object-identifier here.
When debugging, I see that the value of object-identifier is mapped to nameidentifier
Which is accessible with the built-in constant NameIdentifier:
var identity = authState.User.Identity as System.Security.Claims.ClaimsIdentity;
var userId = identity.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier).Value;